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/*PGR-GNU*****************************************************************
File: dagShortestPath.hpp
Copyright (c) 2013-2026 pgRouting developers
Mail: project@pgrouting.org
Copyright (c) 2018 Sourabh Garg
sourabh.garg.mat@gmail.com
------
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
********************************************************************PGR-GNU*/
#ifndef INCLUDE_DAGSHORTESTPATH_DAGSHORTESTPATH_HPP_
#define INCLUDE_DAGSHORTESTPATH_DAGSHORTESTPATH_HPP_
#pragma once
#include <deque>
#include <set>
#include <vector>
#include <algorithm>
#include <sstream>
#include <functional>
#include <limits>
#include <map>
#include <cstdint>
#include <boost/config.hpp>
#include <boost/graph/dijkstra_shortest_paths.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/dag_shortest_paths.hpp>
#include "cpp_common/path.hpp"
#include "cpp_common/base_graph.hpp"
#include "cpp_common/interruption.hpp"
#include "c_types/ii_t_rt.h"
namespace pgrouting {
template <class G>
class Pgr_dag {
public:
typedef typename G::V V;
typedef typename G::E E;
/** dag 1 to many */
std::deque<Path> dag(
G &graph,
int64_t start_vertex,
const std::set<int64_t> &end_vertex,
bool only_cost) {
std::deque<Path> paths;
/* precondition */
if (!graph.has_vertex(start_vertex)) return paths;
/* adjust predecessors and distances vectors */
clear();
size_t n_goals = (std::numeric_limits<size_t>::max)();
predecessors.resize(graph.num_vertices());
distances.resize(
graph.num_vertices(),
std::numeric_limits<double>::infinity());
auto v_source(graph.get_V(start_vertex));
std::set<V> v_targets;
for (const auto &vertex : end_vertex) {
if (graph.has_vertex(vertex)) v_targets.insert(graph.get_V(vertex));
}
if (v_targets.empty()) return paths;
dag_1_to_many(graph, v_source, v_targets, n_goals);
paths = get_paths(graph, v_source, v_targets, only_cost);
std::stable_sort(paths.begin(), paths.end(),
[](const Path &e1, const Path &e2)->bool {
return e1.end_id() < e2.end_id();
});
return paths;
}
/** combinations */
std::deque<Path> dag(
G &graph,
const std::map<int64_t, std::set<int64_t>> &combinations,
bool only_cost) {
std::deque<Path> paths;
for (const auto &c : combinations) {
auto result_paths = dag(graph, c.first, c.second, only_cost);
paths.insert(
paths.end(),
std::make_move_iterator(result_paths.begin()),
std::make_move_iterator(result_paths.end()));
}
return paths;
}
//@}
private:
/** DAG 1 source to many targets */
bool dag_1_to_many(
G &graph,
V source,
const std::set<V> &targets,
size_t n_goals = (std::numeric_limits<size_t>::max)()) {
CHECK_FOR_INTERRUPTS();
try {
boost::dag_shortest_paths(graph.graph, source,
boost::predecessor_map(&predecessors[0])
.weight_map(get(&G::G_T_E::cost, graph.graph))
.distance_map(&distances[0])
.distance_inf(std::numeric_limits<double>::infinity())
.visitor(dijkstra_many_goal_visitor(targets, n_goals)));
} catch(found_goals &) {
return true;
} catch (boost::exception const& ex) {
(void)ex;
throw;
} catch (std::exception &e) {
(void)e;
throw;
} catch (...) {
throw;
}
return true;
}
void clear() {
predecessors.clear();
distances.clear();
nodesInDistance.clear();
}
// used when multiple goals
std::deque<Path> get_paths(
const G &graph,
V source,
std::set<V> &targets,
bool only_cost) const {
std::deque<Path> paths;
for (const auto target : targets) {
paths.push_back(Path(
graph,
source, target,
predecessors, distances,
only_cost, true));
}
return paths;
}
//! @name members
//@{
struct found_goals{}; //!< exception for termination
std::vector< V > predecessors;
std::vector< double > distances;
std::deque< V > nodesInDistance;
std::ostringstream log;
//@}
//! class for stopping when all targets are found
class dijkstra_many_goal_visitor : public boost::default_dijkstra_visitor {
public:
explicit dijkstra_many_goal_visitor(
const std::set<V> &goals,
size_t n_goals) :
m_goals(goals),
m_n_goals(n_goals) {}
template <class B_G>
void examine_vertex(V u, B_G &) {
auto s_it = m_goals.find(u);
if (s_it == m_goals.end()) return;
// found one more goal
m_goals.erase(s_it);
// all goals found
if (m_goals.size() == 0) throw found_goals();
// number of requested goals found
--m_n_goals;
if (m_n_goals == 0) throw found_goals();
}
private:
std::set<V> m_goals;
size_t m_n_goals;
};
};
} // namespace pgrouting
#endif // INCLUDE_DAGSHORTESTPATH_DAGSHORTESTPATH_HPP_
|
