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refactor and improve the round trip computation of multiple SCCs

Browse Source 
Problem:
- old solution was slow
- depending on the result of TarjanSCC, new distance tables and new phantom node vectors were created to run tsp on it

Solution:
- dont create new distance tables and phantom node vectors
- pass an additional vector with the information which locations are in the same component and ignore all others

fix bug for scc split computation
This commit is contained in:
Chau Nguyen 2015-07-05 00:15:55 +02:00 committed by Huyen Chau Nguyen
parent 84c12793e8
commit b15f8f68e4
10 changed files with 634 additions and 287 deletions
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2
CMakeLists.txt
View File

@ -91,7 +91,7 @@ set(
add_library(COORDINATE OBJECT ${CoordinateGlob})
add_library(GITDESCRIPTION OBJECT util/git_sha.cpp)
add_library(OSRM ${OSRMSources} $<TARGET_OBJECTS:ANGLE> $<TARGET_OBJECTS:COORDINATE> $<TARGET_OBJECTS:GITDESCRIPTION> $<TARGET_OBJECTS:FINGERPRINT> $<TARGET_OBJECTS:COORDINATE> $<TARGET_OBJECTS:LOGGER> $<TARGET_OBJECTS:PHANTOMNODE> $<TARGET_OBJECTS:EXCEPTION> $<TARGET_OBJECTS:MERCATOR> $<TARGET_OBJECTS:IMPORT>)
add_library(OSRM ${OSRMSources} $<TARGET_OBJECTS:ANGLE> $<TARGET_OBJECTS:COORDINATE> $<TARGET_OBJECTS:GITDESCRIPTION> $<TARGET_OBJECTS:FINGERPRINT> $<TARGET_OBJECTS:COORDINATE> $<TARGET_OBJECTS:LOGGER> $<TARGET_OBJECTS:RESTRICTION> $<TARGET_OBJECTS:PHANTOMNODE> $<TARGET_OBJECTS:EXCEPTION> $<TARGET_OBJECTS:MERCATOR> $<TARGET_OBJECTS:IMPORT>)
add_library(FINGERPRINT OBJECT util/fingerprint.cpp)
add_dependencies(FINGERPRINT FingerPrintConfigure)

5
algorithms/tarjan_scc.hpp
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@ -201,6 +201,11 @@ template <typename GraphT> class TarjanSCC
return component_size_vector[component_id];
}
unsigned get_component_size_by_id(const unsigned component_id) const
{
return component_size_vector[component_id];
}
unsigned get_component_id(const NodeID node) const { return components_index[node]; }
};

66
data_structures/matrix_graph_wrapper.hpp Normal file
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@ -0,0 +1,66 @@
/*
Copyright (c) 2015, Project OSRM contributors
All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this list
of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef MATRIX_GRAPH_WRAPPER_H
#define MATRIX_GRAPH_WRAPPER_H
#include <vector>
//This Wrapper provides all methods that are needed for TarjanSCC, when the graph is given in a
//matrix representation (e.g. as output from a distance table call)
template <typename T> class MatrixGraphWrapper {
public:
MatrixGraphWrapper(std::vector<T> table, const unsigned number_of_nodes) : table_(table), number_of_nodes_(number_of_nodes) {};
unsigned GetNumberOfNodes() {
return number_of_nodes_;
}
std::vector<unsigned> GetAdjacentEdgeRange(const unsigned node) const {
std::vector<unsigned> edges;
const auto maxint = std::numeric_limits<int>::max();
for (auto i = 0; i < number_of_nodes_; ++i) {
if (*(table_.begin() + node * number_of_nodes_ + i) != maxint) {
edges.push_back(i);
}
}
return edges;
}
unsigned GetTarget(const unsigned edge) {
return edge;
}
private:
std::vector<T> table_;
const unsigned number_of_nodes_;
};
#endif // MATRIX_GRAPH_WRAPPER_H

