/** branching execution method for external candidates */
static
SCIP_DECL_BRANCHEXECEXT(branchExecextPscost)
{ /*lint --e{715}*/
SCIP_BRANCHRULEDATA* branchruledata;
SCIP_VAR** externcands;
SCIP_Real* externcandssol;
SCIP_Real* externcandsscore;
int nprioexterncands;
SCIP_VAR* brvar;
SCIP_Real brpoint;
int nchildren;
assert(branchrule != NULL);
assert(strcmp(SCIPbranchruleGetName(branchrule), BRANCHRULE_NAME) == 0);
assert(scip != NULL);
assert(result != NULL);
branchruledata = SCIPbranchruleGetData(branchrule);
assert(branchruledata != NULL);
SCIPdebugMessage("Execext method of pscost branching\n");
/* get branching candidates */
SCIP_CALL( SCIPgetExternBranchCands(scip, &externcands, &externcandssol, &externcandsscore, NULL, &nprioexterncands, NULL, NULL, NULL) );
assert(nprioexterncands > 0);
/* get current update strategy for pseudo costs, if our multiplier rule is 'u' */
if( branchruledata->strategy == 'u' )
{
SCIP_CALL( SCIPgetCharParam(scip, "branching/lpgainnormalize", &branchruledata->updatestrategy) );
}
/* select branching variable */
SCIP_CALL( selectBranchVar(scip, branchrule, externcands, externcandssol, externcandsscore, nprioexterncands, &brvar, &brpoint) );
if( brvar == NULL )
{
SCIPerrorMessage("branchExecextPscost failed to select a branching variable from %d candidates\n", nprioexterncands);
*result = SCIP_DIDNOTRUN;
return SCIP_OKAY;
}
assert(SCIPvarIsActive(SCIPvarGetProbvar(brvar)));
SCIPdebugMessage("branching on variable <%s>: new intervals: [%g, %g] and [%g, %g]\n",
SCIPvarGetName(brvar), SCIPvarGetLbLocal(brvar), SCIPadjustedVarUb(scip, brvar, brpoint), SCIPadjustedVarLb(scip, brvar, brpoint), SCIPvarGetUbLocal(brvar));
if( branchruledata->nchildren > 2 && SCIPnodeGetDepth(SCIPgetCurrentNode(scip)) <= branchruledata->narymaxdepth )
{
/* do n-ary branching */
SCIP_Real minwidth;
minwidth = 0.0;
if( !SCIPisInfinity(scip, -SCIPvarGetLbGlobal(brvar)) && !SCIPisInfinity(scip, SCIPvarGetUbGlobal(brvar)) )
minwidth = branchruledata->naryminwidth * (SCIPvarGetUbGlobal(brvar) - SCIPvarGetLbGlobal(brvar));
SCIP_CALL( SCIPbranchVarValNary(scip, brvar, brpoint, branchruledata->nchildren, minwidth, branchruledata->narywidthfactor, &nchildren) );
}
else
{
/* do binary branching */
SCIP_CALL( SCIPbranchVarValNary(scip, brvar, brpoint, 2, 0.0, 1.0, &nchildren) );
}
if( nchildren > 1 )
{
*result = SCIP_BRANCHED;
}
else
{
/* if there are no children, then variable should have been fixed by SCIPbranchVarVal */
assert(SCIPisEQ(scip, SCIPvarGetLbLocal(brvar), SCIPvarGetUbLocal(brvar)));
*result = SCIP_REDUCEDDOM;
}
return SCIP_OKAY;
}
/** checks if a given branching candidate is better than a previous one and updates the best branching candidate accordingly */
static
SCIP_RETCODE updateBestCandidate(
SCIP* scip, /**< SCIP data structure */
SCIP_BRANCHRULEDATA* branchruledata, /**< branching rule data */
SCIP_VAR** bestvar, /**< best branching candidate */
SCIP_Real* bestbrpoint, /**< branching point for best branching candidate */
SCIP_Real* bestscore, /**< score of best branching candidate */
SCIP_VAR* cand, /**< branching candidate to consider */
SCIP_Real candscoremin, /**< minimal score of branching candidate */
SCIP_Real candscoremax, /**< maximal score of branching candidate */
SCIP_Real candscoresum, /**< sum of scores of branching candidate */
SCIP_Real candsol /**< proposed branching point of branching candidate */
)
{
SCIP_Real candbrpoint;
SCIP_Real branchscore;
SCIP_Real deltaminus;
