int GetMaxFlowIntPR (PNEANet &Net, const int& SrcNId, const int& SnkNId) {
IAssert(Net->IsNode(SrcNId));
IAssert(Net->IsNode(SnkNId));
if (SrcNId == SnkNId) { return 0; }
TPRManager PRM(Net);
int MaxLabel = PRM.GetMaxLabel();
TNEANet::TNodeI SrcNI = Net->GetNI(SrcNId);
for (int EdgeN = 0; EdgeN < SrcNI.GetOutDeg(); EdgeN++) {
int EId = SrcNI.GetOutEId(EdgeN);
int OutNId = SrcNI.GetOutNId(EdgeN);
if (OutNId != SrcNId) {
int Capacity = PRM.Capacity(EId);
PRM.Flow(EId) = Capacity;
PRM.Excess(OutNId) = Capacity;
}
}
GlobalRelabel(Net, PRM, SrcNId, SnkNId);
PRM.SetLabel(SrcNId, MaxLabel);
int RelabelCount = 1;
int GRRate = Net->GetNodes();
while (PRM.HasActive()) {
int NId = PRM.PopActive();
const TNEANet::TNodeI &NI = Net->GetNI(NId);
int PrevLabel = MaxLabel;
while (PRM.Excess(NId) > 0 && PRM.Label(NId) <= PrevLabel) {
PrevLabel = PRM.Label(NId);
int NbrNId = PushRelabel(PRM, NId, NI);
if (NbrNId != -1 && NbrNId != SnkNId && PRM.Excess(NbrNId) > 0 && !PRM.IsActive(NbrNId)) {
PRM.PushActive(NbrNId);
}
}
if (PRM.Excess(NId) > 0 && PRM.Label(NId) < MaxLabel) {
PRM.PushActive(NId);
}
if (RelabelCount % GRRate == 0) { GlobalRelabel(Net, PRM, SrcNId, SnkNId); }
}
return PRM.Excess(SnkNId);
}
/// Implements the Global Relabeling heuristic. ##TSnap::GlobalRelabel
void GlobalRelabel (PNEANet &Net, TPRManager &PRM, const int& SrcNId, const int& SnkNId) {
TIntQ NodeQ;
int size = Net->GetMxNId();
TIntV NodeV(size);
for (int i = 0; i < size; i++) { NodeV[i] = 0; }
NodeQ.Push(SnkNId);
NodeV[SnkNId] = 1;
int MaxLabel = PRM.GetMaxLabel();
while (!NodeQ.Empty()) {
// Backward search
int NId = NodeQ.Top(); NodeQ.Pop();
const TNEANet::TNodeI &NI = Net->GetNI(NId);
// Check all edges that point out of the current node for those over which flow can be returned.
for (int EdgeN = 0; EdgeN < NI.GetOutDeg(); EdgeN++) {
int OutNId = NI.GetOutNId(EdgeN);
int EId = NI.GetOutEId(EdgeN);
if (!NodeV[OutNId] && PRM.Flow(EId) > 0) {
NodeV[OutNId] = 1;
NodeQ.Push(OutNId);
PRM.SetLabel(OutNId, PRM.Label(NId) + 1);
}
}
// Check all edges that point into the current node for those over which flow can be added.
