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Compute sharing weighted by edge weight

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This ensures that small insignificat turns don't affect the overall
sharing metric too much.
This commit is contained in:
Patrick Niklaus 2018-04-20 22:58:00 +00:00 committed by Patrick Niklaus
parent 1990de7dcc
commit 549216c792
1 changed files with 16 additions and 8 deletions
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24
src/engine/routing_algorithms/alternative_path_mld.cpp
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@ -384,7 +384,7 @@ RandIt filterPackedPathsByLocalOptimality(const WeightedViaNodePackedPath &path,
// Filters unpacked paths compared to all other paths. Mutates range in-place.
// Returns an iterator to the filtered range's new end.
template <typename RandIt> RandIt filterUnpackedPathsBySharing(RandIt first, RandIt last)
template <typename RandIt> RandIt filterUnpackedPathsBySharing(RandIt first, RandIt last, const Facade& facade)
{
util::static_assert_iter_category<RandIt, std::random_access_iterator_tag>();
util::static_assert_iter_value<RandIt, WeightedViaNodeUnpackedPath>();
@ -411,14 +411,22 @@ template <typename RandIt> RandIt filterUnpackedPathsBySharing(RandIt first, Ran
return false;
}
const auto not_seen = [&](const EdgeID edge) { return edges.count(edge) < 1; };
const auto different = std::count_if(begin(unpacked.edges), end(unpacked.edges), not_seen);
EdgeWeight total_weight = 0;
const auto add_if_seen = [&](const EdgeWeight weight, const EdgeID edge) {
auto edge_weight = facade.GetEdgeData(edge).weight;
total_weight += edge_weight;
if (edges.count(edge) > 0)
{
return weight + edge_weight;
}
return weight;
};
const auto difference = different / static_cast<double>(unpacked.edges.size());
BOOST_ASSERT(difference >= 0.);
BOOST_ASSERT(difference <= 1.);
const auto shared_weight = std::accumulate(begin(unpacked.edges), end(unpacked.edges), 0, add_if_seen);
const auto sharing = 1. - difference;
const auto sharing = shared_weight / static_cast<double>(total_weight);
BOOST_ASSERT(sharing >= 0.);
BOOST_ASSERT(sharing <= 1.);
if (sharing > kAtLeastDifferentBy)
{
@ -816,7 +824,7 @@ InternalManyRoutesResult alternativePathSearch(SearchEngineData<Algorithm> &sear
auto unpacked_paths_last = end(unpacked_paths);
unpacked_paths_last = filterUnpackedPathsBySharing(begin(unpacked_paths), end(unpacked_paths));
unpacked_paths_last = filterUnpackedPathsBySharing(begin(unpacked_paths), end(unpacked_paths), facade);
const auto unpacked_paths_first = begin(unpacked_paths);
const auto number_of_unpacked_paths =