SCIP_Real deltaplus;
SCIP_Real pscostdown;
SCIP_Real pscostup;
char strategy;
assert(scip != NULL);
assert(branchruledata != NULL);
assert(bestvar != NULL);
assert(bestbrpoint != NULL);
assert(bestscore != NULL);
assert(cand != NULL);
/* a branching variable candidate should either be an active problem variable or a multi-aggregated variable */
assert(SCIPvarIsActive(SCIPvarGetProbvar(cand)) ||
SCIPvarGetStatus(SCIPvarGetProbvar(cand)) == SCIP_VARSTATUS_MULTAGGR);
if( SCIPvarGetStatus(SCIPvarGetProbvar(cand)) == SCIP_VARSTATUS_MULTAGGR )
{
/* for a multi-aggregated variable, we call updateBestCandidate function recursively with all variables in the multi-aggregation */
SCIP_VAR** multvars;
int nmultvars;
int i;
SCIP_Bool success;
SCIP_Real multvarlb;
SCIP_Real multvarub;
cand = SCIPvarGetProbvar(cand);
multvars = SCIPvarGetMultaggrVars(cand);
nmultvars = SCIPvarGetMultaggrNVars(cand);
/* if we have a candidate branching point, then first register only aggregation variables
* for which we can compute a corresponding branching point too (see also comments below)
* if this fails, then register all (unfixed) aggregation variables, thereby forgetting about candsol
*/
success = FALSE;
if( candsol != SCIP_INVALID ) /*lint !e777*/
{
SCIP_Real* multscalars;
SCIP_Real minact;
SCIP_Real maxact;
SCIP_Real aggrvarsol;
SCIP_Real aggrvarsol1;
SCIP_Real aggrvarsol2;
multscalars = SCIPvarGetMultaggrScalars(cand);
/* for computing the branching point, we need the current bounds of the multi-aggregated variable */
minact = SCIPcomputeVarLbLocal(scip, cand);
maxact = SCIPcomputeVarUbLocal(scip, cand);
for( i = 0; i < nmultvars; ++i )
{
/* skip fixed variables */
multvarlb = SCIPcomputeVarLbLocal(scip, multvars[i]);
multvarub = SCIPcomputeVarUbLocal(scip, multvars[i]);
if( SCIPisEQ(scip, multvarlb, multvarub) )
continue;
assert(multscalars != NULL);
assert(multscalars[i] != 0.0);
/* we cannot ensure that both the upper bound in the left node and the lower bound in the right node
* will be candsol by a clever choice for the branching point of multvars[i],
* but we can try to ensure that at least one of them will be at candsol
*/
if( multscalars[i] > 0.0 )
{
/* cand >= candsol
* if multvars[i] >= (candsol - (maxact - multscalars[i] * ub(multvars[i]))) / multscalars[i]
* = (candsol - maxact) / multscalars[i] + ub(multvars[i])
*/
aggrvarsol1 = (candsol - maxact) / multscalars[i] + multvarub;
/* cand <= candsol
* if multvars[i] <= (candsol - (minact - multscalar[i] * lb(multvars[i]))) / multscalars[i]
* = (candsol - minact) / multscalars[i] + lb(multvars[i])
*/
aggrvarsol2 = (candsol - minact) / multscalars[i] + multvarlb;
}
else
{
/* cand >= candsol
* if multvars[i] <= (candsol - (maxact - multscalars[i] * lb(multvars[i]))) / multscalars[i]
* = (candsol - maxact) / multscalars[i] + lb(multvars[i])
*/
aggrvarsol2 = (candsol - maxact) / multscalars[i] + multvarlb;
/* cand <= candsol
* if multvars[i] >= (candsol - (minact - multscalar[i] * ub(multvars[i]))) / multscalars[i]
* = (candsol - minact) / multscalars[i] + ub(multvars[i])
*/
aggrvarsol1 = (candsol - minact) / multscalars[i] + multvarub;
}
/* by the above choice, aggrvarsol1 <= ub(multvars[i]) and aggrvarsol2 >= lb(multvars[i])
* if aggrvarsol1 <= lb(multvars[i]) or aggrvarsol2 >= ub(multvars[i]), then choose the other one
* if both are out of bounds, then give up
* if both are inside bounds, then choose the one closer to 0.0 (someone has better idea???)