163
plugins/round_trip.hpp
View File

@ -31,11 +31,13 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "plugin_base.hpp"
#include "../algorithms/object_encoder.hpp"
#include "../algorithms/tiny_components.hpp"
#include "../routing_algorithms/tsp_nearest_neighbour.hpp"
#include "../routing_algorithms/tsp_farthest_insertion.hpp"
#include "../routing_algorithms/tsp_brute_force.hpp"
#include "../data_structures/query_edge.hpp"
#include "../data_structures/search_engine.hpp"
#include "../data_structures/matrix_graph_wrapper.hpp"
#include "../descriptors/descriptor_base.hpp"
#include "../descriptors/json_descriptor.hpp"
#include "../util/json_renderer.hpp"
@ -95,97 +97,41 @@ template <class DataFacadeT> class RoundTripPlugin final : public BasePlugin
}
}
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector, std::vector<EdgeWeight> & result_table) {
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector,
std::vector<EdgeWeight> & result_table,
std::vector<std::vector<unsigned>> & components) {
// Run TarjanSCC
auto number_of_locations = phantom_node_vector.size();
const auto maxint = std::numeric_limits<int>::max();
auto wrapper = std::make_shared<MatrixGraphWrapper<EdgeWeight>>(result_table, number_of_locations);
auto empty_restriction = RestrictionMap(std::vector<TurnRestriction>());
auto empty_vector = std::vector<bool>();
auto scc = TarjanSCC<MatrixGraphWrapper<EdgeWeight>>(wrapper, empty_restriction, empty_vector);
scc.run();
//////////////////////////////////// DELETE UNACCESSIBLE LOCATIONS /////////////////////////////////////////
if (*std::max_element(result_table.begin(), result_table.end()) == maxint) {
const int half = number_of_locations / 2;
std::vector<int> to_delete;
for (int j = 0; j < scc.get_number_of_components(); ++j){
components.push_back(std::vector<unsigned>());
}
for (int i = number_of_locations - 1; i >= 0; --i) {
// if the location is unaccessible by most of the other locations, remember the location
if (std::count(result_table.begin() + i * number_of_locations, result_table.begin() + (i+1) * number_of_locations, maxint) > half) {
to_delete.push_back(i);
}
}
//delete all unaccessible locations
for (int k = 0; k < to_delete.size(); ++k) {
// delete its row
result_table.erase(result_table.begin() + to_delete[k] * number_of_locations, result_table.begin() + (to_delete[k]+1) * number_of_locations);
--number_of_locations;
// delete its column
for (int j = 0; j < number_of_locations; ++j) {
result_table.erase(result_table.begin() + j * number_of_locations + to_delete[k]);
}
// delete its PhantomNode
phantom_node_vector.erase(phantom_node_vector.begin() + to_delete[k]);
}
for (int i = 0; i < number_of_locations; ++i) {
components[scc.get_component_id(i)].push_back(i);
}
}
void SetJSONOutput (const RouteParameters &route_parameters,
int tsp_time,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation,
osrm::json::Object & json_result){
void SetLocPermutationOutput(const std::vector<int> & loc_permutation, osrm::json::Object & json_result){
osrm::json::Array json_loc_permutation;
json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
json_loc_permutation.values.insert(json_loc_permutation.values.end(), loc_permutation.begin(), loc_permutation.end());
json_result.values["loc_permutation"] = json_loc_permutation;
json_result.values["distance"] = min_route.shortest_path_length;
json_result.values["runtime"] = tsp_time;
}
void SetDistanceOutput(const int distance, osrm::json::Object & json_result) {
json_result.values["distance"] = distance;
}
void SetRuntimeOutput(const float runtime, osrm::json::Object & json_result) {
json_result.values["runtime"] = runtime;
}
// if (route_parameters.tsp_algo.compare("NN"))
// //######################### NEAREST NEIGHBOUR ###############################//
// TIMER_START(tsp);
// osrm::tsp::NearestNeighbour(route_parameters, phantom_node_vector, *result_table, min_route, min_loc_permutation);
// search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
// TIMER_STOP(tsp);
// SimpleLogger().Write() << "Distance " << min_route.shortest_path_length;
// SimpleLogger().Write() << "Time " << TIMER_MSEC(tsp) + TIMER_MSEC(tsp_pre);
// osrm::json::Array json_loc_permutation;
// json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
// json_result.values["loc_permutation"] = json_loc_permutation;
// json_result.values["distance"] = min_route.shortest_path_length;
// json_result.values["runtime"] = TIMER_MSEC(tsp);
// else if (route_parameters.tsp_algo.compare("BF")
// //########################### BRUTE FORCE ####################################//
// if (route_parameters.coordinates.size() < 12) {
// TIMER_START(tsp);
// osrm::tsp::BruteForce(route_parameters, phantom_node_vector, *result_table, min_route, min_loc_permutation);
// search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
// TIMER_STOP(tsp);
// SimpleLogger().Write() << "Distance " << min_route.shortest_path_length;
// SimpleLogger().Write() << "Time " << TIMER_MSEC(tsp);
// osrm::json::Array json_loc_permutation;
// json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
// json_result.values["loc_permutation"] = json_loc_permutation;
// json_result.values["distance"] = min_route.shortest_path_length;
// json_result.values["runtime"] = TIMER_MSEC(tsp);
// } else {
// json_result.values["distance"] = -1;
// json_result.values["runtime"] = -1;
// }
// else
// //######################## FARTHEST INSERTION ###############################//
// TIMER_START(tsp);
// osrm::tsp::FarthestInsertion(route_parameters, phantom_node_vector, *result_table, min_route, min_loc_permutation);
// search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
// TIMER_STOP(tsp);
// SimpleLogger().Write() << "Distance " << min_route.shortest_path_length;
// SimpleLogger().Write() << "Time " << TIMER_MSEC(tsp);
// osrm::json::Array json_loc_permutation;
// json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
// json_result.values["loc_permutation"] = json_loc_permutation;
// json_result.values["distance"] = min_route.shortest_path_length;
// json_result.values["runtime"] = TIMER_MSEC(tsp);
void SetGeometry(const RouteParameters &route_parameters, const InternalRouteResult & min_route, osrm::json::Object & json_result) {
// return geometry result to json
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
@ -212,20 +158,53 @@ template <class DataFacadeT> class RoundTripPlugin final : public BasePlugin
return 400;
}
SplitUnaccessibleLocations(phantom_node_vector, *result_table);
auto number_of_locations = phantom_node_vector.size();
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(number_of_locations, -1);
//######################## FARTHEST INSERTION ###############################//
TIMER_START(tsp);
osrm::tsp::FarthestInsertionTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
const auto maxint = std::numeric_limits<int>::max();
if (*std::max_element(result_table->begin(), result_table->end()) == maxint) {
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
descriptor->SetConfig(route_parameters);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
std::vector<std::vector<unsigned>> components;
TIMER_START(tsp);
SplitUnaccessibleLocations(phantom_node_vector, *result_table, components);
auto number_of_locations = phantom_node_vector.size();
std::vector<int> min_loc_permutation(number_of_locations, -1);
auto min_dist = 0;
for(auto k = 0; k < components.size(); ++k) {
if (components[k].size() > 1) {
InternalRouteResult min_route;
osrm::tsp::FarthestInsertionTSP(components[k], phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
min_dist += min_route.shortest_path_length;
descriptor->Run(min_route, json_result);
}
}
TIMER_STOP(tsp);
SetJSONOutput(route_parameters, TIMER_MSEC(tsp), min_route, min_loc_permutation, json_result);
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetDistanceOutput(min_dist, json_result);
SetLocPermutationOutput(min_loc_permutation, json_result);
} else {
auto number_of_locations = phantom_node_vector.size();
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(number_of_locations, -1);
//######################## FARTHEST INSERTION ###############################//
TIMER_START(tsp);
osrm::tsp::FarthestInsertionTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
// //######################### NEAREST NEIGHBOUR ###############################//
// TIMER_START(tsp);
// osrm::tsp::NearestNeighbourTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
// search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
// TIMER_STOP(tsp);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
SetLocPermutationOutput(min_loc_permutation, json_result);
SetDistanceOutput(min_route.shortest_path_length, json_result);
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetGeometry(route_parameters, min_route, json_result);
}

