/** problem writing method of reader */ static SCIP_DECL_READERWRITE(readerWriteRlp) { /*lint --e{715}*/ if( genericnames ) { SCIP_CALL( SCIPwriteLp(scip, file, name, transformed, objsense, objscale, objoffset, vars, nvars, nbinvars, nintvars, nimplvars, ncontvars, conss, nconss, result) ); } else { SCIPwarningMessage(scip, "RLP format is LP format with generic variable and constraint names\n"); if( transformed ) { SCIPwarningMessage(scip, "write transformed problem with generic variable and constraint names\n"); SCIP_CALL( SCIPprintTransProblem(scip, file, "rlp", TRUE) ); } else { SCIPwarningMessage(scip, "write original problem with generic variable and constraint names\n"); SCIP_CALL( SCIPprintOrigProblem(scip, file, "rlp", TRUE) ); } *result = SCIP_SUCCESS; } return SCIP_OKAY; }
static void readWarning( SCIP* scip, /**< SCIP data structure */ int linecount, /**< line number of error */ const char* warningmsg /**< warning message */ ) { SCIPwarningMessage(scip, "Line <%d>: %s\n", linecount, warningmsg); }
/** read the problem name out of the statistics */ static SCIP_RETCODE getStatistic( SCIP* scip, /**< SCIP data structure */ CIPINPUT* cipinput /**< CIP parsing data */ ) { char* buf; buf = cipinput->strbuf; if( strncmp(buf, "OBJECTIVE", 9) == 0 ) { cipinput->section = CIP_OBJECTIVE; return SCIP_OKAY; } SCIPdebugMessage("parse statistic\n"); if( strncmp(buf, " Problem name", 14) == 0 ) { char* name; char* s; name = strchr(buf, ':'); if( name == NULL ) { SCIPwarningMessage(scip, "did not find problem name\n"); return SCIP_OKAY; /* no error, might work with empty problem name */ } /* skip ':' */ ++name; /* remove tabs new line form string */ if( NULL != (s = strpbrk(name, "#\r\n")) ) *s = '\0'; /* remove white space in front of the name */ while(isspace((unsigned char)*name)) name++; /* set problem name */ SCIP_CALL( SCIPsetProbName(scip, name) ); SCIPdebugMessage("problem name <%s>\n", name); } return SCIP_OKAY; }
/** read the problem name out of the statistics */ static SCIP_RETCODE getStatistics( SCIP* scip, /**< SCIP data structure */ CIPINPUT* cipinput /**< CIP parsing data */ ) { char* buf; buf = cipinput->strbuf; if( strncmp(buf, "OBJECTIVE", 9) == 0 ) { cipinput->section = CIP_OBJECTIVE; return SCIP_OKAY; } SCIPdebugMessage("parse statistics\n"); if( strncmp(buf, " Problem name", 14) == 0 ) { char* name; char* s; name = strchr(buf, ':'); if( name == NULL ) { SCIPwarningMessage(scip, "did not find problem name (line: %d):\n%s\n", cipinput->linenumber, cipinput->strbuf); return SCIP_OKAY; /* no error, might work with empty problem name */ } /* skip ':' */ ++name; /* make sure that we terminate the string at comments ('#') or newline ('\r', '\n')*/ if( NULL != (s = strpbrk(name, "#\r\n")) ) *s = '\0'; /* remove white space (tabs, ' ') in front of the name */ while( isspace((unsigned char)* name) ) ++name; /* set problem name */ SCIP_CALL( SCIPsetProbName(scip, name) ); SCIPdebugMessage("problem name <%s>\n", name); } return SCIP_OKAY; }
/** reads the masterconss section */ static SCIP_RETCODE readMasterconss( SCIP* scip, /**< SCIP data structure */ DECINPUT* decinput, /**< DEC reading data */ SCIP_READERDATA* readerdata /**< reader data */ ) { assert(scip != NULL); assert(decinput != NULL); assert(readerdata != NULL); while( getNextToken(decinput) ) { SCIP_CONS* cons; /* check if we reached a new section */ if( isNewSection(scip, decinput) ) break; /* the token must be the name of an existing constraint */ cons = SCIPfindCons(scip, decinput->token); if( cons == NULL ) { syntaxError(scip, decinput, "unknown constraint in masterconss section"); break; } else { if( !SCIPhashmapExists( readerdata->constoblock, cons) ) { SCIPwarningMessage(scip, "Cons <%s> has been deleted by presolving, skipping.\n", SCIPconsGetName(cons)); continue; } assert(SCIPhashmapGetImage(readerdata->constoblock, cons) == (void*)(size_t) LINKINGVALUE); SCIPdebugMessage("cons %s is linking constraint\n", decinput->token); } } return SCIP_OKAY; }
/** farkas pricing method of variable pricer for infeasible LPs */ static SCIP_DECL_PRICERFARKAS(pricerFarkasBinpacking) { /*lint --e{715}*/ /** @note In case of this binpacking example, the master LP should not get infeasible after branching, because of the * way branching is performed. Therefore, the Farkas pricing is not implemented. * 1. In case of Ryan/Foster branching, the two items are selected in a way such that the sum of the LP values * of all columns/packings containing both items is fractional. Hence, it exists at least one * column/packing which contains both items and also at least one column/packing for each item containing * this but not the other item. That means, branching in the "same" direction stays LP feasible since there * exists at least one column/packing with both items and branching in the "differ" direction stays LP * feasible since there exists at least one column/packing containing one item, but not the other. * 2. In case of variable branching, we only branch on fractional variables. If a variable is fixed to one, * there is no issue. If a variable is fixed to zero, then we know that for each item which is part of * that column/packing, there exists at least one other column/packing containing this particular item due * to the covering constraints. */ SCIPwarningMessage(scip, "Current master LP is infeasible, but Farkas pricing was not implemented\n"); SCIPABORT(); return SCIP_OKAY; }
/** initialization method of primal heuristic (called after problem was transformed) */ static SCIP_DECL_HEURINIT(heurInitIndicator) { /*lint --e{715}*/ SCIP_HEURDATA* heurdata; assert( heur != NULL ); assert( scip != NULL ); /* get heuristic data */ heurdata = SCIPheurGetData(heur); assert( heurdata != NULL ); if ( heurdata->indicatorconshdlr != NULL ) { heurdata->indicatorconshdlr = SCIPfindConshdlr(scip, "indicator"); if ( heurdata->indicatorconshdlr == NULL ) { SCIPwarningMessage(scip, "Could not find indicator constraint handler.\n"); } } return SCIP_OKAY; }
/** write a DEC file for a given decomposition */ SCIP_RETCODE GCGwriteDecomp( SCIP* scip, /**< SCIP data structure */ FILE* file, /**< File pointer to write to */ DEC_DECOMP* decdecomp /**< Decomposition pointer */ ) { char outname[SCIP_MAXSTRLEN]; assert(scip != NULL); if( decdecomp == NULL ) { SCIPwarningMessage(scip, "Cannot write decomposed problem if decomposition structure is empty!\n"); (void) SCIPsnprintf(outname, SCIP_MAXSTRLEN, "%s", SCIPgetProbName(scip)); } else { (void) SCIPsnprintf(outname, SCIP_MAXSTRLEN, "%s_%d", SCIPgetProbName(scip), DECdecompGetNBlocks(decdecomp)); SCIP_CALL( writeData(scip, file, decdecomp) ); } return SCIP_OKAY; }
/** transforms given solution of the master problem into solution of the original problem * @todo think about types of epsilons used in this method */ SCIP_RETCODE GCGrelaxTransformMastersolToOrigsol( SCIP* scip, /**< SCIP data structure */ SCIP_SOL* mastersol, /**< solution of the master problem, or NULL for current LP solution */ SCIP_SOL** origsol /**< pointer to store the new created original problem's solution */ ) { SCIP* masterprob; int npricingprobs; int* blocknrs; SCIP_Real* blockvalue; SCIP_Real increaseval; SCIP_VAR** mastervars; SCIP_Real* mastervals; int nmastervars; SCIP_VAR** vars; int nvars; SCIP_Real feastol; int i; int j; assert(scip != NULL); assert(origsol != NULL); masterprob = GCGrelaxGetMasterprob(scip); npricingprobs = GCGrelaxGetNPricingprobs(scip); assert( !SCIPisInfinity(scip, SCIPgetSolOrigObj(masterprob, mastersol)) ); SCIP_CALL( SCIPcreateSol(scip, origsol, GCGrelaxGetProbingheur(scip)) ); SCIP_CALL( SCIPallocBufferArray(scip, &blockvalue, npricingprobs) ); SCIP_CALL( SCIPallocBufferArray(scip, &blocknrs, npricingprobs) ); /* get variables of the master problem and their solution values */ SCIP_CALL( SCIPgetVarsData(masterprob, &mastervars, &nmastervars, NULL, NULL, NULL, NULL) ); assert(mastervars != NULL); assert(nmastervars >= 0); SCIP_CALL( SCIPallocBufferArray(scip, &mastervals, nmastervars) ); SCIP_CALL( SCIPgetSolVals(masterprob, mastersol, nmastervars, mastervars, mastervals) ); /* initialize the block values for the pricing problems */ for( i = 0; i < npricingprobs; i++ ) { blockvalue[i] = 0.0; blocknrs[i] = 0; } /* loop over all given master variables */ for( i = 0; i < nmastervars; i++ ) { SCIP_VAR** origvars; int norigvars; SCIP_Real* origvals; SCIP_Bool isray; int blocknr; origvars = GCGmasterVarGetOrigvars(mastervars[i]); norigvars = GCGmasterVarGetNOrigvars(mastervars[i]); origvals = GCGmasterVarGetOrigvals(mastervars[i]); blocknr = GCGvarGetBlock(mastervars[i]); isray = GCGmasterVarIsRay(mastervars[i]); assert(GCGvarIsMaster(mastervars[i])); assert(!SCIPisFeasNegative(scip, mastervals[i])); /** @todo handle infinite master solution values */ assert(!SCIPisInfinity(scip, mastervals[i])); /* first of all, handle variables representing rays */ if( isray ) { assert(blocknr >= 0); /* we also want to take into account variables representing rays, that have a small value (between normal and feas eps), * so we do no feas comparison here */ if( SCIPisPositive(scip, mastervals[i]) ) { /* loop over all original variables contained in the current master variable */ for( j = 0; j < norigvars; j++ ) { if( SCIPisZero(scip, origvals[j]) ) break; assert(!SCIPisZero(scip, origvals[j])); /* the original variable is a linking variable: just transfer the solution value of the direct copy (this is done later) */ if( GCGvarIsLinking(origvars[j]) ) continue; SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origvars[j]), origvals[j] * mastervals[i], SCIPvarGetName(mastervars[i])); /* increase the corresponding value */ SCIP_CALL( SCIPincSolVal(scip, *origsol, origvars[j], origvals[j] * mastervals[i]) ); } } mastervals[i] = 0.0; continue; } /* handle the variables with value >= 1 to get integral values in original solution */ while( SCIPisFeasGE(scip, mastervals[i], 1.0) ) { /* variable was directly transferred to the master problem (only in linking conss or linking variable) */ /** @todo this may be the wrong place for this case, handle it before the while loop * and remove the similar case in the next while loop */ if( blocknr == -1 ) { assert(norigvars == 1); assert(origvals[0] == 1.0); /* increase the corresponding value */ SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origvars[0]), origvals[0] * mastervals[i], SCIPvarGetName(mastervars[i])); SCIP_CALL( SCIPincSolVal(scip, *origsol, origvars[0], origvals[0] * mastervals[i]) ); mastervals[i] = 0.0; } else { assert(blocknr >= 0); /* loop over all original variables contained in the current master variable */ for( j = 0; j < norigvars; j++ ) { SCIP_VAR* pricingvar; int norigpricingvars; SCIP_VAR** origpricingvars; if( SCIPisZero(scip, origvals[j]) ) break; assert(!SCIPisZero(scip, origvals[j])); /* the original variable is a linking variable: just transfer the solution value of the direct copy (this is done above) */ if( GCGvarIsLinking(origvars[j]) ) continue; pricingvar = GCGoriginalVarGetPricingVar(origvars[j]); assert(GCGvarIsPricing(pricingvar)); norigpricingvars = GCGpricingVarGetNOrigvars(pricingvar); origpricingvars = GCGpricingVarGetOrigvars(pricingvar); /* just in case a variable has a value higher than the number of blocks, it represents */ if( norigpricingvars <= blocknrs[blocknr] ) { SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origpricingvars[norigpricingvars-1]), mastervals[i] * origvals[j], SCIPvarGetName(mastervars[i])); /* increase the corresponding value */ SCIP_CALL( SCIPincSolVal(scip, *origsol, origpricingvars[norigpricingvars-1], mastervals[i] * origvals[j]) ); mastervals[i] = 1.0; } /* this should be default */ else { SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origpricingvars[blocknrs[blocknr]]), origvals[j], SCIPvarGetName(mastervars[i]) ); /* increase the corresponding value */ SCIP_CALL( SCIPincSolVal(scip, *origsol, origpricingvars[blocknrs[blocknr]], origvals[j]) ); } } mastervals[i] = mastervals[i] - 1.0; blocknrs[blocknr]++; } } } /* loop over all given master variables */ for( i = 0; i < nmastervars; i++ ) { SCIP_VAR** origvars; int norigvars; SCIP_Real* origvals; int blocknr; origvars = GCGmasterVarGetOrigvars(mastervars[i]); norigvars = GCGmasterVarGetNOrigvars(mastervars[i]); origvals = GCGmasterVarGetOrigvals(mastervars[i]); blocknr = GCGvarGetBlock(mastervars[i]); if( SCIPisFeasZero(scip, mastervals[i]) ) { continue; } assert(SCIPisFeasGE(scip, mastervals[i], 0.0) && SCIPisFeasLT(scip, mastervals[i], 1.0)); while( SCIPisFeasPositive(scip, mastervals[i]) ) { assert(GCGvarIsMaster(mastervars[i])); assert(!GCGmasterVarIsRay(mastervars[i])); if( blocknr == -1 ) { assert(norigvars == 1); assert(origvals[0] == 1.0); SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origvars[0]), origvals[0] * mastervals[i], SCIPvarGetName(mastervars[i]) ); /* increase the corresponding value */ SCIP_CALL( SCIPincSolVal(scip, *origsol, origvars[0], origvals[0] * mastervals[i]) ); mastervals[i] = 0.0; } else { increaseval = MIN(mastervals[i], 1.0 - blockvalue[blocknr]); /* loop over all original variables contained in the current master variable */ for( j = 0; j < norigvars; j++ ) { SCIP_VAR* pricingvar; int norigpricingvars; SCIP_VAR** origpricingvars; if( SCIPisZero(scip, origvals[j]) ) continue; /* the original variable is a linking variable: just transfer the solution value of the direct copy (this is done above) */ if( GCGvarIsLinking(origvars[j]) ) continue; pricingvar = GCGoriginalVarGetPricingVar(origvars[j]); assert(GCGvarIsPricing(pricingvar)); norigpricingvars = GCGpricingVarGetNOrigvars(pricingvar); origpricingvars = GCGpricingVarGetOrigvars(pricingvar); if( norigpricingvars <= blocknrs[blocknr] ) { increaseval = mastervals[i]; SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origpricingvars[norigpricingvars-1]), origvals[j] * increaseval, SCIPvarGetName(mastervars[i]) ); /* increase the corresponding value */ SCIP_CALL( SCIPincSolVal(scip, *origsol, origpricingvars[norigpricingvars-1], origvals[j] * increaseval) ); } else { /* increase the corresponding value */ SCIPdebugMessage("Increasing value of %s by %f because of %s\n", SCIPvarGetName(origpricingvars[blocknrs[blocknr]]), origvals[j] * increaseval, SCIPvarGetName(mastervars[i]) ); SCIP_CALL( SCIPincSolVal(scip, *origsol, origpricingvars[blocknrs[blocknr]], origvals[j] * increaseval) ); } } mastervals[i] = mastervals[i] - increaseval; if( SCIPisFeasZero(scip, mastervals[i]) ) { mastervals[i] = 0.0; } blockvalue[blocknr] += increaseval; /* if the value assigned to the block is equal to 1, this block is full and we take the next block */ if( SCIPisFeasGE(scip, blockvalue[blocknr], 1.0) ) { blockvalue[blocknr] = 0.0; blocknrs[blocknr]++; } } } } SCIPfreeBufferArray(scip, &mastervals); SCIPfreeBufferArray(scip, &blocknrs); SCIPfreeBufferArray(scip, &blockvalue); /* if the solution violates one of its bounds by more than feastol * and less than 10*feastol, round it and print a warning */ SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, NULL, NULL, NULL, NULL) ); SCIP_CALL( SCIPgetRealParam(scip, "numerics/feastol", &feastol) ); for( i = 0; i < nvars; ++i ) { SCIP_Real solval; SCIP_Real lb; SCIP_Real ub; solval = SCIPgetSolVal(scip, *origsol, vars[i]); lb = SCIPvarGetLbLocal(vars[i]); ub = SCIPvarGetUbLocal(vars[i]); if( SCIPisFeasGT(scip, solval, ub) && EPSEQ(solval, ub, 10 * feastol) ) { SCIP_CALL( SCIPsetSolVal(scip, *origsol, vars[i], ub) ); SCIPwarningMessage(scip, "Variable %s rounded from %g to %g in relaxation solution\n", SCIPvarGetName(vars[i]), solval, ub); } else if( SCIPisFeasLT(scip, solval, lb) && EPSEQ(solval, lb, 10 * feastol) ) { SCIP_CALL( SCIPsetSolVal(scip, *origsol, vars[i], lb) ); SCIPwarningMessage(scip, "Variable %s rounded from %g to %g in relaxation solution\n", SCIPvarGetName(vars[i]), solval, lb); } } return SCIP_OKAY; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecObjpscostdiving) /*lint --e{715}*/ { /*lint --e{715}*/ SCIP_HEURDATA* heurdata; SCIP_LPSOLSTAT lpsolstat; SCIP_VAR* var; SCIP_VAR** lpcands; SCIP_Real* lpcandssol; SCIP_Real* lpcandsfrac; SCIP_Real primsol; SCIP_Real frac; SCIP_Real pscostquot; SCIP_Real bestpscostquot; SCIP_Real oldobj; SCIP_Real newobj; SCIP_Real objscale; SCIP_Bool bestcandmayrounddown; SCIP_Bool bestcandmayroundup; SCIP_Bool bestcandroundup; SCIP_Bool mayrounddown; SCIP_Bool mayroundup; SCIP_Bool roundup; SCIP_Bool lperror; SCIP_Longint ncalls; SCIP_Longint nsolsfound; SCIP_Longint nlpiterations; SCIP_Longint maxnlpiterations; int* roundings; int nvars; int varidx; int nlpcands; int startnlpcands; int depth; int maxdepth; int maxdivedepth; int divedepth; int bestcand; int c; assert(heur != NULL); assert(strcmp(SCIPheurGetName(heur), HEUR_NAME) == 0); assert(scip != NULL); assert(result != NULL); assert(SCIPhasCurrentNodeLP(scip)); *result = SCIP_DELAYED; /* do not call heuristic of node was already detected to be infeasible */ if( nodeinfeasible ) return SCIP_OKAY; /* only call heuristic, if an optimal LP solution is at hand */ if( SCIPgetLPSolstat(scip) != SCIP_LPSOLSTAT_OPTIMAL ) return SCIP_OKAY; /* only call heuristic, if the LP objective value is smaller than the cutoff bound */ if( SCIPisGE(scip, SCIPgetLPObjval(scip), SCIPgetCutoffbound(scip)) ) return SCIP_OKAY; /* only call heuristic, if the LP solution is basic (which allows fast resolve in diving) */ if( !SCIPisLPSolBasic(scip) ) return SCIP_OKAY; /* don't dive two times at the same node */ if( SCIPgetLastDivenode(scip) == SCIPgetNNodes(scip) && SCIPgetDepth(scip) > 0 ) return SCIP_OKAY; *result = SCIP_DIDNOTRUN; /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert(heurdata != NULL); /* only apply heuristic, if only a few solutions have been found */ if( heurdata->maxsols >= 0 && SCIPgetNSolsFound(scip) >= heurdata->maxsols ) return SCIP_OKAY; /* only try to dive, if we are in the correct part of the tree, given by minreldepth and maxreldepth */ depth = SCIPgetDepth(scip); maxdepth = SCIPgetMaxDepth(scip); maxdepth = MAX(maxdepth, 30); if( depth < heurdata->minreldepth*maxdepth || depth > heurdata->maxreldepth*maxdepth ) return SCIP_OKAY; /* calculate the maximal number of LP iterations until heuristic is aborted */ nlpiterations = SCIPgetNNodeLPIterations(scip); ncalls = SCIPheurGetNCalls(heur); nsolsfound = 10*SCIPheurGetNBestSolsFound(heur) + heurdata->nsuccess; maxnlpiterations = (SCIP_Longint)((1.0 + 10.0*(nsolsfound+1.0)/(ncalls+1.0)) * heurdata->maxlpiterquot * nlpiterations); maxnlpiterations += heurdata->maxlpiterofs; /* don't try to dive, if we took too many LP iterations during diving */ if( heurdata->nlpiterations >= maxnlpiterations ) return SCIP_OKAY; /* allow at least a certain number of LP iterations in this dive */ maxnlpiterations = MAX(maxnlpiterations, heurdata->nlpiterations + MINLPITER); /* get fractional variables that should be integral */ SCIP_CALL( SCIPgetLPBranchCands(scip, &lpcands, &lpcandssol, &lpcandsfrac, &nlpcands, NULL, NULL) ); /* don't try to dive, if there are no fractional variables */ if( nlpcands == 0 ) return SCIP_OKAY; /* calculate the maximal diving depth */ nvars = SCIPgetNBinVars(scip) + SCIPgetNIntVars(scip); if( SCIPgetNSolsFound(scip) == 0 ) maxdivedepth = (int)(heurdata->depthfacnosol * nvars); else maxdivedepth = (int)(heurdata->depthfac * nvars); maxdivedepth = MIN(maxdivedepth, 10*maxdepth); *result = SCIP_DIDNOTFIND; /* get temporary memory for remembering the current soft roundings */ SCIP_CALL( SCIPallocBufferArray(scip, &roundings, nvars) ); BMSclearMemoryArray(roundings, nvars); /* start diving */ SCIP_CALL( SCIPstartDive(scip) ); SCIPdebugMessage("(node %"SCIP_LONGINT_FORMAT") executing objpscostdiving heuristic: depth=%d, %d fractionals, dualbound=%g, maxnlpiterations=%"SCIP_LONGINT_FORMAT", maxdivedepth=%d\n", SCIPgetNNodes(scip), SCIPgetDepth(scip), nlpcands, SCIPgetDualbound(scip), maxnlpiterations, maxdivedepth); /* dive as long we are in the given diving depth and iteration limits and fractional variables exist, but * - if the last objective change was in a direction, that corresponds to a feasible rounding, we continue in any case * - if possible, we dive at least with the depth 10 * - if the number of fractional variables decreased at least with 1 variable per 2 dive depths, we continue diving */ lperror = FALSE; lpsolstat = SCIP_LPSOLSTAT_OPTIMAL; divedepth = 0; bestcandmayrounddown = FALSE; bestcandmayroundup = FALSE; startnlpcands = nlpcands; while( !lperror && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL && nlpcands > 0 && (divedepth < 10 || nlpcands <= startnlpcands - divedepth/2 || (divedepth < maxdivedepth && nlpcands <= startnlpcands - divedepth/10 && heurdata->nlpiterations < maxnlpiterations)) && !SCIPisStopped(scip) ) { SCIP_RETCODE retcode; divedepth++; /* choose variable for objective change: * - prefer variables that may not be rounded without destroying LP feasibility: * - of these variables, change objective value of variable with largest rel. difference of pseudo cost values * - if all remaining fractional variables may be rounded without destroying LP feasibility: * - change objective value of variable with largest rel. difference of pseudo cost values */ bestcand = -1; bestpscostquot = -1.0; bestcandmayrounddown = TRUE; bestcandmayroundup = TRUE; bestcandroundup = FALSE; for( c = 0; c < nlpcands; ++c ) { var = lpcands[c]; mayrounddown = SCIPvarMayRoundDown(var); mayroundup = SCIPvarMayRoundUp(var); primsol = lpcandssol[c]; frac = lpcandsfrac[c]; if( mayrounddown || mayroundup ) { /* the candidate may be rounded: choose this candidate only, if the best candidate may also be rounded */ if( bestcandmayrounddown || bestcandmayroundup ) { /* choose rounding direction: * - if variable may be rounded in both directions, round corresponding to the pseudo cost values * - otherwise, round in the infeasible direction, because feasible direction is tried by rounding * the current fractional solution */ roundup = FALSE; if( mayrounddown && mayroundup ) calcPscostQuot(scip, var, primsol, frac, 0, &pscostquot, &roundup); else if( mayrounddown ) calcPscostQuot(scip, var, primsol, frac, +1, &pscostquot, &roundup); else calcPscostQuot(scip, var, primsol, frac, -1, &pscostquot, &roundup); /* prefer variables, that have already been soft rounded but failed to get integral */ varidx = SCIPvarGetProbindex(var); assert(0 <= varidx && varidx < nvars); if( roundings[varidx] != 0 ) pscostquot *= 1000.0; /* check, if candidate is new best candidate */ if( pscostquot > bestpscostquot ) { bestcand = c; bestpscostquot = pscostquot; bestcandmayrounddown = mayrounddown; bestcandmayroundup = mayroundup; bestcandroundup = roundup; } } } else { /* the candidate may not be rounded: calculate pseudo cost quotient and preferred direction */ calcPscostQuot(scip, var, primsol, frac, 