void ParQGHandler::separate(ConstSolutionPtr sol, NodePtr , RelaxationPtr rel,
CutManager *cutMan, SolutionPoolPtr s_pool, ModVector &,
ModVector &, bool *sol_found, SeparationStatus *status)
{
double val;
VariableType v_type;
VariableConstIterator v_iter;
const double *x = sol->getPrimal();
*status = SepaContinue;
for (v_iter = rel->varsBegin(); v_iter != rel->varsEnd(); ++v_iter) {
v_type = (*v_iter)->getType();
if (v_type == Binary || v_type == Integer) {
val = x[(*v_iter)->getIndex()];
if (fabs(val - floor(val+0.5)) > intTol_) {
#if SPEW
logger_->msgStream(LogDebug) << me_ << "variable " <<
(*v_iter)->getName() << " has fractional value = " << val <<
std::endl;
#endif
return;
}
}
}
cutIntSol_(sol, cutMan, s_pool, sol_found, status);
return;
}
void KnapCovHandler::separate(ConstSolutionPtr sol, NodePtr,
RelaxationPtr rel, CutManager * cmanager,
SolutionPoolPtr , bool * ,
SeparationStatus * status)
{
// Check integer feasibility of sol, must add cuts if it is not integral.
numvars_ = minlp_->getNumVars();
VariableType type;
const double * x = sol->getPrimal();
// Is the relaxation solution is integer feasible.
bool isintfeas = true;
// Iterators for variables.
VariableConstIterator it;
VariableConstIterator begin = rel->varsBegin();
VariableConstIterator end = rel->varsEnd();
// Temporary variable holder.
ConstVariablePtr var;
// Value of variable.
double value;
bool separated = false;
UInt n_added = 0;
// Check if integrality is satisfied for each integer variable.
for (it=begin; it!=end; ++it) {
var = *it;
type = var->getType();
if (type==Binary || type==Integer) {
value = x[var->getIndex()];
if (fabs(value - floor(value + 0.5)) > intTol_) {
isintfeas = false;
break;
}
}
}
if (isintfeas == false) {
// We do another check in CoverCutGneerator for integrality, may be we
// should eliminate it and use the one above.
// Generate cover cuts from current relaxation.
CoverCutGeneratorPtr cover = (CoverCutGeneratorPtr) new CoverCutGenerator(rel,sol, env_);
// Add cuts to the relaxation by using cut manager.
CutVector violatedcuts = cover->getViolatedCutList();
CutIterator itc;
CutIterator beginc = violatedcuts.begin();
CutIterator endc = violatedcuts.end();
// Serdar I am not sure if we should add the constraints generated by
// addCuts to the constraint vector of knapsack cover handler.
// Currently CutMan2::addCuts does not add the cuts to the relaxation formulation.
cmanager->addCuts(beginc, endc);
cmanager->separate(rel, sol, &separated, &n_added);
if (n_added>0) {
*status = SepaResolve;
}
// Update statistics by using return from cover cut generator.
ConstCovCutGenStatsPtr covstats = cover->getStats();
// Later put the code below to updateStats function.
stats_->knaps += covstats->knaps;
stats_->cuts += covstats->cuts;
stats_->extended += covstats->extended;
stats_->simple += covstats->simple;
stats_->gns += covstats->gns;
stats_->singlectwo += covstats->singlectwo;
}
}
