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Change LinkGraph::EdgeMatrix to a sparse storage format

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Use a btree_map instead of a SmallMatrix.
This avoids excessive storage requirements for large graphs,
and overly expensive edge matrix resize operations.
Remove next_edge iteration mechanism.
This commit is contained in:
Jonathan G Rennison
2022-12-05 18:17:25 +00:00
parent c457dc680b
commit e647075870
16 changed files with 353 additions and 470 deletions
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40
src/linkgraph/mcf.cpp
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@@ -112,8 +112,10 @@ public:
class GraphEdgeIterator {
private:
LinkGraphJob &job; ///< Job being executed
EdgeIterator i; ///< Iterator pointing to current edge.
EdgeIterator end; ///< Iterator pointing beyond last edge.
LinkGraph::EdgeMatrix::const_iterator i; ///< Iterator pointing to current edge.
LinkGraph::EdgeMatrix::const_iterator end; ///< Iterator pointing beyond last edge.
NodeID node; ///< Source node
const LinkGraph::BaseEdge *saved; ///< Saved edge
public:
@@ -122,7 +124,7 @@ public:
* @param job Job to iterate on.
*/
GraphEdgeIterator(LinkGraphJob &job) : job(job),
i(nullptr, nullptr, INVALID_NODE), end(nullptr, nullptr, INVALID_NODE)
i(LinkGraph::EdgeMatrix::const_iterator()), end(LinkGraph::EdgeMatrix::const_iterator()), node(INVALID_NODE), saved(nullptr)
{}
/**
@@ -132,8 +134,9 @@ public:
*/
void SetNode(NodeID source, NodeID node)
{
this->i = this->job[node].Begin();
this->end = this->job[node].End();
this->i = this->job.Graph().GetEdges().lower_bound(std::make_pair(node, (NodeID)0));
this->end = this->job.Graph().GetEdges().end();
this->node = node;
}
/**
@@ -142,8 +145,18 @@ public:
*/
NodeID Next()
{
return this->i != this->end ? (this->i++)->first : INVALID_NODE;
if (this->i == this->end) return INVALID_NODE;
NodeID from = this->i->first.first;
NodeID to = this->i->first.second;
if (from != this->node) return INVALID_NODE;
this->saved = &(this->i->second);
++this->i;
return to;
}
bool SavedEdge() const { return true; }
const LinkGraph::BaseEdge &GetSavedEdge() { return *(this->saved); }
};
/**
@@ -205,6 +218,10 @@ public:
if (this->it == this->end) return INVALID_NODE;
return this->station_to_node[(this->it++)->second];
}
bool SavedEdge() const { return false; }
const LinkGraph::BaseEdge &GetSavedEdge() { NOT_REACHED(); }
};
/**
@@ -303,7 +320,8 @@ void MultiCommodityFlow::Dijkstra(NodeID source_node, PathVector &paths)
iter.SetNode(source_node, from);
for (NodeID to = iter.Next(); to != INVALID_NODE; to = iter.Next()) {
if (to == from) continue; // Not a real edge but a consumption sign.
Edge edge = this->job[from][to];
const LinkGraph::BaseEdge &base_edge = iter.SavedEdge() ? iter.GetSavedEdge() : this->job.GetBaseEdge(from, to);
Edge edge = this->job[from].MakeEdge(base_edge, to);
uint capacity = edge.Capacity();
if (this->max_saturation != UINT_MAX) {
capacity *= this->max_saturation;
@@ -379,7 +397,7 @@ void MultiCommodityFlow::CleanupPaths(NodeID source_id, PathVector &paths)
* @param max_saturation If < UINT_MAX only push flow up to the given
* saturation, otherwise the path can be "overloaded".
*/
uint MultiCommodityFlow::PushFlow(Edge &edge, Path *path, uint accuracy,
uint MultiCommodityFlow::PushFlow(AnnoEdge &edge, Path *path, uint accuracy,
uint max_saturation)
{
assert(edge.UnsatisfiedDemand() > 0);
@@ -428,7 +446,7 @@ void MCF1stPass::EliminateCycle(PathVector &path, Path *cycle_begin, uint flow)
}
}
cycle_begin = path[prev];
Edge edge = this->job[prev][cycle_begin->GetNode()];
AnnoEdge edge = this->job[prev][cycle_begin->GetNode()];
edge.RemoveFlow(flow);
} while (cycle_begin != cycle_end);
}
@@ -556,7 +574,7 @@ MCF1stPass::MCF1stPass(LinkGraphJob &job) : MultiCommodityFlow(job)
bool source_demand_left = false;
for (NodeID dest = 0; dest < size; ++dest) {
Edge edge = job[source][dest];
AnnoEdge edge = job[source][dest];
if (edge.UnsatisfiedDemand() > 0) {
Path *path = paths[dest];
assert(path != nullptr);
@@ -603,7 +621,7 @@ MCF2ndPass::MCF2ndPass(LinkGraphJob &job) : MultiCommodityFlow(job)
bool source_demand_left = false;
for (NodeID dest = 0; dest < size; ++dest) {
Edge edge = this->job[source][dest];
AnnoEdge edge = this->job[source][dest];
Path *path = paths[dest];
if (edge.UnsatisfiedDemand() > 0 && path->GetFreeCapacity() > INT_MIN) {
this->PushFlow(edge, path, accuracy, UINT_MAX);