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/*PGR-GNU*****************************************************************
File: bellman_ford.hpp
Copyright (c) 2018-2026 pgRouting developers
Mail: project@pgrouting.org
Copyright (c) 2018 Sourabh Garg
Mail to: sourabh.garg.mat14@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_BELLMAN_FORD_BELLMAN_FORD_HPP_
#define INCLUDE_BELLMAN_FORD_BELLMAN_FORD_HPP_
#pragma once
#include <deque>
#include <set>
#include <vector>
#include <algorithm>
#include <sstream>
#include <string>
#include <functional>
#include <limits>
#include <map>
#include <cstdint>
#include <boost/config.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/bellman_ford_shortest_paths.hpp>
#include "cpp_common/messages.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_bellman_ford : public pgrouting::Pgr_messages {
public:
typedef typename G::V V;
typedef typename G::E E;
//@{
/** @brief bellman_ford one to a set of many
* @todo document this function
*/
std::deque<Path> bellman_ford(
G &graph,
int64_t start_vertex,
const std::set<int64_t> &end_vertex,
bool only_cost = false) {
// adjust predecessors and distances vectors
clear();
predecessors.resize(graph.num_vertices());
distances.resize(graph.num_vertices());
// get the graphs source and targets
if (!graph.has_vertex(start_vertex)) return std::deque<Path>();
auto v_source(graph.get_V(start_vertex));
std::set<V> s_v_targets;
for (const auto &vertex : end_vertex) {
if (graph.has_vertex(vertex)) {
s_v_targets.insert(graph.get_V(vertex));
}
}
std::vector<V> v_targets(s_v_targets.begin(), s_v_targets.end());
// perform the algorithm
bellman_ford_1_to_many(graph, v_source);
// get the results // route id are the targets
auto 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;
}
/** @brief BellmanFord combinations **/
std::deque<Path> bellman_ford(
G &graph,
const std::map<int64_t, std::set<int64_t>> &combinations,
bool only_cost = false) {
std::deque<Path> paths;
for (const auto &comb : combinations) {
if (!graph.has_vertex(comb.first)) continue;
auto tmp_paths = bellman_ford(graph, comb.first, comb.second, only_cost);
paths.insert(paths.end(), tmp_paths.begin(), tmp_paths.end());
}
return paths;
}
//@}
private:
//! Call to BellmanFord 1 source to many targets
bool bellman_ford_1_to_many(
G &graph,
V source) {
log << std::string(__FUNCTION__) << "\n";
/* abort in case of an interruption occurs (e.g. the query is being cancelled) */
CHECK_FOR_INTERRUPTS();
try {
boost::bellman_ford_shortest_paths(
graph.graph,
static_cast<int>(graph.num_vertices()),
boost::predecessor_map(&predecessors[0])
.weight_map(get(&G::G_T_E::cost, graph.graph))
.distance_map(&distances[0])
.root_vertex(source));
} catch (boost::exception const& ex) {
(void)ex;
throw;
} catch (std::exception &e) {
(void)e;
throw;
} catch (...) {
throw;
}
return true;
}
// To Empty predecessors and distances vector for each function call
void clear() {
predecessors.clear();
distances.clear();
}
// used when multiple goals
std::deque<Path> get_paths(
const G &graph,
V source,
std::vector< 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
//@{
std::vector<V> predecessors;
std::vector<double> distances;
//@}
};
} // namespace pgrouting
#endif // INCLUDE_BELLMAN_FORD_BELLMAN_FORD_HPP_
|