*/
if( SCIPisFeasLE(scip, aggrvarsol1, multvarlb) )
{
if( SCIPisFeasGE(scip, aggrvarsol2, multvarub) )
continue;
else
aggrvarsol = aggrvarsol2;
}
else
{
if( SCIPisFeasGE(scip, aggrvarsol2, multvarub) )
aggrvarsol = aggrvarsol1;
else
aggrvarsol = REALABS(aggrvarsol1) < REALABS(aggrvarsol2) ? aggrvarsol1 : aggrvarsol2;
}
success = TRUE;
SCIP_CALL( updateBestCandidate(scip, branchruledata, bestvar, bestbrpoint, bestscore,
multvars[i], candscoremin, candscoremax, candscoresum, aggrvarsol) );
}
}
if( !success )
for( i = 0; i < nmultvars; ++i )
{
/* skip fixed variables */
multvarlb = SCIPcomputeVarLbLocal(scip, multvars[i]);
multvarub = SCIPcomputeVarUbLocal(scip, multvars[i]);
if( SCIPisEQ(scip, multvarlb, multvarub) )
continue;
SCIP_CALL( updateBestCandidate(scip, branchruledata, bestvar, bestbrpoint, bestscore,
multvars[i], candscoremin, candscoremax, candscoresum, SCIP_INVALID) );
}
assert(*bestvar != NULL); /* if all variables were fixed, something is strange */
return SCIP_OKAY;
}
/* select branching point for this variable */
candbrpoint = SCIPgetBranchingPoint(scip, cand, candsol);
assert(candbrpoint >= SCIPvarGetLbLocal(cand));
assert(candbrpoint <= SCIPvarGetUbLocal(cand));
/* we cannot branch on a huge value for a discrete variable, because we simply cannot enumerate such huge integer values in floating point
* arithmetics
*/
if( SCIPvarGetType(cand) != SCIP_VARTYPE_CONTINUOUS && (SCIPisHugeValue(scip, candbrpoint) || SCIPisHugeValue(scip, -candbrpoint)) )
return SCIP_OKAY;
assert(SCIPvarGetType(cand) == SCIP_VARTYPE_CONTINUOUS || !SCIPisIntegral(scip, candbrpoint));
if( SCIPvarGetType(cand) == SCIP_VARTYPE_CONTINUOUS )
strategy = (branchruledata->strategy == 'u' ? branchruledata->updatestrategy : branchruledata->strategy);
else
strategy = (branchruledata->strategy == 'u' ? 'l' : branchruledata->strategy);
switch( strategy )
{
case 'l':
if( SCIPisInfinity(scip, SCIPgetSolVal(scip, NULL, cand)) || SCIPgetSolVal(scip, NULL, cand) <= SCIPadjustedVarUb(scip, cand, candbrpoint) )
deltaminus = 0.0;
else
deltaminus = SCIPgetSolVal(scip, NULL, cand) - SCIPadjustedVarUb(scip, cand, candbrpoint);
if( SCIPisInfinity(scip, -SCIPgetSolVal(scip, NULL, cand)) || SCIPgetSolVal(scip, NULL, cand) >= SCIPadjustedVarLb(scip, cand, candbrpoint) )
deltaplus = 0.0;
else
deltaplus = SCIPadjustedVarLb(scip, cand, candbrpoint) - SCIPgetSolVal(scip, NULL, cand);
break;
case 'd':
if( SCIPisInfinity(scip, -SCIPvarGetLbLocal(cand)) )
deltaminus = SCIPisInfinity(scip, candscoremax) ? SCIPinfinity(scip) : WEIGHTEDSCORING(branchruledata, candscoremin, candscoremax, candscoresum);
else
deltaminus = SCIPadjustedVarUb(scip, cand, candbrpoint) - SCIPvarGetLbLocal(cand);
if( SCIPisInfinity(scip, SCIPvarGetUbLocal(cand)) )
deltaplus = SCIPisInfinity(scip, candscoremax) ? SCIPinfinity(scip) : WEIGHTEDSCORING(branchruledata, candscoremin, candscoremax, candscoresum);
else
deltaplus = SCIPvarGetUbLocal(cand) - SCIPadjustedVarLb(scip, cand, candbrpoint);
break;
case 's':
if( SCIPisInfinity(scip, -SCIPvarGetLbLocal(cand)) )
deltaplus = SCIPisInfinity(scip, candscoremax) ? SCIPinfinity(scip) : WEIGHTEDSCORING(branchruledata, candscoremin, candscoremax, candscoresum);
else
deltaplus = SCIPadjustedVarUb(scip, cand, candbrpoint) - SCIPvarGetLbLocal(cand);
if( SCIPisInfinity(scip, SCIPvarGetUbLocal(cand)) )
deltaminus = SCIPisInfinity(scip, candscoremax) ? SCIPinfinity(scip) : WEIGHTEDSCORING(branchruledata, candscoremin, candscoremax, candscoresum);
else
deltaminus = SCIPvarGetUbLocal(cand) - SCIPadjustedVarLb(scip, cand, candbrpoint);
break;
case 'v':
deltaplus = SCIPisInfinity(scip, candscoremax) ? SCIPinfinity(scip) : WEIGHTEDSCORING(branchruledata, candscoremin, candscoremax, candscoresum);
deltaminus = deltaplus;
break;
default :
SCIPerrorMessage("branching strategy %c unknown\n", strategy);
SCIPABORT();
return SCIP_INVALIDDATA; /*lint !e527*/
}
if( SCIPisInfinity(scip, deltaminus) || SCIPisInfinity(scip, deltaplus) )
{
branchscore = SCIPinfinity(scip);
}
else
{
pscostdown = SCIPgetVarPseudocostVal(scip, cand, -deltaminus);