0, &pscostquot, &roundup); /* prefer variables, that have already been soft rounded but failed to get integral */ varidx = SCIPvarGetProbindex(var); assert(0 <= varidx && varidx < nvars); if( roundings[varidx] != 0 ) pscostquot *= 1000.0; /* check, if candidate is new best candidate: prefer unroundable candidates in any case */ if( bestcandmayrounddown || bestcandmayroundup || pscostquot > bestpscostquot ) { bestcand = c; bestpscostquot = pscostquot; bestcandmayrounddown = FALSE; bestcandmayroundup = FALSE; bestcandroundup = roundup; } } } assert(bestcand != -1); /* if all candidates are roundable, try to round the solution */ if( bestcandmayrounddown || bestcandmayroundup ) { SCIP_Bool success; /* create solution from diving LP and try to round it */ SCIP_CALL( SCIPlinkLPSol(scip, heurdata->sol) ); SCIP_CALL( SCIProundSol(scip, heurdata->sol, &success) ); if( success ) { SCIPdebugMessage("objpscostdiving found roundable primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol)); /* try to add solution to SCIP */ SCIP_CALL( SCIPtrySol(scip, heurdata->sol, FALSE, FALSE, FALSE, FALSE, &success) ); /* check, if solution was feasible and good enough */ if( success ) { SCIPdebugMessage(" -> solution was feasible and good enough\n"); *result = SCIP_FOUNDSOL; } } } var = lpcands[bestcand]; /* check, if the best candidate was already subject to soft rounding */ varidx = SCIPvarGetProbindex(var); assert(0 <= varidx && varidx < nvars); if( roundings[varidx] == +1 ) { /* variable was already soft rounded upwards: hard round it downwards */ SCIP_CALL( SCIPchgVarUbDive(scip, var, SCIPfeasFloor(scip, lpcandssol[bestcand])) ); SCIPdebugMessage(" dive %d/%d: var <%s>, round=%u/%u, sol=%g, was already soft rounded upwards -> bounds=[%g,%g]\n", divedepth, maxdivedepth, SCIPvarGetName(var), bestcandmayrounddown, bestcandmayroundup, lpcandssol[bestcand], SCIPgetVarLbDive(scip, var), SCIPgetVarUbDive(scip, var)); } else if( roundings[varidx] == -1 ) { /* variable was already soft rounded downwards: hard round it upwards */ SCIP_CALL( SCIPchgVarLbDive(scip, var, SCIPfeasCeil(scip, lpcandssol[bestcand])) ); SCIPdebugMessage(" dive %d/%d: var <%s>, round=%u/%u, sol=%g, was already soft rounded downwards -> bounds=[%g,%g]\n", divedepth, maxdivedepth, SCIPvarGetName(var), bestcandmayrounddown, bestcandmayroundup, lpcandssol[bestcand], SCIPgetVarLbDive(scip, var), SCIPgetVarUbDive(scip, var)); } else { assert(roundings[varidx] == 0); /* apply soft rounding of best candidate via a change in the objective value */ objscale = divedepth * 1000.0; oldobj = SCIPgetVarObjDive(scip, var); if( bestcandroundup ) { /* soft round variable up: make objective value (more) negative */ if( oldobj < 0.0 ) newobj = objscale * oldobj; else newobj = -objscale * oldobj; newobj = MIN(newobj, -objscale); /* remember, that this variable was soft rounded upwards */ roundings[varidx] = +1; } else { /* soft round variable down: make objective value (more) positive */ if( oldobj > 0.0 ) newobj = objscale * oldobj; else newobj = -objscale * oldobj; newobj = MAX(newobj, objscale); /* remember, that this variable was soft rounded downwards */ roundings[varidx] = -1; } SCIP_CALL( SCIPchgVarObjDive(scip, var, newobj) ); SCIPdebugMessage(" dive %d/%d, LP iter %"SCIP_LONGINT_FORMAT"/%"SCIP_LONGINT_FORMAT": var <%s>, round=%u/%u, sol=%g, bounds=[%g,%g], obj=%g, newobj=%g\n", divedepth, maxdivedepth, heurdata->nlpiterations, maxnlpiterations, SCIPvarGetName(var), bestcandmayrounddown, bestcandmayroundup, lpcandssol[bestcand], SCIPgetVarLbDive(scip, var), SCIPgetVarUbDive(scip, var), oldobj, newobj); } /* resolve the diving LP */ nlpiterations = SCIPgetNLPIterations(scip); retcode = SCIPsolveDiveLP(scip, MAX((int)(maxnlpiterations - heurdata->nlpiterations), MINLPITER), &lperror, NULL); lpsolstat = SCIPgetLPSolstat(scip); /* Errors in the LP solver should not kill the overall solving process, if the LP is just needed for a heuristic. * Hence in optimized mode, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG if( lpsolstat != SCIP_LPSOLSTAT_UNBOUNDEDRAY ) { SCIP_CALL( retcode ); } #endif SCIPwarningMessage(scip, "Error while solving LP in Objpscostdiving heuristic; LP solve terminated with code <%d>\n", retcode); SCIPwarningMessage(scip, "This does not affect the remaining solution procedure --> continue\n"); } if( lperror ) break; /* update iteration count */ heurdata->nlpiterations += SCIPgetNLPIterations(scip) - nlpiterations; /* get LP solution status and fractional variables, that should be integral */ if( lpsolstat == SCIP_LPSOLSTAT_OPTIMAL ) { /* get new fractional variables */ SCIP_CALL( SCIPgetLPBranchCands(scip, &lpcands, &lpcandssol, &lpcandsfrac, &nlpcands, NULL, NULL) ); } SCIPdebugMessage(" -> lpsolstat=%d, nfrac=%d\n", lpsolstat, nlpcands); } /* check if a solution has been found */ if( nlpcands == 0 && !lperror && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL ) { SCIP_Bool success; /* create solution from diving LP */ SCIP_CALL( SCIPlinkLPSol(scip, heurdata->sol) ); SCIPdebugMessage("objpscostdiving found primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol)); /* try to add solution to SCIP */ SCIP_CALL( SCIPtrySol(scip, heurdata->sol, FALSE, FALSE, FALSE, FALSE, &success) ); /* check, if solution was feasible and good enough */ if( success ) { SCIPdebugMessage(" -> solution was feasible and good enough\n"); *result = SCIP_FOUNDSOL; } } /* end diving */ SCIP_CALL( SCIPendDive(scip) ); if( *result == SCIP_FOUNDSOL ) heurdata->nsuccess++; /* free temporary memory for remembering the current soft roundings */ SCIPfreeBufferArray(scip, &roundings); SCIPdebugMessage("objpscostdiving heuristic finished\n"); return SCIP_OKAY; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecActconsdiving) /*lint --e{715}*/ { /*lint --e{715}*/ SCIP_HEURDATA* heurdata; SCIP_LPSOLSTAT lpsolstat; SCIP_VAR* var; SCIP_VAR** lpcands; SCIP_Real* lpcandssol; SCIP_Real* lpcandsfrac; SCIP_Real searchubbound; SCIP_Real searchavgbound; SCIP_Real searchbound; SCIP_Real objval; SCIP_Real oldobjval; SCIP_Real frac; SCIP_Real bestfrac; SCIP_Bool bestcandmayrounddown; SCIP_Bool bestcandmayroundup; SCIP_Bool bestcandroundup; SCIP_Bool mayrounddown; SCIP_Bool mayroundup; SCIP_Bool roundup; SCIP_Bool lperror; SCIP_Bool cutoff; SCIP_Bool backtracked; SCIP_Longint ncalls; SCIP_Longint nsolsfound; SCIP_Longint nlpiterations; SCIP_Longint maxnlpiterations; int nlpcands; int startnlpcands; int depth; int maxdepth; int maxdivedepth; int divedepth; SCIP_Real actscore; SCIP_Real downscore; SCIP_Real upscore; SCIP_Real bestactscore; int bestcand; int c; assert(heur != NULL); assert(strcmp(SCIPheurGetName(heur), HEUR_NAME) == 0); assert(scip != NULL); assert(result != NULL); assert(SCIPhasCurrentNodeLP(scip)); *result = SCIP_DELAYED; /* do not call heuristic of node was already detected to be infeasible */ if( nodeinfeasible ) return SCIP_OKAY; /* only call heuristic, if an optimal LP solution is at hand */ if( SCIPgetLPSolstat(scip) != SCIP_LPSOLSTAT_OPTIMAL ) return SCIP_OKAY; /* only call heuristic, if the LP objective value is smaller than the cutoff bound */ if( SCIPisGE(scip, SCIPgetLPObjval(scip), SCIPgetCutoffbound(scip)) ) return SCIP_OKAY; /* only call heuristic, if the LP solution is basic (which allows fast resolve in diving) */ if( !SCIPisLPSolBasic(scip) ) return SCIP_OKAY; /* don't dive two times at the same node */ if( SCIPgetLastDivenode(scip) == SCIPgetNNodes(scip) && SCIPgetDepth(scip) > 0 ) return SCIP_OKAY; *result = SCIP_DIDNOTRUN; /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert(heurdata != NULL); /* only try to dive, if we are in the correct part of the tree, given by minreldepth and maxreldepth */ depth = SCIPgetDepth(scip); maxdepth = SCIPgetMaxDepth(scip); maxdepth = MAX(maxdepth, 30); if( depth < heurdata->minreldepth*maxdepth || depth > heurdata->maxreldepth*maxdepth ) return SCIP_OKAY; /* calculate the maximal number of LP iterations until heuristic is aborted */ nlpiterations = SCIPgetNNodeLPIterations(scip); ncalls = SCIPheurGetNCalls(heur); nsolsfound = 10*SCIPheurGetNBestSolsFound(heur) + heurdata->nsuccess; maxnlpiterations = (SCIP_Longint)((1.0 + 10.0*(nsolsfound+1.0)/(ncalls+1.0)) * heurdata->maxlpiterquot * nlpiterations); maxnlpiterations += heurdata->maxlpiterofs; /* don't try to dive, if we took too many LP iterations during diving */ if( heurdata->nlpiterations >= maxnlpiterations ) return SCIP_OKAY; /* allow at least a certain number of LP iterations in this dive */ maxnlpiterations = MAX(maxnlpiterations, heurdata->nlpiterations + MINLPITER); /* get fractional variables that should be integral */ SCIP_CALL( SCIPgetLPBranchCands(scip, &lpcands, &lpcandssol, &lpcandsfrac, &nlpcands, NULL, NULL) ); /* don't try to dive, if there are no fractional variables */ if( nlpcands == 0 ) return SCIP_OKAY; /* calculate the objective search bound */ if( SCIPgetNSolsFound(scip) == 0 ) { if( heurdata->maxdiveubquotnosol > 0.0 ) searchubbound = SCIPgetLowerbound(scip) + heurdata->maxdiveubquotnosol * (SCIPgetCutoffbound(scip) - SCIPgetLowerbound(scip)); else searchubbound = SCIPinfinity(scip); if( heurdata->maxdiveavgquotnosol > 0.0 ) searchavgbound = SCIPgetLowerbound(scip) + heurdata->maxdiveavgquotnosol * (SCIPgetAvgLowerbound(scip) - SCIPgetLowerbound(scip)); else searchavgbound = SCIPinfinity(scip); } else { if( heurdata->maxdiveubquot > 0.0 ) searchubbound = SCIPgetLowerbound(scip) + heurdata->maxdiveubquot * (SCIPgetCutoffbound(scip) - SCIPgetLowerbound(scip)); else searchubbound = SCIPinfinity(scip); if( heurdata->maxdiveavgquot > 0.0 ) searchavgbound = SCIPgetLowerbound(scip) + heurdata->maxdiveavgquot * (SCIPgetAvgLowerbound(scip) - SCIPgetLowerbound(scip)); else searchavgbound = SCIPinfinity(scip); } searchbound = MIN(searchubbound, searchavgbound); if( SCIPisObjIntegral(scip) ) searchbound = SCIPceil(scip, searchbound); /* calculate the maximal diving depth: 10 * min{number of integer variables, max depth} */ maxdivedepth = SCIPgetNBinVars(scip) + SCIPgetNIntVars(scip); maxdivedepth = MIN(maxdivedepth, maxdepth); maxdivedepth *= 10; *result = SCIP_DIDNOTFIND; /* start diving */ SCIP_CALL( SCIPstartProbing(scip) ); /* enables collection of variable statistics during probing */ SCIPenableVarHistory(scip); /* get LP objective value */ lpsolstat = SCIP_LPSOLSTAT_OPTIMAL; objval = SCIPgetLPObjval(scip); SCIPdebugMessage("(node %"SCIP_LONGINT_FORMAT") executing actconsdiving heuristic: depth=%d, %d fractionals, dualbound=%g, avgbound=%g, cutoffbound=%g, searchbound=%g\n", SCIPgetNNodes(scip), SCIPgetDepth(scip), nlpcands, SCIPgetDualbound(scip), SCIPgetAvgDualbound(scip), SCIPretransformObj(scip, SCIPgetCutoffbound(scip)), SCIPretransformObj(scip, searchbound)); /* dive as long we are in the given objective, depth and iteration limits and fractional variables exist, but * - if possible, we dive at least with the depth 10 * - if the number of fractional variables decreased at least with 1 variable per 2 dive depths, we continue diving */ lperror = FALSE; cutoff = FALSE; divedepth = 0; bestcandmayrounddown = FALSE; bestcandmayroundup = FALSE; startnlpcands = nlpcands; while( !lperror && !cutoff && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL && nlpcands > 0 && (divedepth < 10 || nlpcands <= startnlpcands - divedepth/2 || (divedepth < maxdivedepth && heurdata->nlpiterations < maxnlpiterations && objval < searchbound)) && !SCIPisStopped(scip) ) { divedepth++; SCIP_CALL( SCIPnewProbingNode(scip) ); /* choose variable fixing: * - prefer variables that may not be rounded without destroying LP feasibility: * - of these variables, round variable with least number of locks in corresponding direction * - if all remaining fractional variables may be rounded without destroying LP feasibility: * - round variable with least number of locks in opposite of its feasible rounding direction */ bestcand = -1; bestactscore = -1.0; bestfrac = SCIP_INVALID; bestcandmayrounddown = TRUE; bestcandmayroundup = TRUE; bestcandroundup = FALSE; for( c = 0; c < nlpcands; ++c ) { var = lpcands[c]; mayrounddown = SCIPvarMayRoundDown(var); mayroundup = SCIPvarMayRoundUp(var); frac = lpcandsfrac[c]; if( mayrounddown || mayroundup ) { /* the candidate may be rounded: choose this candidate only, if the best candidate may also be rounded */ if( bestcandmayrounddown || bestcandmayroundup ) { /* choose rounding direction: * - if variable may be rounded in both directions, round corresponding to the fractionality * - otherwise, round in the infeasible direction, because feasible direction is tried by rounding * the current fractional solution */ if( mayrounddown && mayroundup ) roundup = (frac > 0.5); else roundup = mayrounddown; if( roundup ) frac = 1.0 - frac; actscore = getNActiveConsScore(scip, var, &downscore, &upscore); /* penalize too small fractions */ if( frac < 0.01 ) actscore *= 0.01; /* prefer decisions on binary variables */ if( !SCIPvarIsBinary(var) ) actscore *= 0.01; /* check, if candidate is new best candidate */ assert(0.0 < frac && frac < 1.0); if( SCIPisGT(scip, actscore, bestactscore) || (SCIPisGE(scip, actscore, bestactscore) && frac < bestfrac) ) { bestcand = c; bestactscore = actscore; bestfrac = frac; bestcandmayrounddown = mayrounddown; bestcandmayroundup = mayroundup; bestcandroundup = roundup; } } } else { /* the candidate may not be rounded */ actscore = getNActiveConsScore(scip, var, &downscore, &upscore); roundup = (downscore < upscore); if( roundup ) frac = 1.0 - frac; /* penalize too small fractions */ if( frac < 0.01 ) actscore *= 0.01; /* prefer decisions on binary variables */ if( !SCIPvarIsBinary(var) ) actscore *= 0.01; /* check, if candidate is new best candidate: prefer unroundable candidates in any case */ assert(0.0 < frac && frac < 1.0); if( bestcandmayrounddown || bestcandmayroundup || SCIPisGT(scip, actscore, bestactscore) || (SCIPisGE(scip, actscore, bestactscore) && frac < bestfrac) ) { bestcand = c; bestactscore = actscore; bestfrac = frac; bestcandmayrounddown = FALSE; bestcandmayroundup = FALSE; bestcandroundup = roundup; } assert(bestfrac < SCIP_INVALID); } } assert(bestcand != -1); /* if all candidates are roundable, try to round the solution */ if( bestcandmayrounddown || bestcandmayroundup ) { SCIP_Bool success; /* create solution from diving LP and try to round it */ SCIP_CALL( SCIPlinkLPSol(scip, heurdata->sol) ); SCIP_CALL( SCIProundSol(scip, heurdata->sol, &success) ); if( success ) { SCIPdebugMessage("actconsdiving found roundable primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol)); /* try to add solution to SCIP */ SCIP_CALL( SCIPtrySol(scip, heurdata->sol, FALSE, FALSE, FALSE, FALSE, &success) ); /* check, if solution was feasible and good enough */ if( success ) { SCIPdebugMessage(" -> solution was feasible and good enough\n"); *result = SCIP_FOUNDSOL; } } } assert(bestcand != -1); var = lpcands[bestcand]; backtracked = FALSE; do { /* if the variable is already fixed or if the solution value is outside the domain, numerical troubles may have * occured or variable was fixed by propagation while backtracking => Abort diving! */ if( SCIPvarGetLbLocal(var) >= SCIPvarGetUbLocal(var) - 0.5 ) { SCIPdebugMessage("Selected variable <%s> already fixed to [%g,%g] (solval: %.9f), diving aborted \n", SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), lpcandssol[bestcand]); cutoff = TRUE; break; } if( SCIPisFeasLT(scip, lpcandssol[bestcand], SCIPvarGetLbLocal(var)) || SCIPisFeasGT(scip, lpcandssol[bestcand], SCIPvarGetUbLocal(var)) ) { SCIPdebugMessage("selected variable's <%s> solution value is outside the domain [%g,%g] (solval: %.9f), diving aborted\n", SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), lpcandssol[bestcand]); assert(backtracked); break; } /* apply rounding of best candidate */ if( bestcandroundup == !backtracked ) { /* round variable up */ SCIPdebugMessage(" dive %d/%d, LP iter %"SCIP_LONGINT_FORMAT"/%"SCIP_LONGINT_FORMAT": var <%s>, round=%u/%u, sol=%g, oldbounds=[%g,%g], newbounds=[%g,%g]\n", divedepth, maxdivedepth, heurdata->nlpiterations, maxnlpiterations, SCIPvarGetName(var), bestcandmayrounddown, bestcandmayroundup, lpcandssol[bestcand], SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), SCIPfeasCeil(scip, lpcandssol[bestcand]), SCIPvarGetUbLocal(var)); SCIP_CALL( SCIPchgVarLbProbing(scip, var, SCIPfeasCeil(scip, lpcandssol[bestcand])) ); } else { /* round variable down */ SCIPdebugMessage(" dive %d/%d, LP iter %"SCIP_LONGINT_FORMAT"/%"SCIP_LONGINT_FORMAT": var <%s>, round=%u/%u, sol=%g, oldbounds=[%g,%g], newbounds=[%g,%g]\n", divedepth, maxdivedepth, heurdata->nlpiterations, maxnlpiterations, SCIPvarGetName(var), bestcandmayrounddown, bestcandmayroundup, lpcandssol[bestcand], SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), SCIPvarGetLbLocal(var), SCIPfeasFloor(scip, lpcandssol[bestcand])); SCIP_CALL( SCIPchgVarUbProbing(scip, lpcands[bestcand], SCIPfeasFloor(scip, lpcandssol[bestcand])) ); } /* apply domain propagation */ SCIP_CALL( SCIPpropagateProbing(scip, 0, &cutoff, NULL) ); if( !cutoff ) { /* resolve the diving LP */ /* Errors in the LP solver should not kill the overall solving process, if the LP is just needed for a heuristic. * Hence in optimized mode, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ #ifdef NDEBUG SCIP_RETCODE retstat; nlpiterations = SCIPgetNLPIterations(scip); retstat = SCIPsolveProbingLP(scip, MAX((int)(maxnlpiterations - heurdata->nlpiterations), MINLPITER), &lperror, &cutoff); if( retstat != SCIP_OKAY ) { SCIPwarningMessage(scip, "Error while solving LP in Actconsdiving heuristic; LP solve terminated with code <%d>\n",retstat); } #else nlpiterations = SCIPgetNLPIterations(scip); SCIP_CALL( SCIPsolveProbingLP(scip, MAX((int)(maxnlpiterations - heurdata->nlpiterations), MINLPITER), &lperror, &cutoff) ); #endif if( lperror ) break; /* update iteration count */ heurdata->nlpiterations += SCIPgetNLPIterations(scip) - nlpiterations; /* get LP solution status, objective value, and fractional variables, that should be integral */ lpsolstat = SCIPgetLPSolstat(scip); assert(cutoff || (lpsolstat != SCIP_LPSOLSTAT_OBJLIMIT && lpsolstat != SCIP_LPSOLSTAT_INFEASIBLE && (lpsolstat != SCIP_LPSOLSTAT_OPTIMAL || SCIPisLT(scip, SCIPgetLPObjval(scip), SCIPgetCutoffbound(scip))))); } /* perform backtracking if a cutoff was detected */ if( cutoff && !backtracked && heurdata->backtrack ) { SCIPdebugMessage(" *** cutoff detected at level %d - backtracking\n", SCIPgetProbingDepth(scip)); SCIP_CALL( SCIPbacktrackProbing(scip, SCIPgetProbingDepth(scip)-1) ); SCIP_CALL( SCIPnewProbingNode(scip) ); backtracked = TRUE; } else backtracked = FALSE; } while( backtracked ); if( !lperror && !cutoff && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL ) { /* get new objective value */ oldobjval = objval; objval = SCIPgetLPObjval(scip); /* update pseudo cost values */ if( SCIPisGT(scip, objval, oldobjval) ) { if( bestcandroundup ) { SCIP_CALL( SCIPupdateVarPseudocost(scip, lpcands[bestcand], 1.0-lpcandsfrac[bestcand], objval - oldobjval, 1.0) ); } else { SCIP_CALL( SCIPupdateVarPseudocost(scip, lpcands[bestcand], 0.0-lpcandsfrac[bestcand], objval - oldobjval, 1.0) ); } } /* get new fractional variables */ SCIP_CALL( SCIPgetLPBranchCands(scip, &lpcands, &lpcandssol, &lpcandsfrac, &nlpcands, NULL, NULL) ); } SCIPdebugMessage(" -> lpsolstat=%d, objval=%g/%g, nfrac=%d\n", lpsolstat, objval, searchbound, nlpcands); } /* check if a solution has been found */ if( nlpcands == 0 && !lperror && !cutoff && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL ) { SCIP_Bool success; /* create solution from diving LP */ SCIP_CALL( SCIPlinkLPSol(scip, heurdata->sol) ); SCIPdebugMessage("actconsdiving found primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol)); /* try to add solution to SCIP */ SCIP_CALL( SCIPtrySol(scip, heurdata->sol, FALSE, FALSE, FALSE, FALSE, &success) ); /* check, if solution was feasible and good enough */ if( success ) { SCIPdebugMessage(" -> solution was feasible and good enough\n"); *result = SCIP_FOUNDSOL; } } /* end diving */ SCIP_CALL( SCIPendProbing(scip) ); if( *result == SCIP_FOUNDSOL ) heurdata->nsuccess++; SCIPdebugMessage("(node %"SCIP_LONGINT_FORMAT") finished actconsdiving heuristic: %d fractionals, dive %d/%d, LP iter %"SCIP_LONGINT_FORMAT"/%"SCIP_LONGINT_FORMAT", objval=%g/%g, lpsolstat=%d, cutoff=%u\n", SCIPgetNNodes(scip), nlpcands, divedepth, maxdivedepth, heurdata->nlpiterations, maxnlpiterations, SCIPretransformObj(scip, objval), SCIPretransformObj(scip, searchbound), lpsolstat, cutoff); return SCIP_OKAY; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecOneopt) { /*lint --e{715}*/ SCIP_HEURDATA* heurdata; SCIP_SOL* bestsol; /* incumbent solution */ SCIP_SOL* worksol; /* heuristic's working solution */ SCIP_VAR** vars; /* SCIP variables */ SCIP_VAR** shiftcands; /* shiftable variables */ SCIP_ROW** lprows; /* SCIP LP rows */ SCIP_Real* activities; /* row activities for working solution */ SCIP_Real* shiftvals; SCIP_Real lb; SCIP_Real ub; SCIP_Bool localrows; SCIP_Bool valid; int nchgbound; int nbinvars; int nintvars; int nvars; int nlprows; int i; int nshiftcands; int shiftcandssize; SCIP_RETCODE retcode; assert(heur != NULL); assert(scip != NULL); assert(result != NULL); /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert(heurdata != NULL); *result = SCIP_DELAYED; /* we only want to process each solution once */ bestsol = SCIPgetBestSol(scip); if( bestsol == NULL || heurdata->lastsolindex == SCIPsolGetIndex(bestsol) ) return SCIP_OKAY; /* reset the timing mask to its default value (at the root node it could be different) */ if( SCIPgetNNodes(scip) > 1 ) SCIPheurSetTimingmask(heur, HEUR_TIMING); /* get problem variables */ SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, &nbinvars, &nintvars, NULL, NULL) ); nintvars += nbinvars; /* do not run if there are no discrete variables */ if( nintvars == 0 ) { *result = SCIP_DIDNOTRUN; return SCIP_OKAY; } if( heurtiming == SCIP_HEURTIMING_BEFOREPRESOL ) { SCIP* subscip; /* the subproblem created by zeroobj */ SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_Real* subsolvals; /* solution values of the subproblem */ SCIP_Real timelimit; /* time limit for zeroobj subproblem */ SCIP_Real memorylimit; /* memory limit for zeroobj subproblem */ SCIP_SOL* startsol; SCIP_SOL** subsols; int nsubsols; if( !heurdata->beforepresol ) return SCIP_OKAY; /* check whether there is enough time and memory left */ timelimit = 0.0; memorylimit = 0.0; SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); /* substract the memory already used by the main SCIP and the estimated memory usage of external software */ if( !SCIPisInfinity(scip, memorylimit) ) { memorylimit -= SCIPgetMemUsed(scip)/1048576.0; memorylimit -= SCIPgetMemExternEstim(scip)/1048576.0; } /* abort if