978 lines
43 KiB
C++
978 lines
43 KiB
C++
#ifndef ALTERNATIVE_PATH_ROUTING_HPP
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#define ALTERNATIVE_PATH_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/integer_range.hpp"
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#include <boost/assert.hpp>
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#include <algorithm>
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#include <iterator>
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#include <unordered_map>
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#include <unordered_set>
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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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const double VIAPATH_ALPHA = 0.10;
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const double VIAPATH_EPSILON = 0.15; // alternative at most 15% longer
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const double VIAPATH_GAMMA = 0.75; // alternative shares at most 75% with the shortest.
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template <class DataFacadeT>
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class AlternativeRouting final
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: private BasicRoutingInterface<DataFacadeT, AlternativeRouting<DataFacadeT>>
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{
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using super = BasicRoutingInterface<DataFacadeT, AlternativeRouting<DataFacadeT>>;
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using EdgeData = typename DataFacadeT::EdgeData;
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using QueryHeap = SearchEngineData::QueryHeap;
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using SearchSpaceEdge = std::pair<NodeID, NodeID>;
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struct RankedCandidateNode
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{
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RankedCandidateNode(const NodeID node, const int length, const int sharing)
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: node(node), length(length), sharing(sharing)
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{
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}
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NodeID node;
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int length;
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int sharing;
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bool operator<(const RankedCandidateNode &other) const
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{
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return (2 * length + sharing) < (2 * other.length + other.sharing);
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}
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};
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SearchEngineData &engine_working_data;
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public:
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AlternativeRouting(SearchEngineData &engine_working_data)
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: engine_working_data(engine_working_data)
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{
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}
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virtual ~AlternativeRouting() {}
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void operator()(const DataFacadeT &facade,
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const PhantomNodes &phantom_node_pair,
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InternalRouteResult &raw_route_data)
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{
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std::vector<NodeID> alternative_path;
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std::vector<NodeID> via_node_candidate_list;
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std::vector<SearchSpaceEdge> forward_search_space;
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std::vector<SearchSpaceEdge> reverse_search_space;
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// Init queues, semi-expensive because access to TSS invokes a sys-call
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engine_working_data.InitializeOrClearFirstThreadLocalStorage(facade.GetNumberOfNodes());
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engine_working_data.InitializeOrClearSecondThreadLocalStorage(facade.GetNumberOfNodes());
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engine_working_data.InitializeOrClearThirdThreadLocalStorage(facade.GetNumberOfNodes());
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QueryHeap &forward_heap1 = *(engine_working_data.forward_heap_1);
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QueryHeap &reverse_heap1 = *(engine_working_data.reverse_heap_1);
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QueryHeap &forward_heap2 = *(engine_working_data.forward_heap_2);
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QueryHeap &reverse_heap2 = *(engine_working_data.reverse_heap_2);
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int upper_bound_to_shortest_path_weight = INVALID_EDGE_WEIGHT;
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NodeID middle_node = SPECIAL_NODEID;
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const EdgeWeight min_edge_offset =
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std::min(phantom_node_pair.source_phantom.forward_segment_id.enabled
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? -phantom_node_pair.source_phantom.GetForwardWeightPlusOffset()
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: 0,
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phantom_node_pair.source_phantom.reverse_segment_id.enabled
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? -phantom_node_pair.source_phantom.GetReverseWeightPlusOffset()
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: 0);
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if (phantom_node_pair.source_phantom.forward_segment_id.enabled)
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{
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BOOST_ASSERT(phantom_node_pair.source_phantom.forward_segment_id.id !=
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SPECIAL_SEGMENTID);
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forward_heap1.Insert(phantom_node_pair.source_phantom.forward_segment_id.id,
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-phantom_node_pair.source_phantom.GetForwardWeightPlusOffset(),
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phantom_node_pair.source_phantom.forward_segment_id.id);
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}
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if (phantom_node_pair.source_phantom.reverse_segment_id.enabled)
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{
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BOOST_ASSERT(phantom_node_pair.source_phantom.reverse_segment_id.id !=
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SPECIAL_SEGMENTID);
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forward_heap1.Insert(phantom_node_pair.source_phantom.reverse_segment_id.id,
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-phantom_node_pair.source_phantom.GetReverseWeightPlusOffset(),
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phantom_node_pair.source_phantom.reverse_segment_id.id);
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}
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if (phantom_node_pair.target_phantom.forward_segment_id.enabled)
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{
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BOOST_ASSERT(phantom_node_pair.target_phantom.forward_segment_id.id !=
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SPECIAL_SEGMENTID);
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reverse_heap1.Insert(phantom_node_pair.target_phantom.forward_segment_id.id,
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phantom_node_pair.target_phantom.GetForwardWeightPlusOffset(),
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phantom_node_pair.target_phantom.forward_segment_id.id);
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}
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if (phantom_node_pair.target_phantom.reverse_segment_id.enabled)
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{
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BOOST_ASSERT(phantom_node_pair.target_phantom.reverse_segment_id.id !=
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SPECIAL_SEGMENTID);
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reverse_heap1.Insert(phantom_node_pair.target_phantom.reverse_segment_id.id,
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phantom_node_pair.target_phantom.GetReverseWeightPlusOffset(),