pscostup = SCIPgetVarPseudocostVal(scip, cand, deltaplus);
branchscore = SCIPgetBranchScore(scip, cand, pscostdown, pscostup);
assert(!SCIPisNegative(scip, branchscore));
}
SCIPdebugMessage("branching score variable <%s>[%g,%g] = %g; wscore = %g; type=%d bestbrscore=%g\n",
SCIPvarGetName(cand), SCIPvarGetLbLocal(cand), SCIPvarGetUbLocal(cand), branchscore, WEIGHTEDSCORING(branchruledata, candscoremin, candscoremax, candscoresum),
SCIPvarGetType(cand), *bestscore);
if( SCIPisInfinity(scip, branchscore) )
branchscore = 0.9*SCIPinfinity(scip);
if( SCIPisSumGT(scip, branchscore, *bestscore) )
{
(*bestscore) = branchscore;
(*bestvar) = cand;
(*bestbrpoint) = candbrpoint;
}
else if( SCIPisSumEQ(scip, branchscore, *bestscore)
&& !(SCIPisInfinity(scip, -SCIPvarGetLbLocal(*bestvar)) && SCIPisInfinity(scip, SCIPvarGetUbLocal(*bestvar))) )
{
/* if best candidate so far is not unbounded to both sides, maybe take new candidate */
if( (SCIPisInfinity(scip, -SCIPvarGetLbLocal(cand)) || SCIPisInfinity(scip, SCIPvarGetUbLocal(cand))) &&
(SCIPisInfinity(scip, -SCIPvarGetLbLocal(*bestvar)) || SCIPisInfinity(scip, SCIPvarGetUbLocal(*bestvar))) )
{
/* if both variables are unbounded but one of them is bounded on one side, take the one with the larger bound on this side (hope that this avoids branching on always the same variable) */
if( SCIPvarGetUbLocal(cand) > SCIPvarGetUbLocal(*bestvar) || SCIPvarGetLbLocal(cand) < SCIPvarGetLbLocal(*bestvar) )
{
(*bestscore) = branchscore;
(*bestvar) = cand;
(*bestbrpoint) = candbrpoint;
}
}
else if( SCIPvarGetType(*bestvar) == SCIPvarGetType(cand) )
{
/* if both have the same type, take the one with larger diameter */
if( SCIPvarGetUbLocal(*bestvar) - SCIPvarGetLbLocal(*bestvar) < SCIPvarGetUbLocal(cand) - SCIPvarGetLbLocal(cand) )
{
(*bestscore) = branchscore;
(*bestvar) = cand;
(*bestbrpoint) = candbrpoint;
}
}
else if( SCIPvarGetType(*bestvar) > SCIPvarGetType(cand) )
{
/* take the one with better type ("more discrete") */
(*bestscore) = branchscore;
(*bestvar) = cand;
(*bestbrpoint) = candbrpoint;
}
}
return SCIP_OKAY;
}
/** compares the so far best branching candidate with a new candidate and updates best candidate, if new candidate is better */
static
void updateBestCandidate(
SCIP* scip, /**< SCIP data structure */
SCIP_VAR** bestvar, /**< best branching candidate */
SCIP_Real* bestscore, /**< score of best branching candidate */
SCIP_Real* bestobj, /**< absolute objective value of best branching candidate */
SCIP_Real* bestsol, /**< proposed branching point of best branching candidate */
SCIP_VAR* cand, /**< branching candidate to consider */
SCIP_Real candscore, /**< scoring of branching candidate */
SCIP_Real candsol /**< proposed branching point of branching candidate */
)
{
SCIP_Real obj;
assert(scip != NULL);
assert(bestvar != NULL);
assert(bestscore != NULL);
assert(bestobj != NULL);
assert(*bestobj >= 0.0);
assert(cand != NULL);
/* a branching variable candidate should either be an active problem variable or a multi-aggregated variable */
assert(SCIPvarIsActive(SCIPvarGetProbvar(cand)) ||
SCIPvarGetStatus(SCIPvarGetProbvar(cand)) == SCIP_VARSTATUS_MULTAGGR);
if( SCIPvarGetStatus(SCIPvarGetProbvar(cand)) == SCIP_VARSTATUS_MULTAGGR )
{
/* for a multi-aggregated variable, we call updateBestCandidate function recursively with all variables in the multi-aggregation */
SCIP_VAR** multvars;
int nmultvars;
int i;
SCIP_Bool success;
SCIP_Real multvarlb;
SCIP_Real multvarub;
cand = SCIPvarGetProbvar(cand);
multvars = SCIPvarGetMultaggrVars(cand);
nmultvars = SCIPvarGetMultaggrNVars(cand);
/* if we have a candidate branching point, then first register only aggregation variables
* for which we can compute a corresponding branching point too (see also comments below)
* if this fails, then register all (unfixed) aggregation variables, thereby forgetting about candsol
*/
success = FALSE;
if( candsol != SCIP_INVALID ) /*lint !e777*/
{
SCIP_Real* multscalars;
SCIP_Real minact;
SCIP_Real maxact;
SCIP_Real aggrvarsol;
SCIP_Real aggrvarsol1;
SCIP_Real aggrvarsol2;