no time is left or not enough memory to create a copy of SCIP, including external memory usage */ if( timelimit <= 0.0 || memorylimit <= 2.0*SCIPgetMemExternEstim(scip)/1048576.0 ) return SCIP_OKAY; /* initialize the subproblem */ SCIP_CALL( SCIPcreate(&subscip) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); /* copy complete SCIP instance */ valid = FALSE; SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "oneopt", TRUE, FALSE, TRUE, &valid) ); SCIP_CALL( SCIPtransformProb(subscip) ); /* get variable image */ for( i = 0; i < nvars; i++ ) subvars[i] = (SCIP_VAR*) SCIPhashmapGetImage(varmapfw, vars[i]); /* copy the solution */ SCIP_CALL( SCIPallocBufferArray(scip, &subsolvals, nvars) ); SCIP_CALL( SCIPgetSolVals(scip, bestsol, nvars, vars, subsolvals) ); /* create start solution for the subproblem */ SCIP_CALL( SCIPcreateOrigSol(subscip, &startsol, NULL) ); SCIP_CALL( SCIPsetSolVals(subscip, startsol, nvars, subvars, subsolvals) ); /* try to add new solution to sub-SCIP and free it immediately */ valid = FALSE; SCIP_CALL( SCIPtrySolFree(subscip, &startsol, FALSE, FALSE, FALSE, FALSE, &valid) ); SCIPfreeBufferArray(scip, &subsolvals); SCIPhashmapFree(&varmapfw); /* disable statistic timing inside sub SCIP */ SCIP_CALL( SCIPsetBoolParam(subscip, "timing/statistictiming", FALSE) ); /* deactivate basically everything except oneopt in the sub-SCIP */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); SCIP_CALL( SCIPsetHeuristics(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", 1LL) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); /* if necessary, some of the parameters have to be unfixed first */ if( SCIPisParamFixed(subscip, "lp/solvefreq") ) { SCIPwarningMessage(scip, "unfixing parameter lp/solvefreq in subscip of oneopt heuristic\n"); SCIP_CALL( SCIPunfixParam(subscip, "lp/solvefreq") ); } SCIP_CALL( SCIPsetIntParam(subscip, "lp/solvefreq", -1) ); if( SCIPisParamFixed(subscip, "heuristics/oneopt/freq") ) { SCIPwarningMessage(scip, "unfixing parameter heuristics/oneopt/freq in subscip of oneopt heuristic\n"); SCIP_CALL( SCIPunfixParam(subscip, "heuristics/oneopt/freq") ); } SCIP_CALL( SCIPsetIntParam(subscip, "heuristics/oneopt/freq", 1) ); if( SCIPisParamFixed(subscip, "heuristics/oneopt/forcelpconstruction") ) { SCIPwarningMessage(scip, "unfixing parameter heuristics/oneopt/forcelpconstruction in subscip of oneopt heuristic\n"); SCIP_CALL( SCIPunfixParam(subscip, "heuristics/oneopt/forcelpconstruction") ); } SCIP_CALL( SCIPsetBoolParam(subscip, "heuristics/oneopt/forcelpconstruction", TRUE) ); /* avoid recursive call, which would lead to an endless loop */ if( SCIPisParamFixed(subscip, "heuristics/oneopt/beforepresol") ) { SCIPwarningMessage(scip, "unfixing parameter heuristics/oneopt/beforepresol in subscip of oneopt heuristic\n"); SCIP_CALL( SCIPunfixParam(subscip, "heuristics/oneopt/beforepresol") ); } SCIP_CALL( SCIPsetBoolParam(subscip, "heuristics/oneopt/beforepresol", FALSE) ); if( valid ) { retcode = SCIPsolve(subscip); /* errors in solving the subproblem should not kill the overall solving process; * hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while solving subproblem in zeroobj heuristic; sub-SCIP terminated with code <%d>\n",retcode); } #ifdef SCIP_DEBUG SCIP_CALL( SCIPprintStatistics(subscip, NULL) ); #endif } /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until one was accepted */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); valid = FALSE; for( i = 0; i < nsubsols && !valid; ++i ) { SCIP_CALL( createNewSol(scip, subscip, subvars, heur, subsols[i], &valid) ); if( valid ) *result = SCIP_FOUNDSOL; } /* free subproblem */ SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; } /* we can only work on solutions valid in the transformed space */ if( SCIPsolIsOriginal(bestsol) ) return SCIP_OKAY; if( heurtiming == SCIP_HEURTIMING_BEFORENODE && (SCIPhasCurrentNodeLP(scip) || heurdata->forcelpconstruction) ) { SCIP_Bool cutoff; cutoff = FALSE; SCIP_CALL( SCIPconstructLP(scip, &cutoff) ); SCIP_CALL( SCIPflushLP(scip) ); /* get problem variables again, SCIPconstructLP() might have added new variables */ SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, &nbinvars, &nintvars, NULL, NULL) ); nintvars += nbinvars; } /* we need an LP */ if( SCIPgetNLPRows(scip) == 0 ) return SCIP_OKAY; *result = SCIP_DIDNOTFIND; nchgbound = 0; /* initialize data */ nshiftcands = 0; shiftcandssize = 8; heurdata->lastsolindex = SCIPsolGetIndex(bestsol); SCIP_CALL( SCIPcreateSolCopy(scip, &worksol, bestsol) ); SCIPsolSetHeur(worksol,heur); SCIPdebugMessage("Starting bound adjustment in 1-opt heuristic\n"); /* maybe change solution values due to global bound changes first */ for( i = nvars - 1; i >= 0; --i ) { SCIP_VAR* var; SCIP_Real solval; var = vars[i]; lb = SCIPvarGetLbGlobal(var); ub = SCIPvarGetUbGlobal(var); solval = SCIPgetSolVal(scip, bestsol,var); /* old solution value is smaller than the actual lower bound */ if( SCIPisFeasLT(scip, solval, lb) ) { /* set the solution value to the global lower bound */ SCIP_CALL( SCIPsetSolVal(scip, worksol, var, lb) ); ++nchgbound; SCIPdebugMessage("var <%s> type %d, old solval %g now fixed to lb %g\n", SCIPvarGetName(var), SCIPvarGetType(var), solval, lb); } /* old solution value is greater than the actual upper bound */ else if( SCIPisFeasGT(scip, solval, SCIPvarGetUbGlobal(var)) ) { /* set the solution value to the global upper bound */ SCIP_CALL( SCIPsetSolVal(scip, worksol, var, ub) ); ++nchgbound; SCIPdebugMessage("var <%s> type %d, old solval %g now fixed to ub %g\n", SCIPvarGetName(var), SCIPvarGetType(var), solval, ub); } } SCIPdebugMessage("number of bound changes (due to global bounds) = %d\n", nchgbound); SCIP_CALL( SCIPgetLPRowsData(scip, &lprows, &nlprows) ); SCIP_CALL( SCIPallocBufferArray(scip, &activities, nlprows) ); localrows = FALSE; valid = TRUE; /* initialize activities */ for( i = 0; i < nlprows; ++i ) { SCIP_ROW* row; row = lprows[i]; assert(SCIProwGetLPPos(row) == i); if( !SCIProwIsLocal(row) ) { activities[i] = SCIPgetRowSolActivity(scip, row, worksol); SCIPdebugMessage("Row <%s> has activity %g\n", SCIProwGetName(row), activities[i]); if( SCIPisFeasLT(scip, activities[i], SCIProwGetLhs(row)) || SCIPisFeasGT(scip, activities[i], SCIProwGetRhs(row)) ) { valid = FALSE; SCIPdebug( SCIP_CALL( SCIPprintRow(scip, row, NULL) ) ); SCIPdebugMessage("row <%s> activity %g violates bounds, lhs = %g, rhs = %g\n", SCIProwGetName(row), activities[i], SCIProwGetLhs(row), SCIProwGetRhs(row)); break; } } else localrows = TRUE; } if( !valid ) { /** @todo try to correct lp rows */ SCIPdebugMessage("Some global bound changes were not valid in lp rows.\n"); goto TERMINATE; } SCIP_CALL( SCIPallocBufferArray(scip, &shiftcands, shiftcandssize) ); SCIP_CALL( SCIPallocBufferArray(scip, &shiftvals, shiftcandssize) ); SCIPdebugMessage("Starting 1-opt heuristic\n"); /* enumerate all integer variables and find out which of them are shiftable */ for( i = 0; i < nintvars; i++ ) { if( SCIPvarGetStatus(vars[i]) == SCIP_VARSTATUS_COLUMN ) { SCIP_Real shiftval; SCIP_Real solval; /* find out whether the variable can be shifted */ solval = SCIPgetSolVal(scip, worksol, vars[i]); shiftval = calcShiftVal(scip, vars[i], solval, activities); /* insert the variable into the list of shifting candidates */ if( !SCIPisFeasZero(scip, shiftval) ) { SCIPdebugMessage(" -> Variable <%s> can be shifted by <%1.1f> \n", SCIPvarGetName(vars[i]), shiftval); if( nshiftcands == shiftcandssize) { shiftcandssize *= 8; SCIP_CALL( SCIPreallocBufferArray(scip, &shiftcands, shiftcandssize) ); SCIP_CALL( SCIPreallocBufferArray(scip, &shiftvals, shiftcandssize) ); } shiftcands[nshiftcands] = vars[i]; shiftvals[nshiftcands] = shiftval; nshiftcands++; } } } /* if at least one variable can be shifted, shift variables sorted by their objective */ if( nshiftcands > 0 ) { SCIP_Real shiftval; SCIP_Real solval; SCIP_VAR* var; /* the case that exactly one variable can be shifted is slightly easier */ if( nshiftcands == 1 ) { var = shiftcands[0]; assert(var != NULL); solval = SCIPgetSolVal(scip, worksol, var); shiftval = shiftvals[0]; assert(!SCIPisFeasZero(scip,shiftval)); SCIPdebugMessage(" Only one shiftcand found, var <%s>, which is now shifted by<%1.1f> \n", SCIPvarGetName(var), shiftval); SCIP_CALL( SCIPsetSolVal(scip, worksol, var, solval+shiftval) ); } else { SCIP_Real* objcoeffs; SCIP_CALL( SCIPallocBufferArray(scip, &objcoeffs, nshiftcands) ); SCIPdebugMessage(" %d shiftcands found \n", nshiftcands); /* sort the variables by their objective, optionally weighted with the shiftval */ if( heurdata->weightedobj ) { for( i = 0; i < nshiftcands; ++i ) objcoeffs[i] = SCIPvarGetObj(shiftcands[i])*shiftvals[i]; } else { for( i = 0; i < nshiftcands; ++i ) objcoeffs[i] = SCIPvarGetObj(shiftcands[i]); } /* sort arrays with respect to the first one */ SCIPsortRealPtr(objcoeffs, (void**)shiftcands, nshiftcands); /* try to shift each variable -> Activities have to be updated */ for( i = 0; i < nshiftcands; ++i ) { var = shiftcands[i]; assert(var != NULL); solval = SCIPgetSolVal(scip, worksol, var); shiftval = calcShiftVal(scip, var, solval, activities); SCIPdebugMessage(" -> Variable <%s> is now shifted by <%1.1f> \n", SCIPvarGetName(vars[i]), shiftval); assert(i > 0 || !SCIPisFeasZero(scip, shiftval)); assert(SCIPisFeasGE(scip, solval+shiftval, SCIPvarGetLbGlobal(var)) && SCIPisFeasLE(scip, solval+shiftval, SCIPvarGetUbGlobal(var))); SCIP_CALL( SCIPsetSolVal(scip, worksol, var, solval+shiftval) ); SCIP_CALL( updateRowActivities(scip, activities, var, shiftval) ); } SCIPfreeBufferArray(scip, &objcoeffs); } /* if the problem is a pure IP, try to install the solution, if it is a MIP, solve LP again to set the continuous * variables to the best possible value */ if( nvars == nintvars || !SCIPhasCurrentNodeLP(scip) || SCIPgetLPSolstat(scip) != SCIP_LPSOLSTAT_OPTIMAL ) { SCIP_Bool success; /* since we ignore local rows, we cannot guarantee their feasibility and have to set the checklprows flag to * TRUE if local rows are present */ SCIP_CALL( SCIPtrySol(scip, worksol, FALSE, FALSE, FALSE, localrows, &success) ); if( success ) { SCIPdebugMessage("found feasible shifted solution:\n"); SCIPdebug( SCIP_CALL( SCIPprintSol(scip, worksol, NULL, FALSE) ) ); heurdata->lastsolindex = SCIPsolGetIndex(bestsol); *result = SCIP_FOUNDSOL; } } else { SCIP_Bool lperror; #ifdef NDEBUG SCIP_RETCODE retstat; #endif SCIPdebugMessage("shifted solution should be feasible -> solve LP to fix continuous variables to best values\n"); /* start diving to calculate the LP relaxation */ SCIP_CALL( SCIPstartDive(scip) ); /* set the bounds of the variables: fixed for integers, global bounds for continuous */ for( i = 0; i < nvars; ++i ) { if( SCIPvarGetStatus(vars[i]) == SCIP_VARSTATUS_COLUMN ) { SCIP_CALL( SCIPchgVarLbDive(scip, vars[i], SCIPvarGetLbGlobal(vars[i])) ); SCIP_CALL( SCIPchgVarUbDive(scip, vars[i], SCIPvarGetUbGlobal(vars[i])) ); } } /* apply this after global bounds to not cause an error with intermediate empty domains */ for( i = 0; i < nintvars; ++i ) { if( SCIPvarGetStatus(vars[i]) == SCIP_VARSTATUS_COLUMN ) { solval = SCIPgetSolVal(scip, worksol, vars[i]); SCIP_CALL( SCIPchgVarLbDive(scip, vars[i], solval) ); SCIP_CALL( SCIPchgVarUbDive(scip, vars[i], solval) ); } } /* solve LP */ SCIPdebugMessage(" -> old LP iterations: %" SCIP_LONGINT_FORMAT "\n", SCIPgetNLPIterations(scip)); /**@todo in case of an MINLP, if SCIPisNLPConstructed() is TRUE, say, rather solve the NLP instead of the LP */ /* Errors in the LP solver should not kill the overall solving process, if the LP is just needed for a heuristic. * Hence in optimized mode, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ #ifdef NDEBUG retstat = SCIPsolveDiveLP(scip, -1, &lperror, NULL); if( retstat != SCIP_OKAY ) { SCIPwarningMessage(scip, "Error while solving LP in Oneopt heuristic; LP solve terminated with code <%d>\n",retstat); } #else SCIP_CALL( SCIPsolveDiveLP(scip, -1, &lperror, NULL) ); #endif SCIPdebugMessage(" -> new LP iterations: %" SCIP_LONGINT_FORMAT "\n", SCIPgetNLPIterations(scip)); SCIPdebugMessage(" -> error=%u, status=%d\n", lperror, SCIPgetLPSolstat(scip)); /* check if this is a feasible solution */ if( !lperror && SCIPgetLPSolstat(scip) == SCIP_LPSOLSTAT_OPTIMAL ) { SCIP_Bool success; /* copy the current LP solution to the working solution */ SCIP_CALL( SCIPlinkLPSol(scip, worksol) ); SCIP_CALL( SCIPtrySol(scip, worksol, FALSE, FALSE, FALSE, FALSE, &success) ); /* check solution for feasibility */ if( success ) { SCIPdebugMessage("found feasible shifted solution:\n"); SCIPdebug( SCIP_CALL( SCIPprintSol(scip, worksol, NULL, FALSE) ) ); heurdata->lastsolindex = SCIPsolGetIndex(bestsol); *result = SCIP_FOUNDSOL; } } /* terminate the diving */ SCIP_CALL( SCIPendDive(scip) ); } } SCIPdebugMessage("Finished 1-opt heuristic\n"); SCIPfreeBufferArray(scip, &shiftvals); SCIPfreeBufferArray(scip, &shiftcands); TERMINATE: SCIPfreeBufferArray(scip, &activities); SCIP_CALL( SCIPfreeSol(scip, &worksol) ); return SCIP_OKAY; }
/** reads an BLK file */ static SCIP_RETCODE readBLKFile( SCIP* scip, /**< SCIP data structure */ SCIP_READER* reader, /**< reader data structure */ BLKINPUT* blkinput, /**< BLK reading data */ const char* filename /**< name of the input file */ ) { DEC_DECOMP *decdecomp; int i; int nconss; int nblocksread; int nvars; SCIP_READERDATA* readerdata; SCIP_CONS** conss; nblocksread = FALSE; assert(scip != NULL); assert(reader != NULL); assert(blkinput != NULL); if( SCIPgetStage(scip) < SCIP_STAGE_TRANSFORMED ) SCIP_CALL( SCIPtransformProb(scip) ); readerdata = SCIPreaderGetData(reader); assert(readerdata != NULL); readerdata->nlinkingcons = SCIPgetNConss(scip); readerdata->nlinkingvars = 0; nvars = SCIPgetNVars(scip); conss = SCIPgetConss(scip); nconss = SCIPgetNConss(scip); /* alloc: var -> block mapping */ SCIP_CALL( SCIPallocMemoryArray(scip, &readerdata->varstoblock, nvars) ); for( i = 0; i < nvars; i ++ ) { readerdata->varstoblock[i] = NOVALUE; } /* alloc: linkingvar -> blocks mapping */ SCIP_CALL( SCIPallocMemoryArray(scip, &readerdata->linkingvarsblocks, nvars) ); SCIP_CALL( SCIPallocMemoryArray(scip, &readerdata->nlinkingvarsblocks, nvars) ); BMSclearMemoryArray(readerdata->linkingvarsblocks, nvars); BMSclearMemoryArray(readerdata->nlinkingvarsblocks, nvars); /* cons -> block mapping */ SCIP_CALL( SCIPhashmapCreate(&readerdata->constoblock, SCIPblkmem(scip), nconss) ); for( i = 0; i < SCIPgetNConss(scip); i ++ ) { SCIP_CALL( SCIPhashmapInsert(readerdata->constoblock, conss[i], (void*)(size_t) NOVALUE) ); } /* open file */ blkinput->file = SCIPfopen(filename, "r"); if( blkinput->file == NULL ) { SCIPerrorMessage("cannot open file <%s> for reading\n", filename); SCIPprintSysError(filename); return SCIP_NOFILE; } /* parse the file */ blkinput->section = BLK_START; while( blkinput->section != BLK_END && !hasError(blkinput) ) { switch( blkinput->section ) { case BLK_START: SCIP_CALL( readStart(scip, blkinput) ); break; case BLK_PRESOLVED: SCIP_CALL( readPresolved(scip, blkinput) ); if( blkinput->presolved && SCIPgetStage(scip) < SCIP_STAGE_PRESOLVED ) { assert(blkinput->haspresolvesection); /** @bug GCG should be able to presolve the problem first */ SCIPverbMessage(scip, SCIP_VERBLEVEL_MINIMAL, NULL, "decomposition belongs to the presolved problem, please presolve the problem first.\n"); goto TERMINATE; } break; case BLK_NBLOCKS: SCIP_CALL( readNBlocks(scip, blkinput) ); if( blkinput->haspresolvesection && !blkinput->presolved && SCIPgetStage(scip) >= SCIP_STAGE_PRESOLVED ) { SCIPverbMessage(scip, SCIP_VERBLEVEL_MINIMAL, NULL, "decomposition belongs to the unpresolved problem, please re-read the problem and read the decomposition without presolving.\n"); goto TERMINATE; } if( !blkinput->haspresolvesection ) { SCIPwarningMessage(scip, "decomposition has no presolve section at beginning. The behaviour is undefined. See the FAQ for further information.\n"); } break; case BLK_BLOCK: if( nblocksread == FALSE ) { /* alloc n vars per block */ SCIP_CALL( SCIPallocMemoryArray(scip, &readerdata->nblockvars, blkinput->nblocks) ); SCIP_CALL( SCIPallocMemoryArray(scip, &readerdata->nblockcons, blkinput->nblocks) ); SCIP_CALL( SCIPallocMemoryArray(scip, &readerdata->blockcons, blkinput->nblocks) ); for( i = 0; i < blkinput->nblocks; ++i ) { readerdata->nblockvars[i] = 0; readerdata->nblockcons[i] = 0; SCIP_CALL( SCIPallocMemoryArray(scip, &(readerdata->blockcons[i]), nconss) ); /*lint !e866*/ } nblocksread = TRUE; } SCIP_CALL( readBlock(scip, blkinput, readerdata) ); break; case BLK_MASTERCONSS: SCIP_CALL( readMasterconss(scip, blkinput, readerdata) ); break; case BLK_END: /* this is already handled in the while() loop */ default: SCIPerrorMessage("invalid BLK file section <%d>\n", blkinput->section); return SCIP_INVALIDDATA; } } SCIP_CALL( DECdecompCreate(scip, &decdecomp) ); /* fill decomp */ SCIP_CALL( fillDecompStruct(scip, blkinput, decdecomp, readerdata) ); /* add decomp to cons_decomp */ SCIP_CALL( SCIPconshdlrDecompAddDecdecomp(scip, decdecomp) ); for( i = 0; i < nvars; ++i ) { assert(readerdata->linkingvarsblocks[i] != NULL || readerdata->nlinkingvarsblocks[i] == 0); if( readerdata->nlinkingvarsblocks[i] > 0 ) { SCIPfreeMemoryArray(scip, &readerdata->linkingvarsblocks[i]); } } TERMINATE: if( nblocksread ) { for( i = blkinput->nblocks - 1; i >= 0; --i ) { SCIPfreeMemoryArray(scip, &(readerdata->blockcons[i])); } SCIPfreeMemoryArray(scip, &readerdata->blockcons); SCIPfreeMemoryArray(scip, &readerdata->nblockcons); SCIPfreeMemoryArray(scip, &readerdata->nblockvars); } SCIPhashmapFree(&readerdata->constoblock); SCIPfreeMemoryArray(scip, &readerdata->nlinkingvarsblocks); SCIPfreeMemoryArray(scip, &readerdata->linkingvarsblocks); SCIPfreeMemoryArray(scip, &readerdata->varstoblock); /* close file */ SCIPfclose(blkinput->file); return SCIP_OKAY; }
/** writes problem to file */ SCIP_RETCODE SCIPwritePpm( SCIP* scip, /**< SCIP data structure */ FILE* file, /**< output file, or NULL if standard output should be used */ const char* name, /**< problem name */ SCIP_READERDATA* readerdata, /**< information for reader */ SCIP_Bool transformed, /**< TRUE iff problem is the transformed problem */ SCIP_VAR** vars, /**< array with active variables ordered binary, integer, implicit, continuous */ int nvars, /**< number of active variables in the problem */ SCIP_CONS** conss, /**< array with constraints of the problem */ int nconss, /**< number of constraints in the problem */ SCIP_RESULT* result /**< pointer to store the result of the file writing call */ ) { /*lint --e{715}*/ int c; int v; int i; int linecnt; char linebuffer[PPM_MAX_LINELEN]; SCIP_CONSHDLR* conshdlr; const char* conshdlrname; SCIP_CONS* cons; SCIP_VAR** consvars; SCIP_Real* consvals; int nconsvars; int i_max = 1; SCIP_Real maxcoef = 0; SCIP_Bool printbool = FALSE; assert( scip != NULL ); assert(readerdata != NULL); /* print statistics as comment to file */ if(readerdata->rgb_ascii) SCIPinfoMessage(scip, file, "P6\n"); else SCIPinfoMessage(scip, file, "P3\n"); SCIPinfoMessage(scip, file, "# %s\n", name); SCIPinfoMessage(scip, file, "%d %d\n", nvars, nconss); SCIPinfoMessage(scip, file, "255\n"); clearLine(linebuffer, &linecnt); if(!(readerdata->rgb_relativ)) { i_max = 2; } for(i = 0; i < i_max; ++i) { if(i) { printbool = TRUE; SCIPdebugPrintf("Maximal coefficient = %g\n", maxcoef); } for(c = 0; c < nconss; ++c) { cons = conss[c]; assert( cons != NULL); /* in case the transformed is written only constraint are posted which are enabled in the current node */ assert(!transformed || SCIPconsIsEnabled(cons)); conshdlr = SCIPconsGetHdlr(cons); assert( conshdlr != NULL ); conshdlrname = SCIPconshdlrGetName(conshdlr); assert( transformed == SCIPconsIsTransformed(cons) ); if( strcmp(conshdlrname, "linear") == 0 ) { consvars = SCIPgetVarsLinear(scip, cons); nconsvars = SCIPgetNVarsLinear(scip, cons); assert( consvars != NULL || nconsvars == 0 ); if( nconsvars > 0 ) { SCIP_CALL( printLinearCons(scip, file, readerdata, consvars, SCIPgetValsLinear(scip, cons), nconsvars, nvars, transformed, &maxcoef, printbool) ); } } else if( strcmp(conshdlrname, "setppc") == 0 ) { consvars = SCIPgetVarsSetppc(scip, cons); nconsvars = SCIPgetNVarsSetppc(scip, cons); assert( consvars != NULL || nconsvars == 0 ); if( nconsvars > 0 ) { SCIP_CALL( printLinearCons(scip, file, readerdata, consvars, NULL, nconsvars, nvars, transformed, &maxcoef, printbool) ); } } else if( strcmp(conshdlrname, "logicor") == 0 ) { consvars = SCIPgetVarsLogicor(scip, cons); nconsvars = SCIPgetNVarsLogicor(scip, cons); assert( consvars != NULL || nconsvars == 0 ); if( nconsvars > 0 ) { SCIP_CALL( printLinearCons(scip, file, readerdata, consvars, NULL, nconsvars, nvars, transformed, &maxcoef, printbool) ); } } else if( strcmp(conshdlrname, "knapsack") == 0 ) { SCIP_Longint* weights; consvars = SCIPgetVarsKnapsack(scip, cons); nconsvars = SCIPgetNVarsKnapsack(scip, cons); assert( consvars != NULL || nconsvars == 0 ); /* copy Longint array to SCIP_Real array */ weights = SCIPgetWeightsKnapsack(scip, cons); SCIP_CALL( SCIPallocBufferArray(scip, &consvals, nconsvars) ); for( v = 0; v < nconsvars; ++v ) consvals[v] = (SCIP_Real)weights[v]; if( nconsvars > 0 ) { SCIP_CALL( printLinearCons(scip, file, readerdata, consvars, consvals, nconsvars, nvars, transformed, &maxcoef, printbool) ); } SCIPfreeBufferArray(scip, &consvals); } else if( strcmp(conshdlrname, "varbound") == 0 ) { SCIP_CALL( SCIPallocBufferArray(scip, &consvars, 2) ); SCIP_CALL( SCIPallocBufferArray(scip, &consvals, 2) ); consvars[0] = SCIPgetVarVarbound(scip, cons); consvars[1] = SCIPgetVbdvarVarbound(scip, cons); consvals[0] = 1.0; consvals[1] = SCIPgetVbdcoefVarbound(scip, cons); SCIP_CALL( printLinearCons(scip, file, readerdata, consvars, consvals, 2, nvars, transformed, &maxcoef, printbool) ); SCIPfreeBufferArray(scip, &consvars); SCIPfreeBufferArray(scip, &consvals); } else { SCIPwarningMessage(scip, "constraint handler <%s> cannot print requested format\n", conshdlrname ); SCIPinfoMessage(scip, file, "\\ "); SCIP_CALL( SCIPprintCons(scip, cons, file) ); SCIPinfoMessage(scip, file, ";\n"); } } } *result = SCIP_SUCCESS; return SCIP_OKAY; }