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phantom_node_pair.target_phantom.reverse_segment_id.id);
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}
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// search from s and t till new_min/(1+epsilon) > length_of_shortest_path
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while (0 < (forward_heap1.Size() + reverse_heap1.Size()))
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{
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if (0 < forward_heap1.Size())
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{
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AlternativeRoutingStep<true>(facade,
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forward_heap1,
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reverse_heap1,
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&middle_node,
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&upper_bound_to_shortest_path_weight,
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via_node_candidate_list,
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forward_search_space,
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min_edge_offset);
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}
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if (0 < reverse_heap1.Size())
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{
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AlternativeRoutingStep<false>(facade,
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forward_heap1,
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reverse_heap1,
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&middle_node,
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&upper_bound_to_shortest_path_weight,
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via_node_candidate_list,
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reverse_search_space,
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min_edge_offset);
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}
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}
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if (INVALID_EDGE_WEIGHT == upper_bound_to_shortest_path_weight)
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{
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return;
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}
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std::sort(begin(via_node_candidate_list), end(via_node_candidate_list));
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auto unique_end = std::unique(begin(via_node_candidate_list), end(via_node_candidate_list));
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via_node_candidate_list.resize(unique_end - begin(via_node_candidate_list));
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std::vector<NodeID> packed_forward_path;
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std::vector<NodeID> packed_reverse_path;
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const bool path_is_a_loop =
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upper_bound_to_shortest_path_weight !=
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forward_heap1.GetKey(middle_node) + reverse_heap1.GetKey(middle_node);
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if (path_is_a_loop)
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{
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// Self Loop
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packed_forward_path.push_back(middle_node);
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packed_forward_path.push_back(middle_node);
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}
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else
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{
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super::RetrievePackedPathFromSingleHeap(
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forward_heap1, middle_node, packed_forward_path);
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super::RetrievePackedPathFromSingleHeap(
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reverse_heap1, middle_node, packed_reverse_path);
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}
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// this set is is used as an indicator if a node is on the shortest path
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std::unordered_set<NodeID> nodes_in_path(packed_forward_path.size() +
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packed_reverse_path.size());
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nodes_in_path.insert(packed_forward_path.begin(), packed_forward_path.end());
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nodes_in_path.insert(middle_node);
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nodes_in_path.insert(packed_reverse_path.begin(), packed_reverse_path.end());
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std::unordered_map<NodeID, int> approximated_forward_sharing;
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std::unordered_map<NodeID, int> approximated_reverse_sharing;
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// sweep over search space, compute forward sharing for each current edge (u,v)
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for (const SearchSpaceEdge ¤t_edge : forward_search_space)
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{
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const NodeID u = current_edge.first;
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const NodeID v = current_edge.second;
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if (nodes_in_path.find(v) != nodes_in_path.end())
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{
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// current_edge is on shortest path => sharing(v):=queue.GetKey(v);
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approximated_forward_sharing.emplace(v, forward_heap1.GetKey(v));
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}
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else
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{
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// current edge is not on shortest path. Check if we know a value for the other
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// endpoint
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const auto sharing_of_u_iterator = approximated_forward_sharing.find(u);
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if (sharing_of_u_iterator != approximated_forward_sharing.end())
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{
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approximated_forward_sharing.emplace(v, sharing_of_u_iterator->second);
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}
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}
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}
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// sweep over search space, compute backward sharing
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for (const SearchSpaceEdge ¤t_edge : reverse_search_space)
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{
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const NodeID u = current_edge.first;
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const NodeID v = current_edge.second;
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if (nodes_in_path.find(v) != nodes_in_path.end())
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{
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// current_edge is on shortest path => sharing(u):=queue.GetKey(u);
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approximated_reverse_sharing.emplace(v, reverse_heap1.GetKey(v));
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}
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else
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{
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// current edge is not on shortest path. Check if we know a value for the other
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// endpoint
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const auto sharing_of_u_iterator = approximated_reverse_sharing.find(u);
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if (sharing_of_u_iterator != approximated_reverse_sharing.end())
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{
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approximated_reverse_sharing.emplace(v, sharing_of_u_iterator->second);
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}
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}
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}
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// util::SimpleLogger().Write(logDEBUG) << "fwd_search_space size: " <<
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// forward_search_space.size() << ", marked " << approximated_forward_sharing.size() << "
