/** branching execution method for fractional LP solutions */
static
SCIP_DECL_BRANCHEXECLP(branchExeclpnodereopt)
{/*lint --e{715}*/
assert(branchrule != NULL );
assert(*result != SCIP_BRANCHED);
*result = SCIP_DIDNOTRUN;
if( SCIPisReoptEnabled(scip) && SCIPreoptimizeNode(scip, SCIPgetCurrentNode(scip)) )
{
SCIP_VAR** branchcands;
SCIP_Real* branchcandssol;
SCIP_Real* branchcandsfrac;
int nbranchcands;
SCIP_Bool sbinit;
SCIP_Real objsimrootlp;
SCIP_CALL( SCIPgetBoolParam(scip, "reoptimization/strongbranchinginit", &sbinit) );
SCIP_CALL( SCIPgetRealParam(scip, "reoptimization/objsimrootLP", &objsimrootlp) );
if( sbinit && SCIPgetCurrentNode(scip) == SCIPgetRootNode(scip)
&& SCIPgetReoptSimilarity(scip, SCIPgetNReoptRuns(scip), SCIPgetNReoptRuns(scip)) <= objsimrootlp ) /* check objsimrootlp */
{
/* get branching candidates */
SCIP_CALL( SCIPgetLPBranchCands(scip, &branchcands, &branchcandssol, &branchcandsfrac, NULL, &nbranchcands, NULL) );
/* run strong branching initialization */
if( nbranchcands > 0 )
{
SCIP_CALL( SCIPexecRelpscostBranching(scip, TRUE, branchcands, branchcandssol, branchcandsfrac, nbranchcands, FALSE, result) );
assert(*result == SCIP_DIDNOTRUN || *result == SCIP_CUTOFF || *result == SCIP_REDUCEDDOM);
}
}
if( *result != SCIP_CUTOFF && *result != SCIP_REDUCEDDOM)
{
assert((SCIPnodeGetReoptID(SCIPgetCurrentNode(scip)) == 0 && SCIPnodeGetDepth(SCIPgetCurrentNode(scip)) == 0 )
|| 1 <= SCIPnodeGetReoptID(SCIPgetCurrentNode(scip)));
SCIP_CALL( Exec(scip, result) );
}
}
return SCIP_OKAY;
}
/** branching execution method for not completely fixed pseudo solutions */
static SCIP_DECL_BRANCHEXECPS(branchExecpsnodereopt)
{/*lint --e{715}*/
assert(branchrule != NULL );
assert(*result != SCIP_BRANCHED);
*result = SCIP_DIDNOTRUN;
if( SCIPisReoptEnabled(scip) && SCIPreoptimizeNode(scip, SCIPgetCurrentNode(scip)) )
{
assert((SCIPnodeGetReoptID(SCIPgetCurrentNode(scip)) == 0 && SCIPnodeGetDepth(SCIPgetCurrentNode(scip)) == 0 )
|| 1 <= SCIPnodeGetReoptID(SCIPgetCurrentNode(scip)));
SCIP_CALL( Exec(scip, result) );
}
return SCIP_OKAY;
}
/** Execute the branching of nodes with additional constraints. */
static
SCIP_RETCODE Exec(
SCIP* scip, /**< SCIP data structure */
SCIP_RESULT* result /**< pointer to store the result */
)
{
SCIP_REOPTNODE* reoptnode;
SCIP_NODE* curnode;
SCIP_REOPTTYPE reopttype;
SCIP_Bool localrestart;
unsigned int* childids;
unsigned int curid;
int naddedconss;
int nchilds;
int childnodessize;
int ncreatednodes;
int c;
assert(scip != NULL );
assert(SCIPisReoptEnabled(scip));
curnode = SCIPgetCurrentNode(scip);
assert(curnode != NULL);
curid = SCIPnodeGetReoptID(curnode);
assert(curid >= 1 || SCIPgetRootNode(scip) == curnode);
/* calculate local similarity and delete the induced subtree if the similarity is to low */
localrestart = FALSE;
SCIP_CALL( SCIPcheckReoptRestart(scip, curnode, &localrestart) );
ncreatednodes = 0;
if( localrestart )
{
*result = SCIP_DIDNOTRUN;
goto TERMINATE;
}
SCIPdebugMessage("current node is %lld, ID %u:\n", SCIPnodeGetNumber(curnode), curid);
/* get the corresponding node of the reoptimization tree */
reoptnode = SCIPgetReoptnode(scip, curid);
assert(reoptnode != NULL);
reopttype = (SCIP_REOPTTYPE)SCIPreoptnodeGetType(reoptnode);
/* The current node is equal to the root and dual reductions were performed. Since the root has a special role
* within the reoptimiziation we have to split the root node into several nodes and move all stored child nodes to
* the one representing the root node including all dual reductions as before.