/** LP solution separation method of separator */ static SCIP_DECL_SEPAEXECLP(sepaExeclpRapidlearning) {/*lint --e{715}*/ SCIP* subscip; /* the subproblem created by rapid learning */ SCIP_SEPADATA* sepadata; /* separator's private data */ SCIP_VAR** vars; /* original problem's variables */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_HASHMAP* varmapbw; /* mapping of sub-SCIP variables to SCIP variables */ SCIP_CONSHDLR** conshdlrs; /* array of constraint handler's that might that might obtain conflicts */ int* oldnconss; /* number of constraints without rapid learning conflicts */ SCIP_Longint nodelimit; /* node limit for the subproblem */ SCIP_Real timelimit; /* time limit for the subproblem */ SCIP_Real memorylimit; /* memory limit for the subproblem */ int nconshdlrs; /* size of conshdlr and oldnconss array */ int nfixedvars; /* number of variables that could be fixed by rapid learning */ int nvars; /* number of variables */ int restartnum; /* maximal number of conflicts that should be created */ int i; /* counter */ SCIP_Bool success; /* was problem creation / copying constraint successful? */ SCIP_RETCODE retcode; /* used for catching sub-SCIP errors in debug mode */ int nconflicts; /* statistic: number of conflicts applied */ int nbdchgs; /* statistic: number of bound changes applied */ int n1startinfers; /* statistic: number of one side infer values */ int n2startinfers; /* statistic: number of both side infer values */ SCIP_Bool soladded; /* statistic: was a new incumbent found? */ SCIP_Bool dualboundchg; /* statistic: was a new dual bound found? */ SCIP_Bool disabledualreductions; /* TRUE, if dual reductions in sub-SCIP are not valid for original SCIP, * e.g., because a constraint could not be copied or a primal solution * could not be copied back */ int ndiscvars; soladded = FALSE; assert(sepa != NULL); assert(scip != NULL); assert(result != NULL); *result = SCIP_DIDNOTRUN; ndiscvars = SCIPgetNBinVars(scip) + SCIPgetNIntVars(scip)+SCIPgetNImplVars(scip); /* only run when still not fixed binary variables exists */ if( ndiscvars == 0 ) return SCIP_OKAY; /* get separator's data */ sepadata = SCIPsepaGetData(sepa); assert(sepadata != NULL); /* only run for integer programs */ if( !sepadata->contvars && ndiscvars != SCIPgetNVars(scip) ) return SCIP_OKAY; /* only run if there are few enough continuous variables */ if( sepadata->contvars && SCIPgetNContVars(scip) > sepadata->contvarsquot * SCIPgetNVars(scip) ) return SCIP_OKAY; /* do not run if pricers are present */ if( SCIPgetNActivePricers(scip) > 0 ) return SCIP_OKAY; /* if the separator should be exclusive to the root node, this prevents multiple calls due to restarts */ if( SCIPsepaGetFreq(sepa) == 0 && SCIPsepaGetNCalls(sepa) > 0) return SCIP_OKAY; /* call separator at most once per node */ if( SCIPsepaGetNCallsAtNode(sepa) > 0 ) return SCIP_OKAY; /* do not call rapid learning, if the problem is too big */ if( SCIPgetNVars(scip) > sepadata->maxnvars || SCIPgetNConss(scip) > sepadata->maxnconss ) return SCIP_OKAY; if( SCIPisStopped(scip) ) return SCIP_OKAY; *result = SCIP_DIDNOTFIND; SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, NULL, NULL, NULL, NULL) ); /* initializing the subproblem */ SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); SCIP_CALL( SCIPcreate(&subscip) ); SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); success = FALSE; /* copy the subproblem */ SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "rapid", FALSE, FALSE, &success) ); if( sepadata->copycuts ) { /** copies all active cuts from cutpool of sourcescip to linear constraints in targetscip */ SCIP_CALL( SCIPcopyCuts(scip, subscip, varmapfw, NULL, FALSE) ); } for( i = 0; i < nvars; i++ ) subvars[i] = (SCIP_VAR*) (size_t) SCIPhashmapGetImage(varmapfw, vars[i]); SCIPhashmapFree(&varmapfw); /* this avoids dual presolving */ if( !success ) { for( i = 0; i < nvars; i++ ) { SCIP_CALL( SCIPaddVarLocks(subscip, subvars[i], 1, 1 ) ); } } SCIPdebugMessage("Copying SCIP was%s successful.\n", success ? "" : " not"); /* mimic an FD solver: DFS, no LP solving, 1-FUIP instead of all-FUIP */ SCIP_CALL( SCIPsetIntParam(subscip, "lp/solvefreq", -1) ); SCIP_CALL( SCIPsetIntParam(subscip, "conflict/fuiplevels", 1) ); SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/dfs/stdpriority", INT_MAX/4) ); SCIP_CALL( SCIPsetBoolParam(subscip, "constraints/disableenfops", TRUE) ); SCIP_CALL( SCIPsetIntParam(subscip, "propagating/pseudoobj/freq", -1) ); /* use inference branching */ SCIP_CALL( SCIPsetBoolParam(subscip, "branching/inference/useweightedsum", FALSE) ); /* only create short conflicts */ SCIP_CALL( SCIPsetRealParam(subscip, "conflict/maxvarsfac", 0.05) ); /* set limits for the subproblem */ nodelimit = SCIPgetNLPIterations(scip); nodelimit = MAX(sepadata->minnodes, nodelimit); nodelimit = MIN(sepadata->maxnodes, nodelimit); restartnum = 1000; /* check whether there is enough time and memory left */ SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); if( !SCIPisInfinity(scip, memorylimit) ) memorylimit -= SCIPgetMemUsed(scip)/1048576.0; if( timelimit <= 0.0 || memorylimit <= 0.0 ) goto TERMINATE; SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nodelimit/5) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); SCIP_CALL( SCIPsetIntParam(subscip, "limits/restarts", 0) ); SCIP_CALL( SCIPsetIntParam(subscip, "conflict/restartnum", restartnum) ); /* forbid recursive call of heuristics and separators solving subMIPs */ SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) ); /* disable cutting plane separation */ SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); /* disable expensive presolving */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_FAST, TRUE) ); /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); #ifndef SCIP_DEBUG /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); #endif /* add an objective cutoff */ SCIP_CALL( SCIPsetObjlimit(subscip, SCIPgetUpperbound(scip)) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapbw, SCIPblkmem(scip), SCIPcalcHashtableSize(5 * nvars)) ); /* store reversing mapping of variables */ SCIP_CALL( SCIPtransformProb(subscip) ); for( i = 0; i < nvars; ++i) { SCIP_CALL( SCIPhashmapInsert(varmapbw, SCIPvarGetTransVar(subvars[i]), vars[i]) ); } /** allocate memory for constraints storage. Each constraint that will be created from now on will be a conflict. * Therefore, we need to remember oldnconss to get the conflicts from the FD search. */ nconshdlrs = 4; SCIP_CALL( SCIPallocBufferArray(scip, &conshdlrs, nconshdlrs) ); SCIP_CALL( SCIPallocBufferArray(scip, &oldnconss, nconshdlrs) ); /* store number of constraints before rapid learning search */ conshdlrs[0] = SCIPfindConshdlr(subscip, "bounddisjunction"); conshdlrs[1] = SCIPfindConshdlr(subscip, "setppc"); conshdlrs[2] = SCIPfindConshdlr(subscip, "linear"); conshdlrs[3] = SCIPfindConshdlr(subscip, "logicor"); /* redundant constraints might be eliminated in presolving */ SCIP_CALL( SCIPpresolve(subscip)); for( i = 0; i < nconshdlrs; ++i) { if( conshdlrs[i] != NULL ) oldnconss[i] = SCIPconshdlrGetNConss(conshdlrs[i]); } nfixedvars = SCIPgetNFixedVars(scip); /* solve the subproblem */ retcode = SCIPsolve(subscip); /* Errors in solving the subproblem should not kill the overall solving process * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage("Error while solving subproblem in rapid learning separator; sub-SCIP terminated with code <%d>\n",retcode); } /* abort solving, if limit of applied conflicts is reached */ if( SCIPgetNConflictConssApplied(subscip) >= restartnum ) { SCIPdebugMessage("finish after %lld successful conflict calls.\n", SCIPgetNConflictConssApplied(subscip)); } /* if the first 20% of the solution process were successful, proceed */ else if( (sepadata->applyprimalsol && SCIPgetNSols(subscip) > 0 && SCIPisFeasLT(scip, SCIPgetUpperbound(subscip), SCIPgetUpperbound(scip) ) ) || (sepadata->applybdchgs && SCIPgetNFixedVars(subscip) > nfixedvars) || (sepadata->applyconflicts && SCIPgetNConflictConssApplied(subscip) > 0) ) { SCIPdebugMessage("proceed solving after the first 20%% of the solution process, since:\n"); if( SCIPgetNSols(subscip) > 0 && SCIPisFeasLE(scip, SCIPgetUpperbound(subscip), SCIPgetUpperbound(scip) ) ) { SCIPdebugMessage(" - there was a better solution (%f < %f)\n",SCIPgetUpperbound(subscip), SCIPgetUpperbound(scip)); } if( SCIPgetNFixedVars(subscip) > nfixedvars ) { SCIPdebugMessage(" - there were %d variables fixed\n", SCIPgetNFixedVars(scip)-nfixedvars ); } if( SCIPgetNConflictConssFound(subscip) > 0 ) { SCIPdebugMessage(" - there were %lld conflict constraints created\n", SCIPgetNConflictConssApplied(subscip)); } /* set node limit to 100% */ SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nodelimit) ); /* solve the subproblem */ retcode = SCIPsolve(subscip); /* Errors in solving the subproblem should not kill the overall solving process * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage("Error while solving subproblem in rapid learning separator; sub-SCIP terminated with code <%d>\n",retcode); } } else { SCIPdebugMessage("do not proceed solving after the first 20%% of the solution process.\n"); } #ifdef SCIP_DEBUG SCIP_CALL( SCIPprintStatistics(subscip, NULL) ); #endif disabledualreductions = FALSE; /* check, whether a solution was found */ if( sepadata->applyprimalsol && SCIPgetNSols(subscip) > 0 && SCIPfindHeur(scip, "trysol") != NULL ) { SCIP_HEUR* heurtrysol; SCIP_SOL** subsols; int nsubsols; /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until was declared to be feasible */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); soladded = FALSE; heurtrysol = SCIPfindHeur(scip, "trysol"); /* sequentially add solutions to trysol heuristic */ for( i = 0; i < nsubsols && !soladded; ++i ) { SCIPdebugMessage("Try to create new solution by copying subscip solution.\n"); SCIP_CALL( createNewSol(scip, subscip, subvars, heurtrysol, subsols[i], &soladded) ); } if( !soladded || !SCIPisEQ(scip, SCIPgetSolOrigObj(subscip, subsols[i-1]), SCIPgetSolOrigObj(subscip, subsols[0])) ) disabledualreductions = TRUE; } /* if the sub problem was solved completely, we update the dual bound */ dualboundchg = FALSE; if( sepadata->applysolved && !disabledualreductions && (SCIPgetStatus(subscip) == SCIP_STATUS_OPTIMAL || SCIPgetStatus(subscip) == SCIP_STATUS_INFEASIBLE) ) { /* we need to multiply the dualbound with the scaling factor and add the offset, * because this information has been disregarded in the sub-SCIP */ SCIPdebugMessage("Update old dualbound %g to new dualbound %g.\n", SCIPgetDualbound(scip), SCIPgetTransObjscale(scip) * SCIPgetDualbound(subscip) + SCIPgetTransObjoffset(scip)); SCIP_CALL( SCIPupdateLocalDualbound(scip, SCIPgetDualbound(subscip) * SCIPgetTransObjscale(scip) + SCIPgetTransObjoffset(scip)) ); dualboundchg = TRUE; } /* check, whether conflicts were created */ nconflicts = 0; if( sepadata->applyconflicts && !disabledualreductions && SCIPgetNConflictConssApplied(subscip) > 0 ) { SCIP_HASHMAP* consmap; int hashtablesize; assert(SCIPgetNConflictConssApplied(subscip) < (SCIP_Longint) INT_MAX); hashtablesize = (int) SCIPgetNConflictConssApplied(subscip); assert(hashtablesize < INT_MAX/5); hashtablesize *= 5; /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&consmap, SCIPblkmem(scip), SCIPcalcHashtableSize(hashtablesize)) ); /* loop over all constraint handlers that might contain conflict constraints */ for( i = 0; i < nconshdlrs; ++i) { /* copy constraints that have been created in FD run */ if( conshdlrs[i] != NULL && SCIPconshdlrGetNConss(conshdlrs[i]) > oldnconss[i] ) { SCIP_CONS** conss; int c; int nconss; nconss = SCIPconshdlrGetNConss(conshdlrs[i]); conss = SCIPconshdlrGetConss(conshdlrs[i]); /* loop over all constraints that have been added in sub-SCIP run, these are the conflicts */ for( c = oldnconss[i]; c < nconss; ++c) { SCIP_CONS* cons; SCIP_CONS* conscopy; cons = conss[c]; assert(cons != NULL); success = FALSE; SCIP_CALL( SCIPgetConsCopy(subscip, scip, cons, &conscopy, conshdlrs[i], varmapbw, consmap, NULL, SCIPconsIsInitial(cons), SCIPconsIsSeparated(cons), SCIPconsIsEnforced(cons), SCIPconsIsChecked(cons), SCIPconsIsPropagated(cons), TRUE, FALSE, SCIPconsIsDynamic(cons), SCIPconsIsRemovable(cons), FALSE, TRUE, &success) ); if( success ) { nconflicts++; SCIP_CALL( SCIPaddCons(scip, conscopy) ); SCIP_CALL( SCIPreleaseCons(scip, &conscopy) ); } else { SCIPdebugMessage("failed to copy conflict constraint %s back to original SCIP\n", SCIPconsGetName(cons)); } } } } SCIPhashmapFree(&consmap); } /* check, whether tighter global bounds were detected */ nbdchgs = 0; if( sepadata->applybdchgs && !disabledualreductions ) for( i = 0; i < nvars; ++i ) { SCIP_Bool infeasible; SCIP_Bool tightened; assert(SCIPisLE(scip, SCIPvarGetLbGlobal(vars[i]), SCIPvarGetLbGlobal(subvars[i]))); assert(SCIPisLE(scip, SCIPvarGetLbGlobal(subvars[i]), SCIPvarGetUbGlobal(subvars[i]))); assert(SCIPisLE(scip, SCIPvarGetUbGlobal(subvars[i]), SCIPvarGetUbGlobal(vars[i]))); /* update the bounds of the original SCIP, if a better bound was proven in the sub-SCIP */ SCIP_CALL( SCIPtightenVarUb(scip, vars[i], SCIPvarGetUbGlobal(subvars[i]), FALSE, &infeasible, &tightened) ); if( tightened ) nbdchgs++; SCIP_CALL( SCIPtightenVarLb(scip, vars[i], SCIPvarGetLbGlobal(subvars[i]), FALSE, &infeasible, &tightened) ); if( tightened ) nbdchgs++; } n1startinfers = 0; n2startinfers = 0; /* install start values for inference branching */ if( sepadata->applyinfervals && (!sepadata->reducedinfer || soladded || nbdchgs+nconflicts > 0) ) { for( i = 0; i < nvars; ++i ) { SCIP_Real downinfer; SCIP_Real upinfer; SCIP_Real downvsids; SCIP_Real upvsids; SCIP_Real downconflen; SCIP_Real upconflen; /* copy downwards branching statistics */ downvsids = SCIPgetVarVSIDS(subscip, subvars[i], SCIP_BRANCHDIR_DOWNWARDS); downconflen = SCIPgetVarAvgConflictlength(subscip, subvars[i], SCIP_BRANCHDIR_DOWNWARDS); downinfer = SCIPgetVarAvgInferences(subscip, subvars[i], SCIP_BRANCHDIR_DOWNWARDS); /* copy upwards branching statistics */ upvsids = SCIPgetVarVSIDS(subscip, subvars[i], SCIP_BRANCHDIR_UPWARDS); upconflen = SCIPgetVarAvgConflictlength(subscip, subvars[i], SCIP_BRANCHDIR_UPWARDS); upinfer = SCIPgetVarAvgInferences(subscip, subvars[i], SCIP_BRANCHDIR_UPWARDS); /* memorize statistics */ if( downinfer+downconflen+downvsids > 0.0 || upinfer+upconflen+upvsids != 0 ) n1startinfers++; if( downinfer+downconflen+downvsids > 0.0 && upinfer+upconflen+upvsids != 0 ) n2startinfers++; SCIP_CALL( SCIPinitVarBranchStats(scip, vars[i], 0.0, 0.0, downvsids, upvsids, downconflen, upconflen, downinfer, upinfer, 0.0, 0.0) ); } } SCIPdebugPrintf("XXX Rapidlearning added %d conflicts, changed %d bounds, %s primal solution, %s dual bound improvement.\n", nconflicts, nbdchgs, soladded ? "found" : "no", dualboundchg ? "found" : "no"); SCIPdebugPrintf("YYY Infervalues initialized on one side: %5.2f %% of variables, %5.2f %% on both sides\n", 100.0 * n1startinfers/(SCIP_Real)nvars, 100.0 * n2startinfers/(SCIP_Real)nvars); /* change result pointer */ if( nconflicts > 0 || dualboundchg ) *result = SCIP_CONSADDED; else if( nbdchgs > 0 ) *result = SCIP_REDUCEDDOM; /* free local data */ SCIPfreeBufferArray(scip, &oldnconss); SCIPfreeBufferArray(scip, &conshdlrs); SCIPhashmapFree(&varmapbw); TERMINATE: /* free subproblem */ SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecIntdiving) /*lint --e{715}*/ { /*lint --e{715}*/ SCIP_HEURDATA* heurdata; SCIP_LPSOLSTAT lpsolstat; SCIP_VAR** pseudocands; SCIP_VAR** fixcands; SCIP_Real* fixcandscores; SCIP_Real searchubbound; SCIP_Real searchavgbound; SCIP_Real searchbound; SCIP_Real objval; SCIP_Bool lperror; SCIP_Bool cutoff; SCIP_Bool backtracked; SCIP_Longint ncalls; SCIP_Longint nsolsfound; SCIP_Longint nlpiterations; SCIP_Longint maxnlpiterations; int nfixcands; int nbinfixcands; int depth; int maxdepth; int maxdivedepth; int divedepth; int nextcand; int c; assert(heur != NULL); assert(strcmp(SCIPheurGetName(heur), HEUR_NAME) == 0); assert(scip != NULL); assert(result != NULL); assert(SCIPhasCurrentNodeLP(scip)); *result = SCIP_DELAYED; /* do not call heuristic of node was already detected to be infeasible */ if( nodeinfeasible ) return SCIP_OKAY; /* only call heuristic, if an optimal LP solution is at hand */ if( SCIPgetLPSolstat(scip) != SCIP_LPSOLSTAT_OPTIMAL ) return SCIP_OKAY; /* only call heuristic, if the LP objective value is smaller than the cutoff bound */ if( SCIPisGE(scip, SCIPgetLPObjval(scip), SCIPgetCutoffbound(scip)) ) return SCIP_OKAY; /* only call heuristic, if the LP solution is basic (which allows fast resolve in diving) */ if( !SCIPisLPSolBasic(scip) ) return SCIP_OKAY; /* don't dive two times at the same node */ if( SCIPgetLastDivenode(scip) == SCIPgetNNodes(scip) && SCIPgetDepth(scip) > 0 ) return SCIP_OKAY; *result = SCIP_DIDNOTRUN; /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert(heurdata != NULL); /* only try to dive, if we are in the correct part of the tree, given by minreldepth and maxreldepth */ depth = SCIPgetDepth(scip); maxdepth = SCIPgetMaxDepth(scip); maxdepth = MAX(maxdepth, 100); if( depth < heurdata->minreldepth*maxdepth || depth > heurdata->maxreldepth*maxdepth ) return SCIP_OKAY; /* calculate the maximal number of LP iterations until heuristic is aborted */ nlpiterations = SCIPgetNNodeLPIterations(scip); ncalls = SCIPheurGetNCalls(heur); nsolsfound = 10*SCIPheurGetNBestSolsFound(heur) + heurdata->nsuccess; maxnlpiterations = (SCIP_Longint)((1.0 + 10.0*(nsolsfound+1.0)/(ncalls+1.0)) * heurdata->maxlpiterquot * nlpiterations); maxnlpiterations += heurdata->maxlpiterofs; /* don't try to dive, if we took too many LP iterations during diving */ if( heurdata->nlpiterations >= maxnlpiterations ) return SCIP_OKAY; /* allow at least a certain number of LP iterations in this dive */ maxnlpiterations = MAX(maxnlpiterations, heurdata->nlpiterations + MINLPITER); /* get unfixed integer variables */ SCIP_CALL( SCIPgetPseudoBranchCands(scip, &pseudocands, &nfixcands, NULL) ); /* don't try to dive, if there are no fractional variables */ if( nfixcands == 0 ) return SCIP_OKAY; /* calculate the objective search bound */ if( SCIPgetNSolsFound(scip) == 0 ) { if( heurdata->maxdiveubquotnosol > 0.0 ) searchubbound = SCIPgetLowerbound(scip) + heurdata->maxdiveubquotnosol * (SCIPgetCutoffbound(scip) - SCIPgetLowerbound(scip)); else searchubbound = SCIPinfinity(scip); if( heurdata->maxdiveavgquotnosol > 0.0 ) searchavgbound = SCIPgetLowerbound(scip) + heurdata->maxdiveavgquotnosol * (SCIPgetAvgLowerbound(scip) - SCIPgetLowerbound(scip)); else searchavgbound = SCIPinfinity(scip); } else { if( heurdata->maxdiveubquot > 0.0 ) searchubbound = SCIPgetLowerbound(scip) + heurdata->maxdiveubquot * (SCIPgetCutoffbound(scip) - SCIPgetLowerbound(scip)); else searchubbound = SCIPinfinity(scip); if( heurdata->maxdiveavgquot > 0.0 ) searchavgbound = SCIPgetLowerbound(scip) + heurdata->maxdiveavgquot * (SCIPgetAvgLowerbound(scip) - SCIPgetLowerbound(scip)); else searchavgbound = SCIPinfinity(scip); } searchbound = MIN(searchubbound, searchavgbound); if( SCIPisObjIntegral(scip) ) searchbound = SCIPceil(scip, searchbound); /* calculate the maximal diving depth: 10 * min{number of integer variables, max depth} */ maxdivedepth = SCIPgetNBinVars(scip) + SCIPgetNIntVars(scip); maxdivedepth = MIN(maxdivedepth, maxdepth); maxdivedepth *= 10; *result = SCIP_DIDNOTFIND; /* start diving */ SCIP_CALL( SCIPstartProbing(scip) ); /* enables collection of variable statistics during probing */ SCIPenableVarHistory(scip); SCIPdebugMessage("(node %" SCIP_LONGINT_FORMAT ") executing intdiving heuristic: depth=%d, %d non-fixed, dualbound=%g, searchbound=%g\n", SCIPgetNNodes(scip), SCIPgetDepth(scip), nfixcands, SCIPgetDualbound(scip), SCIPretransformObj(scip, searchbound)); /* copy the pseudo candidates into own array, because we want to reorder them */ SCIP_CALL( SCIPduplicateBufferArray(scip, &fixcands, pseudocands, nfixcands) ); /* sort non-fixed variables by non-increasing inference score, but prefer binaries over integers in any case */ SCIP_CALL( SCIPallocBufferArray(scip, &fixcandscores, nfixcands) ); nbinfixcands = 0; for( c = 0; c < nfixcands; ++c ) { SCIP_VAR* var; SCIP_Real score; int colveclen; int left; int right; int i; assert(c >= nbinfixcands); var = fixcands[c]; assert(SCIPvarIsIntegral(var)); colveclen = (SCIPvarGetStatus(var) == SCIP_VARSTATUS_COLUMN ? SCIPcolGetNNonz(SCIPvarGetCol(var)) : 0); if( SCIPvarIsBinary(var) ) { score = 500.0 * SCIPvarGetNCliques(var, TRUE) + 100.0 * SCIPvarGetNImpls(var, TRUE) + SCIPgetVarAvgInferenceScore(scip, var) + (SCIP_Real)colveclen/100.0; /* shift the non-binary variables one slot to the right */ for( i = c; i > nbinfixcands; --i ) { fixcands[i] = fixcands[i-1]; fixcandscores[i] = fixcandscores[i-1]; } /* put the new candidate into the first nbinfixcands slot */ left = 0; right = nbinfixcands; nbinfixcands++; } else { score = 5.0 * (SCIPvarGetNCliques(var, FALSE) + SCIPvarGetNCliques(var, TRUE)) + SCIPvarGetNImpls(var, FALSE) + SCIPvarGetNImpls(var, TRUE) + SCIPgetVarAvgInferenceScore(scip, var) + (SCIP_Real)colveclen/10000.0; /* put the new candidate in the slots after the binary candidates */ left = nbinfixcands; right = c; } for( i = right; i > left && score > fixcandscores[i-1]; --i ) { fixcands[i] = fixcands[i-1]; fixcandscores[i] = fixcandscores[i-1]; } fixcands[i] = var; fixcandscores[i] = score; SCIPdebugMessage(" <%s>: ncliques=%d/%d, nimpls=%d/%d, inferencescore=%g, colveclen=%d -> score=%g\n", SCIPvarGetName(var), SCIPvarGetNCliques(var, FALSE), SCIPvarGetNCliques(var, TRUE), SCIPvarGetNImpls(var, FALSE), SCIPvarGetNImpls(var, TRUE), SCIPgetVarAvgInferenceScore(scip, var), colveclen, score); } SCIPfreeBufferArray(scip, &fixcandscores); /* get LP objective value */ lpsolstat = SCIP_LPSOLSTAT_OPTIMAL; objval = SCIPgetLPObjval(scip); /* dive as long we are in the given objective, depth and iteration limits, but if possible, we dive at least with * the depth 10 */ lperror = FALSE; cutoff = FALSE; divedepth = 0; nextcand = 0; while( !lperror && !cutoff && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL && (divedepth < 10 || (divedepth < maxdivedepth && heurdata->nlpiterations < maxnlpiterations && objval < searchbound)) && !SCIPisStopped(scip) ) { SCIP_VAR* var; SCIP_Real bestsolval; SCIP_Real bestfixval; int bestcand; SCIP_Longint nnewlpiterations; SCIP_Longint nnewdomreds; /* open a new probing node if this will not exceed the maximal tree depth, otherwise stop here */ if( SCIPgetDepth(scip) < SCIPgetDepthLimit(scip) ) { SCIP_CALL( SCIPnewProbingNode(scip) ); divedepth++; } else break; nnewlpiterations = 0; nnewdomreds = 0; /* fix binary variable that is closest to 1 in the LP solution to 1; * if all binary variables are fixed, fix integer variable with least fractionality in LP solution */ bestcand = -1; bestsolval = -1.0; bestfixval = 1.0; /* look in the binary variables for fixing candidates */ for( c = nextcand; c < nbinfixcands; ++c ) { SCIP_Real solval; var = fixcands[c]; /* ignore already fixed variables */ if( var == NULL ) continue; if( SCIPvarGetLbLocal(var) > 0.5 || SCIPvarGetUbLocal(var) < 0.5 ) { fixcands[c] = NULL; continue; } /* get the LP solution value */ solval = SCIPvarGetLPSol(var); if( solval > bestsolval ) { bestcand = c; bestfixval = 1.0; bestsolval = solval; if( SCIPisGE(scip, bestsolval, 1.0) ) { /* we found an unfixed binary variable with