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// nodes";
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// util::SimpleLogger().Write(logDEBUG) << "rev_search_space size: " <<
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// reverse_search_space.size() << ", marked " << approximated_reverse_sharing.size() << "
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// nodes";
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std::vector<NodeID> preselected_node_list;
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for (const NodeID node : via_node_candidate_list)
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{
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if (node == middle_node)
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continue;
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const auto fwd_iterator = approximated_forward_sharing.find(node);
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const int fwd_sharing =
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(fwd_iterator != approximated_forward_sharing.end()) ? fwd_iterator->second : 0;
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const auto rev_iterator = approximated_reverse_sharing.find(node);
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const int rev_sharing =
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(rev_iterator != approximated_reverse_sharing.end()) ? rev_iterator->second : 0;
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const int approximated_sharing = fwd_sharing + rev_sharing;
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const int approximated_length = forward_heap1.GetKey(node) + reverse_heap1.GetKey(node);
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const bool length_passes =
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(approximated_length < upper_bound_to_shortest_path_weight * (1 + VIAPATH_EPSILON));
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const bool sharing_passes =
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(approximated_sharing <= upper_bound_to_shortest_path_weight * VIAPATH_GAMMA);
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const bool stretch_passes =
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(approximated_length - approximated_sharing) <
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((1. + VIAPATH_ALPHA) *
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(upper_bound_to_shortest_path_weight - approximated_sharing));
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if (length_passes && sharing_passes && stretch_passes)
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{
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preselected_node_list.emplace_back(node);
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}
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}
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std::vector<NodeID> &packed_shortest_path = packed_forward_path;
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if (!path_is_a_loop)
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{
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std::reverse(packed_shortest_path.begin(), packed_shortest_path.end());
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packed_shortest_path.emplace_back(middle_node);
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packed_shortest_path.insert(
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packed_shortest_path.end(), packed_reverse_path.begin(), packed_reverse_path.end());
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}
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std::vector<RankedCandidateNode> ranked_candidates_list;
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// prioritizing via nodes for deep inspection
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for (const NodeID node : preselected_node_list)
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{
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int length_of_via_path = 0, sharing_of_via_path = 0;
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ComputeLengthAndSharingOfViaPath(facade,
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node,
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&length_of_via_path,
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&sharing_of_via_path,
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packed_shortest_path,
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min_edge_offset);
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const int maximum_allowed_sharing =
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static_cast<int>(upper_bound_to_shortest_path_weight * VIAPATH_GAMMA);
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if (sharing_of_via_path <= maximum_allowed_sharing &&
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length_of_via_path <= upper_bound_to_shortest_path_weight * (1 + VIAPATH_EPSILON))
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{
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ranked_candidates_list.emplace_back(node, length_of_via_path, sharing_of_via_path);
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}
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}
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std::sort(ranked_candidates_list.begin(), ranked_candidates_list.end());
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NodeID selected_via_node = SPECIAL_NODEID;
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int length_of_via_path = INVALID_EDGE_WEIGHT;
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NodeID s_v_middle = SPECIAL_NODEID, v_t_middle = SPECIAL_NODEID;
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for (const RankedCandidateNode &candidate : ranked_candidates_list)
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{
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if (ViaNodeCandidatePassesTTest(facade,
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forward_heap1,
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reverse_heap1,
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forward_heap2,
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reverse_heap2,
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candidate,
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upper_bound_to_shortest_path_weight,
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&length_of_via_path,
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&s_v_middle,
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&v_t_middle,
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min_edge_offset))
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{
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// select first admissable
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selected_via_node = candidate.node;
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break;
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}
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}
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// Unpack shortest path and alternative, if they exist
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if (INVALID_EDGE_WEIGHT != upper_bound_to_shortest_path_weight)
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{
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BOOST_ASSERT(!packed_shortest_path.empty());
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raw_route_data.unpacked_path_segments.resize(1);
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raw_route_data.source_traversed_in_reverse.push_back(
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(packed_shortest_path.front() !=
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phantom_node_pair.source_phantom.forward_segment_id.id));
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raw_route_data.target_traversed_in_reverse.push_back(
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(packed_shortest_path.back() !=
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phantom_node_pair.target_phantom.forward_segment_id.id));
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super::UnpackPath(facade,
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// -- packed input
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packed_shortest_path.begin(),
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packed_shortest_path.end(),
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// -- start of route
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phantom_node_pair,
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// -- unpacked output
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raw_route_data.unpacked_path_segments.front());
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raw_route_data.shortest_path_length = upper_bound_to_shortest_path_weight;
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}
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if (SPECIAL_NODEID != selected_via_node)