129
plugins/round_trip_BF.hpp
View File

@ -96,47 +96,41 @@ template <class DataFacadeT> class RoundTripPluginBF final : public BasePlugin
}
}
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector, std::vector<EdgeWeight> & result_table) {
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector,
std::vector<EdgeWeight> & result_table,
std::vector<std::vector<unsigned>> & components) {
// Run TarjanSCC
auto number_of_locations = phantom_node_vector.size();
const auto maxint = std::numeric_limits<int>::max();
auto wrapper = std::make_shared<MatrixGraphWrapper<EdgeWeight>>(result_table, number_of_locations);
auto empty_restriction = RestrictionMap(std::vector<TurnRestriction>());
auto empty_vector = std::vector<bool>();
auto scc = TarjanSCC<MatrixGraphWrapper<EdgeWeight>>(wrapper, empty_restriction, empty_vector);
scc.run();
//////////////////////////////////// DELETE UNACCESSIBLE LOCATIONS /////////////////////////////////////////
if (*std::max_element(result_table.begin(), result_table.end()) == maxint) {
const int half = number_of_locations / 2;
std::vector<int> to_delete;
for (int j = 0; j < scc.get_number_of_components(); ++j){
components.push_back(std::vector<unsigned>());
}
for (int i = number_of_locations - 1; i >= 0; --i) {
// if the location is unaccessible by most of the other locations, remember the location
if (std::count(result_table.begin() + i * number_of_locations, result_table.begin() + (i+1) * number_of_locations, maxint) > half) {
to_delete.push_back(i);
}
}
//delete all unaccessible locations
for (int k = 0; k < to_delete.size(); ++k) {
// delete its row
result_table.erase(result_table.begin() + to_delete[k] * number_of_locations, result_table.begin() + (to_delete[k]+1) * number_of_locations);
--number_of_locations;
// delete its column
for (int j = 0; j < number_of_locations; ++j) {
result_table.erase(result_table.begin() + j * number_of_locations + to_delete[k]);
}
// delete its PhantomNode
phantom_node_vector.erase(phantom_node_vector.begin() + to_delete[k]);
}
for (int i = 0; i < number_of_locations; ++i) {
components[scc.get_component_id(i)].push_back(i);
}
}
void SetJSONOutput (const RouteParameters &route_parameters,
int tsp_time,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation,
osrm::json::Object & json_result){
void SetLocPermutationOutput(const std::vector<int> & loc_permutation, osrm::json::Object & json_result){
osrm::json::Array json_loc_permutation;
json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
json_loc_permutation.values.insert(json_loc_permutation.values.end(), loc_permutation.begin(), loc_permutation.end());
json_result.values["loc_permutation"] = json_loc_permutation;
json_result.values["distance"] = min_route.shortest_path_length;
json_result.values["runtime"] = tsp_time;
}
void SetDistanceOutput(const int distance, osrm::json::Object & json_result) {
json_result.values["distance"] = distance;
}
void SetRuntimeOutput(const float runtime, osrm::json::Object & json_result) {
json_result.values["runtime"] = runtime;
}
void SetGeometry(const RouteParameters &route_parameters, const InternalRouteResult & min_route, osrm::json::Object & json_result) {
// return geometry result to json
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
@ -145,6 +139,7 @@ template <class DataFacadeT> class RoundTripPluginBF final : public BasePlugin
descriptor->Run(min_route, json_result);
}
int HandleRequest(const RouteParameters &route_parameters,
osrm::json::Object &json_result) override final
{
@ -163,39 +158,57 @@ template <class DataFacadeT> class RoundTripPluginBF final : public BasePlugin
return 400;
}
SplitUnaccessibleLocations(phantom_node_vector, *result_table);
if (route_parameters.coordinates.size() < 14) {
const auto maxint = std::numeric_limits<int>::max();
if (*std::max_element(result_table->begin(), result_table->end()) == maxint) {
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
descriptor->SetConfig(route_parameters);
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(phantom_node_vector.size(), -1);
//########################### BRUTE FORCE ####################################//
if (route_parameters.coordinates.size() < 11) {
std::vector<std::vector<unsigned>> components;
TIMER_START(tsp);
osrm::tsp::BruteForceTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
SplitUnaccessibleLocations(phantom_node_vector, *result_table, components);
std::vector<int> min_loc_permutation(phantom_node_vector.size(), -1);
auto min_dist = 0;
for(auto k = 0; k < components.size(); ++k) {
if (components[k].size() > 1) {
InternalRouteResult min_route;
//run nearest neighbour
osrm::tsp::BruteForceTSP(components[k], phantom_node_vector, *result_table, min_route, min_loc_permutation);
//compute route
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
//return geometry
min_dist += min_route.shortest_path_length;
descriptor->Run(min_route, json_result);
}
}
TIMER_STOP(tsp);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetDistanceOutput(min_dist, json_result);
SetLocPermutationOutput(min_loc_permutation, json_result);
} else {
auto number_of_locations = phantom_node_vector.size();
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(number_of_locations, -1);
//########################### BRUTE FORCE ####################################//
TIMER_START(tsp);
osrm::tsp::BruteForceTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
osrm::json::Array json_loc_permutation;
json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
json_result.values["loc_permutation"] = json_loc_permutation;
json_result.values["distance"] = min_route.shortest_path_length;
SimpleLogger().Write() << "BF GEOM DISTANCE " << min_route.shortest_path_length;
json_result.values["runtime"] = TIMER_MSEC(tsp);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
SetLocPermutationOutput(min_loc_permutation, json_result);
SetDistanceOutput(min_route.shortest_path_length, json_result);
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetGeometry(route_parameters, min_route, json_result);
}
} else {
json_result.values["distance"] = -1;
json_result.values["runtime"] = -1;
SetRuntimeOutput(-1, json_result);
SetDistanceOutput(-1, json_result);
}
// return geometry result to json
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
descriptor->SetConfig(route_parameters);
descriptor->Run(min_route, json_result);
return 200;
}

