1c1bfd7541
Fixes issue #1864. Given the simple set-up: a --> b --> c ^-----------| This would translate into an edge based graph (ab) -> (bc), (bc) -> (ca), (ca) -> (ab). Starting at the end of the one-way street (ab) and going to the beginning, the query has to find a self-loop within the graph (ab) -> (bc) -> (ca) -> (ab), as both nodes map to the same segment (ab).
248 lines
8.9 KiB
C++
248 lines
8.9 KiB
C++
#ifndef MANY_TO_MANY_ROUTING_HPP
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#define MANY_TO_MANY_ROUTING_HPP
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#include "engine/routing_algorithms/routing_base.hpp"
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#include "engine/search_engine_data.hpp"
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#include "util/typedefs.hpp"
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#include <boost/assert.hpp>
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#include <limits>
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#include <memory>
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#include <unordered_map>
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#include <vector>
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namespace osrm
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{
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namespace engine
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{
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namespace routing_algorithms
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{
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template <class DataFacadeT>
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class ManyToManyRouting final
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: public BasicRoutingInterface<DataFacadeT, ManyToManyRouting<DataFacadeT>>
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{
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using super = BasicRoutingInterface<DataFacadeT, ManyToManyRouting<DataFacadeT>>;
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using QueryHeap = SearchEngineData::QueryHeap;
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SearchEngineData &engine_working_data;
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struct NodeBucket
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{
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unsigned target_id; // essentially a row in the distance matrix
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EdgeWeight distance;
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NodeBucket(const unsigned target_id, const EdgeWeight distance)
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: target_id(target_id), distance(distance)
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{
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}
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};
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using SearchSpaceWithBuckets = std::unordered_map<NodeID, std::vector<NodeBucket>>;
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public:
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ManyToManyRouting(DataFacadeT *facade, SearchEngineData &engine_working_data)
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: super(facade), engine_working_data(engine_working_data)
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{
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}
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~ManyToManyRouting() {}
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std::shared_ptr<std::vector<EdgeWeight>>
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operator()(const std::vector<PhantomNode> &phantom_sources_array,
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const std::vector<PhantomNode> &phantom_targets_array) const
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{
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const auto number_of_sources = phantom_sources_array.size();
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const auto number_of_targets = phantom_targets_array.size();
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std::shared_ptr<std::vector<EdgeWeight>> result_table =
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std::make_shared<std::vector<EdgeWeight>>(number_of_targets * number_of_sources,
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std::numeric_limits<EdgeWeight>::max());
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engine_working_data.InitializeOrClearFirstThreadLocalStorage(
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super::facade->GetNumberOfNodes());
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QueryHeap &query_heap = *(engine_working_data.forward_heap_1);
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SearchSpaceWithBuckets search_space_with_buckets;
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unsigned target_id = 0;
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for (const auto &phantom : phantom_targets_array)
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{
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query_heap.Clear();
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// insert target(s) at distance 0
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if (SPECIAL_NODEID != phantom.forward_node_id)
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{
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query_heap.Insert(phantom.forward_node_id, phantom.GetForwardWeightPlusOffset(),
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phantom.forward_node_id);
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}
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if (SPECIAL_NODEID != phantom.reverse_node_id)
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{
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query_heap.Insert(phantom.reverse_node_id, phantom.GetReverseWeightPlusOffset(),
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phantom.reverse_node_id);
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}
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// explore search space
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while (!query_heap.Empty())
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{
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BackwardRoutingStep(target_id, query_heap, search_space_with_buckets);
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}
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++target_id;
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}
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// for each source do forward search
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unsigned source_id = 0;
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for (const auto &phantom : phantom_sources_array)
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{
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query_heap.Clear();
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// insert target(s) at distance 0
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if (SPECIAL_NODEID != phantom.forward_node_id)
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{
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query_heap.Insert(phantom.forward_node_id, -phantom.GetForwardWeightPlusOffset(),
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phantom.forward_node_id);
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}
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if (SPECIAL_NODEID != phantom.reverse_node_id)
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{
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query_heap.Insert(phantom.reverse_node_id, -phantom.GetReverseWeightPlusOffset(),
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phantom.reverse_node_id);
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}
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// explore search space
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while (!query_heap.Empty())
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{
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ForwardRoutingStep(source_id, number_of_targets, query_heap,
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search_space_with_buckets, result_table);
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}
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++source_id;
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}
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// BOOST_ASSERT(source_id == target_id);
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return result_table;
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}
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void ForwardRoutingStep(const unsigned source_id,
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const unsigned number_of_targets,
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QueryHeap &query_heap,
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const SearchSpaceWithBuckets &search_space_with_buckets,
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std::shared_ptr<std::vector<EdgeWeight>> result_table) const
