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[routing] Review fixes

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Mikhail Gorbushin 2019-11-27 18:43:05 +03:00 • committed by Vladimir Byko-Ianko
parent 49024a9130
commit ea7b0abadc
1 changed files with 13 additions and 5 deletions
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18
routing/base/astar_algorithm.hpp
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@ -279,9 +279,17 @@ private:
return bestDistance.at(queue.top().vertex);
}
// p_f(v) = 0.5*(π_f(v) - π_r(v)) + 0.5*π_r(t)
// p_r(v) = 0.5*(π_r(v) - π_f(v)) + 0.5*π_f(s)
// p_r(v) + p_f(v) = const. Note: this condition is called consistence.
// p_f(v) = 0.5*(π_f(v) - π_r(v))
// p_r(v) = 0.5*(π_r(v) - π_f(v))
// p_r(v) + p_f(v) = const. This condition is called consistence.
//
// Note. Adding constant terms to p_f(v) or p_r(v) does
// not violate the consistence so a common choice is
// p_f(v) = 0.5*(π_f(v) - π_r(v)) + 0.5*π_r(t)
// p_r(v) = 0.5*(π_r(v) - π_f(v)) + 0.5*π_f(s)
// which leads to p_f(t) = 0 and p_r(s) = 0.
// However, with constants set to zero understanding
// particular routes when debugging turned out to be easier.
Weight ConsistentHeuristic(Vertex const & v) const
{
auto const piF = graph.HeuristicCostEstimate(v, finalVertex);
@ -568,7 +576,7 @@ AStarAlgorithm<Vertex, Edge, Weight>::FindPathBidirectional(P & params,
// We do not yet have the proof that we will not miss a good path by doing so.
// The shortest reduced path corresponds to the shortest real path
// because the heuristics we use are consistent.
// because the heuristic we use are consistent.
// It would be a mistake to make a decision based on real path lengths because
// several top states in a priority queue may have equal reduced path lengths and
// different real path lengths.
@ -587,7 +595,7 @@ AStarAlgorithm<Vertex, Edge, Weight>::FindPathBidirectional(P & params,
cur->forward ? cur->finalVertex : cur->startVertex);
cur->GetAdjacencyList(stateV.vertex, adj);
auto const pV = stateV.heuristic;
auto const & pV = stateV.heuristic;
for (auto const & edge : adj)
{
State stateW(edge.GetTarget(), kZeroDistance);