107
plugins/round_trip_FI.hpp
View File

@ -95,47 +95,41 @@ template <class DataFacadeT> class RoundTripPluginFI final : public BasePlugin
}
}
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector, std::vector<EdgeWeight> & result_table) {
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector,
std::vector<EdgeWeight> & result_table,
std::vector<std::vector<unsigned>> & components) {
// Run TarjanSCC
auto number_of_locations = phantom_node_vector.size();
const auto maxint = std::numeric_limits<int>::max();
auto wrapper = std::make_shared<MatrixGraphWrapper<EdgeWeight>>(result_table, number_of_locations);
auto empty_restriction = RestrictionMap(std::vector<TurnRestriction>());
auto empty_vector = std::vector<bool>();
auto scc = TarjanSCC<MatrixGraphWrapper<EdgeWeight>>(wrapper, empty_restriction, empty_vector);
scc.run();
//////////////////////////////////// DELETE UNACCESSIBLE LOCATIONS /////////////////////////////////////////
if (*std::max_element(result_table.begin(), result_table.end()) == maxint) {
const int half = number_of_locations / 2;
std::vector<int> to_delete;
for (int j = 0; j < scc.get_number_of_components(); ++j){
components.push_back(std::vector<unsigned>());
}
for (int i = number_of_locations - 1; i >= 0; --i) {
// if the location is unaccessible by most of the other locations, remember the location
if (std::count(result_table.begin() + i * number_of_locations, result_table.begin() + (i+1) * number_of_locations, maxint) > half) {
to_delete.push_back(i);
}
}
//delete all unaccessible locations
for (int k = 0; k < to_delete.size(); ++k) {
// delete its row
result_table.erase(result_table.begin() + to_delete[k] * number_of_locations, result_table.begin() + (to_delete[k]+1) * number_of_locations);
--number_of_locations;
// delete its column
for (int j = 0; j < number_of_locations; ++j) {
result_table.erase(result_table.begin() + j * number_of_locations + to_delete[k]);
}
// delete its PhantomNode
phantom_node_vector.erase(phantom_node_vector.begin() + to_delete[k]);
}
for (int i = 0; i < number_of_locations; ++i) {
components[scc.get_component_id(i)].push_back(i);
}
}
void SetJSONOutput (const RouteParameters &route_parameters,
int tsp_time,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation,
osrm::json::Object & json_result){
void SetLocPermutationOutput(const std::vector<int> & loc_permutation, osrm::json::Object & json_result){
osrm::json::Array json_loc_permutation;
json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
json_loc_permutation.values.insert(json_loc_permutation.values.end(), loc_permutation.begin(), loc_permutation.end());
json_result.values["loc_permutation"] = json_loc_permutation;
json_result.values["distance"] = min_route.shortest_path_length;
json_result.values["runtime"] = tsp_time;
}
void SetDistanceOutput(const int distance, osrm::json::Object & json_result) {
json_result.values["distance"] = distance;
}
void SetRuntimeOutput(const float runtime, osrm::json::Object & json_result) {
json_result.values["runtime"] = runtime;
}
void SetGeometry(const RouteParameters &route_parameters, const InternalRouteResult & min_route, osrm::json::Object & json_result) {
// return geometry result to json
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
@ -162,19 +156,48 @@ template <class DataFacadeT> class RoundTripPluginFI final : public BasePlugin
return 400;
}
SplitUnaccessibleLocations(phantom_node_vector, *result_table);
const auto maxint = std::numeric_limits<int>::max();
if (*std::max_element(result_table->begin(), result_table->end()) == maxint) {
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
descriptor->SetConfig(route_parameters);
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(phantom_node_vector.size(), -1);
//######################## FARTHEST INSERTION ###############################//
TIMER_START(tsp);
osrm::tsp::FarthestInsertionTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
std::vector<std::vector<unsigned>> components;
TIMER_START(tsp);
SplitUnaccessibleLocations(phantom_node_vector, *result_table, components);
auto number_of_locations = phantom_node_vector.size();
std::vector<int> min_loc_permutation(number_of_locations, -1);
auto min_dist = 0;
for(auto k = 0; k < components.size(); ++k) {
if (components[k].size() > 1) {
InternalRouteResult min_route;
osrm::tsp::FarthestInsertionTSP(components[k], phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
min_dist += min_route.shortest_path_length;
descriptor->Run(min_route, json_result);
}
}
TIMER_STOP(tsp);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetDistanceOutput(min_dist, json_result);
SetLocPermutationOutput(min_loc_permutation, json_result);
} else {
auto number_of_locations = phantom_node_vector.size();
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(number_of_locations, -1);
//######################## FARTHEST INSERTION ###############################//
TIMER_START(tsp);
osrm::tsp::FarthestInsertionTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
SetJSONOutput(route_parameters, TIMER_MSEC(tsp), min_route, min_loc_permutation, json_result);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
SetLocPermutationOutput(min_loc_permutation, json_result);
SetDistanceOutput(min_route.shortest_path_length, json_result);
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetGeometry(route_parameters, min_route, json_result);
}
return 200;
}

