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/*PGR-GNU*****************************************************************
File: astar.hpp
Copyright (c) 2023-2026 pgRouting developers
Mail: project@pgrouting.org
Copyright (c) 2023 Vicky Vergara
Copyright (c) 2015 Vicky Vergara
Mail: vicky at erosion.dev
------
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_ASTAR_ASTAR_HPP_
#define INCLUDE_ASTAR_ASTAR_HPP_
#pragma once
#include <deque>
#include <vector>
#include <limits>
#include <set>
#include <map>
#include <cstdint>
#include <boost/graph/astar_search.hpp>
#include "visitors/astar_visitors.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 detail {
template <typename B_G, typename V>
class distance_heuristic : public boost::astar_heuristic<B_G, double> {
public:
distance_heuristic(
B_G &g,
const std::set<V> &destinations,
int heuristic,
double factor)
: m_g(g),
m_goals(destinations),
m_factor(factor),
m_heuristic(heuristic) {}
double operator()(V u) {
if (m_heuristic == 0) return 0;
if (m_goals.empty()) return 0;
double best_h((std::numeric_limits<double>::max)());
for (auto goal : m_goals) {
double current((std::numeric_limits<double>::max)());
double dx = m_g[goal].x() - m_g[u].x();
double dy = m_g[goal].y() - m_g[u].y();
switch (m_heuristic) {
case 0:
current = 0;
break;
case 1:
current = std::fabs((std::max)(dx, dy)) * m_factor;
break;
case 2:
current = std::fabs((std::min)(dx, dy)) * m_factor;
break;
case 3:
current = (dx * dx + dy * dy) * m_factor * m_factor;
break;
case 4:
current = std::sqrt(dx * dx + dy * dy) * m_factor;
break;
case 5:
current = (std::fabs(dx) + std::fabs(dy)) * m_factor;
break;
default:
current = 0;
}
if (current < best_h) {
best_h = current;
}
}
{
auto s_it = m_goals.find(u);
if (!(s_it == m_goals.end())) {
// found one more goal
m_goals.erase(s_it);
}
}
return best_h;
}
private:
B_G &m_g;
std::set<V> m_goals;
double m_factor;
int m_heuristic;
};
template <typename G, typename V>
bool astar_1_to_many(
G &graph,
std::vector<V> &predecessors,
std::vector<double> &distances,
V departure,
const std::set<V> &destinations,
int heuristic,
double factor,
double epsilon) {
typedef typename G::B_G B_G;
bool found = false;
CHECK_FOR_INTERRUPTS();
try {
boost::astar_search(
graph.graph, departure,
distance_heuristic<B_G, V>(
graph.graph, destinations,
heuristic, factor * epsilon),
boost::predecessor_map(&predecessors[0])
.weight_map(get(&pgrouting::Basic_edge::cost, graph.graph))
.distance_map(&distances[0])
.visitor(pgrouting::visitors::astar_many_goals_visitor<V>(destinations)));
}
catch(pgrouting::found_goals &) {
found = true; // Target vertex found
}
return found;
}
template <typename G, typename V>
std::deque<pgrouting::Path> get_paths(
const G &graph,
const std::vector<V> &predecessors,
const std::vector<double> &distances,
V source,
const std::set<V> &targets,
bool only_cost) {
using Path = pgrouting::Path;
std::deque<Path> paths;
for (const auto &target : targets) {
auto p = Path(graph,
source, target,
predecessors, distances,
false);
paths.push_back(Path(graph, p, only_cost));
}
return paths;
}
} // namespace detail
namespace pgrouting {
namespace algorithms {
template < class G >
std::deque<Path> astar(
G &graph,
const std::map<int64_t, std::set<int64_t>> &combinations,
int heuristic,
double factor,
double epsilon,
bool only_cost) {
typedef typename G::V V;
std::deque<Path> paths;
for (const auto &c : combinations) {
if (!graph.has_vertex(c.first)) continue;
std::vector<V> predecessors(graph.num_vertices());
std::vector<double> distances(graph.num_vertices());
auto departure(graph.get_V(c.first));
std::set<V> destinations;
for (const auto &vertex : c.second) {
if (graph.has_vertex(vertex)) {
destinations.insert(graph.get_V(vertex));
}
}
detail::astar_1_to_many(graph, predecessors, distances, departure, destinations, heuristic, factor, epsilon);
auto r_paths = detail::get_paths(graph, predecessors, distances, departure, destinations, only_cost);
std::stable_sort(r_paths.begin(), r_paths.end(),
[](const Path &e1, const Path &e2)->bool {
return e1.end_id() < e2.end_id();
});
paths.insert(paths.end(), r_paths.begin(), r_paths.end());
}
return paths;
}
} // namespace algorithms
} // namespace pgrouting
#endif // INCLUDE_ASTAR_ASTAR_HPP_
|
