void Magnusson::backtrack(Node* start, TrackingAlgorithm::Path& p, TrackingAlgorithm::VisitorFunction nodeVisitor)
{
p.clear();
Node* current = start;
while(current != &(graph_->getSourceNode()))
{
nodeVisitor(current);
Arc* bestArc = nullptr;
if(current == start)
bestArc = selectorFunction_(current);
else
bestArc = current->getBestInArc();
assert(bestArc != nullptr);
assert(bestArc->isEnabled());
if(bestArc->getType() != Arc::Dummy)
bestArc->markUsed();
p.push_back(bestArc);
current = bestArc->getSourceNode();
}
nodeVisitor(current);
std::reverse(p.begin(), p.end());
}
void Magnusson::cleanUpUsedSwapArcs(TrackingAlgorithm::Path &p, std::vector<Path>& paths)
{
std::vector<Arc*> usedSwapArcs;
// if a swap arc was used, we can find the path that was affected by this and create the two paths after swapping
bool foundSwapArc = true;
while(foundSwapArc)
{
foundSwapArc = false;
for(std::vector<Arc*>::reverse_iterator p_it = p.rbegin(); p_it != p.rend(); ++p_it)
{
// FIXME: sometimes points to free'd memory location?
Arc* arc = *p_it;
if(arc->getType() == Arc::Swap)
{
assert(arc->getUserData());
Arc* arcToRemove = std::static_pointer_cast<MagnussonSwapArcUserData>(arc->getUserData())->getCutArc();
Arc* replacementP = std::static_pointer_cast<MagnussonSwapArcUserData>(arc->getUserData())->getReplacementAArc();
Arc* replacementPath = std::static_pointer_cast<MagnussonSwapArcUserData>(arc->getUserData())->getReplacementBArc();
assert(arcToRemove != nullptr);
assert(replacementP != nullptr);
assert(replacementPath != nullptr);
DEBUG_MSG("Trying to remove swap arc between " << arc->getSourceNode()->getUserData()->toString() << " and " << arc->getTargetNode()->getUserData()->toString());
for(Path& path : paths)
{
for(Node::ArcIt path_it = path.begin(); path_it != path.end(); ++path_it)
{
Arc* a = *path_it;
if(a == arcToRemove)
{
// found candidate. store part of original path that will be used by new path
Path temp(path_it+1, path.end());
for(Node::ArcIt temp_it = temp.begin(); temp_it != temp.end(); ++temp_it)
{
assert((*temp_it)->getType() != Arc::Swap);
}
// update original path by appending the replacement arc and the remainder of path P
path.erase(path_it, path.end());
path.push_back(replacementPath);
path.insert(path.end(), p_it.base(), p.end());
// update path p
p.erase(p_it.base()-1, p.end());
p.push_back(replacementP);
p.insert(p.end(), temp.begin(), temp.end());
if(usedArcsScoreZero_)
{
replacementPath->markUsed();
replacementP->markUsed();
// "unuse" the arc that was previously used
arcToRemove->markUsed(false);
}
// remove all this swap arc
usedSwapArcs.push_back(arc);
#if DEBUG_LOG
DEBUG_MSG("updated two paths. removed swap arc between " << arc->getSourceNode()->getUserData()->toString() << " and " << arc->getTargetNode()->getUserData()->toString());
graph_->print();
#endif
foundSwapArc = true;
break;
}
}
if(foundSwapArc)
break;
}
assert(foundSwapArc);
break;
}
}
}
for(Arc* a: usedSwapArcs)
{
removeSwapArc(a);
}
#ifdef DEBUG_LOG
DEBUG_MSG("Paths after removing swaps:");
printPath(p);
for(Path& path : paths)
printPath(path);
for(Node::ArcIt p_it = p.begin(); p_it != p.end(); ++p_it)
{
assert((*p_it)->getType() != Arc::Swap);
}
#endif
}