multscalars = SCIPvarGetMultaggrScalars(cand);
/* for computing the branching point, we need the current bounds of the multi-aggregated variable */
minact = SCIPcomputeVarLbLocal(scip, cand);
maxact = SCIPcomputeVarUbLocal(scip, cand);
for( i = 0; i < nmultvars; ++i )
{
/* skip fixed variables */
multvarlb = SCIPcomputeVarLbLocal(scip, multvars[i]);
multvarub = SCIPcomputeVarUbLocal(scip, multvars[i]);
if( SCIPisEQ(scip, multvarlb, multvarub) )
continue;
assert(multscalars != NULL);
assert(multscalars[i] != 0.0);
/* we cannot ensure that both the upper bound in the left node and the lower bound in the right node
* will be candsol by a clever choice for the branching point of multvars[i],
* but we can try to ensure that at least one of them will be at candsol
*/
if( multscalars[i] > 0.0 )
{
/* cand >= candsol
* if multvars[i] >= (candsol - (maxact - multscalars[i] * ub(multvars[i]))) / multscalars[i]
* = (candsol - maxact) / multscalars[i] + ub(multvars[i])
*/
aggrvarsol1 = (candsol - maxact) / multscalars[i] + multvarub;
/* cand <= candsol
* if multvars[i] <= (candsol - (minact - multscalar[i] * lb(multvars[i]))) / multscalars[i]
* = (candsol - minact) / multscalars[i] + lb(multvars[i])
*/
aggrvarsol2 = (candsol - minact) / multscalars[i] + multvarlb;
}
else
{
/* cand >= candsol
* if multvars[i] <= (candsol - (maxact - multscalars[i] * lb(multvars[i]))) / multscalars[i]
* = (candsol - maxact) / multscalars[i] + lb(multvars[i])
*/
aggrvarsol2 = (candsol - maxact) / multscalars[i] + multvarlb;
/* cand <= candsol
* if multvars[i] >= (candsol - (minact - multscalar[i] * ub(multvars[i]))) / multscalars[i]
* = (candsol - minact) / multscalars[i] + ub(multvars[i])
*/
aggrvarsol1 = (candsol - minact) / multscalars[i] + multvarub;
}
/* by the above choice, aggrvarsol1 <= ub(multvars[i]) and aggrvarsol2 >= lb(multvars[i])
* if aggrvarsol1 <= lb(multvars[i]) or aggrvarsol2 >= ub(multvars[i]), then choose the other one
* if both are out of bounds, then give up
* if both are inside bounds, then choose the one closer to 0.0 (someone has better idea???)
*/
if( SCIPisFeasLE(scip, aggrvarsol1, multvarlb) )
{
if( SCIPisFeasGE(scip, aggrvarsol2, multvarub) )
continue;
else
aggrvarsol = aggrvarsol2;
}
else
{
if( SCIPisFeasGE(scip, aggrvarsol2, multvarub) )
aggrvarsol = aggrvarsol1;
else
aggrvarsol = REALABS(aggrvarsol1) < REALABS(aggrvarsol2) ? aggrvarsol1 : aggrvarsol2;
}
success = TRUE;
updateBestCandidate(scip, bestvar, bestscore, bestobj, bestsol,
multvars[i], candscore, aggrvarsol);
}
}
if( !success )
for( i = 0; i < nmultvars; ++i )
{
/* skip fixed variables */
multvarlb = SCIPcomputeVarLbLocal(scip, multvars[i]);
multvarub = SCIPcomputeVarUbLocal(scip, multvars[i]);
if( SCIPisEQ(scip, multvarlb, multvarub) )
continue;
updateBestCandidate(scip, bestvar, bestscore, bestobj, bestsol,
multvars[i], candscore, SCIP_INVALID);
}
assert(*bestvar != NULL); /* if all variables were fixed, something is strange */
return;
}
candscore *= SCIPvarGetBranchFactor(cand);
obj = SCIPvarGetObj(cand);
obj = REALABS(obj);
if( SCIPisInfinity(scip, *bestscore)
|| (!SCIPisInfinity(scip, candscore) &&
(SCIPisLT(scip, candscore, *bestscore) || (SCIPisLE(scip, candscore, *bestscore) && obj > *bestobj))) )
{
*bestvar = cand;
*bestscore = candscore;
*bestobj = obj;
*bestsol = candsol;
}
}
/** selects a random active variable from a given list of variables */
static
void getRandomVariable(
SCIP* scip, /**< SCIP data structure */
SCIP_VAR** cands, /**< array of branching candidates */
SCIP_Real* candssol, /**< relaxation solution values of branching candidates, or NULL */
int ncands, /**< number of branching candidates */
SCIP_VAR** bestcand, /**< buffer to store pointer to best candidate */
SCIP_Real* bestcandsol, /**< buffer to store solution value of best candidate */
unsigned int* seed /**< seed for random number generator */
)
{
int idx;
int firstidx;
assert(scip != NULL);
assert(cands != NULL);
assert(ncands > 0);
assert(bestcand != NULL);
assert(bestcandsol != NULL);
assert(seed != NULL);
idx = SCIPgetRandomInt(0, ncands-1, seed);
assert(idx >= 0);