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{
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std::vector<NodeID> packed_alternate_path;
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// retrieve alternate path
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RetrievePackedAlternatePath(forward_heap1,
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reverse_heap1,
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forward_heap2,
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reverse_heap2,
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s_v_middle,
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v_t_middle,
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packed_alternate_path);
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raw_route_data.alt_source_traversed_in_reverse.push_back(
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(packed_alternate_path.front() !=
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phantom_node_pair.source_phantom.forward_segment_id.id));
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raw_route_data.alt_target_traversed_in_reverse.push_back(
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(packed_alternate_path.back() !=
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phantom_node_pair.target_phantom.forward_segment_id.id));
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// unpack the alternate path
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super::UnpackPath(facade,
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packed_alternate_path.begin(),
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packed_alternate_path.end(),
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phantom_node_pair,
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raw_route_data.unpacked_alternative);
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raw_route_data.alternative_path_length = length_of_via_path;
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}
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else
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{
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BOOST_ASSERT(raw_route_data.alternative_path_length == INVALID_EDGE_WEIGHT);
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}
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}
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private:
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// unpack alternate <s,..,v,..,t> by exploring search spaces from v
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void RetrievePackedAlternatePath(const QueryHeap &forward_heap1,
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const QueryHeap &reverse_heap1,
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const QueryHeap &forward_heap2,
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const QueryHeap &reverse_heap2,
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const NodeID s_v_middle,
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const NodeID v_t_middle,
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std::vector<NodeID> &packed_path) const
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{
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// fetch packed path [s,v)
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std::vector<NodeID> packed_v_t_path;
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super::RetrievePackedPathFromHeap(forward_heap1, reverse_heap2, s_v_middle, packed_path);
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packed_path.pop_back(); // remove middle node. It's in both half-paths
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// fetch patched path [v,t]
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super::RetrievePackedPathFromHeap(
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forward_heap2, reverse_heap1, v_t_middle, packed_v_t_path);
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packed_path.insert(packed_path.end(), packed_v_t_path.begin(), packed_v_t_path.end());
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}
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// TODO: reorder parameters
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// compute and unpack <s,..,v> and <v,..,t> by exploring search spaces
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// from v and intersecting against queues. only half-searches have to be
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// done at this stage
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void ComputeLengthAndSharingOfViaPath(const DataFacadeT &facade,
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const NodeID via_node,
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int *real_length_of_via_path,
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int *sharing_of_via_path,
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const std::vector<NodeID> &packed_shortest_path,
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const EdgeWeight min_edge_offset)
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{
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engine_working_data.InitializeOrClearSecondThreadLocalStorage(facade.GetNumberOfNodes());
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QueryHeap &existing_forward_heap = *engine_working_data.forward_heap_1;
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QueryHeap &existing_reverse_heap = *engine_working_data.reverse_heap_1;
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QueryHeap &new_forward_heap = *engine_working_data.forward_heap_2;
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QueryHeap &new_reverse_heap = *engine_working_data.reverse_heap_2;
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std::vector<NodeID> packed_s_v_path;
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std::vector<NodeID> packed_v_t_path;
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std::vector<NodeID> partially_unpacked_shortest_path;
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std::vector<NodeID> partially_unpacked_via_path;
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NodeID s_v_middle = SPECIAL_NODEID;
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int upper_bound_s_v_path_length = INVALID_EDGE_WEIGHT;
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new_reverse_heap.Insert(via_node, 0, via_node);
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// compute path <s,..,v> by reusing forward search from s
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const bool constexpr STALLING_ENABLED = true;
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const bool constexpr DO_NOT_FORCE_LOOPS = false;
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while (!new_reverse_heap.Empty())
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{
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super::RoutingStep(facade,
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new_reverse_heap,
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existing_forward_heap,
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s_v_middle,
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upper_bound_s_v_path_length,
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min_edge_offset,
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false,
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STALLING_ENABLED,
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DO_NOT_FORCE_LOOPS,
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DO_NOT_FORCE_LOOPS);
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}
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// compute path <v,..,t> by reusing backward search from node t
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NodeID v_t_middle = SPECIAL_NODEID;
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int upper_bound_of_v_t_path_length = INVALID_EDGE_WEIGHT;
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new_forward_heap.Insert(via_node, 0, via_node);
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while (!new_forward_heap.Empty())
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{
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super::RoutingStep(facade,
|
|
new_forward_heap,
|
|
existing_reverse_heap,
|
|
v_t_middle,
|
|
upper_bound_of_v_t_path_length,
|
|
min_edge_offset,
|
|
true,
|
|
STALLING_ENABLED,
|
|
DO_NOT_FORCE_LOOPS,
|
|
DO_NOT_FORCE_LOOPS);
|
|
}
|
|
*real_length_of_via_path = upper_bound_s_v_path_length + upper_bound_of_v_t_path_length;
|
|
|
|
if (SPECIAL_NODEID == s_v_middle || SPECIAL_NODEID == v_t_middle)
|
|
{
|
|
return;
|
|
}
|
|
|
|
// retrieve packed paths
|
|
super::RetrievePackedPathFromHeap(
|
|
existing_forward_heap, new_reverse_heap, s_v_middle, packed_s_v_path);
|
|
super::RetrievePackedPathFromHeap(
|
|
new_forward_heap, existing_reverse_heap, v_t_middle, packed_v_t_path);
|
|
|
|
// partial unpacking, compute sharing
|
|
// First partially unpack s-->v until paths deviate, note length of common path.