*
* @note If the type is infsubtree, there cannot exist a child node and the method SCIPapplyReopt adds a global valid
* constraint only.
*/
if( curid == 0 )
{
if( reopttype == SCIP_REOPTTYPE_STRBRANCHED || reopttype == SCIP_REOPTTYPE_INFSUBTREE )
{
int ncreatedchilds;
/* apply the reoptimization at the root node */
SCIP_CALL( SCIPsplitReoptRoot(scip, &ncreatedchilds, &naddedconss) );
if( reopttype == SCIP_REOPTTYPE_INFSUBTREE )
{
assert(ncreatedchilds == 0);
assert(naddedconss == 1);
/* there is nothing to do */
*result = SCIP_DIDNOTRUN;
goto TERMINATE;
}
assert(reopttype == SCIP_REOPTTYPE_STRBRANCHED);
assert(ncreatedchilds >= 2);
ncreatednodes += ncreatedchilds;
/* We decrease the counter by one because after splitting the root node and moving all children to the node
* representing the original root with all fixings (caused by dual reductions), we continue reactivating the
* original children nodes of the root. Thus, the node containing all the fixings can be replaced by the children
* nodes
*/
--ncreatednodes;
}
goto REVIVE;
}
/* if we reach this part of the code the current has to be different to the root node */
assert(curid >= 1);
REVIVE:
/* get the IDs of all child nodes */
childnodessize = SCIPreoptnodeGetNChildren(reoptnode);
SCIP_CALL( SCIPallocBufferArray(scip, &childids, childnodessize) );
SCIP_CALL( SCIPgetReoptChildIDs(scip, curnode, childids, childnodessize, &nchilds) );
if( childnodessize < nchilds )
{
childnodessize = SCIPreoptnodeGetNChildren(reoptnode);
SCIP_CALL( SCIPreallocBufferArray(scip, &childids, childnodessize) );
SCIP_CALL( SCIPgetReoptChildIDs(scip, curnode, childids, childnodessize, &nchilds) );
}
assert(nchilds <= childnodessize);
naddedconss = 0;
for(c = 0; c < nchilds; c++)
{
SCIP_NODE** childnodes;
SCIP_Bool success;
unsigned int childid;
int ncreatedchilds;
childid = childids[c];
assert(childid >= 1);
SCIPdebugMessage("process child at ID %u\n", childid);
reoptnode = SCIPgetReoptnode(scip, childid);
assert(reoptnode != NULL);
reopttype = (SCIP_REOPTTYPE)SCIPreoptnodeGetType(reoptnode);
ncreatedchilds = 0;
/* check whether node need to be split */
if( reopttype == SCIP_REOPTTYPE_STRBRANCHED || reopttype == SCIP_REOPTTYPE_INFSUBTREE )
{
/* by default we assume the node get split into two node (because using a constraint to split the node is
* the default case
*/
childnodessize = 2;
}
else
{
/* we only need to reconstruct the node */
childnodessize = 1;
}
/* allocate buffer */
SCIP_CALL( SCIPallocBufferArray(scip, &childnodes, childnodessize) );
/* apply the reoptimization */
SCIP_CALL( SCIPapplyReopt(scip, reoptnode, childid, SCIPnodeGetEstimate(curnode), childnodes, &ncreatedchilds,
&naddedconss, childnodessize, &success) );
if( !success )
{
assert(ncreatedchilds > childnodessize);
/* reallocate buffer memory */
childnodessize = ncreatedchilds+1;
SCIP_CALL( SCIPreallocBufferArray(scip, &childnodes, childnodessize) );
/* apply the reoptimization */
SCIP_CALL( SCIPapplyReopt(scip, reoptnode, childid, SCIPnodeGetEstimate(curnode), childnodes, &ncreatedchilds,
&naddedconss, childnodessize, &success) );
}
assert(success);
/* free buffer memory */
SCIPfreeBufferArray(scip, &childnodes);
ncreatednodes += ncreatedchilds;
}
if( ncreatednodes == 0 )
*result = SCIP_DIDNOTRUN;
else