/* handle case where cands[idx] is fixed by selecting next idx with unfixed var
* this may happen if we are inside a multi-aggregation */
firstidx = idx;
while( SCIPisEQ(scip, SCIPvarGetLbLocal(cands[idx]), SCIPvarGetUbLocal(cands[idx])) )
{
++idx;
if( idx == ncands )
idx = 0;
if( idx == firstidx )
{
/* odd: all variables seem to be fixed */
SCIPdebugMessage("Warning: all branching candidates seem to be fixed\n");
return;
}
}
/* a branching variable candidate should either be an active problem variable or a multi-aggregated variable */
assert(SCIPvarIsActive(SCIPvarGetProbvar(cands[idx])) ||
SCIPvarGetStatus(SCIPvarGetProbvar(cands[idx])) == SCIP_VARSTATUS_MULTAGGR);
if( SCIPvarGetStatus(SCIPvarGetProbvar(cands[idx])) == SCIP_VARSTATUS_MULTAGGR )
{
/* for a multi-aggregated variable, we call the getRandomVariable function recursively with all variables in the multi-aggregation */
SCIP_VAR* cand;
cand = SCIPvarGetProbvar(cands[idx]);
getRandomVariable(scip, SCIPvarGetMultaggrVars(cand), NULL, SCIPvarGetMultaggrNVars(cand), bestcand, bestcandsol, seed);
return;
}
assert(idx >= 0 && idx < ncands);
*bestcand = cands[idx];
assert(*bestcand != NULL);
if( candssol != NULL )
*bestcandsol = candssol[idx];
}
/** reads a given SCIP solution file, problem has to be transformed in advance */
static
SCIP_RETCODE readSol(
SCIP* scip, /**< SCIP data structure */
const char* fname /**< name of the input file */
)
{
SCIP_SOL* sol;
SCIP_FILE* file;
SCIP_Bool error;
SCIP_Bool unknownvariablemessage;
SCIP_Bool stored;
SCIP_Bool usevartable;
int lineno;
assert(scip != NULL);
assert(fname != NULL);
SCIP_CALL( SCIPgetBoolParam(scip, "misc/usevartable", &usevartable) );
if( !usevartable )
{
SCIPerrorMessage("Cannot read solution file if vartable is disabled. Make sure parameter 'misc/usevartable' is set to TRUE.\n");
return SCIP_READERROR;
}
/* open input file */
file = SCIPfopen(fname, "r");
if( file == NULL )
{
SCIPerrorMessage("cannot open file <%s> for reading\n", fname);
SCIPprintSysError(fname);
return SCIP_NOFILE;
}
/* create zero solution */
SCIP_CALL( SCIPcreateSol(scip, &sol, NULL) );
/* read the file */
error = FALSE;
unknownvariablemessage = FALSE;
lineno = 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;
int nread;
/* get next line */
if( SCIPfgets(buffer, (int) sizeof(buffer), file) == NULL )
break;
lineno++;
/* there are some lines which may preceed the solution information */
if( strncasecmp(buffer, "solution status:", 16) == 0 || strncasecmp(buffer, "objective value:", 16) == 0 ||
strncasecmp(buffer, "Log started", 11) == 0 || strncasecmp(buffer, "Variable Name", 13) == 0 ||
strncasecmp(buffer, "All other variables", 19) == 0 || strncasecmp(buffer, "\n", 1) == 0 ||
strncasecmp(buffer, "NAME", 4) == 0 || strncasecmp(buffer, "ENDATA", 6) == 0 ) /* allow parsing of SOL-format on the MIPLIB 2003 pages */
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, fname, buffer);
error = TRUE;
break;
}
/* find the variable */
var = SCIPfindVar(scip, varname);
if( var == NULL )
{
if( !unknownvariablemessage )
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "unknown variable <%s> in line %d of solution file <%s>\n",
varname, lineno, fname);
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, " (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, fname);
error = TRUE;
break;
}
}
/* set the solution value of the variable, if not multiaggregated */
if( SCIPisTransformed(scip) && SCIPvarGetStatus(SCIPvarGetProbvar(var)) == SCIP_VARSTATUS_MULTAGGR )
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "ignored solution value for multiaggregated variable <%s>\n", SCIPvarGetName(var));
}
else
{
SCIP_RETCODE retcode;
retcode = SCIPsetSolVal(scip, sol, var, value);
if( retcode == SCIP_INVALIDDATA )
{
if( SCIPvarGetStatus(SCIPvarGetProbvar(var)) == SCIP_VARSTATUS_FIXED )
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "ignored conflicting solution value for fixed variable <%s>\n",
SCIPvarGetName(var));
}
else
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "ignored solution value for multiaggregated variable <%s>\n",
