/** execution method of primal heuristic */
static
SCIP_DECL_HEUREXEC(heurExecRandrounding) /*lint --e{715}*/
{ /*lint --e{715}*/
SCIP_HEURDATA* heurdata;
SCIP_Bool propagate;
assert(strcmp(SCIPheurGetName(heur), HEUR_NAME) == 0);
assert(result != NULL);
assert(SCIPhasCurrentNodeLP(scip));
*result = SCIP_DIDNOTRUN;
/* only call heuristic, if an optimal LP solution is at hand or if relaxation solution is available */
if( SCIPgetLPSolstat(scip) != SCIP_LPSOLSTAT_OPTIMAL && ! SCIPisRelaxSolValid(scip) )
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;
/* get heuristic data */
heurdata = SCIPheurGetData(heur);
assert(heurdata != NULL);
/* don't call heuristic, if we have already processed the current LP solution but no relaxation solution is available */
if ( SCIPgetNLPs(scip) == heurdata->lastlp && ! SCIPisRelaxSolValid(scip) )
return SCIP_OKAY;
propagate = (!heurdata->propagateonlyroot || SCIPgetDepth(scip) == 0);
/* try to round LP solution */
SCIP_CALL( performLPRandRounding(scip, heurdata, heurtiming, propagate, result) );
return SCIP_OKAY;
}
/** execution method of primal heuristic */
static
SCIP_DECL_HEUREXEC(heurExecGcgrens)
{ /*lint --e{715}*/
SCIP* masterprob;
SCIP_HEURDATA* heurdata; /* heuristic's data */
SCIP_Longint nstallnodes; /* number of stalling nodes for the subproblem */
assert( heur != NULL );
assert( scip != NULL );
assert( result != NULL );
/* get master problem */
masterprob = GCGrelaxGetMasterprob(scip);
assert( masterprob != NULL);
/* get heuristic's data */
heurdata = SCIPheurGetData(heur);
assert( heurdata != NULL );
*result = SCIP_DELAYED;
/* do not execute the heuristic on invalid relaxation solutions
* (which is the case if the node has been cut off)
*/
if( !SCIPisRelaxSolValid(scip) )
{
SCIPdebugMessage("skipping GCG RENS: invalid relaxation solution\n");
return SCIP_OKAY;
}
/* only call heuristic, if an optimal LP solution is at hand */
if( SCIPgetStage(masterprob) > SCIP_STAGE_SOLVING || SCIPgetLPSolstat(masterprob) != SCIP_LPSOLSTAT_OPTIMAL )
return SCIP_OKAY;
*result = SCIP_DIDNOTRUN;
/* only continue with some fractional variables */
if( SCIPgetNExternBranchCands(scip) == 0 )
return SCIP_OKAY;
/* calculate the maximal number of branching nodes until heuristic is aborted */
nstallnodes = (SCIP_Longint)(heurdata->nodesquot * SCIPgetNNodes(scip));
/* reward RENS if it succeeded often */
nstallnodes = (SCIP_Longint)(nstallnodes * 3.0 * (SCIPheurGetNBestSolsFound(heur)+1.0)/(SCIPheurGetNCalls(heur) + 1.0));
nstallnodes -= 100 * SCIPheurGetNCalls(heur); /* count the setup costs for the sub-SCIP as 100 nodes */
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 )
{
SCIPdebugMessage("skipping RENS: nstallnodes=%"SCIP_LONGINT_FORMAT", minnodes=%"SCIP_LONGINT_FORMAT"\n", nstallnodes, heurdata->minnodes);
return SCIP_OKAY;
}
if( SCIPisStopped(scip) )
return SCIP_OKAY;
*result = SCIP_DIDNOTFIND;
SCIP_CALL( SCIPapplyGcgrens(scip, heur, result, heurdata->minfixingrate, heurdata->minimprove,
heurdata->maxnodes, nstallnodes, heurdata->binarybounds, heurdata->uselprows) );
return SCIP_OKAY;
}