110
plugins/round_trip_NN.hpp
View File

@ -96,47 +96,41 @@ template <class DataFacadeT> class RoundTripPluginNN final : public BasePlugin
}
}
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector, std::vector<EdgeWeight> & result_table) {
void SplitUnaccessibleLocations(PhantomNodeArray & phantom_node_vector,
std::vector<EdgeWeight> & result_table,
std::vector<std::vector<unsigned>> & components) {
// Run TarjanSCC
auto number_of_locations = phantom_node_vector.size();
const auto maxint = std::numeric_limits<int>::max();
auto wrapper = std::make_shared<MatrixGraphWrapper<EdgeWeight>>(result_table, number_of_locations);
auto empty_restriction = RestrictionMap(std::vector<TurnRestriction>());
auto empty_vector = std::vector<bool>();
auto scc = TarjanSCC<MatrixGraphWrapper<EdgeWeight>>(wrapper, empty_restriction, empty_vector);
scc.run();
//////////////////////////////////// DELETE UNACCESSIBLE LOCATIONS /////////////////////////////////////////
if (*std::max_element(result_table.begin(), result_table.end()) == maxint) {
const int half = number_of_locations / 2;
std::vector<int> to_delete;
for (int j = 0; j < scc.get_number_of_components(); ++j){
components.push_back(std::vector<unsigned>());
}
for (int i = number_of_locations - 1; i >= 0; --i) {
// if the location is unaccessible by most of the other locations, remember the location
if (std::count(result_table.begin() + i * number_of_locations, result_table.begin() + (i+1) * number_of_locations, maxint) > half) {
to_delete.push_back(i);
}
}
//delete all unaccessible locations
for (int k = 0; k < to_delete.size(); ++k) {
// delete its row
result_table.erase(result_table.begin() + to_delete[k] * number_of_locations, result_table.begin() + (to_delete[k]+1) * number_of_locations);
--number_of_locations;
// delete its column
for (int j = 0; j < number_of_locations; ++j) {
result_table.erase(result_table.begin() + j * number_of_locations + to_delete[k]);
}
// delete its PhantomNode
phantom_node_vector.erase(phantom_node_vector.begin() + to_delete[k]);
}
for (int i = 0; i < number_of_locations; ++i) {
components[scc.get_component_id(i)].push_back(i);
}
}
void SetJSONOutput (const RouteParameters &route_parameters,
int tsp_time,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation,
osrm::json::Object & json_result){
void SetLocPermutationOutput(const std::vector<int> & loc_permutation, osrm::json::Object & json_result){
osrm::json::Array json_loc_permutation;
json_loc_permutation.values.insert(json_loc_permutation.values.end(), min_loc_permutation.begin(), min_loc_permutation.end());
json_loc_permutation.values.insert(json_loc_permutation.values.end(), loc_permutation.begin(), loc_permutation.end());
json_result.values["loc_permutation"] = json_loc_permutation;
json_result.values["distance"] = min_route.shortest_path_length;
json_result.values["runtime"] = tsp_time;
}
void SetDistanceOutput(const int distance, osrm::json::Object & json_result) {
json_result.values["distance"] = distance;
}
void SetRuntimeOutput(const float runtime, osrm::json::Object & json_result) {
json_result.values["runtime"] = runtime;
}
void SetGeometry(const RouteParameters &route_parameters, const InternalRouteResult & min_route, osrm::json::Object & json_result) {
// return geometry result to json
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
@ -163,19 +157,51 @@ template <class DataFacadeT> class RoundTripPluginNN final : public BasePlugin
return 400;
}
SplitUnaccessibleLocations(phantom_node_vector, *result_table);
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(phantom_node_vector.size(), -1);
//######################### NEAREST NEIGHBOUR ###############################//
TIMER_START(tsp);
osrm::tsp::NearestNeighbourTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
const auto maxint = std::numeric_limits<int>::max();
if (*std::max_element(result_table->begin(), result_table->end()) == maxint) {
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor;
descriptor = osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
descriptor->SetConfig(route_parameters);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
std::vector<std::vector<unsigned>> components;
TIMER_START(tsp);
SplitUnaccessibleLocations(phantom_node_vector, *result_table, components);
SetJSONOutput(route_parameters, TIMER_MSEC(tsp), min_route, min_loc_permutation, json_result);
std::vector<int> min_loc_permutation(phantom_node_vector.size(), -1);
auto min_dist = 0;
for(auto k = 0; k < components.size(); ++k) {
if (components[k].size() > 1) {
InternalRouteResult min_route;
//run nearest neighbour
osrm::tsp::NearestNeighbourTSP(components[k], phantom_node_vector, *result_table, min_route, min_loc_permutation);
//compute route
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
//return geometry
min_dist += min_route.shortest_path_length;
descriptor->Run(min_route, json_result);
}
}
TIMER_STOP(tsp);
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetDistanceOutput(min_dist, json_result);
SetLocPermutationOutput(min_loc_permutation, json_result);
} else {
auto number_of_locations = phantom_node_vector.size();
InternalRouteResult min_route;
std::vector<int> min_loc_permutation(number_of_locations, -1);
//######################### NEAREST NEIGHBOUR ###############################//
TIMER_START(tsp);
osrm::tsp::NearestNeighbourTSP(phantom_node_vector, *result_table, min_route, min_loc_permutation);
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, route_parameters.uturns, min_route);
TIMER_STOP(tsp);
BOOST_ASSERT(min_route.segment_end_coordinates.size() == route_parameters.coordinates.size());
SetLocPermutationOutput(min_loc_permutation, json_result);
SetDistanceOutput(min_route.shortest_path_length, json_result);
SetRuntimeOutput(TIMER_MSEC(tsp), json_result);
SetGeometry(route_parameters, min_route, json_result);
}
return 200;
}