*result = SCIP_BRANCHED;
/* free the buffer memory */
SCIPfreeBufferArray(scip, &childids);
TERMINATE:
SCIPdebugMessage("**** finish reoptimizing %d child nodes of node %lld ****\n", ncreatednodes, SCIPnodeGetNumber(curnode));
return SCIP_OKAY;
}
/** execution method of primal heuristic */
static
SCIP_DECL_HEUREXEC(heurExecReoptsols)
{/*lint --e{715}*/
SCIP_HEURDATA* heurdata;
SCIP_SOL** sols;
SCIP_Real objsimsol;
SCIP_Bool sepabestsol;
int allocmem;
int nchecksols;
int nsolsadded;
#ifdef SCIP_MORE_DEBUG
int nsolsaddedrun;
#endif
int run;
int max_run;
assert(heur != NULL);
assert(scip != NULL);
*result = SCIP_DIDNOTRUN;
if( !SCIPisReoptEnabled(scip) )
return SCIP_OKAY;
heurdata = SCIPheurGetData(heur);
assert(heurdata != NULL);
max_run = heurdata->maxruns == -1 ? 0 : MAX(0, SCIPgetNReoptRuns(scip)-1-heurdata->maxruns); /*lint !e666*/
nchecksols = heurdata->maxsols == -1 ? INT_MAX : heurdata->maxsols;
SCIP_CALL( SCIPgetRealParam(scip, "reoptimization/objsimsol", &objsimsol) );
SCIP_CALL( SCIPgetBoolParam(scip, "reoptimization/sepabestsol", &sepabestsol) );
/* allocate a buffer array to store the solutions */
allocmem = 20;
SCIP_CALL( SCIPallocBufferArray(scip, &sols, allocmem) );
nsolsadded = 0;
for( run = SCIPgetNReoptRuns(scip); run > max_run && nchecksols > 0; run-- )
{
SCIP_Real sim;
int nsols;
#ifdef SCIP_MORE_DEBUG
nsolsaddedrun = 0;
#endif
nsols = 0;
if( objsimsol == -1 )
sim = 1;
else
sim = SCIPgetReoptSimilarity(scip, run, SCIPgetNReoptRuns(scip)-1);
if( sim >= objsimsol )
{
int s;
/* get solutions of a specific run */
SCIP_CALL( SCIPgetReopSolsRun(scip, run, sols, allocmem, &nsols) );
/* check memory and reallocate */
if( nsols > allocmem )
{
allocmem = nsols;
SCIP_CALL( SCIPreallocBufferArray(scip, &sols, allocmem) );
SCIP_CALL( SCIPgetReopSolsRun(scip, run, sols, allocmem, &nsols) );
}
assert(nsols <= allocmem);
/* update the solutions
* stop, if the maximal number of solutions to be checked is reached
*/
for( s = 0; s < nsols && nchecksols > 0; s++ )
{
SCIP_SOL* sol;
SCIP_Real objsol;
sol = sols[s];
SCIP_CALL( SCIPrecomputeSolObj(scip, sol) );
objsol = SCIPgetSolTransObj(scip, sol);
/* we do not want to add solutions with objective value +infinity.
* moreover, the solution should improve the current primal bound
*/
if( !SCIPisInfinity(scip, objsol) && !SCIPisInfinity(scip, -objsol)
&& SCIPisFeasLT(scip, objsol, SCIPgetCutoffbound(scip)) )
{
SCIP_Bool stored;
SCIP_Bool feasible;
if( sepabestsol )
{
SCIP_CALL( SCIPcheckSolOrig(scip, sol, &feasible, FALSE, TRUE) );
}
else
feasible = TRUE;
if( feasible)
{
/* create a new solution */
SCIP_CALL( createNewSol(scip, heur, sol, &stored) );
if( stored )
{
nsolsadded++;
#ifdef SCIP_MORE_DEBUG
nsolsaddedrun++;
#endif
heurdata->nimprovingsols++;
}
}
}
nchecksols--;
heurdata->ncheckedsols++;
}
}
#ifdef SCIP_MORE_DEBUG
printf(">> heuristic <%s> found %d of %d improving solutions from run %d.\n", HEUR_NAME, nsolsaddedrun, nsols, run);
#endif
}
SCIPdebugMessage(">> heuristic <%s> found %d improving solutions.\n", HEUR_NAME, nsolsadded);
if( nsolsadded > 0 )
*result = SCIP_FOUNDSOL;
else
*result = SCIP_DIDNOTFIND;
/* reset the marks of the checked solutions */
SCIPresetReoptSolMarks(scip);
/* free the buffer array */
SCIPfreeBufferArray(scip, &sols);
return SCIP_OKAY;
}
