osrm-backend/include/contractor/contract_excludable_graph.hpp
Patrick Niklaus 61c430c098 Implement exclude flags on CH using shared core
The core is fully contracted for each exclude flag
and stored in a merged graph data structure.
2017-09-01 21:26:00 +02:00

88 lines
3.3 KiB
C++

#ifndef OSRM_CONTRACTOR_CONTRACT_EXCLUDABLE_GRAPH_HPP
#define OSRM_CONTRACTOR_CONTRACT_EXCLUDABLE_GRAPH_HPP
#include "contractor/contracted_edge_container.hpp"
#include "contractor/contractor_graph.hpp"
#include "contractor/graph_contractor.hpp"
#include "contractor/graph_contractor_adaptors.hpp"
#include "contractor/query_graph.hpp"
namespace osrm
{
namespace contractor
{
using GraphFilterAndCore =
std::tuple<QueryGraph, std::vector<std::vector<bool>>, std::vector<std::vector<bool>>>;
inline auto contractExcludableGraph(ContractorGraph contractor_graph_,
std::vector<EdgeWeight> node_weights,
const std::vector<std::vector<bool>> &filters,
const float core_factor = 1.0)
{
auto num_nodes = contractor_graph_.GetNumberOfNodes();
ContractedEdgeContainer edge_container;
ContractorGraph shared_core_graph;
std::vector<bool> is_shared_core;
{
ContractorGraph contractor_graph = std::move(contractor_graph_);
std::vector<bool> always_allowed(num_nodes, true);
for (const auto &filter : filters)
{
for (const auto node : util::irange<NodeID>(0, num_nodes))
{
always_allowed[node] = always_allowed[node] && filter[node];
}
}
// By not contracting all contractable nodes we avoid creating
// a very dense core. This increases the overall graph sizes a little bit
// but increases the final CH quality and contraction speed.
constexpr float BASE_CORE = 0.9;
is_shared_core = contractGraph(contractor_graph,
std::move(always_allowed),
node_weights,
std::min<float>(BASE_CORE, core_factor));
// Add all non-core edges to container
{
auto non_core_edges = toEdges<QueryEdge>(contractor_graph);
auto new_end =
std::remove_if(non_core_edges.begin(), non_core_edges.end(), [&](const auto &edge) {
return is_shared_core[edge.source] && is_shared_core[edge.target];
});
non_core_edges.resize(new_end - non_core_edges.begin());
edge_container.Insert(std::move(non_core_edges));
}
// Extract core graph for further contraction
shared_core_graph = contractor_graph.Filter(
[&is_shared_core](const NodeID node) { return is_shared_core[node]; });
}
std::vector<std::vector<bool>> cores;
for (const auto &filter : filters)
{
auto filtered_core_graph =
shared_core_graph.Filter([&filter](const NodeID node) { return filter[node]; });
auto core = contractGraph(
filtered_core_graph, is_shared_core, is_shared_core, node_weights, core_factor);
if (core_factor == 1.0)
{
core.clear();
}
cores.push_back(std::move(core));
edge_container.Merge(toEdges<QueryEdge>(std::move(filtered_core_graph)));
}
return GraphFilterAndCore{QueryGraph{num_nodes, std::move(edge_container.edges)},
edge_container.MakeEdgeFilters(),
std::move(cores)};
}
}
}
#endif