for (int EdgeN = 0; EdgeN < NI.GetInDeg(); EdgeN++) {
int InNId = NI.GetInNId(EdgeN);
int EId = NI.GetInEId(EdgeN);
if (!NodeV[InNId] && PRM.Capacity(EId) > PRM.Flow(EId)) {
NodeV[InNId] = 1;
NodeQ.Push(InNId);
PRM.SetLabel(InNId, PRM.Label(NId) + 1);
}
}
}
for (TNEANet::TNodeI NI = Net->BegNI(); NI != Net->EndNI(); NI++) {
int NId = NI.GetId();
if (NodeV[NId]) {
if (PRM.Excess(NId) > 0 && PRM.Label(NId) < MaxLabel && NId != SnkNId) {
if (!PRM.IsActive(NId)) { PRM.PushActive(NId); }
}
} else {
if (PRM.IsActive(NId)) { PRM.RemoveActive(NId); }
PRM.SetLabel(NId, MaxLabel);
}
}
}
// Returns the NId where the two directions of search meet up, or -1 if no augmenting path exists. ##TSnap::IntFlowBiDBFS
int IntFlowBiDBFS (const PNEANet &Net, const int& CapIndex, TIntV &Flow, TIntQ &FwdNodeQ, TIntH &PredEdgeH, TIntQ &BwdNodeQ, TIntH &SuccEdgeH, const int& SrcNId, const int& SnkNId) {
FwdNodeQ.Push(SrcNId);
PredEdgeH.AddDat(SrcNId, -1);
BwdNodeQ.Push(SnkNId);
SuccEdgeH.AddDat(SnkNId, -1);
while (!FwdNodeQ.Empty() && !BwdNodeQ.Empty()) {
// Forward search
const TNEANet::TNodeI &FwdNI = Net->GetNI(FwdNodeQ.Top()); FwdNodeQ.Pop();
// Check all edges that point into the current node for those over which flow can be returned.
for (int EdgeN = 0; EdgeN < FwdNI.GetInDeg(); EdgeN++) {
int NextNId = FwdNI.GetInNId(EdgeN);
int NextEId = FwdNI.GetInEId(EdgeN);
if (!PredEdgeH.IsKey(NextNId) && Flow[NextEId] > 0) {
PredEdgeH.AddDat(NextNId, NextEId);
if (SuccEdgeH.IsKey(NextNId)) {
return NextNId;
}
FwdNodeQ.Push(NextNId);
}
}
// Check all edges that point out of the current node for those over which flow can be added.
for (int EdgeN = 0; EdgeN < FwdNI.GetOutDeg(); EdgeN++) {
int NextNId = FwdNI.GetOutNId(EdgeN);
int NextEId = FwdNI.GetOutEId(EdgeN);
if (!PredEdgeH.IsKey(NextNId) && Net->GetIntAttrIndDatE(NextEId, CapIndex) > Flow[NextEId]) {
PredEdgeH.AddDat(NextNId, NextEId);
if (SuccEdgeH.IsKey(NextNId)) {
return NextNId;
}
FwdNodeQ.Push(NextNId);
}
}
// Backward search
const TNEANet::TNodeI &BwdNI = Net->GetNI(BwdNodeQ.Top()); BwdNodeQ.Pop();
// Check all edges that point out of the current node for those over which flow can be returned.
for (int EdgeN = 0; EdgeN < BwdNI.GetOutDeg(); EdgeN++) {
int PrevNId = BwdNI.GetOutNId(EdgeN);
int PrevEId = BwdNI.GetOutEId(EdgeN);
if (!SuccEdgeH.IsKey(PrevNId) && Flow[PrevEId] > 0) {
SuccEdgeH.AddDat(PrevNId, PrevEId);
if (PredEdgeH.IsKey(PrevNId)) {
return PrevNId;
}
BwdNodeQ.Push(PrevNId);
}
}
// Check all edges that point into the current node for those over which flow can be added.
for (int EdgeN = 0; EdgeN < BwdNI.GetInDeg(); EdgeN++) {
int PrevNId = BwdNI.GetInNId(EdgeN);
int PrevEId = BwdNI.GetInEId(EdgeN);
if (!SuccEdgeH.IsKey(PrevNId) && Net->GetIntAttrIndDatE(PrevEId, CapIndex) > Flow[PrevEId]) {
SuccEdgeH.AddDat(PrevNId, PrevEId);
if (PredEdgeH.IsKey(PrevNId)) {
return PrevNId;
}
BwdNodeQ.Push(PrevNId);
}
}
}
return -1;
}