|
|
const auto s_v_min_path_size =
|
|
std::min(packed_s_v_path.size(), packed_shortest_path.size()) - 1;
|
|
for (const auto current_node : util::irange<std::size_t>(0UL, s_v_min_path_size))
|
|
{
|
|
if (packed_s_v_path[current_node] == packed_shortest_path[current_node] &&
|
|
packed_s_v_path[current_node + 1] == packed_shortest_path[current_node + 1])
|
|
{
|
|
EdgeID edgeID = facade.FindEdgeInEitherDirection(packed_s_v_path[current_node],
|
|
packed_s_v_path[current_node + 1]);
|
|
*sharing_of_via_path += facade.GetEdgeData(edgeID).weight;
|
|
}
|
|
else
|
|
{
|
|
if (packed_s_v_path[current_node] == packed_shortest_path[current_node])
|
|
{
|
|
super::UnpackEdge(facade,
|
|
packed_s_v_path[current_node],
|
|
packed_s_v_path[current_node + 1],
|
|
partially_unpacked_via_path);
|
|
super::UnpackEdge(facade,
|
|
packed_shortest_path[current_node],
|
|
packed_shortest_path[current_node + 1],
|
|
partially_unpacked_shortest_path);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
// traverse partially unpacked edge and note common prefix
|
|
const int64_t packed_path_length =
|
|
static_cast<int64_t>(std::min(partially_unpacked_via_path.size(),
|
|
partially_unpacked_shortest_path.size())) -
|
|
1;
|
|
for (int64_t current_node = 0; (current_node < packed_path_length) &&
|
|
(partially_unpacked_via_path[current_node] ==
|
|
partially_unpacked_shortest_path[current_node] &&
|
|
partially_unpacked_via_path[current_node + 1] ==
|
|
partially_unpacked_shortest_path[current_node + 1]);
|
|
++current_node)
|
|
{
|
|
EdgeID selected_edge =
|
|
facade.FindEdgeInEitherDirection(partially_unpacked_via_path[current_node],
|
|
partially_unpacked_via_path[current_node + 1]);
|
|
*sharing_of_via_path += facade.GetEdgeData(selected_edge).weight;
|
|
}
|
|
|
|
// Second, partially unpack v-->t in reverse order until paths deviate and note lengths
|
|
int64_t via_path_index = static_cast<int64_t>(packed_v_t_path.size()) - 1;
|
|
int64_t shortest_path_index = static_cast<int64_t>(packed_shortest_path.size()) - 1;
|
|
for (; via_path_index > 0 && shortest_path_index > 0;
|
|
--via_path_index, --shortest_path_index)
|
|
{
|
|
if (packed_v_t_path[via_path_index - 1] ==
|
|
packed_shortest_path[shortest_path_index - 1] &&
|
|
packed_v_t_path[via_path_index] == packed_shortest_path[shortest_path_index])
|
|
{
|
|
EdgeID edgeID = facade.FindEdgeInEitherDirection(
|
|
packed_v_t_path[via_path_index - 1], packed_v_t_path[via_path_index]);
|
|
*sharing_of_via_path += facade.GetEdgeData(edgeID).weight;
|
|
}
|
|
else
|
|
{
|
|
if (packed_v_t_path[via_path_index] == packed_shortest_path[shortest_path_index])
|
|
{
|
|
super::UnpackEdge(facade,
|
|
packed_v_t_path[via_path_index - 1],
|
|
packed_v_t_path[via_path_index],
|
|
partially_unpacked_via_path);
|
|
super::UnpackEdge(facade,
|
|
packed_shortest_path[shortest_path_index - 1],
|
|
packed_shortest_path[shortest_path_index],
|
|
partially_unpacked_shortest_path);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
via_path_index = static_cast<int64_t>(partially_unpacked_via_path.size()) - 1;
|
|
shortest_path_index = static_cast<int64_t>(partially_unpacked_shortest_path.size()) - 1;
|
|
for (; via_path_index > 0 && shortest_path_index > 0;
|
|
--via_path_index, --shortest_path_index)
|
|
{
|
|
if (partially_unpacked_via_path[via_path_index - 1] ==
|
|
partially_unpacked_shortest_path[shortest_path_index - 1] &&
|
|
partially_unpacked_via_path[via_path_index] ==
|
|
partially_unpacked_shortest_path[shortest_path_index])
|
|
{
|
|
EdgeID edgeID = facade.FindEdgeInEitherDirection(
|
|
partially_unpacked_via_path[via_path_index - 1],
|
|
partially_unpacked_via_path[via_path_index]);
|
|
*sharing_of_via_path += facade.GetEdgeData(edgeID).weight;
|
|
}
|
|
else
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
// finished partial unpacking spree! Amount of sharing is stored to appropriate pointer
|
|
// variable
|
|
}
|
|
|
|
// int approximateAmountOfSharing(
|
|
// const NodeID alternate_path_middle_node_id,
|
|
// QueryHeap & forward_heap,
|
|
// QueryHeap & reverse_heap,
|
|
// const std::vector<NodeID> & packed_shortest_path
|
|
// ) const {
|
|
// std::vector<NodeID> packed_alternate_path;
|
|
// super::RetrievePackedPathFromHeap(
|
|
// forward_heap,
|
|
// reverse_heap,
|
|
// alternate_path_middle_node_id,
|
|
// packed_alternate_path
|
|
// );
|
|
|
|