LP solution value of 1.0 - there cannot be a better candidate */ break; } else if( SCIPisLE(scip, bestsolval, 0.0) ) { /* the variable is currently at 0.0 - this is the only situation where we want to fix it to 0.0 */ bestfixval = 0.0; } } } /* if all binary variables are fixed, look in the integer variables for a fixing candidate */ if( bestcand == -1 ) { SCIP_Real bestfrac; bestfrac = SCIP_INVALID; for( c = MAX(nextcand, nbinfixcands); c < nfixcands; ++c ) { SCIP_Real solval; SCIP_Real frac; var = fixcands[c]; /* ignore already fixed variables */ if( var == NULL ) continue; if( SCIPvarGetUbLocal(var) - SCIPvarGetLbLocal(var) < 0.5 ) { fixcands[c] = NULL; continue; } /* get the LP solution value */ solval = SCIPvarGetLPSol(var); frac = SCIPfrac(scip, solval); /* ignore integer variables that are currently integral */ if( SCIPisFeasFracIntegral(scip, frac) ) continue; if( frac < bestfrac ) { bestcand = c; bestsolval = solval; bestfrac = frac; bestfixval = SCIPfloor(scip, bestsolval + 0.5); if( SCIPisZero(scip, bestfrac) ) { /* we found an unfixed integer variable with integral LP solution value */ break; } } } } assert(-1 <= bestcand && bestcand < nfixcands); /* if there is no unfixed candidate left, we are done */ if( bestcand == -1 ) break; var = fixcands[bestcand]; assert(var != NULL); assert(SCIPvarIsIntegral(var)); assert(SCIPvarGetUbLocal(var) - SCIPvarGetLbLocal(var) > 0.5); assert(SCIPisGE(scip, bestfixval, SCIPvarGetLbLocal(var))); assert(SCIPisLE(scip, bestfixval, SCIPvarGetUbLocal(var))); backtracked = FALSE; do { /* if the variable is already fixed or if the solution value is outside the domain, numerical troubles may have * occured or variable was fixed by propagation while backtracking => Abort diving! */ if( SCIPvarGetLbLocal(var) >= SCIPvarGetUbLocal(var) - 0.5 ) { SCIPdebugMessage("Selected variable <%s> already fixed to [%g,%g], diving aborted \n", SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var)); cutoff = TRUE; break; } if( SCIPisFeasLT(scip, bestfixval, SCIPvarGetLbLocal(var)) || SCIPisFeasGT(scip, bestfixval, SCIPvarGetUbLocal(var)) ) { SCIPdebugMessage("selected variable's <%s> solution value is outside the domain [%g,%g] (solval: %.9f), diving aborted\n", SCIPvarGetName(var), SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), bestfixval); assert(backtracked); break; } /* apply fixing of best candidate */ SCIPdebugMessage(" dive %d/%d, LP iter %" SCIP_LONGINT_FORMAT "/%" SCIP_LONGINT_FORMAT ", %d unfixed: var <%s>, sol=%g, oldbounds=[%g,%g], fixed to %g\n", divedepth, maxdivedepth, heurdata->nlpiterations, maxnlpiterations, SCIPgetNPseudoBranchCands(scip), SCIPvarGetName(var), bestsolval, SCIPvarGetLbLocal(var), SCIPvarGetUbLocal(var), bestfixval); SCIP_CALL( SCIPfixVarProbing(scip, var, bestfixval) ); /* apply domain propagation */ SCIP_CALL( SCIPpropagateProbing(scip, 0, &cutoff, &nnewdomreds) ); if( !cutoff ) { /* if the best candidate was just fixed to its LP value and no domain reduction was found, the LP solution * stays valid, and the LP does not need to be resolved */ if( nnewdomreds > 0 || !SCIPisEQ(scip, bestsolval, bestfixval) ) { /* resolve the diving LP */ /* Errors in the LP solver should not kill the overall solving process, if the LP is just needed for a heuristic. * Hence in optimized mode, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ #ifdef NDEBUG SCIP_RETCODE retstat; nlpiterations = SCIPgetNLPIterations(scip); retstat = SCIPsolveProbingLP(scip, MAX((int)(maxnlpiterations - heurdata->nlpiterations), MINLPITER), &lperror, &cutoff); if( retstat != SCIP_OKAY ) { SCIPwarningMessage(scip, "Error while solving LP in Intdiving heuristic; LP solve terminated with code <%d>\n",retstat); } #else nlpiterations = SCIPgetNLPIterations(scip); SCIP_CALL( SCIPsolveProbingLP(scip, MAX((int)(maxnlpiterations - heurdata->nlpiterations), MINLPITER), &lperror, &cutoff) ); #endif if( lperror ) break; /* update iteration count */ nnewlpiterations = SCIPgetNLPIterations(scip) - nlpiterations; heurdata->nlpiterations += nnewlpiterations; /* get LP solution status */ lpsolstat = SCIPgetLPSolstat(scip); assert(cutoff || (lpsolstat != SCIP_LPSOLSTAT_OBJLIMIT && lpsolstat != SCIP_LPSOLSTAT_INFEASIBLE && (lpsolstat != SCIP_LPSOLSTAT_OPTIMAL || SCIPisLT(scip, SCIPgetLPObjval(scip), SCIPgetCutoffbound(scip))))); } } /* perform backtracking if a cutoff was detected */ if( cutoff && !backtracked && heurdata->backtrack ) { SCIPdebugMessage(" *** cutoff detected at level %d - backtracking\n", SCIPgetProbingDepth(scip)); SCIP_CALL( SCIPbacktrackProbing(scip, SCIPgetProbingDepth(scip)-1) ); /* after backtracking there has to be at least one open node without exceeding the maximal tree depth */ assert(SCIPgetDepthLimit(scip) > SCIPgetDepth(scip)); SCIP_CALL( SCIPnewProbingNode(scip) ); bestfixval = SCIPvarIsBinary(var) ? 1.0 - bestfixval : (SCIPisGT(scip, bestsolval, bestfixval) && SCIPisFeasLE(scip, bestfixval + 1, SCIPvarGetUbLocal(var)) ? bestfixval + 1 : bestfixval - 1); backtracked = TRUE; } else backtracked = FALSE; } while( backtracked ); if( !lperror && !cutoff && lpsolstat == SCIP_LPSOLSTAT_OPTIMAL ) { SCIP_Bool success; /* get new objective value */ objval = SCIPgetLPObjval(scip); if( nnewlpiterations > 0 || !SCIPisEQ(scip, bestsolval, bestfixval) ) { /* we must start again with the first candidate, since the LP solution changed */ nextcand = 0; /* create solution from diving LP and try to round it */ SCIP_CALL( SCIPlinkLPSol(scip, heurdata->sol) ); SCIP_CALL( SCIProundSol(scip, heurdata->sol, &success) ); if( success ) { SCIPdebugMessage("intdiving found roundable primal solution: obj=%g\n", SCIPgetSolOrigObj(scip, heurdata->sol)); /* try to add solution to SCIP */ SCIP_CALL( SCIPtrySol(scip, heurdata->sol, FALSE, FALSE, FALSE, FALSE, &success) ); /* check, if solution was feasible and good enough */ if( success ) { SCIPdebugMessage(" -> solution was feasible and good enough\n"); *result = SCIP_FOUNDSOL; } } } else nextcand = bestcand+1; /* continue with the next candidate in the following loop */ } SCIPdebugMessage(" -> lpsolstat=%d, objval=%g/%g\n", lpsolstat, objval, searchbound); } /* free temporary memory */ SCIPfreeBufferArray(scip, &fixcands); /* end diving */ SCIP_CALL( SCIPendProbing(scip) ); if( *result == SCIP_FOUNDSOL ) heurdata->nsuccess++; SCIPdebugMessage("intdiving heuristic finished\n"); return SCIP_OKAY; }
/* Read SAT formula in "CNF File Format". * * The specification is taken from the * * Satisfiability Suggested Format * * Online available at http://www.intellektik.informatik.tu-darmstadt.de/SATLIB/Benchmarks/SAT/satformat.ps * * The method reads all files of CNF format. Other formats (SAT, SATX, SATE) are not supported. */ static SCIP_RETCODE readCnf( SCIP* scip, /**< SCIP data structure */ SCIP_FILE* file /**< input file */ ) { SCIP_RETCODE retcode; SCIP_VAR** vars; SCIP_VAR** clausevars; SCIP_CONS* cons; int* varsign; char* tok; char* nexttok; char line[MAXLINELEN]; char format[SCIP_MAXSTRLEN]; char varname[SCIP_MAXSTRLEN]; char s[SCIP_MAXSTRLEN]; SCIP_Bool dynamicconss; SCIP_Bool dynamiccols; SCIP_Bool dynamicrows; SCIP_Bool useobj; int linecount; int clauselen; int clausenum; int nvars; int nclauses; int varnum; int v; assert(scip != NULL); assert(file != NULL); retcode = SCIP_OKAY; linecount = 0; /* read header */ SCIP_CALL( readCnfLine(scip, file, line, (int) sizeof(line), &linecount) ); if( *line != 'p' ) { readError(scip, linecount, "problem declaration line expected"); return SCIP_READERROR; } if( sscanf(line, "p %8s %d %d", format, &nvars, &nclauses) != 3 ) { readError(scip, linecount, "invalid problem declaration (must be 'p cnf <nvars> <nclauses>')"); return SCIP_READERROR; } if( strcmp(format, "cnf") != 0 ) { (void) SCIPsnprintf(s, SCIP_MAXSTRLEN, "invalid format tag <%s> (must be 'cnf')", format); readError(scip, linecount, s); return SCIP_READERROR; } if( nvars <= 0 ) { (void) SCIPsnprintf(s, SCIP_MAXSTRLEN, "invalid number of variables <%d> (must be positive)", nvars); readError(scip, linecount, s); return SCIP_READERROR; } if( nclauses <= 0 ) { (void) SCIPsnprintf(s, SCIP_MAXSTRLEN, "invalid number of clauses <%d> (must be positive)", nclauses); readError(scip, linecount, s); return SCIP_READERROR; } /* get parameter values */ SCIP_CALL( SCIPgetBoolParam(scip, "reading/cnfreader/dynamicconss", &dynamicconss) ); SCIP_CALL( SCIPgetBoolParam(scip, "reading/cnfreader/dynamiccols", &dynamiccols) ); SCIP_CALL( SCIPgetBoolParam(scip, "reading/cnfreader/dynamicrows", &dynamicrows) ); SCIP_CALL( SCIPgetBoolParam(scip, "reading/cnfreader/useobj", &useobj) ); /* get temporary memory */ SCIP_CALL( SCIPallocBufferArray(scip, &vars, nvars) ); SCIP_CALL( SCIPallocBufferArray(scip, &clausevars, nvars) ); SCIP_CALL( SCIPallocBufferArray(scip, &varsign, nvars) ); /* create the variables */ for( v = 0; v < nvars; ++v ) { (void) SCIPsnprintf(varname, SCIP_MAXSTRLEN, "x%d", v+1); SCIP_CALL( SCIPcreateVar(scip, &vars[v], varname, 0.0, 1.0, 0.0, SCIP_VARTYPE_BINARY, !dynamiccols, dynamiccols, NULL, NULL, NULL, NULL, NULL) ); SCIP_CALL( SCIPaddVar(scip, vars[v]) ); varsign[v] = 0; } /* read clauses */ clausenum = 0; clauselen = 0; do { retcode = readCnfLine(scip, file, line, (int) sizeof(line), &linecount); if( retcode != SCIP_OKAY ) goto TERMINATE; if( *line != '\0' && *line != '%' ) { tok = SCIPstrtok(line, " \f\n\r\t", &nexttok); while( tok != NULL ) { /* parse literal and check for errors */ if( sscanf(tok, "%d", &v) != 1 ) { (void) SCIPsnprintf(s, SCIP_MAXSTRLEN, "invalid literal <%s>", tok); readError(scip, linecount, s); retcode = SCIP_READERROR; goto TERMINATE; } /* interpret literal number: v == 0: end of clause, v < 0: negated literal, v > 0: positive literal */ if( v == 0 ) { /* end of clause: construct clause and add it to SCIP */ if( clauselen == 0 ) readWarning(scip, linecount, "empty clause detected in line -- problem infeasible"); clausenum++; (void) SCIPsnprintf(s, SCIP_MAXSTRLEN, "c%d", clausenum); if( SCIPfindConshdlr(scip, "logicor") != NULL ) { /* if the constraint handler logicor exit create a logicor constraint */ SCIP_CALL( SCIPcreateConsLogicor(scip, &cons, s, clauselen, clausevars, !dynamicrows, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, dynamicconss, dynamicrows, FALSE) ); } else if( SCIPfindConshdlr(scip, "setppc") != NULL ) { /* if the constraint handler logicor does not exit but constraint * handler setppc create a setppc constraint */ SCIP_CALL( SCIPcreateConsSetcover(scip, &cons, s, clauselen, clausevars, !dynamicrows, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, dynamicconss, dynamicrows, FALSE) ); } else { /* if none of the previous constraint handler exits create a linear * constraint */ SCIP_Real* vals; int i; SCIP_CALL( SCIPallocBufferArray(scip, &vals, clauselen) ); for( i = 0; i < clauselen; ++i ) vals[i] = 1.0; SCIP_CALL( SCIPcreateConsLinear(scip, &cons, s, clauselen, clausevars, vals, 1.0, SCIPinfinity(scip), !dynamicrows, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, dynamicconss, dynamicrows, FALSE) ); SCIPfreeBufferArray(scip, &vals); } SCIP_CALL( SCIPaddCons(scip, cons) ); SCIP_CALL( SCIPreleaseCons(scip, &cons) ); clauselen = 0; } else if( v >= -nvars && v <= nvars ) { if( clauselen >= nvars ) { readError(scip, linecount, "too many literals in clause"); retcode = SCIP_READERROR; goto TERMINATE; } /* add literal to clause */ varnum = ABS(v)-1; if( v < 0 ) { SCIP_CALL( SCIPgetNegatedVar(scip, vars[varnum], &clausevars[clauselen]) ); varsign[varnum]--; } else { clausevars[clauselen] = vars[varnum]; varsign[varnum]++; } clauselen++; } else { (void) SCIPsnprintf(s, SCIP_MAXSTRLEN, "invalid variable number <%d>", ABS(v)); readError(scip, linecount, s); retcode = SCIP_READERROR; goto TERMINATE; } /* get next token */ tok = SCIPstrtok(NULL, " \f\n\r\t", &nexttok); } } } while( *line != '\0' && *line != '%' ); /* check for additional literals */ if( clauselen > 0 ) { SCIPwarningMessage(scip, "found %d additional literals after last clause\n", clauselen); } /* check number of clauses */ if( clausenum != nclauses ) { SCIPwarningMessage(scip, "expected %d clauses, but found %d\n", nclauses, clausenum); } TERMINATE: /* change objective values and release variables */ SCIP_CALL( SCIPsetObjsense(scip, SCIP_OBJSENSE_MAXIMIZE) ); if( useobj ) { for( v = 0; v < nvars; ++v ) { SCIP_CALL( SCIPchgVarObj(scip, vars[v], (SCIP_Real)varsign[v]) ); SCIP_CALL( SCIPreleaseVar(scip, &vars[v]) ); } } /* free temporary memory */ SCIPfreeBufferArray(scip, &varsign); SCIPfreeBufferArray(scip, &clausevars); SCIPfreeBufferArray(scip, &vars); return retcode; }
/** reduced cost pricing method of variable pricer for feasible LPs */ static SCIP_DECL_PRICERREDCOST(pricerRedcostBinpacking) { /*lint --e{715}*/ SCIP* subscip; SCIP_PRICERDATA* pricerdata; SCIP_CONS** conss; SCIP_VAR** vars; int* ids; SCIP_Bool addvar; SCIP_SOL** sols; int nsols; int s; int nitems; SCIP_Longint capacity; SCIP_Real timelimit; SCIP_Real memorylimit; assert(scip != NULL); assert(pricer != NULL); (*result) = SCIP_DIDNOTRUN; /* get the pricer data */ pricerdata = SCIPpricerGetData(pricer); assert(pricerdata != NULL); capacity = pricerdata->capacity; conss = pricerdata->conss; ids = pricerdata->ids; nitems = pricerdata->nitems; /* get the remaining time and memory limit */ SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); if( !SCIPisInfinity(scip, memorylimit) ) memorylimit -= SCIPgetMemUsed(scip)/1048576.0; /* initialize SCIP */ SCIP_CALL( SCIPcreate(&subscip) ); SCIP_CALL( SCIPincludeDefaultPlugins(subscip) ); /* create problem in sub SCIP */ SCIP_CALL( SCIPcreateProbBasic(subscip, "pricing") ); SCIP_CALL( SCIPsetObjsense(subscip, SCIP_OBJSENSE_MAXIMIZE) ); /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); /* set time and memory limit */ SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); SCIP_CALL( SCIPallocMemoryArray(subscip, &vars, nitems) ); /* initialization local pricing problem */ SCIP_CALL( initPricing(scip, pricerdata, subscip, vars) ); SCIPdebugMessage("solve pricer problem\n"); /* solve sub SCIP */ SCIP_CALL( SCIPsolve(subscip) ); sols = SCIPgetSols(subscip); nsols = SCIPgetNSols(subscip); addvar = FALSE; /* loop over all solutions and create the corresponding column to master if the reduced cost are negative for master, * that is the objective value i greater than 1.0 */ for( s = 0; s < nsols; ++s ) { SCIP_Bool feasible; SCIP_SOL* sol; /* the soultion should be sorted w.r.t. the objective function value */ assert(s == 0 || SCIPisFeasGE(subscip, SCIPgetSolOrigObj(subscip, sols[s-1]), SCIPgetSolOrigObj(subscip, sols[s]))); sol = sols[s]; assert(sol != NULL); /* check if solution is feasible in original sub SCIP */ SCIP_CALL( SCIPcheckSolOrig(subscip, sol, &feasible, FALSE, FALSE ) ); if( !feasible ) { SCIPwarningMessage(scip, "solution in pricing problem (capacity <%d>) is infeasible\n", capacity); continue; } /* check if the solution has a value greater than 1.0 */ if( SCIPisFeasGT(subscip, SCIPgetSolOrigObj(subscip, sol), 1.0) ) { SCIP_VAR* var; SCIP_VARDATA* vardata; int* consids; char strtmp[SCIP_MAXSTRLEN]; char name[SCIP_MAXSTRLEN]; int nconss; int o; int v; SCIPdebug( SCIP_CALL( SCIPprintSol(subscip, sol, NULL, FALSE) ) ); nconss = 0; (void) SCIPsnprintf(name, SCIP_MAXSTRLEN, "items"); SCIP_CALL( SCIPallocBufferArray(scip, &consids, nitems) ); /* check which variables are fixed -> which item belongs to this packing */ for( o = 0, v = 0; o < nitems; ++o ) { if( !SCIPconsIsEnabled(conss[o]) ) continue; assert(SCIPgetNFixedonesSetppc(scip, conss[o]) == 0); if( SCIPgetSolVal(subscip, sol, vars[v]) > 0.5 ) { (void) SCIPsnprintf(strtmp, SCIP_MAXSTRLEN, "_%d", ids[o]); strcat(name, strtmp); consids[nconss] = o; nconss++; } else assert( SCIPisFeasEQ(subscip, SCIPgetSolVal(subscip, sol, vars[v]), 0.0) ); v++; } SCIP_CALL( SCIPvardataCreateBinpacking(scip, &vardata, consids, nconss) ); /* create variable for a new column with objective function coefficient 0.0 */ SCIP_CALL( SCIPcreateVarBinpacking(scip, &var, name, 1.0, FALSE, TRUE, vardata) ); /* add the new variable to the pricer store */ SCIP_CALL( SCIPaddPricedVar(scip, var, 1.0) ); addvar = TRUE; /* change the upper bound of the binary variable to lazy since the upper bound is already enforced due to * the objective function the set covering constraint; The reason for doing is that, is to avoid the bound * of x <= 1 in the LP relaxation since this bound constraint would produce a dual variable which might have * a positive reduced cost */ SCIP_CALL( SCIPchgVarUbLazy(scip, var, 1.0) ); /* check which variable are fixed -> which orders belong to this packing */ for( v = 0; v < nconss; ++v ) { assert(SCIPconsIsEnabled(conss[consids[v]])); SCIP_CALL( SCIPaddCoefSetppc(scip, conss[consids[v]], var) ); } SCIPdebug(SCIPprintVar(scip, var, NULL) ); SCIP_CALL( SCIPreleaseVar(scip, &var) ); SCIPfreeBufferArray(scip, &consids); } else break; } /* free pricer MIP */ SCIPfreeMemoryArray(subscip, &vars); if( addvar || SCIPgetStatus(subscip) == SCIP_STATUS_OPTIMAL ) (*result) = SCIP_SUCCESS; /* free sub SCIP */ SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecCrossover) { /*lint --e{715}*/ SCIP_HEURDATA* heurdata; /* primal heuristic data */ SCIP* subscip; /* the subproblem created by crossover */ SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_VAR** vars; /* original problem's variables */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_SOL** sols; SCIP_Real memorylimit; /* memory limit for the subproblem */ SCIP_Real timelimit; /* time limit for the subproblem */ SCIP_Real cutoff; /* objective cutoff for the subproblem */ SCIP_Real upperbound; SCIP_Bool success; SCIP_Longint nstallnodes; /* node limit for the subproblem */ int* selection; /* pool of solutions crossover uses */ int nvars; /* number of original problem's variables */ int nbinvars; int nintvars; int nusedsols; int i; SCIP_RETCODE retcode; assert(heur != NULL); assert(scip != NULL); assert(result != NULL); /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert(heurdata != NULL); nusedsols = heurdata->nusedsols; *result = SCIP_DELAYED; /* only call heuristic, if enough solutions are at hand */ if( SCIPgetNSols(scip) < nusedsols ) return SCIP_OKAY; sols = SCIPgetSols(scip); assert(sols != NULL); /* if one good solution was found, heuristic should not be delayed any longer */ if( sols[nusedsols-1] != heurdata->prevlastsol ) { heurdata->nextnodenumber = SCIPgetNNodes(scip); if( sols[0] != heurdata->prevbestsol ) heurdata->nfailures = 0; } /* in nonrandomized mode: only recall heuristic, if at least one new good solution was found in the meantime */ else if( !heurdata->randomization ) return SCIP_OKAY; /* if heuristic should be delayed, wait until certain number of nodes is reached */ if( SCIPgetNNodes(scip) < heurdata->nextnodenumber ) return SCIP_OKAY; /* only call heuristic, if enough nodes were processed since last incumbent */ if( SCIPgetNNodes(scip) - SCIPgetSolNodenum(scip,SCIPgetBestSol(scip)) < heurdata->nwaitingnodes && (SCIPgetDepth(scip) > 0 || !heurdata->dontwaitatroot) ) return SCIP_OKAY; *result = SCIP_DIDNOTRUN; /* calculate the maximal number of branching nodes until heuristic is aborted */ nstallnodes = (SCIP_Longint)(heurdata->nodesquot * SCIPgetNNodes(scip)); /* reward Crossover if it succeeded often */ nstallnodes = (SCIP_Longint) (nstallnodes * (1.0 + 2.0*(SCIPheurGetNBestSolsFound(heur)+1.0)/(SCIPheurGetNCalls(heur)+1.0))); /* count the setup costs for the sub-MIP as 100 nodes */ nstallnodes -= 100 * SCIPheurGetNCalls(heur); nstallnodes += heurdata->nodesofs; /* determine the node limit for the current process */ nstallnodes -= heurdata->usednodes; nstallnodes = MIN(nstallnodes, heurdata->maxnodes); /* check whether we have enough nodes left to call subproblem solving */ if( nstallnodes < heurdata->minnodes ) return SCIP_OKAY; if( SCIPisStopped(scip) ) return SCIP_OKAY; *result = SCIP_DIDNOTFIND; SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, &nbinvars, &nintvars, NULL, NULL) ); assert(nvars > 0); /* check whether discrete variables are available */ if( nbinvars == 0 && nintvars == 0 ) return SCIP_OKAY; /* initializing the subproblem */ SCIP_CALL( SCIPcreate(&subscip) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); success = FALSE; if( heurdata->uselprows ) { char probname[SCIP_MAXSTRLEN]; /* copy all plugins */ SCIP_CALL( SCIPincludeDefaultPlugins(subscip) ); /* get name of the original problem and add the string "_crossoversub" */ (void) SCIPsnprintf(probname, SCIP_MAXSTRLEN, "%s_crossoversub", SCIPgetProbName(scip)); /* create the subproblem */ SCIP_CALL( SCIPcreateProb(subscip, probname, NULL, NULL, NULL, NULL, NULL, NULL, NULL) ); /* copy all variables */ SCIP_CALL( SCIPcopyVars(scip, subscip, varmapfw, NULL, TRUE) ); } else { SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "crossover", TRUE, FALSE, TRUE, &success) ); if( heurdata->copycuts ) { /** copies all active cuts from cutpool of sourcescip to linear constraints in targetscip */ SCIP_CALL( SCIPcopyCuts(scip, subscip, varmapfw, NULL, TRUE, NULL) ); } } SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); SCIP_CALL( SCIPallocBufferArray(scip, &selection, nusedsols) ); for( i = 0; i < nvars; i++ ) subvars[i] = (SCIP_VAR*) (size_t) SCIPhashmapGetImage(varmapfw, vars[i]); /* free hash map */ SCIPhashmapFree(&varmapfw); success = FALSE; /* create a new problem, which fixes variables with same value in a certain set of solutions */ SCIP_CALL( setupSubproblem(scip, subscip, subvars, selection, heurdata, &success) ); heurdata->prevbestsol = SCIPgetBestSol(scip); heurdata->prevlastsol = sols[heurdata->nusedsols-1]; /* if creation of sub-SCIP was aborted (e.g. due to number of fixings), free sub-SCIP and abort */ if( !success ) { *result = SCIP_DIDNOTRUN; /* this run will be counted as a failure since no new solution tuple could be generated or the neighborhood of the * solution was not fruitful in the sense that it was too big */ updateFailureStatistic(scip, heurdata); goto TERMINATE; } /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); /* check whether there is enough time and memory left */ SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); /* substract the memory already used by the main SCIP and the estimated memory usage of external software */ if( !SCIPisInfinity(scip, memorylimit) ) { memorylimit -= SCIPgetMemUsed(scip)/1048576.0; memorylimit -= SCIPgetMemExternEstim(scip)/1048576.0; } /* abort if no time is left or not enough memory to create a copy of SCIP, including external memory usage */ if( timelimit <= 0.0 || memorylimit <= 2.0*SCIPgetMemExternEstim(scip)/1048576.0 ) goto TERMINATE; /* set limits for the subproblem */ SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nstallnodes) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); /* forbid recursive