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/Src/Dependencies/Boost/boost/graph/sequential_vertex_coloring.hpp

http://hadesmem.googlecode.com/
C++ Header | 124 lines | 65 code | 17 blank | 42 comment | 12 complexity | 4845de2fa259990ff89f50f8a03046a0 MD5 | raw file
  1//=======================================================================
  2// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
  3// Copyright 2004 The Trustees of Indiana University
  4// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
  5//
  6// Distributed under the Boost Software License, Version 1.0. (See
  7// accompanying file LICENSE_1_0.txt or copy at
  8// http://www.boost.org/LICENSE_1_0.txt)
  9//=======================================================================
 10#ifndef BOOST_GRAPH_SEQUENTIAL_VERTEX_COLORING_HPP
 11#define BOOST_GRAPH_SEQUENTIAL_VERTEX_COLORING_HPP
 12
 13#include <vector>
 14#include <boost/graph/graph_traits.hpp>
 15#include <boost/tuple/tuple.hpp>
 16#include <boost/property_map/property_map.hpp>
 17#include <boost/limits.hpp>
 18
 19#ifdef BOOST_NO_TEMPLATED_ITERATOR_CONSTRUCTORS
 20#  include <iterator>
 21#endif
 22
 23/* This algorithm is to find coloring of a graph
 24
 25   Algorithm: 
 26   Let G = (V,E) be a graph with vertices (somehow) ordered v_1, v_2, ...,
 27   v_n. For k = 1, 2, ..., n the sequential algorithm assigns v_k to the
 28   smallest possible color. 
 29
 30   Reference:
 31
 32   Thomas F. Coleman and Jorge J. More, Estimation of sparse Jacobian
 33   matrices and graph coloring problems. J. Numer. Anal. V20, P187-209, 1983
 34
 35   v_k is stored as o[k] here. 
 36
 37   The color of the vertex v will be stored in color[v].
 38   i.e., vertex v belongs to coloring color[v] */
 39
 40namespace boost {
 41  template <class VertexListGraph, class OrderPA, class ColorMap>
 42  typename property_traits<ColorMap>::value_type
 43  sequential_vertex_coloring(const VertexListGraph& G, OrderPA order, 
 44                             ColorMap color)
 45  {
 46    typedef graph_traits<VertexListGraph> GraphTraits;
 47    typedef typename GraphTraits::vertex_descriptor Vertex;
 48    typedef typename property_traits<ColorMap>::value_type size_type;
 49    
 50    size_type max_color = 0;
 51    const size_type V = num_vertices(G);
 52
 53    // We need to keep track of which colors are used by
 54    // adjacent vertices. We do this by marking the colors
 55    // that are used. The mark array contains the mark
 56    // for each color. The length of mark is the
 57    // number of vertices since the maximum possible number of colors
 58    // is the number of vertices.
 59    std::vector<size_type> mark(V, 
 60                                std::numeric_limits<size_type>::max BOOST_PREVENT_MACRO_SUBSTITUTION());
 61    
 62    //Initialize colors 
 63    typename GraphTraits::vertex_iterator v, vend;
 64    for (boost::tie(v, vend) = vertices(G); v != vend; ++v)
 65      put(color, *v, V-1);
 66    
 67    //Determine the color for every vertex one by one
 68    for ( size_type i = 0; i < V; i++) {
 69      Vertex current = get(order,i);
 70      typename GraphTraits::adjacency_iterator v, vend;
 71      
 72      //Mark the colors of vertices adjacent to current.
 73      //i can be the value for marking since i increases successively
 74      for (boost::tie(v,vend) = adjacent_vertices(current, G); v != vend; ++v)
 75        mark[get(color,*v)] = i; 
 76      
 77      //Next step is to assign the smallest un-marked color
 78      //to the current vertex.
 79      size_type j = 0;
 80
 81      //Scan through all useable colors, find the smallest possible
 82      //color that is not used by neighbors.  Note that if mark[j]
 83      //is equal to i, color j is used by one of the current vertex's
 84      //neighbors.
 85      while ( j < max_color && mark[j] == i ) 
 86        ++j;
 87      
 88      if ( j == max_color )  //All colors are used up. Add one more color
 89        ++max_color;
 90
 91      //At this point, j is the smallest possible color
 92      put(color, current, j);  //Save the color of vertex current
 93    }
 94    
 95    return max_color;
 96  }
 97
 98  template<class VertexListGraph, class ColorMap>
 99  typename property_traits<ColorMap>::value_type
100  sequential_vertex_coloring(const VertexListGraph& G, ColorMap color)
101  {
102    typedef typename graph_traits<VertexListGraph>::vertex_descriptor
103      vertex_descriptor;
104    typedef typename graph_traits<VertexListGraph>::vertex_iterator
105      vertex_iterator;
106
107    std::pair<vertex_iterator, vertex_iterator> v = vertices(G);
108#ifndef BOOST_NO_TEMPLATED_ITERATOR_CONSTRUCTORS
109    std::vector<vertex_descriptor> order(v.first, v.second);
110#else
111    std::vector<vertex_descriptor> order;
112    order.reserve(std::distance(v.first, v.second));
113    while (v.first != v.second) order.push_back(*v.first++);
114#endif
115    return sequential_vertex_coloring
116             (G, 
117              make_iterator_property_map
118              (order.begin(), identity_property_map(), 
119               graph_traits<VertexListGraph>::null_vertex()), 
120              color);
121  }
122}
123
124#endif