SCIPvarGetName(var));
}
}
else
{
SCIP_CALL( retcode );
}
}
}
/* close input file */
SCIPfclose(file);
if( !error )
{
/* add and free the solution */
if( SCIPisTransformed(scip) )
{
SCIP_CALL( SCIPtrySolFree(scip, &sol, TRUE, TRUE, TRUE, TRUE, &stored) );
/* display result */
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "primal solution from solution file <%s> was %s\n",
fname, stored ? "accepted" : "rejected - solution is infeasible or objective too poor");
}
else
{
/* add primal solution to solution candidate storage, frees the solution afterwards */
SCIP_CALL( SCIPaddSolFree(scip, &sol, &stored) );
/* display result */
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "primal solution from solution file <%s> was %s\n",
fname, stored ? "accepted as candidate, will be checked when solving starts" : "rejected - solution objective too poor");
}
return SCIP_OKAY;
}
else
{
/* free solution */
SCIP_CALL( SCIPfreeSol(scip, &sol) );
return SCIP_READERROR;
}
}
/** reads a given xml solution file */
static
SCIP_RETCODE readXMLSol(
SCIP* scip, /**< SCIP data structure */
const char* filename /**< name of the input file */
)
{
SCIP_Bool unknownvariablemessage;
SCIP_SOL* sol;
SCIP_Bool error;
XML_NODE* start;
const XML_NODE* varsnode;
const XML_NODE* varnode;
const char* tag;
assert( scip != NULL );
assert( filename != NULL );
/* read xml file */
start = xmlProcess(filename);
if( start == NULL )
{
SCIPerrorMessage("Some error occured during parsing the XML solution file.\n");
return SCIP_READERROR;
}
/* create zero solution */
SCIP_CALL( SCIPcreateSol(scip, &sol, NULL) );
error = FALSE;
/* find variable sections */
tag = "variables";
varsnode = xmlFindNodeMaxdepth(start, tag, 0, 3);
if( varsnode == NULL )
{
/* free xml data */
xmlFreeNode(start);
SCIPerrorMessage("Variable section not found.\n");
return SCIP_READERROR;
}
/* loop through all variables */
unknownvariablemessage = FALSE;
for( varnode = xmlFirstChild(varsnode); varnode != NULL; varnode = xmlNextSibl(varnode) )
{
SCIP_VAR* var;
const char* varname;
const char* varvalue;
SCIP_Real value;
int nread;
/* find variable name */
varname = xmlGetAttrval(varnode, "name");
if( varname == NULL )
{
SCIPerrorMessage("Attribute \"name\" of variable not found.\n");
error = TRUE;
break;
}
/* find the variable */
var = SCIPfindVar(scip, varname);
if( var == NULL )
{
if( !unknownvariablemessage )
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "unknown variable <%s> of solution file <%s>\n",
varname, filename);
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, " (further unknown variables are ignored)\n");
unknownvariablemessage = TRUE;
}
continue;
}
/* find value of variable */
varvalue = xmlGetAttrval(varnode, "value");
if( varvalue == NULL )
{
SCIPerrorMessage("Attribute \"value\" of variable not found.\n");
error = TRUE;
break;
}
/* cast the value */
if( strncasecmp(varvalue, "inv", 3) == 0 )
continue;
else if( strncasecmp(varvalue, "+inf", 4) == 0 || strncasecmp(varvalue, "inf", 3) == 0 )
value = SCIPinfinity(scip);
else if( strncasecmp(varvalue, "-inf", 4) == 0 )
value = -SCIPinfinity(scip);
else
{
nread = sscanf(varvalue, "%lf", &value);
if( nread != 1 )
{
SCIPwarningMessage(scip, "invalid solution value <%s> for variable <%s> in XML solution file <%s>\n", varvalue, varname, filename);
error = TRUE;
break;
}
}
/* set the solution value of the variable, if not multiaggregated */
if( SCIPisTransformed(scip) && SCIPvarGetStatus(SCIPvarGetProbvar(var)) == SCIP_VARSTATUS_MULTAGGR )
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "ignored solution value for multiaggregated variable <%s>\n", SCIPvarGetName(var));
}
else
{
SCIP_RETCODE retcode;
retcode = SCIPsetSolVal(scip, sol, var, value);
if( retcode == SCIP_INVALIDDATA )
{
if( SCIPvarGetStatus(SCIPvarGetProbvar(var)) == SCIP_VARSTATUS_FIXED )
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "ignored conflicting solution value for fixed variable <%s>\n",
SCIPvarGetName(var));
}
else
{
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "ignored solution value for multiaggregated variable <%s>\n",
