pgr_sequentialVertexColoring.hpp

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/*PGR-GNU*****************************************************************
File: pgr_sequentialVertexColoring.hpp
 
Copyright (c) 2020 pgRouting developers
Mail: [email protected]
 
Copyright (c) 2020 Ashish Kumar
Mail: [email protected]
 
------
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_COLORING_PGR_SEQUENTIALVERTEXCOLORING_HPP_
#define INCLUDE_COLORING_PGR_SEQUENTIALVERTEXCOLORING_HPP_
#pragma once
 
 
#include <boost/property_map/property_map.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/property_map/vector_property_map.hpp>
#include <boost/type_traits.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/sequential_vertex_coloring.hpp>
 
#include <algorithm>
#include <vector>
#include <map>
 
#include "cpp_common/pgr_base_graph.hpp"
#include "cpp_common/interruption.h"
 
 
namespace pgrouting {
namespace functions {
 
//*************************************************************
 
template < class G >
class Pgr_sequentialVertexColoring {
 public:
     typedef typename G::V V;
     typedef typename G::E E;
     typedef boost::adjacency_list < boost::listS, boost::vecS, boost::undirectedS > Graph;
     typedef boost::graph_traits < Graph > ::vertices_size_type vertices_size_type;
 
     std::vector < pgr_vertex_color_rt > sequentialVertexColoring(G &graph) {
         std::vector < pgr_vertex_color_rt > results;
 
         auto i_map = boost::get(boost::vertex_index, graph.graph);
 
         // vector which will store the color of all the vertices in the graph
         std::vector < vertices_size_type > colors(boost::num_vertices(graph.graph));
 
         // An iterator property map which records the color of each vertex
         auto color_map = boost::make_iterator_property_map(colors.begin(), i_map);
 
         /* abort in case of an interruption occurs (e.g. the query is being cancelled) */
         CHECK_FOR_INTERRUPTS();
 
         try {
             boost::sequential_vertex_coloring(graph.graph, color_map);
         } catch (boost::exception const& ex) {
             (void)ex;
             throw;
         } catch (std::exception &e) {
             (void)e;
             throw;
         } catch (...) {
             throw;
         }
 
         results = get_results(colors, graph);
 
         return results;
     }
 
 
 private:
     std::vector < pgr_vertex_color_rt > get_results(
             std::vector < vertices_size_type > &colors,
             const G &graph) {
         std::vector < pgr_vertex_color_rt > results;
 
         typename boost::graph_traits < Graph > ::vertex_iterator v, vend;
 
         for (boost::tie(v, vend) = vertices(graph.graph); v != vend; ++v) {
             int64_t node = graph[*v].id;
             auto color = colors[*v];
             results.push_back({ node, static_cast<int64_t>(color + 1) });
         }
 
         // ordering the results in an increasing order of the node id
         std::sort(results.begin(), results.end(),
             [](const pgr_vertex_color_rt row1, const pgr_vertex_color_rt row2) {
                 return row1.node < row2.node;
             });
 
         return results;
     }
};
}  // namespace functions
}  // namespace pgrouting
 
#endif  // INCLUDE_COLORING_PGR_SEQUENTIALVERTEXCOLORING_HPP_