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/*PGR-GNU*****************************************************************
File: pgr_linear.c
Generated with Template by:
Copyright (c) 2015 pgRouting developers
Mail: project@pgrouting.org
Function's developer:
Copyright (c) 2016 Rohith Reddy
Mail:
------
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_CONTRACTION_PGR_LINEARCONTRACTION_HPP_
#define INCLUDE_CONTRACTION_PGR_LINEARCONTRACTION_HPP_
#pragma once
#include <queue>
#include <functional>
#include <vector>
#include <boost/graph/iteration_macros.hpp>
#include <boost/graph/filtered_graph.hpp>
#include "cpp_common/identifiers.hpp"
namespace pgrouting {
namespace contraction {
template < class G >
class Pgr_linear {
private:
typedef typename G::V V;
typedef typename G::V_i V_i;
typedef typename G::B_G B_G;
public:
void operator()(G &graph, Identifiers<V>& forbidden_vertices) {
doContraction(graph, forbidden_vertices);
}
Pgr_linear():last_edge_id(0) {}
private:
int64_t get_next_id() {
return --last_edge_id;
}
public:
void setForbiddenVertices(
Identifiers<V> forbidden_vertices) {
m_forbiddenVertices = forbidden_vertices;
}
bool is_contractible(G &graph, V v) {
return graph.is_linear(v) && !m_forbiddenVertices.has(v);
}
void calculateVertices(G &graph) {
m_linearVertices.clear();
V_i vi;
BGL_FORALL_VERTICES_T(v, graph.graph, B_G) {
if (is_contractible(graph, v)) {
m_linearVertices += v;
}
}
}
void doContraction(G &graph, Identifiers<V> forbidden_vertices) {
m_forbiddenVertices = forbidden_vertices;
calculateVertices(graph);
while (!m_linearVertices.empty()) {
V v = m_linearVertices.front();
m_linearVertices -= v;
pgassert(is_contractible(graph, v));
one_cycle(graph, v);
}
}
void one_cycle(G &graph, V v) {
pgassert(is_contractible(graph, v));
Identifiers<V> adjacent_vertices =
graph.find_adjacent_vertices(v);
pgassert(adjacent_vertices.size() == 2);
V u = adjacent_vertices.front();
adjacent_vertices.pop_front();
V w = adjacent_vertices.front();
adjacent_vertices.pop_front();
pgassert(v != u);
pgassert(v != w);
pgassert(u != w);
if (graph.is_directed()) {
/*
* u --> v --> w
*/
process_shortcut(graph, u, v, w);
/*
* w --> v --> u
*/
process_shortcut(graph, w, v, u);
} else {
pgassert(graph.is_undirected());
/*
* u - v - w
*/
process_shortcut(graph, u, v, w);
}
graph[v].contracted_vertices().clear();
boost::clear_vertex(v, graph.graph);
m_linearVertices -= v;
if (is_contractible(graph, u)) {
one_cycle(graph, u);
} else {
m_linearVertices -= u;
}
if (is_contractible(graph, w)) {
one_cycle(graph, w);
} else {
m_linearVertices -= w;
}
}
/**
*
* u ----e1{v1}----> v ----e2{v2}----> w
*
* e1: min cost edge from u to v
* e2: min cost edge from v to w
*
* result:
* u ---{v+v1+v2}---> w
*
*/
void process_shortcut(G &graph, V u, V v, V w) {
auto e1 = graph.get_min_cost_edge(u, v);
auto e2 = graph.get_min_cost_edge(v, w);
if (std::get<2>(e1) && std::get<2>(e2)) {
auto contracted_vertices = std::get<1>(e1) + std::get<1>(e2);
double cost = std::get<0>(e1) + std::get<0>(e2);
contracted_vertices += graph[v].id;
contracted_vertices += graph[v].contracted_vertices();
// Create shortcut
CH_edge shortcut(
get_next_id(),
graph[u].id,
graph[w].id,
cost);
shortcut.contracted_vertices() = contracted_vertices;
graph.add_shortcut(shortcut, u, w);
}
}
private:
Identifiers<V> m_linearVertices;
Identifiers<V> m_forbiddenVertices;
int64_t last_edge_id;
};
} // namespace contraction
} // namespace pgrouting
#endif // INCLUDE_CONTRACTION_PGR_LINEARCONTRACTION_HPP_
|