// if(packed_shortest_path.size() < 2 || packed_alternate_path.size() < 2) {
|
|
// return 0;
|
|
// }
|
|
|
|
// int sharing = 0;
|
|
// int aindex = 0;
|
|
// //compute forward sharing
|
|
// while( (packed_alternate_path[aindex] == packed_shortest_path[aindex]) &&
|
|
// (packed_alternate_path[aindex+1] == packed_shortest_path[aindex+1]) ) {
|
|
// // util::SimpleLogger().Write() << "retrieving edge (" <<
|
|
// packed_alternate_path[aindex] << "," << packed_alternate_path[aindex+1] << ")";
|
|
// EdgeID edgeID = facade->FindEdgeInEitherDirection(packed_alternate_path[aindex],
|
|
// packed_alternate_path[aindex+1]);
|
|
// sharing += facade->GetEdgeData(edgeID).weight;
|
|
// ++aindex;
|
|
// }
|
|
|
|
// aindex = packed_alternate_path.size()-1;
|
|
// int bindex = packed_shortest_path.size()-1;
|
|
// //compute backward sharing
|
|
// while( aindex > 0 && bindex > 0 && (packed_alternate_path[aindex] ==
|
|
// packed_shortest_path[bindex]) && (packed_alternate_path[aindex-1] ==
|
|
// packed_shortest_path[bindex-1]) ) {
|
|
// EdgeID edgeID = facade->FindEdgeInEitherDirection(packed_alternate_path[aindex],
|
|
// packed_alternate_path[aindex-1]);
|
|
// sharing += facade->GetEdgeData(edgeID).weight;
|
|
// --aindex; --bindex;
|
|
// }
|
|
// return sharing;
|
|
// }
|
|
|
|
// todo: reorder parameters
|
|
template <bool is_forward_directed>
|
|
void AlternativeRoutingStep(const DataFacadeT &facade,
|
|
QueryHeap &heap1,
|
|
QueryHeap &heap2,
|
|
NodeID *middle_node,
|
|
int *upper_bound_to_shortest_path_weight,
|
|
std::vector<NodeID> &search_space_intersection,
|
|
std::vector<SearchSpaceEdge> &search_space,
|
|
const EdgeWeight min_edge_offset) const
|
|
{
|
|
QueryHeap &forward_heap = (is_forward_directed ? heap1 : heap2);
|
|
QueryHeap &reverse_heap = (is_forward_directed ? heap2 : heap1);
|
|
|
|
const NodeID node = forward_heap.DeleteMin();
|
|
const int weight = forward_heap.GetKey(node);
|
|
// const NodeID parentnode = forward_heap.GetData(node).parent;
|
|
// util::SimpleLogger().Write() << (is_forward_directed ? "[fwd] " : "[rev] ") << "settled
|
|
// edge ("
|
|
// << parentnode << "," << node << "), dist: " << weight;
|
|
|
|
const int scaled_weight =
|
|
static_cast<int>((weight + min_edge_offset) / (1. + VIAPATH_EPSILON));
|
|
if ((INVALID_EDGE_WEIGHT != *upper_bound_to_shortest_path_weight) &&
|
|
(scaled_weight > *upper_bound_to_shortest_path_weight))
|
|
{
|
|
forward_heap.DeleteAll();
|
|
return;
|
|
}
|
|
|
|
search_space.emplace_back(forward_heap.GetData(node).parent, node);
|
|
|
|
if (reverse_heap.WasInserted(node))
|
|
{
|
|
search_space_intersection.emplace_back(node);
|
|
const int new_weight = reverse_heap.GetKey(node) + weight;
|
|
if (new_weight < *upper_bound_to_shortest_path_weight)
|
|
{
|
|
if (new_weight >= 0)
|
|
{
|
|
*middle_node = node;
|
|
*upper_bound_to_shortest_path_weight = new_weight;
|
|
// util::SimpleLogger().Write() << "accepted middle_node " << *middle_node
|
|
// << " at
|
|
// weight " << new_weight;
|
|
// } else {
|
|
// util::SimpleLogger().Write() << "discarded middle_node " << *middle_node
|
|
// << "
|
|
// at weight " << new_weight;
|
|
}
|
|
else
|
|
{
|
|
// check whether there is a loop present at the node
|
|
const auto loop_weight = super::GetLoopWeight(facade, node);
|
|
const int new_weight_with_loop = new_weight + loop_weight;
|
|
if (loop_weight != INVALID_EDGE_WEIGHT &&
|
|
new_weight_with_loop <= *upper_bound_to_shortest_path_weight)
|
|
{
|
|
*middle_node = node;
|
|
*upper_bound_to_shortest_path_weight = loop_weight;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
for (auto edge : facade.GetAdjacentEdgeRange(node))
|
|
{
|
|
const EdgeData &data = facade.GetEdgeData(edge);
|
|
const bool edge_is_forward_directed =
|
|
(is_forward_directed ? data.forward : data.backward);
|
|
if (edge_is_forward_directed)
|
|
{
|
|
const NodeID to = facade.GetTarget(edge);
|
|
const int edge_weight = data.weight;
|
|
|
|
BOOST_ASSERT(edge_weight > 0);
|
|
const int to_weight = weight + edge_weight;
|
|
|
|
// New Node discovered -> Add to Heap + Node Info Storage
|
|
if (!forward_heap.WasInserted(to))
|
|
{
|
|
forward_heap.Insert(to, to_weight, node);
|
|
}
|
|
// Found a shorter Path -> Update weight
|
|
else if (to_weight < forward_heap.GetKey(to))
|
|
{
|
|
// new parent
|
|
forward_heap.GetData(to).parent = node;
|
|