43
routing_algorithms/tsp_brute_force.hpp
View File

@ -51,19 +51,19 @@ namespace osrm
namespace tsp
{
int ReturnDistance(const std::vector<EdgeWeight> & dist_table, const std::vector<int> location_order, const int min_route_dist, const int number_of_locations) {
template <typename number>
int ReturnDistance(const std::vector<EdgeWeight> & dist_table, const std::vector<number> & location_order, const int min_route_dist, const int number_of_locations, const int component_size) {
int i = 0;
int route_dist = 0;
// compute length and stop if length is longer than route already found
while (i < number_of_locations - 1 && route_dist < min_route_dist) {
while (i < component_size - 1 && route_dist < min_route_dist) {
//get distance from location i to location i+1
route_dist += *(dist_table.begin() + (location_order[i] * number_of_locations) + location_order[i+1]);
++i;
}
//get distance from last location to first location
route_dist += *(dist_table.begin() + (location_order[number_of_locations-1] * number_of_locations) + location_order[0]);
route_dist += *(dist_table.begin() + (location_order[component_size-1] * number_of_locations) + location_order[0]);
if (route_dist < min_route_dist) {
return route_dist;
@ -73,6 +73,39 @@ int ReturnDistance(const std::vector<EdgeWeight> & dist_table, const std::vector
}
}
void BruteForceTSP(std::vector<unsigned> & location,
const PhantomNodeArray & phantom_node_vector,
const std::vector<EdgeWeight> & dist_table,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation) {
const auto number_of_location = phantom_node_vector.size();
const int component_size = location.size();
int min_route_dist = std::numeric_limits<int>::max();
std::vector<unsigned> min_location;
// check length of all possible permutation of the location ids
do {
// int new_distance = ReturnDistance(dist_table, location, min_route_dist, number_of_location, component_size);
int new_distance = 4;
if (new_distance != -1) {
min_route_dist = new_distance;
min_location = location;
}
} while(std::next_permutation(location.begin(), location.end()));
PhantomNodes viapoint;
for (int i = 0; i < component_size - 1; ++i) {
viapoint = PhantomNodes{phantom_node_vector[min_location[i]][0], phantom_node_vector[min_location[i + 1]][0]};
min_route.segment_end_coordinates.emplace_back(viapoint);
min_loc_permutation[min_location[i]] = i;
}
min_loc_permutation[min_location[component_size - 1]] = component_size - 1;
viapoint = PhantomNodes{phantom_node_vector[min_location[component_size - 1]][0], phantom_node_vector[min_location[0]][0]};
min_route.segment_end_coordinates.emplace_back(viapoint);
}
void BruteForceTSP(const PhantomNodeArray & phantom_node_vector,
const std::vector<EdgeWeight> & dist_table,
InternalRouteResult & min_route,
@ -87,7 +120,7 @@ void BruteForceTSP(const PhantomNodeArray & phantom_node_vector,
// check length of all possible permutation of the location ids
do {
int new_distance = ReturnDistance(dist_table, location_ids, min_route_dist, number_of_locations);
int new_distance = ReturnDistance(dist_table, location_ids, min_route_dist, number_of_locations, number_of_locations);
if (new_distance != -1) {
min_route_dist = new_distance;
//TODO: this gets copied right? fix this