call of heuristics and separators solving subMIPs */ SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) ); /* disable cutting plane separation */ SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); /* disable expensive presolving */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_FAST, TRUE) ); /* use best estimate node selection */ if( SCIPfindNodesel(subscip, "estimate") != NULL && !SCIPisParamFixed(subscip, "nodeselection/estimate/stdpriority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/estimate/stdpriority", INT_MAX/4) ); } /* use inference branching */ if( SCIPfindBranchrule(subscip, "inference") != NULL && !SCIPisParamFixed(subscip, "branching/inference/priority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "branching/inference/priority", INT_MAX/4) ); } /* disable conflict analysis */ if( !SCIPisParamFixed(subscip, "conflict/useprop") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useprop", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/useinflp") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useinflp", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/useboundlp") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useboundlp", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/usesb") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usesb", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/usepseudo") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usepseudo", FALSE) ); } /* add an objective cutoff */ cutoff = SCIPinfinity(scip); assert(!SCIPisInfinity(scip, SCIPgetUpperbound(scip))); upperbound = SCIPgetUpperbound(scip) - SCIPsumepsilon(scip); if( !SCIPisInfinity(scip,-1.0*SCIPgetLowerbound(scip)) ) { cutoff = (1-heurdata->minimprove)*SCIPgetUpperbound(scip) + heurdata->minimprove*SCIPgetLowerbound(scip); } else { if( SCIPgetUpperbound ( scip ) >= 0 ) cutoff = ( 1 - heurdata->minimprove ) * SCIPgetUpperbound ( scip ); else cutoff = ( 1 + heurdata->minimprove ) * SCIPgetUpperbound ( scip ); } cutoff = MIN(upperbound, cutoff ); SCIP_CALL( SCIPsetObjlimit(subscip, cutoff) ); /* permute the subproblem to increase diversification */ if( heurdata->permute ) { SCIP_CALL( SCIPpermuteProb(subscip, (unsigned int) SCIPheurGetNCalls(heur), TRUE, TRUE, TRUE, TRUE, TRUE) ); } /* solve the subproblem */ SCIPdebugMessage("Solve Crossover subMIP\n"); retcode = SCIPsolve(subscip); /* Errors in solving the subproblem should not kill the overall solving process. * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while solving subproblem in Crossover heuristic; sub-SCIP terminated with code <%d>\n", retcode); } heurdata->usednodes += SCIPgetNNodes(subscip); /* check, whether a solution was found */ if( SCIPgetNSols(subscip) > 0 ) { SCIP_SOL** subsols; int nsubsols; int solindex; /* index of the solution created by crossover */ /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until one was accepted */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); success = FALSE; solindex = -1; for( i = 0; i < nsubsols && !success; ++i ) { SCIP_CALL( createNewSol(scip, subscip, subvars, heur, subsols[i], &solindex, &success) ); } if( success ) { int tmp; assert(solindex != -1); *result = SCIP_FOUNDSOL; /* insert all crossings of the new solution and (nusedsols-1) of its parents into the hashtable * in order to avoid incest ;) */ for( i = 0; i < nusedsols; i++ ) { SOLTUPLE* elem; tmp = selection[i]; selection[i] = solindex; SCIP_CALL( createSolTuple(scip, &elem, selection, nusedsols, heurdata) ); SCIP_CALL( SCIPhashtableInsert(heurdata->hashtable, elem) ); selection[i] = tmp; } /* if solution was among the best ones, crossover should not be called until another good solution was found */ if( !heurdata->randomization ) { heurdata->prevbestsol = SCIPgetBestSol(scip); heurdata->prevlastsol = SCIPgetSols(scip)[heurdata->nusedsols-1]; } } /* if solution is not better then incumbent or could not be added to problem => run is counted as a failure */ if( !success || solindex != SCIPsolGetIndex(SCIPgetBestSol(scip)) ) updateFailureStatistic(scip, heurdata); } else { /* if no new solution was found, run was a failure */ updateFailureStatistic(scip, heurdata); } TERMINATE: /* free subproblem */ SCIPfreeBufferArray(scip, &selection); SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** main procedure of the RENS heuristic, creates and solves a subMIP */ SCIP_RETCODE SCIPapplyGcgrens( SCIP* scip, /**< original SCIP data structure */ SCIP_HEUR* heur, /**< heuristic data structure */ SCIP_RESULT* result, /**< result data structure */ SCIP_Real minfixingrate, /**< minimum percentage of integer variables that have to be fixed */ SCIP_Real minimprove, /**< factor by which RENS should at least improve the incumbent */ SCIP_Longint maxnodes, /**< maximum number of nodes for the subproblem */ SCIP_Longint nstallnodes, /**< number of stalling nodes for the subproblem */ SCIP_Bool binarybounds, /**< should general integers get binary bounds [floor(.),ceil(.)]? */ SCIP_Bool uselprows /**< should subproblem be created out of the rows in the LP rows? */ ) { SCIP* subscip; /* the subproblem created by RENS */ SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_VAR** vars; /* original problem's variables */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_Real cutoff; /* objective cutoff for the subproblem */ SCIP_Real timelimit; SCIP_Real memorylimit; int nvars; int i; SCIP_Bool success; SCIP_RETCODE retcode; assert(scip != NULL); assert(heur != NULL); assert(result != NULL); assert(maxnodes >= 0); assert(nstallnodes >= 0); assert(0.0 <= minfixingrate && minfixingrate <= 1.0); assert(0.0 <= minimprove && minimprove <= 1.0); SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, NULL, NULL, NULL, NULL) ); /* initialize the subproblem */ SCIP_CALL( SCIPcreate(&subscip) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); if( uselprows ) { char probname[SCIP_MAXSTRLEN]; /* copy all plugins */ SCIP_CALL( SCIPincludeDefaultPlugins(subscip) ); /* get name of the original problem and add the string "_gcgrenssub" */ (void) SCIPsnprintf(probname, SCIP_MAXSTRLEN, "%s_gcgrenssub", SCIPgetProbName(scip)); /* create the subproblem */ SCIP_CALL( SCIPcreateProb(subscip, probname, NULL, NULL, NULL, NULL, NULL, NULL, NULL) ); /* copy all variables */ SCIP_CALL( SCIPcopyVars(scip, subscip, varmapfw, NULL, TRUE) ); } else { SCIP_Bool valid; SCIP_HEURDATA* heurdata; valid = FALSE; SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "gcgrens", TRUE, FALSE, TRUE, &valid) ); /** @todo check for thread safeness */ /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert( heurdata != NULL ); if( heurdata->copycuts ) { /** copies all active cuts from cutpool of sourcescip to linear constraints in targetscip */ SCIP_CALL( SCIPcopyCuts(scip, subscip, varmapfw, NULL, TRUE, NULL) ); } SCIPdebugMessage("Copying the SCIP instance was %s complete.\n", valid ? "" : "not "); } for( i = 0; i < nvars; i++ ) subvars[i] = (SCIP_VAR*) SCIPhashmapGetImage(varmapfw, vars[i]); /* free hash map */ SCIPhashmapFree(&varmapfw); /* create a new problem, which fixes variables with same value in bestsol and LP relaxation */ SCIP_CALL( createSubproblem(scip, subscip, subvars, minfixingrate, binarybounds, uselprows, &success) ); SCIPdebugMessage("RENS subproblem: %d vars, %d cons, success=%u\n", SCIPgetNVars(subscip), SCIPgetNConss(subscip), success); /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); /* check whether there is enough time and memory left */ timelimit = 0.0; memorylimit = 0.0; SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); if( !SCIPisInfinity(scip, memorylimit) ) memorylimit -= SCIPgetMemUsed(scip)/1048576.0; if( timelimit <= 0.0 || memorylimit <= 0.0 ) goto TERMINATE; /* set limits for the subproblem */ SCIP_CALL( SCIPsetLongintParam(subscip, "limits/stallnodes", nstallnodes) ); SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", maxnodes) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); /* forbid recursive call of heuristics and separators solving sub-SCIPs */ SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) ); /* disable cutting plane separation */ SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); /* disable expensive presolving */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_FAST, TRUE) ); /* use best estimate node selection */ if( SCIPfindNodesel(scip, "estimate") != NULL ) { SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/estimate/stdpriority", INT_MAX/4) ); } /* use inference branching */ if( SCIPfindBranchrule(scip, "inference") != NULL ) { SCIP_CALL( SCIPsetIntParam(subscip, "branching/inference/priority", INT_MAX/4) ); } /* disable conflict analysis */ SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useprop", FALSE) ); SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useinflp", FALSE) ); SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useboundlp", FALSE) ); SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usesb", FALSE) ); SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usepseudo", FALSE) ); #ifdef SCIP_DEBUG /* for debugging RENS, enable MIP output */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 5) ); SCIP_CALL( SCIPsetIntParam(subscip, "display/freq", 100000000) ); #endif /* if the subproblem could not be created, free memory and return */ if( !success ) { *result = SCIP_DIDNOTRUN; SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; } /* if there is already a solution, add an objective cutoff */ if( SCIPgetNSols(scip) > 0 ) { SCIP_Real upperbound; assert( !SCIPisInfinity(scip,SCIPgetUpperbound(scip)) ); upperbound = SCIPgetUpperbound(scip) - SCIPsumepsilon(scip); if( !SCIPisInfinity(scip,-1.0*SCIPgetLowerbound(scip)) ) { cutoff = (1-minimprove)*SCIPgetUpperbound(scip) + minimprove*SCIPgetLowerbound(scip); } else { if( SCIPgetUpperbound ( scip ) >= 0 ) cutoff = ( 1 - minimprove ) * SCIPgetUpperbound ( scip ); else cutoff = ( 1 + minimprove ) * SCIPgetUpperbound ( scip ); } cutoff = MIN(upperbound, cutoff); SCIP_CALL( SCIPsetObjlimit(subscip, cutoff) ); } /* presolve the subproblem */ retcode = SCIPpresolve(subscip); /* Errors in solving the subproblem should not kill the overall solving process * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while presolving subproblem in GCG RENS heuristic; sub-SCIP terminated with code <%d>\n",retcode); } SCIPdebugMessage("GCG RENS presolved subproblem: %d vars, %d cons, success=%u\n", SCIPgetNVars(subscip), SCIPgetNConss(subscip), success); /* after presolving, we should have at least reached a certain fixing rate over ALL variables (including continuous) * to ensure that not only the MIP but also the LP relaxation is easy enough */ if( ( nvars - SCIPgetNVars(subscip) ) / (SCIP_Real)nvars >= minfixingrate / 2.0 ) { SCIP_SOL** subsols; int nsubsols; /* solve the subproblem */ SCIPdebugMessage("solving subproblem: nstallnodes=%"SCIP_LONGINT_FORMAT", maxnodes=%"SCIP_LONGINT_FORMAT"\n", nstallnodes, maxnodes); retcode = SCIPsolve(subscip); /* Errors in solving the subproblem should not kill the overall solving process * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while solving subproblem in GCG RENS heuristic; sub-SCIP terminated with code <%d>\n",retcode); } /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until one was accepted */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); success = FALSE; for( i = 0; i < nsubsols && !success; ++i ) { SCIP_CALL( createNewSol(scip, subscip, subvars, heur, subsols[i], &success) ); } if( success ) *result = SCIP_FOUNDSOL; } TERMINATE: /* free subproblem */ SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** writes problem to file */ SCIP_RETCODE SCIPwriteCcg( SCIP* scip, /**< SCIP data structure */ FILE* file, /**< output file, or NULL if standard output should be used */ const char* name, /**< problem name */ SCIP_Bool transformed, /**< TRUE iff problem is the transformed problem */ SCIP_VAR** vars, /**< array with active variables ordered binary, integer, implicit, continuous */ int nvars, /**< number of active variables in the problem */ SCIP_CONS** conss, /**< array with constraints of the problem */ int nconss, /**< number of constraints in the problem */ SCIP_RESULT* result /**< pointer to store the result of the file writing call */ ) { /*lint --e{715}*/ int c; int v; int i; SCIP_CONSHDLR* conshdlr; const char* conshdlrname; SCIP_CONS* cons; SCIP_VAR** consvars; SCIP_Real* consvals; int nconsvars; SparseGraph G; assert( scip != NULL ); assert( nvars >= 0 ); /* initialize graph */ SCIP_CALL( initGraph(scip, &G, (unsigned int) nvars, 10) ); /* check all constraints */ for( c = 0; c < nconss; ++c) { cons = conss[c]; assert( cons != NULL); /* in case the transformed is written only constraint are posted which are enabled in the current node */ assert(!transformed || SCIPconsIsEnabled(cons)); conshdlr = SCIPconsGetHdlr(cons); assert( conshdlr != NULL ); conshdlrname = SCIPconshdlrGetName(conshdlr); assert( transformed == SCIPconsIsTransformed(cons) ); if( strcmp(conshdlrname, "linear") == 0 ) { consvars = SCIPgetVarsLinear(scip, cons); nconsvars = SCIPgetNVarsLinear(scip, cons); assert( consvars != NULL || nconsvars == 0 ); if( nconsvars > 0 ) { SCIP_CALL( handleLinearCons(scip, SCIPgetVarsLinear(scip, cons), SCIPgetValsLinear(scip, cons), SCIPgetNVarsLinear(scip, cons), transformed, &G) ); } } else if( strcmp(conshdlrname, "setppc") == 0 ) { consvars = SCIPgetVarsSetppc(scip, cons); nconsvars = SCIPgetNVarsSetppc(scip, cons); assert( consvars != NULL || nconsvars == 0 ); if( nconsvars > 0 ) { SCIP_CALL( handleLinearCons(scip, consvars, NULL, nconsvars, transformed, &G) ); } } else if( strcmp(conshdlrname, "logicor") == 0 ) { consvars = SCIPgetVarsLogicor(scip, cons); nconsvars = SCIPgetNVarsLogicor(scip, cons); assert( consvars != NULL || nconsvars == 0 ); if( nconsvars > 0 ) { SCIP_CALL( handleLinearCons(scip, SCIPgetVarsLogicor(scip, cons), NULL, SCIPgetNVarsLogicor(scip, cons), transformed, &G) ); } } else if( strcmp(conshdlrname, "knapsack") == 0 ) { SCIP_Longint* w; consvars = SCIPgetVarsKnapsack(scip, cons); nconsvars = SCIPgetNVarsKnapsack(scip, cons); assert( consvars != NULL || nconsvars == 0 ); /* copy Longint array to SCIP_Real array */ w = SCIPgetWeightsKnapsack(scip, cons); SCIP_CALL( SCIPallocBufferArray(scip, &consvals, nconsvars) ); for( v = 0; v < nconsvars; ++v ) consvals[v] = (SCIP_Real)w[v]; if( nconsvars > 0 ) { SCIP_CALL( handleLinearCons(scip, consvars, consvals, nconsvars, transformed, &G) ); } SCIPfreeBufferArray(scip, &consvals); } else if( strcmp(conshdlrname, "varbound") == 0 ) { SCIP_CALL( SCIPallocBufferArray(scip, &consvars, 2) ); SCIP_CALL( SCIPallocBufferArray(scip, &consvals, 2) ); consvars[0] = SCIPgetVarVarbound(scip, cons); consvars[1] = SCIPgetVbdvarVarbound(scip, cons); consvals[0] = 1.0; consvals[1] = SCIPgetVbdcoefVarbound(scip, cons); SCIP_CALL( handleLinearCons(scip, consvars, consvals, 2, transformed, &G) ); SCIPfreeBufferArray(scip, &consvars); SCIPfreeBufferArray(scip, &consvals); } else { SCIPwarningMessage(scip, "constraint handler <%s> cannot print requested format\n", conshdlrname ); SCIPinfoMessage(scip, file, "\\ "); SCIP_CALL( SCIPprintCons(scip, cons, file) ); SCIPinfoMessage(scip, file, ";\n"); } } /* output graph */ SCIPinfoMessage(scip, file, "c graph generated from %s\n", name); SCIPinfoMessage(scip, file, "p edge %d %d\n", nvars, G.m); for( i = 0; i < nvars; ++i ) { unsigned int k; int a; k = 0; a = G.A[i][k]; while( a >= 0 ) { /* only output edges from lower to higher number */ if( i < a ) { /* note: node numbers start with 1 in the DIMACS format */ SCIPinfoMessage(scip, file, "e %d %d %f\n", i+1, a+1, G.W[i][k]); } a = G.A[i][++k]; assert( k <= G.size[i] ); } assert( k == G.deg[i] ); } freeGraph(scip, &G); *result = SCIP_SUCCESS; return SCIP_OKAY; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecLocalbranching) { /*lint --e{715}*/ SCIP_Longint maxnnodes; /* maximum number of subnodes */ SCIP_Longint nsubnodes; /* nodelimit for subscip */ SCIP_HEURDATA* heurdata; SCIP* subscip; /* the subproblem created by localbranching */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_SOL* bestsol; /* best solution so far */ SCIP_EVENTHDLR* eventhdlr; /* event handler for LP events */ SCIP_Real timelimit; /* timelimit for subscip (equals remaining time of scip) */ SCIP_Real cutoff; /* objective cutoff for the subproblem */ SCIP_Real upperbound; SCIP_Real memorylimit; SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_VAR** vars; int nvars; int i; SCIP_Bool success; SCIP_RETCODE retcode; assert(heur != NULL); assert(scip != NULL); assert(result != NULL); *result = SCIP_DIDNOTRUN; /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert( heurdata != NULL ); /* there should be enough binary variables that a local branching constraint makes sense */ if( SCIPgetNBinVars(scip) < 2*heurdata->neighborhoodsize ) return SCIP_OKAY; *result = SCIP_DELAYED; /* only call heuristic, if an IP solution is at hand */ if( SCIPgetNSols(scip) <= 0 ) return SCIP_OKAY; bestsol = SCIPgetBestSol(scip); assert(bestsol != NULL); /* only call heuristic, if the best solution comes from transformed problem */ if( SCIPsolIsOriginal(bestsol) ) return SCIP_OKAY; /* only call heuristic, if enough nodes were processed since last incumbent */ if( SCIPgetNNodes(scip) - SCIPgetSolNodenum(scip, bestsol) < heurdata->nwaitingnodes) return SCIP_OKAY; /* only call heuristic, if the best solution does not come from trivial heuristic */ if( SCIPsolGetHeur(bestsol) != NULL && strcmp(SCIPheurGetName(SCIPsolGetHeur(bestsol)), "trivial") == 0 ) return SCIP_OKAY; /* reset neighborhood and minnodes, if new solution was found */ if( heurdata->lastsol != bestsol ) { heurdata->curneighborhoodsize = heurdata->neighborhoodsize; heurdata->curminnodes = heurdata->minnodes; heurdata->emptyneighborhoodsize = 0; heurdata->callstatus = EXECUTE; heurdata->lastsol = bestsol; } /* if no new solution was found and local branching also seems to fail, just keep on waiting */ if( heurdata->callstatus == WAITFORNEWSOL ) return SCIP_OKAY; *result = SCIP_DIDNOTRUN; /* calculate the maximal number of branching nodes until heuristic is aborted */ maxnnodes = (SCIP_Longint)(heurdata->nodesquot * SCIPgetNNodes(scip)); /* reward local branching if it succeeded often */ maxnnodes = (SCIP_Longint)(maxnnodes * (1.0 + 2.0*(SCIPheurGetNBestSolsFound(heur)+1.0)/(SCIPheurGetNCalls(heur)+1.0))); maxnnodes -= 100 * SCIPheurGetNCalls(heur); /* count the setup costs for the sub-MIP as 100 nodes */ maxnnodes += heurdata->nodesofs; /* determine the node limit for the current process */ nsubnodes = maxnnodes - heurdata->usednodes; nsubnodes = MIN(nsubnodes, heurdata->maxnodes); /* check whether we have enough nodes left to call sub problem solving */ if( nsubnodes < heurdata->curminnodes ) return SCIP_OKAY; if( SCIPisStopped(scip) ) return SCIP_OKAY; *result = SCIP_DIDNOTFIND; SCIPdebugMessage("running localbranching heuristic ...\n"); /* get the data of the variables and the best solution */ SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, NULL, NULL, NULL, NULL) ); /* initializing the subproblem */ SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); SCIP_CALL( SCIPcreate(&subscip) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); success = FALSE; eventhdlr = NULL; if( heurdata->uselprows ) { char probname[SCIP_MAXSTRLEN]; /* copy all plugins */ SCIP_CALL( SCIPincludeDefaultPlugins(subscip) ); /* get name of the original problem and add the string "_localbranchsub" */ (void) SCIPsnprintf(probname, SCIP_MAXSTRLEN, "%s_localbranchsub", SCIPgetProbName(scip)); /* create the subproblem */ SCIP_CALL( SCIPcreateProb(subscip, probname, NULL, NULL, NULL, NULL, NULL, NULL, NULL) ); /* copy all variables */ SCIP_CALL( SCIPcopyVars(scip, subscip, varmapfw, NULL, TRUE) ); } else { SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "localbranchsub", TRUE, FALSE, TRUE, &success) ); if( heurdata->copycuts ) { /* copies all active cuts from cutpool of sourcescip to linear constraints in targetscip */ SCIP_CALL( SCIPcopyCuts(scip, subscip, varmapfw, NULL, TRUE, NULL) ); } /* create event handler for LP events */ SCIP_CALL( SCIPincludeEventhdlrBasic(subscip, &eventhdlr, EVENTHDLR_NAME, EVENTHDLR_DESC, eventExecLocalbranching, NULL) ); if( eventhdlr == NULL ) { SCIPerrorMessage("event handler for "HEUR_NAME" heuristic not found.\n"); return SCIP_PLUGINNOTFOUND; } } SCIPdebugMessage("Copying the plugins was %ssuccessful.