// decreased weight
|
|
forward_heap.DecreaseKey(to, to_weight);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// conduct T-Test
|
|
bool ViaNodeCandidatePassesTTest(const DataFacadeT &facade,
|
|
QueryHeap &existing_forward_heap,
|
|
QueryHeap &existing_reverse_heap,
|
|
QueryHeap &new_forward_heap,
|
|
QueryHeap &new_reverse_heap,
|
|
const RankedCandidateNode &candidate,
|
|
const int length_of_shortest_path,
|
|
int *length_of_via_path,
|
|
NodeID *s_v_middle,
|
|
NodeID *v_t_middle,
|
|
const EdgeWeight min_edge_offset) const
|
|
{
|
|
new_forward_heap.Clear();
|
|
new_reverse_heap.Clear();
|
|
std::vector<NodeID> packed_s_v_path;
|
|
std::vector<NodeID> packed_v_t_path;
|
|
|
|
*s_v_middle = SPECIAL_NODEID;
|
|
int upper_bound_s_v_path_length = INVALID_EDGE_WEIGHT;
|
|
// compute path <s,..,v> by reusing forward search from s
|
|
new_reverse_heap.Insert(candidate.node, 0, candidate.node);
|
|
const bool constexpr STALLING_ENABLED = true;
|
|
const bool constexpr DO_NOT_FORCE_LOOPS = false;
|
|
while (new_reverse_heap.Size() > 0)
|
|
{
|
|
super::RoutingStep(facade,
|
|
new_reverse_heap,
|
|
existing_forward_heap,
|
|
*s_v_middle,
|
|
upper_bound_s_v_path_length,
|
|
min_edge_offset,
|
|
false,
|
|
STALLING_ENABLED,
|
|
DO_NOT_FORCE_LOOPS,
|
|
DO_NOT_FORCE_LOOPS);
|
|
}
|
|
|
|
if (INVALID_EDGE_WEIGHT == upper_bound_s_v_path_length)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// compute path <v,..,t> by reusing backward search from t
|
|
*v_t_middle = SPECIAL_NODEID;
|
|
int upper_bound_of_v_t_path_length = INVALID_EDGE_WEIGHT;
|
|
new_forward_heap.Insert(candidate.node, 0, candidate.node);
|
|
while (new_forward_heap.Size() > 0)
|
|
{
|
|
super::RoutingStep(facade,
|
|
new_forward_heap,
|
|
existing_reverse_heap,
|
|
*v_t_middle,
|
|
upper_bound_of_v_t_path_length,
|
|
min_edge_offset,
|
|
true,
|
|
STALLING_ENABLED,
|
|
DO_NOT_FORCE_LOOPS,
|
|
DO_NOT_FORCE_LOOPS);
|
|
}
|
|
|
|
if (INVALID_EDGE_WEIGHT == upper_bound_of_v_t_path_length)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
*length_of_via_path = upper_bound_s_v_path_length + upper_bound_of_v_t_path_length;
|
|
|
|
// retrieve packed paths
|
|
super::RetrievePackedPathFromHeap(
|
|
existing_forward_heap, new_reverse_heap, *s_v_middle, packed_s_v_path);
|
|
|
|
super::RetrievePackedPathFromHeap(
|
|
new_forward_heap, existing_reverse_heap, *v_t_middle, packed_v_t_path);
|
|
|
|
NodeID s_P = *s_v_middle, t_P = *v_t_middle;
|
|
if (SPECIAL_NODEID == s_P)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
if (SPECIAL_NODEID == t_P)
|
|
{
|
|
return false;
|
|
}
|
|
const int T_threshold = static_cast<int>(VIAPATH_EPSILON * length_of_shortest_path);
|
|
int unpacked_until_weight = 0;
|
|
|
|
std::stack<SearchSpaceEdge> unpack_stack;
|
|
// Traverse path s-->v
|
|
for (std::size_t i = packed_s_v_path.size() - 1; (i > 0) && unpack_stack.empty(); --i)
|
|
{
|
|
const EdgeID current_edge_id =
|
|
facade.FindEdgeInEitherDirection(packed_s_v_path[i - 1], packed_s_v_path[i]);
|
|
const int length_of_current_edge = facade.GetEdgeData(current_edge_id).weight;
|
|
if ((length_of_current_edge + unpacked_until_weight) >= T_threshold)
|
|
{
|
|
unpack_stack.emplace(packed_s_v_path[i - 1], packed_s_v_path[i]);
|
|
}
|
|
else
|
|
{
|
|
unpacked_until_weight += length_of_current_edge;
|
|
s_P = packed_s_v_path[i - 1];
|
|
}
|
|
}
|
|
|
|
while (!unpack_stack.empty())
|
|
{
|
|
const SearchSpaceEdge via_path_edge = unpack_stack.top();
|
|
unpack_stack.pop();
|
|
EdgeID edge_in_via_path_id =
|
|
facade.FindEdgeInEitherDirection(via_path_edge.first, via_path_edge.second);
|
|
|
|
if (SPECIAL_EDGEID == edge_in_via_path_id)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
const EdgeData ¤t_edge_data = facade.GetEdgeData(edge_in_via_path_id);
|
|
const bool current_edge_is_shortcut = current_edge_data.shortcut;
|
|
if (current_edge_is_shortcut)
|
|
{
|
|
const NodeID via_path_middle_node_id = current_edge_data.id;
|
|
const EdgeID second_segment_edge_id =
|
|
facade.FindEdgeInEitherDirection(via_path_middle_node_id, via_path_edge.second);
|
|
const int second_segment_length = facade.GetEdgeData(second_segment_edge_id).weight;
|
|
// attention: !unpacking in reverse!
|
|
// Check if second segment is the one to go over treshold? if yes add second segment
|
|
// to stack, else push first segment to stack and add weight of second one.