174
routing_algorithms/tsp_farthest_insertion.hpp
View File

@ -31,6 +31,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "../data_structures/search_engine.hpp"
#include "../util/string_util.hpp"
#include "../tools/tsp_logs.hpp"
#include <osrm/json_container.hpp>
@ -41,12 +42,136 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <vector>
#include <limits>
#include <iostream>
namespace osrm
{
namespace tsp
{
void GetLongestRoundTrip(const int current_loc,
std::list<int> & current_trip,
const std::vector<EdgeWeight> & dist_table,
const int number_of_locations,
int & longest_min_tour,
std::list<int>::iterator & following_loc){
// for all nodes in the current trip find the best insertion resulting in the shortest path
for (auto from_node = current_trip.begin(); from_node != std::prev(current_trip.end()); ++from_node) {
auto to_node = std::next(from_node);
auto dist_from = *(dist_table.begin() + (*from_node * number_of_locations) + current_loc);
auto dist_to = *(dist_table.begin() + (current_loc * number_of_locations) + *to_node);
auto trip_dist = dist_from + dist_to - *(dist_table.begin() + (*from_node * number_of_locations) + *to_node);
// from all possible insertions to the current trip, choose the longest of all minimal insertions
if (trip_dist < longest_min_tour) {
longest_min_tour = trip_dist;
following_loc = to_node;
}
}
{ // check insertion between last and first location too
auto from_node = std::prev(current_trip.end());
auto to_node = current_trip.begin();
auto dist_from = *(dist_table.begin() + (*from_node * number_of_locations) + current_loc);
auto dist_to = *(dist_table.begin() + (current_loc * number_of_locations) + *to_node);
auto trip_dist = dist_from + dist_to - *(dist_table.begin() + (*from_node * number_of_locations) + *to_node);
if (trip_dist < longest_min_tour) {
longest_min_tour = trip_dist;
following_loc = to_node;
}
}
}
void ComputeRouteAndPermutation(const PhantomNodeArray & phantom_node_vector,
std::list<int> & current_trip,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation) {
// given he final trip, compute total distance and return the route and location permutation
PhantomNodes viapoint;
int perm = 0;
for (auto it = current_trip.begin(); it != std::prev(current_trip.end()); ++it) {
auto from_node = *it;
auto to_node = *std::next(it);
viapoint = PhantomNodes{phantom_node_vector[from_node][0], phantom_node_vector[to_node][0]};
min_route.segment_end_coordinates.emplace_back(viapoint);
min_loc_permutation[from_node] = perm;
++perm;
}
// check dist between last and first location too
viapoint = PhantomNodes{phantom_node_vector[*std::prev(current_trip.end())][0], phantom_node_vector[current_trip.front()][0]};
min_route.segment_end_coordinates.emplace_back(viapoint);
min_loc_permutation[*std::prev(current_trip.end())] = perm;
}
void FarthestInsertionTSP(const std::vector<unsigned> & locations,
const PhantomNodeArray & phantom_node_vector,
const std::vector<EdgeWeight> & dist_table,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation) {
//////////////////////////////////////////////////////////////////////////////////////////////////
// START FARTHEST INSERTION HERE
// 1. start at a random round trip of 2 locations
// 2. find the location that is the farthest away from the visited locations and whose insertion will make the round trip the longest
// 3. add the found location to the current round trip such that round trip is the shortest
// 4. repeat 2-3 until all locations are visited
// 5. DONE!
//////////////////////////////////////////////////////////////////////////////////////////////////
const int number_of_locations = phantom_node_vector.size();
const int size_of_component = locations.size();
// list of the trip that will be found incrementally
std::list<int> current_trip;
// tracks which nodes have been already visited
std::vector<bool> visited(number_of_locations, false);
auto max_dist = 0;
auto index = -1;
for (auto x : locations) {
for (auto y : locations) {
if (*(dist_table.begin() + x * number_of_locations + y) > max_dist) {
max_dist = *(dist_table.begin() + x * number_of_locations + y);
index = x * number_of_locations + y;
}
}
}
const int max_from = index / number_of_locations;
const int max_to = index % number_of_locations;
visited[max_from] = true;
visited[max_to] = true;
current_trip.push_back(max_from);
current_trip.push_back(max_to);
// add all other nodes missing (two nodes are already in the initial start trip)
for (int j = 2; j < size_of_component; ++j) {
auto shortest_max_tour = -1;
int next_node = -1;
std::list<int>::iterator min_max_insert;
// find unvisited loc i that is the farthest away from all other visited locs
for (auto i : locations) {
if (!visited[i]) {
// longest_min_tour is the distance of the longest of all insertions with the minimal distance
auto longest_min_tour = std::numeric_limits<int>::max();
// following_loc is the location that comes after the location that is to be inserted
std::list<int>::iterator following_loc;
GetLongestRoundTrip(i, current_trip, dist_table, number_of_locations, longest_min_tour, following_loc);
// add the location to the current trip such that it results in the shortest total tour
if (longest_min_tour > shortest_max_tour) {
shortest_max_tour = longest_min_tour;
next_node = i;
min_max_insert = following_loc;
}
}
}
// mark as visited and insert node
visited[next_node] = true;
current_trip.insert(min_max_insert, next_node);
}
ComputeRouteAndPermutation(phantom_node_vector, current_trip, min_route, min_loc_permutation);
}
void FarthestInsertionTSP(const PhantomNodeArray & phantom_node_vector,
const std::vector<EdgeWeight> & dist_table,
InternalRouteResult & min_route,
@ -66,14 +191,11 @@ void FarthestInsertionTSP(const PhantomNodeArray & phantom_node_vector,
// tracks which nodes have been already visited
std::vector<bool> visited(number_of_locations, false);
// PrintDistTable(dist_table, number_of_locations);
// find the pair of location with the biggest distance and make the pair the initial start trip
const auto index = std::distance(dist_table.begin(), std::max_element(dist_table.begin(), dist_table.end()));
const int max_from = index / number_of_locations;
const int max_to = index % number_of_locations;
visited[max_from] = true;
visited[max_to] = true;
current_trip.push_back(max_from);
@ -93,32 +215,7 @@ void FarthestInsertionTSP(const PhantomNodeArray & phantom_node_vector,
// following_loc is the location that comes after the location that is to be inserted
std::list<int>::iterator following_loc;
// for all nodes in the current trip find the best insertion resulting in the shortest path
for (auto from_node = current_trip.begin(); from_node != std::prev(current_trip.end()); ++from_node) {
auto to_node = std::next(from_node);
auto dist_from = *(dist_table.begin() + (*from_node * number_of_locations) + i);
auto dist_to = *(dist_table.begin() + (i * number_of_locations) + *to_node);
auto trip_dist = dist_from + dist_to - *(dist_table.begin() + (*from_node * number_of_locations) + *to_node);
// from all possible insertions to the current trip, choose the longest of all minimal insertions
if (trip_dist < longest_min_tour) {
longest_min_tour = trip_dist;
following_loc = to_node;
}
}
{ // check insertion between last and first location too
auto from_node = std::prev(current_trip.end());
auto to_node = current_trip.begin();
auto dist_from = *(dist_table.begin() + (*from_node * number_of_locations) + i);
auto dist_to = *(dist_table.begin() + (i * number_of_locations) + *to_node);
auto trip_dist = dist_from + dist_to - *(dist_table.begin() + (*from_node * number_of_locations) + *to_node);
if (trip_dist < longest_min_tour) {
longest_min_tour = trip_dist;
following_loc = to_node;
}
}
GetLongestRoundTrip(i, current_trip, dist_table, number_of_locations, longest_min_tour, following_loc);
// add the location to the current trip such that it results in the shortest total tour
if (longest_min_tour > shortest_max_tour) {
@ -133,24 +230,7 @@ void FarthestInsertionTSP(const PhantomNodeArray & phantom_node_vector,
current_trip.insert(min_max_insert, next_node);
}
// given he final trip, compute total distance and return the route and location permutation
PhantomNodes viapoint;
int perm = 0;
for (auto it = current_trip.begin(); it != std::prev(current_trip.end()); ++it) {
auto from_node = *it;
auto to_node = *std::next(it);
viapoint = PhantomNodes{phantom_node_vector[from_node][0], phantom_node_vector[to_node][0]};
min_route.segment_end_coordinates.emplace_back(viapoint);
min_loc_permutation[from_node] = perm;
++perm;
}
{ // check dist between last and first location too
viapoint = PhantomNodes{phantom_node_vector[*std::prev(current_trip.end())][0], phantom_node_vector[current_trip.front()][0]};
min_route.segment_end_coordinates.emplace_back(viapoint);
min_loc_permutation[*std::prev(current_trip.end())] = perm;
}
ComputeRouteAndPermutation(phantom_node_vector, current_trip, min_route, min_loc_permutation);
}