\n", success ? "" : "not "); for (i = 0; i < nvars; ++i) subvars[i] = (SCIP_VAR*) SCIPhashmapGetImage(varmapfw, vars[i]); /* free hash map */ SCIPhashmapFree(&varmapfw); /* if the subproblem could not be created, free memory and return */ if( !success ) { *result = SCIP_DIDNOTRUN; goto TERMINATE; } /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); #ifndef SCIP_DEBUG /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); #endif /* check whether there is enough time and memory left */ SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); /* substract the memory already used by the main SCIP and the estimated memory usage of external software */ if( !SCIPisInfinity(scip, memorylimit) ) { memorylimit -= SCIPgetMemUsed(scip)/1048576.0; memorylimit -= SCIPgetMemExternEstim(scip)/1048576.0; } /* abort if no time is left or not enough memory to create a copy of SCIP, including external memory usage */ if( timelimit <= 0.0 || memorylimit <= 2.0*SCIPgetMemExternEstim(scip)/1048576.0 ) goto TERMINATE; /* set limits for the subproblem */ heurdata->nodelimit = nsubnodes; SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nsubnodes) ); SCIP_CALL( SCIPsetLongintParam(subscip, "limits/stallnodes", MAX(10, nsubnodes/10)) ); SCIP_CALL( SCIPsetIntParam(subscip, "limits/bestsol", 3) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); /* forbid recursive call of heuristics and separators solving subMIPs */ SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) ); /* disable cutting plane separation */ SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); /* disable expensive presolving */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_FAST, TRUE) ); /* use best estimate node selection */ if( SCIPfindNodesel(subscip, "estimate") != NULL && !SCIPisParamFixed(subscip, "nodeselection/estimate/stdpriority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/estimate/stdpriority", INT_MAX/4) ); } /* use inference branching */ if( SCIPfindBranchrule(subscip, "inference") != NULL && !SCIPisParamFixed(subscip, "branching/inference/priority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "branching/inference/priority", INT_MAX/4) ); } /* disable conflict analysis */ if( !SCIPisParamFixed(subscip, "conflict/useprop") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useprop", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/useinflp") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useinflp", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/useboundlp") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useboundlp", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/usesb") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usesb", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/usepseudo") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usepseudo", FALSE) ); } /* employ a limit on the number of enforcement rounds in the quadratic constraint handler; this fixes the issue that * sometimes the quadratic constraint handler needs hundreds or thousands of enforcement rounds to determine the * feasibility status of a single node without fractional branching candidates by separation (namely for uflquad * instances); however, the solution status of the sub-SCIP might get corrupted by this; hence no deductions shall be * made for the original SCIP */ if( SCIPfindConshdlr(subscip, "quadratic") != NULL && !SCIPisParamFixed(subscip, "constraints/quadratic/enfolplimit") ) { SCIP_CALL( SCIPsetIntParam(subscip, "constraints/quadratic/enfolplimit", 500) ); } /* copy the original problem and add the local branching constraint */ if( heurdata->uselprows ) { SCIP_CALL( createSubproblem(scip, subscip, subvars) ); } SCIP_CALL( addLocalBranchingConstraint(scip, subscip, subvars, heurdata) ); /* add an objective cutoff */ cutoff = SCIPinfinity(scip); assert( !SCIPisInfinity(scip,SCIPgetUpperbound(scip)) ); upperbound = SCIPgetUpperbound(scip) - SCIPsumepsilon(scip); if( !SCIPisInfinity(scip,-1.0*SCIPgetLowerbound(scip)) ) { cutoff = (1-heurdata->minimprove)*SCIPgetUpperbound(scip) + heurdata->minimprove*SCIPgetLowerbound(scip); } else { if( SCIPgetUpperbound ( scip ) >= 0 ) cutoff = ( 1 - heurdata->minimprove ) * SCIPgetUpperbound ( scip ); else cutoff = ( 1 + heurdata->minimprove ) * SCIPgetUpperbound ( scip ); } cutoff = MIN(upperbound, cutoff ); SCIP_CALL( SCIPsetObjlimit(subscip, cutoff) ); /* catch LP events of sub-SCIP */ if( !heurdata->uselprows ) { assert(eventhdlr != NULL); SCIP_CALL( SCIPtransformProb(subscip) ); SCIP_CALL( SCIPcatchEvent(subscip, SCIP_EVENTTYPE_LPSOLVED, eventhdlr, (SCIP_EVENTDATA*) heurdata, NULL) ); } /* solve the subproblem */ SCIPdebugMessage("solving local branching subproblem with neighborhoodsize %d and maxnodes %"SCIP_LONGINT_FORMAT"\n", heurdata->curneighborhoodsize, nsubnodes); retcode = SCIPsolve(subscip); /* drop LP events of sub-SCIP */ if( !heurdata->uselprows ) { assert(eventhdlr != NULL); SCIP_CALL( SCIPdropEvent(subscip, SCIP_EVENTTYPE_LPSOLVED, eventhdlr, (SCIP_EVENTDATA*) heurdata, -1) ); } /* Errors in solving the subproblem should not kill the overall solving process * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while solving subproblem in local branching heuristic; sub-SCIP terminated with code <%d>\n",retcode); } /* print solving statistics of subproblem if we are in SCIP's debug mode */ SCIPdebug( SCIP_CALL( SCIPprintStatistics(subscip, NULL) ) ); heurdata->usednodes += SCIPgetNNodes(subscip); SCIPdebugMessage("local branching used %"SCIP_LONGINT_FORMAT"/%"SCIP_LONGINT_FORMAT" nodes\n", SCIPgetNNodes(subscip), nsubnodes); /* check, whether a solution was found */ if( SCIPgetNSols(subscip) > 0 ) { SCIP_SOL** subsols; int nsubsols; /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until one was accepted */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); success = FALSE; for( i = 0; i < nsubsols && !success; ++i ) { SCIP_CALL( createNewSol(scip, subscip, subvars, heur, subsols[i], &success) ); } if( success ) { SCIPdebugMessage("-> accepted solution of value %g\n", SCIPgetSolOrigObj(subscip, subsols[i])); *result = SCIP_FOUNDSOL; } } /* check the status of the sub-MIP */ switch( SCIPgetStatus(subscip) ) { case SCIP_STATUS_OPTIMAL: case SCIP_STATUS_BESTSOLLIMIT: heurdata->callstatus = WAITFORNEWSOL; /* new solution will immediately be installed at next call */ SCIPdebugMessage(" -> found new solution\n"); break; case SCIP_STATUS_NODELIMIT: case SCIP_STATUS_STALLNODELIMIT: case SCIP_STATUS_TOTALNODELIMIT: heurdata->callstatus = EXECUTE; heurdata->curneighborhoodsize = (heurdata->emptyneighborhoodsize + heurdata->curneighborhoodsize)/2; heurdata->curminnodes *= 2; SCIPdebugMessage(" -> node limit reached: reduced neighborhood to %d, increased minnodes to %d\n", heurdata->curneighborhoodsize, heurdata->curminnodes); if( heurdata->curneighborhoodsize <= heurdata->emptyneighborhoodsize ) { heurdata->callstatus = WAITFORNEWSOL; SCIPdebugMessage(" -> new neighborhood was already proven to be empty: wait for new solution\n"); } break; case SCIP_STATUS_INFEASIBLE: case SCIP_STATUS_INFORUNBD: heurdata->emptyneighborhoodsize = heurdata->curneighborhoodsize; heurdata->curneighborhoodsize += heurdata->curneighborhoodsize/2; heurdata->curneighborhoodsize = MAX(heurdata->curneighborhoodsize, heurdata->emptyneighborhoodsize + 2); heurdata->callstatus = EXECUTE; SCIPdebugMessage(" -> neighborhood is empty: increased neighborhood to %d\n", heurdata->curneighborhoodsize); break; case SCIP_STATUS_UNKNOWN: case SCIP_STATUS_USERINTERRUPT: case SCIP_STATUS_TIMELIMIT: case SCIP_STATUS_MEMLIMIT: case SCIP_STATUS_GAPLIMIT: case SCIP_STATUS_SOLLIMIT: case SCIP_STATUS_UNBOUNDED: default: heurdata->callstatus = WAITFORNEWSOL; SCIPdebugMessage(" -> unexpected sub-MIP status <%d>: waiting for new solution\n", SCIPgetStatus(subscip)); break; } TERMINATE: /* free subproblem */ SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** main procedure of the zeroobj heuristic, creates and solves a sub-SCIP */ SCIP_RETCODE SCIPapplyZeroobj( SCIP* scip, /**< original SCIP data structure */ SCIP_HEUR* heur, /**< heuristic data structure */ SCIP_RESULT* result, /**< result data structure */ SCIP_Real minimprove, /**< factor by which zeroobj should at least improve the incumbent */ SCIP_Longint nnodes /**< node limit for the subproblem */ ) { SCIP* subscip; /* the subproblem created by zeroobj */ SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_VAR** vars; /* original problem's variables */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_HEURDATA* heurdata; /* heuristic's private data structure */ SCIP_EVENTHDLR* eventhdlr; /* event handler for LP events */ SCIP_Real cutoff; /* objective cutoff for the subproblem */ SCIP_Real timelimit; /* time limit for zeroobj subproblem */ SCIP_Real memorylimit; /* memory limit for zeroobj subproblem */ SCIP_Real large; int nvars; /* number of original problem's variables */ int i; SCIP_Bool success; SCIP_Bool valid; SCIP_RETCODE retcode; SCIP_SOL** subsols; int nsubsols; assert(scip != NULL); assert(heur != NULL); assert(result != NULL); assert(nnodes >= 0); assert(0.0 <= minimprove && minimprove <= 1.0); *result = SCIP_DIDNOTRUN; /* only call heuristic once at the root */ if( SCIPgetDepth(scip) <= 0 && SCIPheurGetNCalls(heur) > 0 ) return SCIP_OKAY; /* get heuristic data */ heurdata = SCIPheurGetData(heur); assert(heurdata != NULL); /* only call the heuristic if we do not have an incumbent */ if( SCIPgetNSolsFound(scip) > 0 && heurdata->onlywithoutsol ) return SCIP_OKAY; /* check whether there is enough time and memory left */ timelimit = 0.0; memorylimit = 0.0; SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); /* substract the memory already used by the main SCIP and the estimated memory usage of external software */ if( !SCIPisInfinity(scip, memorylimit) ) { memorylimit -= SCIPgetMemUsed(scip)/1048576.0; memorylimit -= SCIPgetMemExternEstim(scip)/1048576.0; } /* abort if no time is left or not enough memory to create a copy of SCIP, including external memory usage */ if( timelimit <= 0.0 || memorylimit <= 2.0*SCIPgetMemExternEstim(scip)/1048576.0 ) return SCIP_OKAY; *result = SCIP_DIDNOTFIND; /* get variable data */ SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, NULL, NULL, NULL, NULL) ); /* initialize the subproblem */ SCIP_CALL( SCIPcreate(&subscip) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); /* different methods to create sub-problem: either copy LP relaxation or the CIP with all constraints */ valid = FALSE; /* copy complete SCIP instance */ SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "zeroobj", TRUE, FALSE, TRUE, &valid) ); SCIPdebugMessage("Copying the SCIP instance was %s complete.\n", valid ? "" : "not "); /* create event handler for LP events */ eventhdlr = NULL; SCIP_CALL( SCIPincludeEventhdlrBasic(subscip, &eventhdlr, EVENTHDLR_NAME, EVENTHDLR_DESC, eventExecZeroobj, NULL) ); if( eventhdlr == NULL ) { SCIPerrorMessage("event handler for "HEUR_NAME" heuristic not found.\n"); return SCIP_PLUGINNOTFOUND; } /* determine large value to set variables to */ large = SCIPinfinity(scip); if( !SCIPisInfinity(scip, 0.1 / SCIPfeastol(scip)) ) large = 0.1 / SCIPfeastol(scip); /* get variable image and change to 0.0 in sub-SCIP */ for( i = 0; i < nvars; i++ ) { SCIP_Real adjustedbound; SCIP_Real lb; SCIP_Real ub; SCIP_Real inf; subvars[i] = (SCIP_VAR*) SCIPhashmapGetImage(varmapfw, vars[i]); SCIP_CALL( SCIPchgVarObj(subscip, subvars[i], 0.0) ); lb = SCIPvarGetLbGlobal(subvars[i]); ub = SCIPvarGetUbGlobal(subvars[i]); inf = SCIPinfinity(subscip); /* adjust infinite bounds in order to avoid that variables with non-zero objective * get fixed to infinite value in zeroobj subproblem */ if( SCIPisInfinity(subscip, ub ) ) { adjustedbound = MAX(large, lb+large); adjustedbound = MIN(adjustedbound, inf); SCIP_CALL( SCIPchgVarUbGlobal(subscip, subvars[i], adjustedbound) ); } if( SCIPisInfinity(subscip, -lb ) ) { adjustedbound = MIN(-large, ub-large); adjustedbound = MAX(adjustedbound, -inf); SCIP_CALL( SCIPchgVarLbGlobal(subscip, subvars[i], adjustedbound) ); } } /* free hash map */ SCIPhashmapFree(&varmapfw); /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); /* set limits for the subproblem */ SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nnodes) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); SCIP_CALL( SCIPsetIntParam(subscip, "limits/solutions", 1) ); /* forbid recursive call of heuristics and separators solving sub-SCIPs */ SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) ); /* disable expensive techniques that merely work on the dual bound */ /* disable cutting plane separation */ SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); /* disable expensive presolving */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_FAST, TRUE) ); if( !SCIPisParamFixed(subscip, "presolving/maxrounds") ) { SCIP_CALL( SCIPsetIntParam(subscip, "presolving/maxrounds", 50) ); } /* use best dfs node selection */ if( SCIPfindNodesel(subscip, "dfs") != NULL && !SCIPisParamFixed(subscip, "nodeselection/dfs/stdpriority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/dfs/stdpriority", INT_MAX/4) ); } /* use inference branching */ if( SCIPfindBranchrule(subscip, "inference") != NULL && !SCIPisParamFixed(subscip, "branching/inference/priority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "branching/leastinf/priority", INT_MAX/4) ); } /* employ a limit on the number of enforcement rounds in the quadratic constraint handler; this fixes the issue that * sometimes the quadratic constraint handler needs hundreds or thousands of enforcement rounds to determine the * feasibility status of a single node without fractional branching candidates by separation (namely for uflquad * instances); however, the solution status of the sub-SCIP might get corrupted by this; hence no deductions shall be * made for the original SCIP */ if( SCIPfindConshdlr(subscip, "quadratic") != NULL && !SCIPisParamFixed(subscip, "constraints/quadratic/enfolplimit") ) { SCIP_CALL( SCIPsetIntParam(subscip, "constraints/quadratic/enfolplimit", 10) ); } /* disable feaspump and fracdiving */ if( !SCIPisParamFixed(subscip, "heuristics/feaspump/freq") ) { SCIP_CALL( SCIPsetIntParam(subscip, "heuristics/feaspump/freq", -1) ); } if( !SCIPisParamFixed(subscip, "heuristics/fracdiving/freq") ) { SCIP_CALL( SCIPsetIntParam(subscip, "heuristics/fracdiving/freq", -1) ); } /* restrict LP iterations */ SCIP_CALL( SCIPsetLongintParam(subscip, "lp/iterlim", 2*heurdata->maxlpiters / MAX(1,nnodes)) ); SCIP_CALL( SCIPsetLongintParam(subscip, "lp/rootiterlim", heurdata->maxlpiters) ); #ifdef SCIP_DEBUG /* for debugging zeroobj, enable MIP output */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 5) ); SCIP_CALL( SCIPsetIntParam(subscip, "display/freq", 100000000) ); #endif /* if there is already a solution, add an objective cutoff */ if( SCIPgetNSols(scip) > 0 ) { SCIP_Real upperbound; SCIP_CONS* origobjcons; #ifndef NDEBUG int nobjvars; nobjvars = 0; #endif cutoff = SCIPinfinity(scip); assert( !SCIPisInfinity(scip,SCIPgetUpperbound(scip)) ); upperbound = SCIPgetUpperbound(scip) - SCIPsumepsilon(scip); if( !SCIPisInfinity(scip,-1.0*SCIPgetLowerbound(scip)) ) { cutoff = (1-minimprove)*SCIPgetUpperbound(scip) + minimprove*SCIPgetLowerbound(scip); } else { if( SCIPgetUpperbound(scip) >= 0 ) cutoff = ( 1 - minimprove ) * SCIPgetUpperbound ( scip ); else cutoff = ( 1 + minimprove ) * SCIPgetUpperbound ( scip ); } cutoff = MIN(upperbound, cutoff); SCIP_CALL( SCIPcreateConsLinear(subscip, &origobjcons, "objbound_of_origscip", 0, NULL, NULL, -SCIPinfinity(subscip), cutoff, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE) ); for( i = 0; i < nvars; ++i) { if( !SCIPisFeasZero(subscip, SCIPvarGetObj(vars[i])) ) { SCIP_CALL( SCIPaddCoefLinear(subscip, origobjcons, subvars[i], SCIPvarGetObj(vars[i])) ); #ifndef NDEBUG nobjvars++; #endif } } SCIP_CALL( SCIPaddCons(subscip, origobjcons) ); SCIP_CALL( SCIPreleaseCons(subscip, &origobjcons) ); assert(nobjvars == SCIPgetNObjVars(scip)); } /* catch LP events of sub-SCIP */ SCIP_CALL( SCIPtransformProb(subscip) ); SCIP_CALL( SCIPcatchEvent(subscip, SCIP_EVENTTYPE_NODESOLVED, eventhdlr, (SCIP_EVENTDATA*) heurdata, NULL) ); SCIPdebugMessage("solving subproblem: nnodes=%"SCIP_LONGINT_FORMAT"\n", nnodes); retcode = SCIPsolve(subscip); /* drop LP events of sub-SCIP */ SCIP_CALL( SCIPdropEvent(subscip, SCIP_EVENTTYPE_NODESOLVED, eventhdlr, (SCIP_EVENTDATA*) heurdata, -1) ); /* errors in solving the subproblem should not kill the overall solving process; * hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while solving subproblem in zeroobj heuristic; sub-SCIP terminated with code <%d>\n",retcode); } /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until one was accepted */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); success = FALSE; for( i = 0; i < nsubsols && (!success || heurdata->addallsols); ++i ) { SCIP_CALL( createNewSol(scip, subscip, subvars, heur, subsols[i], &success) ); if( success ) *result = SCIP_FOUNDSOL; } #ifdef SCIP_DEBUG SCIP_CALL( SCIPprintStatistics(subscip, NULL) ); #endif /* free subproblem */ SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** reads the given solution file */ static SCIP_RETCODE readSol( SCIP* scip, /**< SCIP data structure */ const char* filename /**< name of the input file */ ) { SCIP_FILE* file; SCIP_Bool error; SCIP_Bool unknownvariablemessage; int lineno; int nfixed; assert(scip != NULL); assert(filename != NULL); /* open input file */ file = SCIPfopen(filename, "r"); if( file == NULL ) { SCIPerrorMessage("cannot open file <%s> for reading\n", filename); SCIPprintSysError(filename); return SCIP_NOFILE; } /* read the file */ error = FALSE; unknownvariablemessage = FALSE; lineno = 0; nfixed = 0; while( !SCIPfeof(file) && !error ) { char buffer[SCIP_MAXSTRLEN]; char varname[SCIP_MAXSTRLEN]; char valuestring[SCIP_MAXSTRLEN]; char objstring[SCIP_MAXSTRLEN]; SCIP_VAR* var; SCIP_Real value; SCIP_Bool infeasible; SCIP_Bool fixed; int nread; /* get next line */ if( SCIPfgets(buffer, (int) sizeof(buffer), file) == NULL ) break; lineno++; /* the lines "solution status: ..." and "objective value: ..." may preceed the solution information */ if( strncasecmp(buffer, "solution status:", 16) == 0 || strncasecmp(buffer, "objective value:", 16) == 0 ) continue; /* parse the line */ nread = sscanf(buffer, "%s %s %s\n", varname, valuestring, objstring); if( nread < 2 ) { SCIPerrorMessage("invalid input line %d in solution file <%s>: <%s>\n", lineno, filename, buffer); error = TRUE; break; } /* find the variable */ var = SCIPfindVar(scip, varname); if( var == NULL ) { if( !unknownvariablemessage ) { SCIPwarningMessage(scip, "unknown variable <%s> in line %d of solution file <%s>\n", varname, lineno, filename); SCIPwarningMessage(scip, " (further unknown variables are ignored)\n"); unknownvariablemessage = TRUE; } continue; } /* cast the value */ if( strncasecmp(valuestring, "inv", 3) == 0 ) continue; else if( strncasecmp(valuestring, "+inf", 4) == 0 || strncasecmp(valuestring, "inf", 3) == 0 ) value = SCIPinfinity(scip); else if( strncasecmp(valuestring, "-inf", 4) == 0 ) value = -SCIPinfinity(scip); else { nread = sscanf(valuestring, "%lf", &value); if( nread != 1 ) { SCIPerrorMessage("invalid solution value <%s> for variable <%s> in line %d of solution file <%s>\n", valuestring, varname, lineno, filename); error = TRUE; break; } } /* fix the variable */ SCIP_CALL( SCIPfixVar(scip, var, value, &infeasible, &fixed) ); if( infeasible ) { SCIPerrorMessage("infeasible solution value of <%s>[%.15g,%.15g] to %.15g in line %d of solution file <%s>\n", varname, SCIPvarGetLbGlobal(var), SCIPvarGetUbGlobal(var), value, lineno, filename); error = TRUE; break; } if( fixed ) nfixed++; } /* close input file */ SCIPfclose(file); /* display result */ SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "fixed %d variables from solution file <%s>\n", nfixed, filename); if( error ) return SCIP_READERROR; else return SCIP_OKAY; }
/** problem reading method of reader */ static SCIP_DECL_READERREAD(readerReadBpa) { /*lint --e{715}*/ SCIP_FILE* file; SCIP_Longint* weights; int* ids; SCIP_Bool error; char name[SCIP_MAXSTRLEN]; char format[16]; char buffer[SCIP_MAXSTRLEN]; int capacity; int nitems; int bestsolvalue; int nread; int weight; int nweights; int lineno; *result = SCIP_DIDNOTRUN; /* open file */ file = SCIPfopen(filename, "r"); if( file == NULL ) { SCIPerrorMessage("cannot open file <%s> for reading\n", filename); SCIPprintSysError(filename); return SCIP_NOFILE; } lineno = 0; /* read problem name */ if( !SCIPfeof(file) ) { /* get next line */ if( SCIPfgets(buffer, sizeof(buffer), file) == NULL ) return SCIP_READERROR; lineno++; /* parse dimension line */ sprintf(format, "%%%ds\n", SCIP_MAXSTRLEN); nread = sscanf(buffer, format, name); if( nread == 0 ) { SCIPwarningMessage(scip, "invalid input line %d in file <%s>: <%s>\n", lineno, filename, buffer); return SCIP_READERROR; } SCIPdebugMessage("problem name <%s>\n", name); } /* read problem dimension */ if( !SCIPfeof(file) ) { /* get next line */ if( SCIPfgets(buffer, sizeof(buffer), file) == NULL ) return SCIP_READERROR; lineno++; /* parse dimension line */ nread = sscanf(buffer, "%d %d %d\n", &capacity, &nitems, &bestsolvalue); if( nread < 2 ) { SCIPwarningMessage(scip, "invalid input line %d in file <%s>: <%s>\n", lineno, filename, buffer); return SCIP_READERROR; } SCIPdebugMessage("capacity = <%d>, number of items = <%d>, best known solution = <%d>\n", capacity, nitems, bestsolvalue); } /* allocate buffer memory for storing the weights and ids temporary */ SCIP_CALL( SCIPallocBufferArray(scip, &weights, nitems) ); SCIP_CALL( SCIPallocBufferArray(scip, &ids, nitems) ); /* pasre weights */ nweights = 0; error = FALSE; while( !SCIPfeof(file) && !error ) { /* get next line */ if( SCIPfgets(buffer, sizeof(buffer), file) == NULL ) break; lineno++; /* parse the line */ nread = sscanf(buffer, "%d\n", &weight); if( nread == 0 ) { SCIPwarningMessage(scip, "invalid input line %d in file <%s>: <%s>\n", lineno, filename, buffer); error = TRUE; break; } SCIPdebugMessage("found weight %d <%d>\n", nweights, weight); weights[nweights] = weight; ids[nweights] = nweights; nweights++; if( nweights == nitems ) break; } if( nweights < nitems ) { SCIPwarningMessage(scip, "set nitems from <%d> to <%d> since the file <%s> only contains <%d> weights\n", nitems, weights, filename, weights); nitems = nweights; } if( !error ) { /* create a new problem in SCIP */ SCIP_CALL( SCIPprobdataCreate(scip, name, ids, weights, nitems, (SCIP_Longint)capacity) ); } (void)SCIPfclose(file); SCIPfreeBufferArray(scip, &ids); SCIPfreeBufferArray(scip, &weights); if( error ) return SCIP_READERROR; *result = SCIP_SUCCESS; return SCIP_OKAY; }
/** reads the next line from the input file into the line buffer; skips comments; * returns whether a line could be read */ static SCIP_Bool getNextLine( SCIP* scip, /**< SCIP data structure */ LPINPUT* lpinput /**< LP reading data */ ) { int i; assert(lpinput != NULL); /* if we previously detected a comment we have to parse the remaining line away if there is something left */ if( !lpinput->endline && lpinput->comment ) { SCIPdebugMessage("Throwing rest of comment away.\n"); do { lpinput->linebuf[LP_MAX_LINELEN-2] = '\0'; (void)SCIPfgets(lpinput->linebuf, (int) sizeof(lpinput->linebuf), lpinput->file); } while( lpinput->linebuf[LP_MAX_LINELEN-2] != '\0' ); lpinput->comment = FALSE; lpinput->endline = TRUE; } /* read next line */ lpinput->linepos = 0; lpinput->linebuf[LP_MAX_LINELEN-2] = '\0'; if( SCIPfgets(lpinput->linebuf, (int) sizeof(lpinput->linebuf), lpinput->file) == NULL ) { /* clear the line, this is really necessary here! */ BMSclearMemoryArray(lpinput->linebuf, LP_MAX_LINELEN); return FALSE; } lpinput->linenumber++; /* if line is too long for our buffer correct the buffer and correct position in file */ if( lpinput->linebuf[LP_MAX_LINELEN-2] != '\0' ) { char* last; /* buffer is full; erase last token since it might be incomplete */ lpinput->endline = FALSE; last = strrchr(lpinput->linebuf, ' '); if( last == NULL ) { SCIPwarningMessage(scip, "we read %d characters from the file; this might indicate a corrupted input file!", LP_MAX_LINELEN - 2); lpinput->linebuf[LP_MAX_LINELEN-2] = '\0'; SCIPdebugMessage("the buffer might be corrupted\n"); } else { SCIPfseek(lpinput->file, -(long) strlen(last) - 1, SEEK_CUR); SCIPdebugMessage("correct buffer, reread the last %ld characters\n", (long) strlen(last) + 1); *last = '\0'; } } else { /* found end of line */ lpinput->endline = TRUE; } lpinput->linebuf[LP_MAX_LINELEN-1] = '\0'; /* we want to use lookahead of one char -> we need two \0 at the end */ lpinput->comment = FALSE; /* skip characters after comment symbol */ for( i = 0; commentchars[i] != '\0'; ++i ) { char* commentstart; commentstart = strchr(lpinput->linebuf, commentchars[i]); if( commentstart != NULL ) { *commentstart = '\0'; *(commentstart+1) = '\0'; /* we want to use lookahead of one char -> we need two \0 at the end */ lpinput->comment = TRUE; break; } } return TRUE; }