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{
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const NodeID node = query_heap.DeleteMin();
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const int source_distance = query_heap.GetKey(node);
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// check if each encountered node has an entry
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const auto bucket_iterator = search_space_with_buckets.find(node);
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// iterate bucket if there exists one
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if (bucket_iterator != search_space_with_buckets.end())
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{
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const std::vector<NodeBucket> &bucket_list = bucket_iterator->second;
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for (const NodeBucket ¤t_bucket : bucket_list)
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{
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// get target id from bucket entry
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const unsigned target_id = current_bucket.target_id;
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const int target_distance = current_bucket.distance;
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auto ¤t_distance = (*result_table)[source_id * number_of_targets + target_id];
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// check if new distance is better
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const EdgeWeight new_distance = source_distance + target_distance;
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if (new_distance < 0)
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{
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const EdgeWeight loop_weight = super::GetLoopWeight(node);
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const int new_distance_with_loop = new_distance + loop_weight;
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if (loop_weight != INVALID_EDGE_WEIGHT && new_distance_with_loop >= 0)
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{
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current_distance = std::min(current_distance, new_distance_with_loop);
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}
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}
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else if (new_distance < current_distance)
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{
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(*result_table)[source_id * number_of_targets + target_id] = new_distance;
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}
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}
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}
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if (StallAtNode<true>(node, source_distance, query_heap))
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{
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return;
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}
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RelaxOutgoingEdges<true>(node, source_distance, query_heap);
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}
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void BackwardRoutingStep(const unsigned target_id,
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QueryHeap &query_heap,
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SearchSpaceWithBuckets &search_space_with_buckets) const
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{
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const NodeID node = query_heap.DeleteMin();
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const int target_distance = query_heap.GetKey(node);
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// store settled nodes in search space bucket
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search_space_with_buckets[node].emplace_back(target_id, target_distance);
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if (StallAtNode<false>(node, target_distance, query_heap))
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{
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return;
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}
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RelaxOutgoingEdges<false>(node, target_distance, query_heap);
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}
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template <bool forward_direction>
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inline void
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RelaxOutgoingEdges(const NodeID node, const EdgeWeight distance, QueryHeap &query_heap) const
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{
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for (auto edge : super::facade->GetAdjacentEdgeRange(node))
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{
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const auto &data = super::facade->GetEdgeData(edge);
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const bool direction_flag = (forward_direction ? data.forward : data.backward);
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if (direction_flag)
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{
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const NodeID to = super::facade->GetTarget(edge);
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const int edge_weight = data.distance;
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BOOST_ASSERT_MSG(edge_weight > 0, "edge_weight invalid");
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const int to_distance = distance + edge_weight;
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// New Node discovered -> Add to Heap + Node Info Storage
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if (!query_heap.WasInserted(to))
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{
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query_heap.Insert(to, to_distance, node);
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}
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// Found a shorter Path -> Update distance
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else if (to_distance < query_heap.GetKey(to))
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{
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// new parent
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query_heap.GetData(to).parent = node;
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query_heap.DecreaseKey(to, to_distance);
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}
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}
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}
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}
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// Stalling
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template <bool forward_direction>
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inline bool
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StallAtNode(const NodeID node, const EdgeWeight distance, QueryHeap &query_heap) const
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{
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for (auto edge : super::facade->GetAdjacentEdgeRange(node))
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{
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const auto &data = super::facade->GetEdgeData(edge);
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const bool reverse_flag = ((!forward_direction) ? data.forward : data.backward);
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if (reverse_flag)
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{
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const NodeID to = super::facade->GetTarget(edge);
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const int edge_weight = data.distance;
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BOOST_ASSERT_MSG(edge_weight > 0, "edge_weight invalid");
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if (query_heap.WasInserted(to))
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{
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if (query_heap.GetKey(to) + edge_weight < distance)
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{
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return true;
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}
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}
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}
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}
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return false;
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}
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};
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}
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}
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}
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#endif
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