122
routing_algorithms/tsp_nearest_neighbour.hpp
View File

@ -48,6 +48,128 @@ namespace osrm
namespace tsp
{
void NearestNeighbourTSP(const std::vector<unsigned> & locations,
const PhantomNodeArray & phantom_node_vector,
const std::vector<EdgeWeight> & dist_table,
InternalRouteResult & min_route,
std::vector<int> & min_loc_permutation) {
//////////////////////////////////////////////////////////////////////////////////////////////////
// START GREEDY NEAREST NEIGHBOUR HERE
// 1. grab a random location and mark as starting point
// 2. find the nearest unvisited neighbour, set it as the current location and mark as visited
// 3. repeat 2 until there is no unvisited location
// 4. return route back to starting point
// 5. compute route
// 6. repeat 1-5 with different starting points and choose iteration with shortest trip
// 7. DONE!
//////////////////////////////////////////////////////////////////////////////////////////////////
const auto number_of_locations = phantom_node_vector.size();
const int size_of_component = locations.size();
min_route.shortest_path_length = std::numeric_limits<int>::max();
// ALWAYS START AT ANOTHER STARTING POINT
for(auto start_node : locations)
{
int curr_node = start_node;
InternalRouteResult raw_route;
//TODO: Should we always use the same vector or does it not matter at all because of loop scope?
std::vector<int> loc_permutation(number_of_locations, -1);
loc_permutation[start_node] = 0;
// visited[i] indicates whether node i was already visited by the salesman
std::vector<bool> visited(number_of_locations, false);
visited[start_node] = true;
PhantomNodes viapoint;
// 3. REPEAT FOR EVERY UNVISITED NODE
int trip_dist = 0;
for(int via_point = 1; via_point < size_of_component; ++via_point)
{
int min_dist = std::numeric_limits<int>::max();
int min_id = -1;
// 2. FIND NEAREST NEIGHBOUR
for (auto next : locations) {
if(!visited[next] &&
*(dist_table.begin() + curr_node * number_of_locations + next) < min_dist) {
min_dist = *(dist_table.begin() + curr_node * number_of_locations + next);
min_id = next;
}
}
loc_permutation[min_id] = via_point;
visited[min_id] = true;
viapoint = PhantomNodes{phantom_node_vector[curr_node][0], phantom_node_vector[min_id][0]};
raw_route.segment_end_coordinates.emplace_back(viapoint);
trip_dist += min_dist;
curr_node = min_id;
}
// 4. ROUTE BACK TO STARTING POINT
viapoint = PhantomNodes{raw_route.segment_end_coordinates.back().target_phantom, phantom_node_vector[start_node][0]};
raw_route.segment_end_coordinates.emplace_back(viapoint);
// check round trip with this starting point is shorter than the shortest round trip found till now
if (trip_dist < min_route.shortest_path_length) {
min_route = raw_route;
min_route.shortest_path_length = trip_dist;
//TODO: this gets copied right? fix this
min_loc_permutation = loc_permutation;
}
}
// // ALWAYS START AT ANOTHER STARTING POINT
// for(auto start_node : locations) {
// SimpleLogger().Write() << "STARTING AT " << start_node;
// int curr_node = start_node;
// InternalRouteResult raw_route;
// //TODO: Should we always use the same vector or does it not matter at all because of loop scope?
// std::vector<int> loc_permutation(number_of_locations, -1);
// // visited[i] indicates whether node i was already visited by the salesman
// std::vector<bool> visited(number_of_locations, false);
// visited[start_node] = true;
// loc_permutation[start_node] = 0;
// PhantomNodes viapoint;
// // 3. REPEAT FOR EVERY UNVISITED NODE
// int trip_dist = 0;
// for(int via_point = 1; via_point < size_of_component; ++via_point)
// {
// int min_dist = std::numeric_limits<int>::max();
// int min_id = -1;
// // 2. FIND NEAREST NEIGHBOUR
// for (auto next : locations) {
// if(!visited[next] &&
// *(dist_table.begin() + curr_node * number_of_locations + next) < min_dist) {
// min_dist = *(dist_table.begin() + curr_node * number_of_locations + next);
// min_id = next;
// }
// }
// loc_permutation[min_id] = via_point;
// visited[min_id] = true;
// SimpleLogger().Write() << "MOVING TO " << min_id;
// viapoint = PhantomNodes{phantom_node_vector[curr_node][0], phantom_node_vector[min_id][0]};
// raw_route.segment_end_coordinates.emplace_back(viapoint);
// trip_dist += min_dist;
// curr_node = min_id;
// }
// // 4. ROUTE BACK TO STARTING POINT
// viapoint = PhantomNodes{raw_route.segment_end_coordinates.back().target_phantom, phantom_node_vector[start_node][0]};
// raw_route.segment_end_coordinates.emplace_back(viapoint);
// // check round trip with this starting point is shorter than the shortest round trip found till now
// if (trip_dist < min_route.shortest_path_length) {
// min_route = raw_route;
// min_route.shortest_path_length = trip_dist;
// //TODO: this gets copied right? fix this
// min_loc_permutation = loc_permutation;
// }
// }
}
void NearestNeighbourTSP(const PhantomNodeArray & phantom_node_vector,
const std::vector<EdgeWeight> & dist_table,
InternalRouteResult & min_route,