85 lines
2.5 KiB
C++
85 lines
2.5 KiB
C++
#ifndef TRIP_BRUTE_FORCE_HPP
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#define TRIP_BRUTE_FORCE_HPP
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#include "util/dist_table_wrapper.hpp"
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#include "util/simple_logger.hpp"
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#include "util/typedefs.hpp"
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#include "osrm/json_container.hpp"
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#include <algorithm>
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#include <cstdlib>
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#include <iterator>
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#include <limits>
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#include <string>
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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 trip
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{
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// computes the distance of a given permutation
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EdgeWeight ReturnDistance(const util::DistTableWrapper<EdgeWeight> &dist_table,
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const std::vector<NodeID> &location_order,
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const EdgeWeight min_route_dist,
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const std::size_t component_size)
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{
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EdgeWeight route_dist = 0;
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std::size_t i = 0;
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while (i < location_order.size() && (route_dist < min_route_dist))
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{
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route_dist += dist_table(location_order[i], location_order[(i + 1) % component_size]);
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BOOST_ASSERT_MSG(dist_table(location_order[i], location_order[(i + 1) % component_size]) !=
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INVALID_EDGE_WEIGHT,
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"invalid route found");
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++i;
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}
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return route_dist;
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}
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// computes the route by computing all permutations and selecting the shortest
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template <typename NodeIDIterator>
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std::vector<NodeID> BruteForceTrip(const NodeIDIterator start,
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const NodeIDIterator end,
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const std::size_t number_of_locations,
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const util::DistTableWrapper<EdgeWeight> &dist_table)
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{
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(void)number_of_locations; // unused
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const auto component_size = std::distance(start, end);
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std::vector<NodeID> perm(start, end);
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std::vector<NodeID> route;
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route.reserve(component_size);
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EdgeWeight min_route_dist = INVALID_EDGE_WEIGHT;
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// check length of all possible permutation of the component ids
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BOOST_ASSERT_MSG(perm.size() > 0, "no permutation given");
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BOOST_ASSERT_MSG(*(std::max_element(std::begin(perm), std::end(perm))) < number_of_locations,
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"invalid node id");
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BOOST_ASSERT_MSG(*(std::min_element(std::begin(perm), std::end(perm))) >= 0, "invalid node id");
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do
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{
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const auto new_distance = ReturnDistance(dist_table, perm, min_route_dist, component_size);
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if (new_distance <= min_route_dist)
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{
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min_route_dist = new_distance;
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route = perm;
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}
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} while (std::next_permutation(std::begin(perm), std::end(perm)));
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return route;
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}
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}
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}
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}
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#endif // TRIP_BRUTE_FORCE_HPP
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