// Remove the top node from the heap void CbcTree::pop() { # if CBC_DEBUG_HEAP > 2 CbcNode *node = nodes_.front() ; CbcNodeInfo *info = node->nodeInfo() ; assert(info) ; std::cout << " HEAP: Popping node " << node->nodeNumber() << "(" << std::hex << node << std::dec << ") obj " << node->objectiveValue() << ", ref " << info->decrement(0) << ", todo " << info->numberBranchesLeft() << ", refd by " << info->numberPointingToThis() << "." << std::endl ; # endif # if CBC_DEBUG_HEAP > 0 validateHeap() ; # endif nodes_.front()->setOnTree(false); std::pop_heap(nodes_.begin(), nodes_.end(), comparison_); nodes_.pop_back(); # if CBC_DEBUG_HEAP > 0 validateHeap() ; # endif }
// Add a node to the heap void CbcTree::push(CbcNode * x) { x->setNodeNumber(maximumNodeNumber_); maximumNodeNumber_++; # if CBC_DEBUG_HEAP > 2 CbcNodeInfo *info = x->nodeInfo() ; assert(info) ; std::cout << " HEAP: Pushing node " << x->nodeNumber() << "(" << std::hex << x << std::dec << ") obj " << x->objectiveValue() << ", ref " << info->decrement(0) << ", todo " << info->numberBranchesLeft() << ", refd by " << info->numberPointingToThis() << "." << std::endl ; assert(x->objectiveValue() != COIN_DBL_MAX); # endif # if CBC_DEBUG_HEAP > 0 validateHeap() ; # endif x->setOnTree(true); nodes_.push_back(x); std::push_heap(nodes_.begin(), nodes_.end(), comparison_); # if CBC_DEBUG_HEAP > 0 validateHeap() ; # endif }
/* Return the best node from the heap. Note that best is offered a chance (checkIsCutoff) to reevaluate itself and make arbitrary changes. A caller should be prepared to check that the returned node is acceptable. There's quite a bit of suspect code here, much of it disabled in some way. The net effect at present is to return the top node on the heap after offering the node an opportunity to reevaluate itself. Documentation for checkIsCutoff() puts no restrictions on allowable changes. -- lh, 100921 -- */ CbcNode * CbcTree::bestNode(double cutoff) { # if CBC_DEBUG_HEAP > 0 validateHeap() ; # endif /* This code is problematic. As of 100921, there's really no loop. If front() == null, an assert will trigger. checkIsCutoff seems to be work in progress; comments assert that it can make pretty much arbitrary changes to best. If best can change its objective, there's a good possibility the heap is invalid. */ CbcNode * best = NULL; while (!best && nodes_.size()) { best = nodes_.front(); if (best) assert(best->objectiveValue() != COIN_DBL_MAX && best->nodeInfo()); if (best && best->objectiveValue() != COIN_DBL_MAX && best->nodeInfo()) assert (best->nodeInfo()->numberBranchesLeft()); if (best && best->objectiveValue() >= cutoff) { // double check in case node can change its mind! best->checkIsCutoff(cutoff); } if (!best || best->objectiveValue() >= cutoff) { #ifdef JJF_ZERO // take off std::pop_heap(nodes_.begin(), nodes_.end(), comparison_); nodes_.pop_back(); delete best; best = NULL; #else // let code get rid of it assert (best); #endif } } /* See if the comparison object wants us to do a full scan with the alternative criteria. The net effect is to confirm best by the alternative criteria, or identify a competitor and erase it. This code is problematic. Nulling an arbitrary node will in general break the heap property. Disabled some time ago, as noted in several places. */ if (false && best && comparison_.test_->fullScan()) { CbcNode * saveBest = best; size_t n = nodes_.size(); size_t iBest = -1; for (size_t i = 0; i < n; i++) { // temp assert (nodes_[i]); assert (nodes_[i]->nodeInfo()); if (nodes_[i] && nodes_[i]->objectiveValue() != COIN_DBL_MAX && nodes_[i]->nodeInfo()) assert (nodes_[i]->nodeInfo()->numberBranchesLeft()); if (nodes_[i] && nodes_[i]->objectiveValue() < cutoff && comparison_.alternateTest(best, nodes_[i])) { best = nodes_[i]; iBest = i; } } if (best == saveBest) { // can pop // take off std::pop_heap(nodes_.begin(), nodes_.end(), comparison_); nodes_.pop_back(); } else { // make impossible nodes_[iBest] = NULL; } } else if (best) { # if CBC_DEBUG_HEAP > 2 CbcNode *node = nodes_.front() ; CbcNodeInfo *info = node->nodeInfo() ; assert(info) ; std::cout << " bestNode: Popping node " << node->nodeNumber() << "(" << std::hex << node << std::dec << ") obj " << node->objectiveValue() << ", ref " << info->decrement(0) << ", todo " << info->numberBranchesLeft() << ", refd by " << info->numberPointingToThis() << "." << std::endl ; # endif // take off std::pop_heap(nodes_.begin(), nodes_.end(), comparison_); nodes_.pop_back(); } #if CBC_DEBUG_HEAP > 0 validateHeap() ; #endif if (best) best->setOnTree(false); return best; }