/** execution method of primal heuristic */ static SCIP_DECL_HEUREXEC(heurExecMutation) { /*lint --e{715}*/ SCIP_Longint maxnnodes; SCIP_Longint nsubnodes; /* node limit for the subproblem */ SCIP_HEURDATA* heurdata; /* heuristic's data */ SCIP* subscip; /* the subproblem created by mutation */ SCIP_VAR** vars; /* original problem's variables */ SCIP_VAR** subvars; /* subproblem's variables */ SCIP_HASHMAP* varmapfw; /* mapping of SCIP variables to sub-SCIP variables */ SCIP_Real cutoff; /* objective cutoff for the subproblem */ SCIP_Real maxnnodesr; SCIP_Real memorylimit; SCIP_Real timelimit; /* timelimit for the subproblem */ SCIP_Real upperbound; int nvars; /* number of original problem's variables */ int i; SCIP_Bool success; SCIP_RETCODE retcode; assert( heur != NULL ); assert( scip != NULL ); assert( result != NULL ); /* get heuristic's data */ heurdata = SCIPheurGetData(heur); assert( heurdata != NULL ); *result = SCIP_DELAYED; /* only call heuristic, if feasible solution is available */ if( SCIPgetNSols(scip) <= 0 ) return SCIP_OKAY; /* only call heuristic, if the best solution comes from transformed problem */ assert( SCIPgetBestSol(scip) != NULL ); if( SCIPsolIsOriginal(SCIPgetBestSol(scip)) ) return SCIP_OKAY; /* only call heuristic, if enough nodes were processed since last incumbent */ if( SCIPgetNNodes(scip) - SCIPgetSolNodenum(scip,SCIPgetBestSol(scip)) < heurdata->nwaitingnodes) return SCIP_OKAY; *result = SCIP_DIDNOTRUN; /* only call heuristic, if discrete variables are present */ if( SCIPgetNBinVars(scip) == 0 && SCIPgetNIntVars(scip) == 0 ) return SCIP_OKAY; /* calculate the maximal number of branching nodes until heuristic is aborted */ maxnnodesr = heurdata->nodesquot * SCIPgetNNodes(scip); /* reward mutation if it succeeded often, count the setup costs for the sub-MIP as 100 nodes */ maxnnodesr *= 1.0 + 2.0 * (SCIPheurGetNBestSolsFound(heur)+1.0)/(SCIPheurGetNCalls(heur) + 1.0); maxnnodes = (SCIP_Longint) maxnnodesr - 100 * SCIPheurGetNCalls(heur); maxnnodes += heurdata->nodesofs; /* determine the node limit for the current process */ nsubnodes = maxnnodes - heurdata->usednodes; nsubnodes = MIN(nsubnodes, heurdata->maxnodes); /* check whether we have enough nodes left to call subproblem solving */ if( nsubnodes < heurdata->minnodes ) return SCIP_OKAY; if( SCIPisStopped(scip) ) return SCIP_OKAY; *result = SCIP_DIDNOTFIND; SCIP_CALL( SCIPgetVarsData(scip, &vars, &nvars, NULL, NULL, NULL, NULL) ); /* initializing the subproblem */ SCIP_CALL( SCIPallocBufferArray(scip, &subvars, nvars) ); SCIP_CALL( SCIPcreate(&subscip) ); /* create the variable mapping hash map */ SCIP_CALL( SCIPhashmapCreate(&varmapfw, SCIPblkmem(subscip), SCIPcalcHashtableSize(5 * nvars)) ); if( heurdata->uselprows ) { char probname[SCIP_MAXSTRLEN]; /* copy all plugins */ SCIP_CALL( SCIPincludeDefaultPlugins(subscip) ); /* get name of the original problem and add the string "_mutationsub" */ (void) SCIPsnprintf(probname, SCIP_MAXSTRLEN, "%s_mutationsub", SCIPgetProbName(scip)); /* create the subproblem */ SCIP_CALL( SCIPcreateProb(subscip, probname, NULL, NULL, NULL, NULL, NULL, NULL, NULL) ); /* copy all variables */ SCIP_CALL( SCIPcopyVars(scip, subscip, varmapfw, NULL, TRUE) ); } else { SCIP_Bool valid; valid = FALSE; SCIP_CALL( SCIPcopy(scip, subscip, varmapfw, NULL, "rens", TRUE, FALSE, TRUE, &valid) ); if( heurdata->copycuts ) { /* copies all active cuts from cutpool of sourcescip to linear constraints in targetscip */ SCIP_CALL( SCIPcopyCuts(scip, subscip, varmapfw, NULL, TRUE, NULL) ); } SCIPdebugMessage("Copying the SCIP instance was %s complete.\n", valid ? "" : "not "); } for( i = 0; i < nvars; i++ ) subvars[i] = (SCIP_VAR*) SCIPhashmapGetImage(varmapfw, vars[i]); /* free hash map */ SCIPhashmapFree(&varmapfw); /* create a new problem, which fixes variables with same value in bestsol and LP relaxation */ SCIP_CALL( createSubproblem(scip, subscip, subvars, heurdata->minfixingrate, &heurdata->randseed, heurdata->uselprows) ); /* do not abort subproblem on CTRL-C */ SCIP_CALL( SCIPsetBoolParam(subscip, "misc/catchctrlc", FALSE) ); /* disable output to console */ SCIP_CALL( SCIPsetIntParam(subscip, "display/verblevel", 0) ); /* check whether there is enough time and memory left */ SCIP_CALL( SCIPgetRealParam(scip, "limits/time", &timelimit) ); if( !SCIPisInfinity(scip, timelimit) ) timelimit -= SCIPgetSolvingTime(scip); SCIP_CALL( SCIPgetRealParam(scip, "limits/memory", &memorylimit) ); /* substract the memory already used by the main SCIP and the estimated memory usage of external software */ if( !SCIPisInfinity(scip, memorylimit) ) { memorylimit -= SCIPgetMemUsed(scip)/1048576.0; memorylimit -= SCIPgetMemExternEstim(scip)/1048576.0; } /* abort if no time is left or not enough memory to create a copy of SCIP, including external memory usage */ if( timelimit <= 0.0 || memorylimit <= 2.0*SCIPgetMemExternEstim(scip)/1048576.0 ) goto TERMINATE; /* set limits for the subproblem */ SCIP_CALL( SCIPsetLongintParam(subscip, "limits/nodes", nsubnodes) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/time", timelimit) ); SCIP_CALL( SCIPsetRealParam(subscip, "limits/memory", memorylimit) ); /* forbid recursive call of heuristics and separators solving subMIPs */ SCIP_CALL( SCIPsetSubscipsOff(subscip, TRUE) ); /* disable cutting plane separation */ SCIP_CALL( SCIPsetSeparating(subscip, SCIP_PARAMSETTING_OFF, TRUE) ); /* disable expensive presolving */ SCIP_CALL( SCIPsetPresolving(subscip, SCIP_PARAMSETTING_FAST, TRUE) ); /* use best estimate node selection */ if( SCIPfindNodesel(subscip, "estimate") != NULL && !SCIPisParamFixed(subscip, "nodeselection/estimate/stdpriority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "nodeselection/estimate/stdpriority", INT_MAX/4) ); } /* use inference branching */ if( SCIPfindBranchrule(subscip, "inference") != NULL && !SCIPisParamFixed(subscip, "branching/inference/priority") ) { SCIP_CALL( SCIPsetIntParam(subscip, "branching/inference/priority", INT_MAX/4) ); } /* disable conflict analysis */ if( !SCIPisParamFixed(subscip, "conflict/useprop") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useprop", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/useinflp") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useinflp", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/useboundlp") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/useboundlp", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/usesb") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usesb", FALSE) ); } if( !SCIPisParamFixed(subscip, "conflict/usepseudo") ) { SCIP_CALL( SCIPsetBoolParam(subscip, "conflict/usepseudo", FALSE) ); } /* employ a limit on the number of enforcement rounds in the quadratic constraint handlers; this fixes the issue that * sometimes the quadratic constraint handler needs hundreds or thousands of enforcement rounds to determine the * feasibility status of a single node without fractional branching candidates by separation (namely for uflquad * instances); however, the solution status of the sub-SCIP might get corrupted by this; hence no decutions shall be * made for the original SCIP */ if( SCIPfindConshdlr(subscip, "quadratic") != NULL && !SCIPisParamFixed(subscip, "constraints/quadratic/enfolplimit") ) { SCIP_CALL( SCIPsetIntParam(subscip, "constraints/quadratic/enfolplimit", 10) ); } /* add an objective cutoff */ cutoff = SCIPinfinity(scip); assert( !SCIPisInfinity(scip, SCIPgetUpperbound(scip)) ); upperbound = SCIPgetUpperbound(scip) - SCIPsumepsilon(scip); if( !SCIPisInfinity(scip, -1.0 * SCIPgetLowerbound(scip)) ) { cutoff = (1-heurdata->minimprove) * SCIPgetUpperbound(scip) + heurdata->minimprove * SCIPgetLowerbound(scip); } else { if( SCIPgetUpperbound ( scip ) >= 0 ) cutoff = ( 1 - heurdata->minimprove ) * SCIPgetUpperbound ( scip ); else cutoff = ( 1 + heurdata->minimprove ) * SCIPgetUpperbound ( scip ); } cutoff = MIN(upperbound, cutoff ); SCIP_CALL( SCIPsetObjlimit(subscip, cutoff) ); /* solve the subproblem */ SCIPdebugMessage("Solve Mutation subMIP\n"); retcode = SCIPsolve(subscip); /* Errors in solving the subproblem should not kill the overall solving process * Hence, the return code is caught and a warning is printed, only in debug mode, SCIP will stop. */ if( retcode != SCIP_OKAY ) { #ifndef NDEBUG SCIP_CALL( retcode ); #endif SCIPwarningMessage(scip, "Error while solving subproblem in Mutation heuristic; sub-SCIP terminated with code <%d>\n",retcode); } heurdata->usednodes += SCIPgetNNodes(subscip); /* check, whether a solution was found */ if( SCIPgetNSols(subscip) > 0 ) { SCIP_SOL** subsols; int nsubsols; /* check, whether a solution was found; * due to numerics, it might happen that not all solutions are feasible -> try all solutions until one was accepted */ nsubsols = SCIPgetNSols(subscip); subsols = SCIPgetSols(subscip); success = FALSE; for( i = 0; i < nsubsols && !success; ++i ) { SCIP_CALL( createNewSol(scip, subscip, subvars, heur, subsols[i], &success) ); } if( success ) *result = SCIP_FOUNDSOL; } TERMINATE: /* free subproblem */ SCIPfreeBufferArray(scip, &subvars); SCIP_CALL( SCIPfree(&subscip) ); return SCIP_OKAY; }
/** read objective sense, offset, and scale */ static SCIP_RETCODE getObjective( SCIP* scip, /**< SCIP data structure */ CIPINPUT* cipinput, /**< CIP parsing data */ SCIP_Real* objscale, /**< buffer where to multiply with objective scale */ SCIP_Real* objoffset /**< buffer where to add with objective offset */ ) { char* buf; char* name; assert(objscale != NULL); assert(objoffset != NULL); buf = cipinput->strbuf; if( strncmp(buf, "VARIABLES", 8) == 0 ) cipinput->section = CIP_VARS; else if( strncmp(buf, "FIXED", 5) == 0 ) cipinput->section = CIP_FIXEDVARS; else if( strncmp(buf, "CONSTRAINTS", 11) == 0 ) cipinput->section = CIP_CONSTRAINTS; else if( strncmp(buf, "END", 3) == 0 ) cipinput->section = CIP_END; if( cipinput->section != CIP_OBJECTIVE ) return SCIP_OKAY; SCIPdebugMessage("parse objective information\n"); /* remove white space */ while ( isspace((unsigned char)* buf) ) ++buf; if( strncasecmp(buf, "Sense", 5) == 0 ) { SCIP_OBJSENSE objsense; name = strchr(buf, ':'); if( name == NULL ) { SCIPwarningMessage(scip, "did not find objective sense (line: %d):\n%s\n", cipinput->linenumber, cipinput->strbuf); return SCIP_OKAY; /* no error - might work with default */ } /* skip ':' */ ++name; /* remove white space in front of the name */ while( isspace((unsigned char)* name) ) ++name; if( strncasecmp(name, "minimize", 3) == 0 ) objsense = SCIP_OBJSENSE_MINIMIZE; else if( strncasecmp(name, "maximize", 3) == 0 ) objsense = SCIP_OBJSENSE_MAXIMIZE; else { SCIPwarningMessage(scip, "unknown objective sense '%s' (line: %d):\n%s\n", name, cipinput->linenumber, cipinput->strbuf); return SCIP_OKAY; /* no error - might work with default */ } /* set problem name */ SCIP_CALL( SCIPsetObjsense(scip, objsense) ); SCIPdebugMessage("objective sense <%s>\n", objsense == SCIP_OBJSENSE_MINIMIZE ? "minimize" : "maximize"); } else if( strncasecmp(buf, "Offset", 6) == 0 ) { SCIP_Real off = 0; char* endptr; name = strchr(buf, ':'); if( name == NULL ) { SCIPwarningMessage(scip, "did not find offset (line: %d)\n", cipinput->linenumber); return SCIP_OKAY; } /* skip ':' */ ++name; /* remove white space in front of the name */ while(isspace((unsigned char)*name)) ++name; if ( SCIPstrToRealValue(name, &off, &endptr) ) { *objoffset += off; SCIPdebugMessage("offset <%g> (total: %g)\n", off, *objoffset); } else { SCIPwarningMessage(scip, "could not parse offset (line: %d)\n%s\n", cipinput->linenumber, cipinput->strbuf); return SCIP_OKAY; } } else if( strncasecmp(buf, "Scale", 5) == 0 ) { SCIP_Real scale = 1.0; char* endptr; name = strchr(buf, ':'); if( name == NULL ) { SCIPwarningMessage(scip, "did not find scale (line: %d)\n", cipinput->linenumber); return SCIP_OKAY; } /* skip ':' */ ++name; /* remove white space in front of the name */ while(isspace((unsigned char)*name)) ++name; if ( SCIPstrToRealValue(name, &scale, &endptr) ) { *objscale *= scale; SCIPdebugMessage("objscale <%g> (total: %g)\n", scale, *objscale); } else { SCIPwarningMessage(scip, "could not parse objective scale (line: %d)\n%s\n", cipinput->linenumber, cipinput->strbuf); return SCIP_OKAY; } } return SCIP_OKAY; }
/** read fixed variable */ static SCIP_RETCODE getFixedVariable( SCIP* scip, /**< SCIP data structure */ CIPINPUT* cipinput /**< CIP parsing data */ ) { SCIP_Bool success; SCIP_VAR* var; char* buf; char* endptr; char name[SCIP_MAXSTRLEN]; buf = cipinput->strbuf; if( strncmp(buf, "CONSTRAINTS", 11) == 0 ) cipinput->section = CIP_CONSTRAINTS; else if( strncmp(buf, "END", 3) == 0 ) cipinput->section = CIP_END; if( cipinput->section != CIP_FIXEDVARS ) return SCIP_OKAY; SCIPdebugMessage("parse fixed variable\n"); /* parse the variable */ SCIP_CALL( SCIPparseVar(scip, &var, buf, TRUE, FALSE, NULL, NULL, NULL, NULL, NULL, &endptr, &success) ); if( !success ) { SCIPerrorMessage("syntax error in variable information (line: %d):\n%s\n", cipinput->linenumber, cipinput->strbuf); cipinput->haserror = TRUE; return SCIP_OKAY; } /* skip intermediate stuff */ buf = endptr; while ( *buf != '\0' && (*buf == ' ' || *buf == ',') ) ++buf; /* check whether variable is fixed */ if ( strncmp(buf, "fixed:", 6) == 0 ) { SCIP_CALL( SCIPaddVar(scip, var) ); SCIPdebug( SCIP_CALL( SCIPprintVar(scip, var, NULL) ) ); } else if ( strncmp(buf, "negated:", 8) == 0 ) { SCIP_CONS* lincons; SCIP_VAR* negvar; SCIP_Real vals[2]; SCIP_VAR* vars[2]; buf += 8; /* we can just parse the next variable (ignoring all other information in between) */ SCIP_CALL( SCIPparseVarName(scip, buf, &negvar, &endptr) ); if ( negvar == NULL ) { SCIPerrorMessage("could not parse negated variable (line: %d):\n%s\n", cipinput->linenumber, cipinput->strbuf); cipinput->haserror = TRUE; return SCIP_OKAY; } assert(SCIPvarIsBinary(var)); assert(SCIPvarIsBinary(negvar)); SCIP_CALL( SCIPaddVar(scip, var) ); SCIPdebugMessage("creating negated variable <%s> (of <%s>) ...\n", SCIPvarGetName(var), SCIPvarGetName(negvar) ); SCIPdebug( SCIP_CALL( SCIPprintVar(scip, var, NULL) ) ); /* add linear constraint for negation */ (void) SCIPsnprintf(name, SCIP_MAXSTRLEN, "neg_%s", SCIPvarGetName(var) ); vars[0] = var; vars[1] = negvar; vals[0] = 1.0; vals[1] = 1.0; SCIPdebugMessage("coupling constraint:\n"); SCIP_CALL( SCIPcreateConsLinear(scip, &lincons, name, 2, vars, vals, 1.0, 1.0, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE, TRUE, FALSE) ); SCIPdebugPrintCons(scip, lincons, NULL); SCIP_CALL( SCIPaddCons(scip, lincons) ); SCIP_CALL( SCIPreleaseCons(scip, &lincons) ); } else if ( strncmp(buf, "aggregated:", 11) == 0 ) { /* handle (multi-)aggregated variables */ SCIP_CONS* lincons; SCIP_Real* vals; SCIP_VAR** vars; SCIP_Real rhs = 0.0; const char* str; int nvarssize = 20; int requsize; int nvars; buf += 11; SCIPdebugMessage("parsing aggregated variable <%s> ...\n", SCIPvarGetName(var)); /* first parse constant */ if ( ! SCIPstrToRealValue(buf, &rhs, &endptr) ) { SCIPerrorMessage("expected constant when aggregated variable information (line: %d):\n%s\n", cipinput->linenumber, buf); cipinput->haserror = TRUE; return SCIP_OKAY; } /* check whether constant is 0.0 */ str = endptr; while ( *str != '\0' && isspace(*str) ) ++str; /* if next char is '<' we found a variable -> constant is 0 */ if ( *str != '<' ) { SCIPdebugMessage("constant: %f\n", rhs); buf = endptr; } else { /* otherwise keep buf */ rhs = 0.0; } /* initialize buffers for storing the variables and values */ SCIP_CALL( SCIPallocBufferArray(scip, &vars, nvarssize) ); SCIP_CALL( SCIPallocBufferArray(scip, &vals, nvarssize) ); vars[0] = var; vals[0] = -1.0; --nvarssize; /* parse linear sum to get variables and coefficients */ SCIP_CALL( SCIPparseVarsLinearsum(scip, buf, &(vars[1]), &(vals[1]), &nvars, nvarssize, &requsize, &endptr, &success) ); if ( success && requsize > nvarssize ) { /* realloc buffers and try again */ nvarssize = requsize; SCIP_CALL( SCIPreallocBufferArray(scip, &vars, nvarssize + 1) ); SCIP_CALL( SCIPreallocBufferArray(scip, &vals, nvarssize + 1) ); SCIP_CALL( SCIPparseVarsLinearsum(scip, buf, &(vars[1]), &(vals[1]), &nvars, nvarssize, &requsize, &endptr, &success) ); assert( ! success || requsize <= nvarssize); /* if successful, then should have had enough space now */ } if( success ) { /* add aggregated variable */ SCIP_CALL( SCIPaddVar(scip, var) ); /* special handling of variables that seem to be slack variables of indicator constraints */ str = SCIPvarGetName(var); if ( strncmp(str, "indslack", 8) == 0 ) { (void) strcpy(name, "indlin"); (void) strncat(name, str+8, SCIP_MAXSTRLEN-7); } else if ( strncmp(str, "t_indslack", 10) == 0 ) { (void) strcpy(name, "indlin"); (void) strncat(name, str+10, SCIP_MAXSTRLEN-7); } else (void) SCIPsnprintf(name, SCIP_MAXSTRLEN, "%s", SCIPvarGetName(var) ); /* add linear constraint for (multi-)aggregation */ SCIPdebugMessage("coupling constraint:\n"); SCIP_CALL( SCIPcreateConsLinear(scip, &lincons, name, nvars + 1, vars, vals, -rhs, -rhs, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE, TRUE, FALSE) ); SCIPdebugPrintCons(scip, lincons, NULL); SCIP_CALL( SCIPaddCons(scip, lincons) ); SCIP_CALL( SCIPreleaseCons(scip, &lincons) ); } else { SCIPwarningMessage(scip, "Could not read (multi-)aggregated variable <%s>: dependent variables unkown - consider changing the order (line: %d):\n%s\n", SCIPvarGetName(var), cipinput->linenumber, buf); } SCIPfreeBufferArray(scip, &vals); SCIPfreeBufferArray(scip, &vars); } else { SCIPerrorMessage("unknown section when parsing variables (line: %d):\n%s\n", cipinput->linenumber, buf); cipinput->haserror = TRUE; return SCIP_OKAY; } SCIP_CALL( SCIPreleaseVar(scip, &var) ); return SCIP_OKAY; }
/** reads an objective or constraint with name and coefficients */ static SCIP_RETCODE readCoefficients( SCIP* scip, /**< SCIP data structure */ LPINPUT* lpinput, /**< LP reading data */ SCIP_Bool isobjective, /**< indicates whether we are currently reading the coefficients of the objective */ char* name, /**< pointer to store the name of the line; must be at least of size * LP_MAX_LINELEN */ SCIP_VAR*** vars, /**< pointer to store the array with variables (must be freed by caller) */ SCIP_Real** coefs, /**< pointer to store the array with coefficients (must be freed by caller) */ int* ncoefs, /**< pointer to store the number of coefficients */ SCIP_Bool* newsection /**< pointer to store whether a new section was encountered */ ) { SCIP_Bool havesign; SCIP_Bool havevalue; SCIP_Real coef; int coefsign; int coefssize; assert(lpinput != NULL); assert(name != NULL); assert(vars != NULL); assert(coefs != NULL); assert(ncoefs != NULL); assert(newsection != NULL); *vars = NULL; *coefs = NULL; *name = '\0'; *ncoefs = 0; *newsection = FALSE; /* read the first token, which may be the name of the line */ if( getNextToken(scip, lpinput) ) { /* check if we reached a new section */ if( isNewSection(scip, lpinput) ) { *newsection = TRUE; return SCIP_OKAY; } /* remember the token in the token buffer */ swapTokenBuffer(lpinput); /* get the next token and check, whether it is a colon */ if( getNextToken(scip, lpinput) ) { if( strcmp(lpinput->token, ":") == 0 ) { /* the second token was a colon: the first token is the line name */ (void)SCIPmemccpy(name, lpinput->tokenbuf, '\0', LP_MAX_LINELEN); name[LP_MAX_LINELEN - 1] = '\0'; SCIPdebugMessage("(line %d) read constraint name: '%s'\n", lpinput->linenumber, name); } else { /* the second token was no colon: push the tokens back onto the token stack and parse them as coefficients */ pushToken(lpinput); pushBufferToken(lpinput); } } else { /* there was only one token left: push it back onto the token stack and parse it as coefficient */ pushBufferToken(lpinput); } } /* initialize buffers for storing the coefficients */ coefssize = LP_INIT_COEFSSIZE; SCIP_CALL( SCIPallocMemoryArray(scip, vars, coefssize) ); SCIP_CALL( SCIPallocMemoryArray(scip, coefs, coefssize) ); /* read the coefficients */ coefsign = +1; coef = 1.0; havesign = FALSE; havevalue = FALSE; *ncoefs = 0; while( getNextToken(scip, lpinput) ) { SCIP_VAR* var; /* check if we read a sign */ if( isSign(lpinput, &coefsign) ) { SCIPdebugMessage("(line %d) read coefficient sign: %+d\n", lpinput->linenumber, coefsign); havesign = TRUE; continue; } /* check if we read a value */ if( isValue(scip, lpinput, &coef) ) { SCIPdebugMessage("(line %d) read coefficient value: %g with sign %+d\n", lpinput->linenumber, coef, coefsign); if( havevalue ) { syntaxError(scip, lpinput, "two consecutive values."); return SCIP_OKAY; } havevalue = TRUE; continue; } /* check if we reached an equation sense */ if( isSense(lpinput, NULL) ) { if( isobjective ) { syntaxError(scip, lpinput, "no sense allowed in objective"); return SCIP_OKAY; } /* put the sense back onto the token stack */ pushToken(lpinput); break; } /* check if we reached a new section, that will be only allowed when having no current sign and value and if we * are not in the quadratic part */ if( (isobjective || (!havevalue && !havesign)) && isNewSection(scip, lpinput) ) { if( havesign && !havevalue ) { SCIPwarningMessage(scip, "skipped single sign %c without value or variable in objective\n", coefsign == 1 ? '+' : '-'); } else if( isobjective && havevalue && !SCIPisZero(scip, coef) ) { SCIPwarningMessage(scip, "constant term %+g in objective is skipped\n", coef * coefsign); } *newsection = TRUE; return SCIP_OKAY; } /* check if we start a quadratic part */ if( *lpinput->token == '[' ) { syntaxError(scip, lpinput, "diff reader does not support quadratic objective function."); return SCIP_READERROR; } /* all but the first coefficient need a sign */ if( *ncoefs > 0 && !havesign ) { syntaxError(scip, lpinput, "expected sign ('+' or '-') or sense ('<' or '>')."); return SCIP_OKAY; } /* check if the last variable should be squared */ if( *lpinput->token == '^' ) { syntaxError(scip, lpinput, "diff reader does not support quadratic objective function."); return SCIP_READERROR; } else { /* the token is a variable name: get the corresponding variable */ SCIP_CALL( getVariable(scip, lpinput->token, &var) ); } /* insert the linear coefficient */ SCIPdebugMessage("(line %d) read linear coefficient: %+g<%s>\n", lpinput->linenumber, coefsign * coef, SCIPvarGetName(var)); if( !SCIPisZero(scip, coef) ) { /* resize the vars and coefs array if needed */ if( *ncoefs >= coefssize ) { coefssize *= 2; coefssize = MAX(coefssize, (*ncoefs)+1); SCIP_CALL( SCIPreallocMemoryArray(scip, vars, coefssize) ); SCIP_CALL( SCIPreallocMemoryArray(scip, coefs, coefssize) ); } assert(*ncoefs < coefssize); /* add coefficient */ (*vars)[*ncoefs] = var; (*coefs)[*ncoefs] = coefsign * coef; (*ncoefs)++; } /* reset the flags and coefficient value for the next coefficient */ coefsign = +1; coef = 1.0; havesign = FALSE; havevalue = FALSE; } return SCIP_OKAY; }