|
|
if (unpacked_until_weight + second_segment_length >= T_threshold)
|
|
{
|
|
unpack_stack.emplace(via_path_middle_node_id, via_path_edge.second);
|
|
}
|
|
else
|
|
{
|
|
unpacked_until_weight += second_segment_length;
|
|
unpack_stack.emplace(via_path_edge.first, via_path_middle_node_id);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// edge is not a shortcut, set the start node for T-Test to end of edge.
|
|
unpacked_until_weight += current_edge_data.weight;
|
|
s_P = via_path_edge.first;
|
|
}
|
|
}
|
|
|
|
int t_test_path_length = unpacked_until_weight;
|
|
unpacked_until_weight = 0;
|
|
// Traverse path s-->v
|
|
BOOST_ASSERT(!packed_v_t_path.empty());
|
|
for (unsigned i = 0, packed_path_length = static_cast<unsigned>(packed_v_t_path.size() - 1);
|
|
(i < packed_path_length) && unpack_stack.empty();
|
|
++i)
|
|
{
|
|
const EdgeID edgeID =
|
|
facade.FindEdgeInEitherDirection(packed_v_t_path[i], packed_v_t_path[i + 1]);
|
|
int length_of_current_edge = facade.GetEdgeData(edgeID).weight;
|
|
if (length_of_current_edge + unpacked_until_weight >= T_threshold)
|
|
{
|
|
unpack_stack.emplace(packed_v_t_path[i], packed_v_t_path[i + 1]);
|
|
}
|
|
else
|
|
{
|
|
unpacked_until_weight += length_of_current_edge;
|
|
t_P = packed_v_t_path[i + 1];
|
|
}
|
|
}
|
|
|
|
while (!unpack_stack.empty())
|
|
{
|
|
const SearchSpaceEdge via_path_edge = unpack_stack.top();
|
|
unpack_stack.pop();
|
|
EdgeID edge_in_via_path_id =
|
|
facade.FindEdgeInEitherDirection(via_path_edge.first, via_path_edge.second);
|
|
if (SPECIAL_EDGEID == edge_in_via_path_id)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
const EdgeData ¤t_edge_data = facade.GetEdgeData(edge_in_via_path_id);
|
|
const bool IsViaEdgeShortCut = current_edge_data.shortcut;
|
|
if (IsViaEdgeShortCut)
|
|
{
|
|
const NodeID middleOfViaPath = current_edge_data.id;
|
|
EdgeID edgeIDOfFirstSegment =
|
|
facade.FindEdgeInEitherDirection(via_path_edge.first, middleOfViaPath);
|
|
int lengthOfFirstSegment = facade.GetEdgeData(edgeIDOfFirstSegment).weight;
|
|
// Check if first segment is the one to go over treshold? if yes first segment to
|
|
// stack, else push second segment to stack and add weight of first one.
|
|
if (unpacked_until_weight + lengthOfFirstSegment >= T_threshold)
|
|
{
|
|
unpack_stack.emplace(via_path_edge.first, middleOfViaPath);
|
|
}
|
|
else
|
|
{
|
|
unpacked_until_weight += lengthOfFirstSegment;
|
|
unpack_stack.emplace(middleOfViaPath, via_path_edge.second);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// edge is not a shortcut, set the start node for T-Test to end of edge.
|
|
unpacked_until_weight += current_edge_data.weight;
|
|
t_P = via_path_edge.second;
|
|
}
|
|
}
|
|
|
|
t_test_path_length += unpacked_until_weight;
|
|
// Run actual T-Test query and compare if weight equal.
|
|
engine_working_data.InitializeOrClearThirdThreadLocalStorage(facade.GetNumberOfNodes());
|
|
|
|
QueryHeap &forward_heap3 = *engine_working_data.forward_heap_3;
|
|
QueryHeap &reverse_heap3 = *engine_working_data.reverse_heap_3;
|
|
int upper_bound = INVALID_EDGE_WEIGHT;
|
|
NodeID middle = SPECIAL_NODEID;
|
|
|
|
forward_heap3.Insert(s_P, 0, s_P);
|
|
reverse_heap3.Insert(t_P, 0, t_P);
|
|
// exploration from s and t until deletemin/(1+epsilon) > _lengt_oO_sShortest_path
|
|
while ((forward_heap3.Size() + reverse_heap3.Size()) > 0)
|
|
{
|
|
if (!forward_heap3.Empty())
|
|
{
|
|
super::RoutingStep(facade,
|
|
forward_heap3,
|
|
reverse_heap3,
|
|
middle,
|
|
upper_bound,
|
|
min_edge_offset,
|
|
true,
|
|
STALLING_ENABLED,
|
|
DO_NOT_FORCE_LOOPS,
|
|
DO_NOT_FORCE_LOOPS);
|
|
}
|
|
if (!reverse_heap3.Empty())
|
|
{
|
|
super::RoutingStep(facade,
|
|
reverse_heap3,
|
|
forward_heap3,
|
|
middle,
|
|
upper_bound,
|
|
min_edge_offset,
|
|
false,
|
|
STALLING_ENABLED,
|
|
DO_NOT_FORCE_LOOPS,
|
|
DO_NOT_FORCE_LOOPS);
|
|
}
|
|
}
|
|
return (upper_bound <= t_test_path_length);
|
|
}
|
|
};
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif /* ALTERNATIVE_PATH_ROUTING_HPP */
|