SCIPvarGetName(var));
}
}
else
{
SCIP_CALL( retcode );
}
}
}
if( !error )
{
SCIP_Bool stored;
/* add and free the solution */
if( SCIPisTransformed(scip) )
{
SCIP_CALL( SCIPtrySolFree(scip, &sol, TRUE, TRUE, TRUE, TRUE, &stored) );
/* display result */
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "primal solution from solution file <%s> was %s\n",
filename, stored ? "accepted" : "rejected - solution is infeasible or objective too poor");
}
else
{
SCIP_CALL( SCIPaddSolFree(scip, &sol, &stored) );
/* display result */
SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "primal solution from solution file <%s> was %s\n",
filename, stored ? "accepted as candidate, will be checked when solving starts" : "rejected - solution objective too poor");
}
}
else
{
/* free solution */
SCIP_CALL( SCIPfreeSol(scip, &sol) );
/* free xml data */
xmlFreeNode(start);
return SCIP_READERROR;
}
/* free xml data */
xmlFreeNode(start);
return SCIP_OKAY;
}
/** reads the blocks section */
static
SCIP_RETCODE readBlock(
SCIP* scip, /**< SCIP data structure */
DECINPUT* decinput, /**< DEC reading data */
SCIP_READERDATA* readerdata /**< reader data */
)
{
int oldblock;
int varidx;
int consindex;
int i;
int blockid;
int nvars;
SCIP_CONS* cons;
SCIP_VAR** vars;
SCIP_Bool conshasvar;
assert(decinput != NULL);
assert(readerdata != NULL);
while( getNextToken(decinput) )
{
/* check if we reached a new section */
if( isNewSection(scip, decinput) )
break;
/* the token must be the name of an existing cons */
cons = SCIPfindCons(scip, decinput->token);
if( cons == NULL )
{
syntaxError(scip, decinput, "unknown constraint in block section");
break;
}
conshasvar = FALSE;
/* get all vars for the specific constraint */
nvars = SCIPgetNVarsXXX(scip, cons);
vars = NULL;
if( nvars > 0 )
{
SCIP_CALL( SCIPallocMemoryArray(scip, &vars, nvars) );
SCIP_CALL( SCIPgetVarsXXX(scip, cons, vars, nvars) );
}
blockid = decinput->blocknr;
for( i = 0; i < nvars; i ++ )
{
SCIP_VAR* var;
assert(vars != NULL); /* for flexelint */
if( decinput->presolved )
{
var = SCIPvarGetProbvar(vars[i]);
if( !SCIPisVarRelevant(var) )
continue;
}
else
var = vars[i];
conshasvar = TRUE;
/* store for each var whether it is in none, one or more blocks */
varidx = SCIPvarGetProbindex(var);
assert(varidx >= 0 && varidx < SCIPgetNVars(scip));
oldblock = readerdata->varstoblock[varidx];
assert(oldblock == NOVALUE || oldblock == LINKINGVALUE || (oldblock >= 0 && oldblock < decinput->nblocks));
/* variable was assigned to no block before, just assign it to the new block */
if( oldblock == NOVALUE )
{
SCIPdebugMessage("\tVar %s temporary in block %d.\n", SCIPvarGetName(vars[i]), blockid);
readerdata->varstoblock[varidx] = blockid;
++(readerdata->nblockvars[blockid]);
}
/* variable was assigned to another (non-linking) block before, so it becomes a linking variable, now */
else if( (oldblock != LINKINGVALUE) && oldblock != blockid )
{
SCIPdebugMessage("\tVar %s is linking (old %d != %d new).\n", SCIPvarGetName(vars[i]), oldblock, blockid);
assert(oldblock != blockid);
readerdata->varstoblock[varidx] = LINKINGVALUE;
/* decrease the value again if it is a linking var */
--(readerdata->nblockvars[oldblock]);
++(readerdata->nlinkingvars);
}
}
SCIPfreeMemoryArrayNull(scip, &vars);
if( !conshasvar )
{
assert(!SCIPhashmapExists(readerdata->constoblock, cons));
SCIPwarningMessage(scip, "Cons <%s> has been deleted by presolving, skipping.\n", SCIPconsGetName(cons));
continue;
}
/*
* saving block <-> constraint
*/
/** @todo check if linking constraints are not in the subscipcons */
consindex = readerdata->nblockconss[blockid];
readerdata->blockconss[blockid][consindex] = cons;
++(readerdata->nblockconss[blockid]);
assert(SCIPhashmapGetImage(readerdata->constoblock, cons) == (void*)(size_t) LINKINGVALUE);
SCIPdebugMessage("cons %s is in block %d\n", SCIPconsGetName(cons), blockid);
SCIP_CALL( SCIPhashmapSetImage(readerdata->constoblock, cons, (void*) ((size_t) blockid)) );
--(readerdata->nlinkingconss);
}
return SCIP_OKAY;
}
