| // Copyright 2004 The Trustees of Indiana University. |
| |
| // Use, modification and distribution is subject to the Boost Software |
| // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| // Authors: Douglas Gregor |
| // Andrew Lumsdaine |
| |
| #ifndef BOOST_GRAPH_PARALLEL_PROPERTIES_HPP |
| #define BOOST_GRAPH_PARALLEL_PROPERTIES_HPP |
| |
| #ifndef BOOST_GRAPH_USE_MPI |
| #error "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included" |
| #endif |
| |
| #include <boost/graph/properties.hpp> |
| #include <boost/property_map/parallel/distributed_property_map.hpp> |
| |
| namespace boost { |
| /*************************************************************************** |
| * Property map reduction operations |
| ***************************************************************************/ |
| /** |
| * Metafunction that produces a reduction operation for the given |
| * property. The default behavior merely forwards to @ref |
| * basic_reduce, but it is expected that this class template will be |
| * specified for important properties. |
| */ |
| template<typename Property> |
| struct property_reduce |
| { |
| template<typename Value> |
| class apply : public parallel::basic_reduce<Value> {}; |
| }; |
| |
| /** |
| * Reduction of vertex colors can only darken, not lighten, the |
| * color. Black cannot turn black, grey can only turn black, and |
| * white can be changed to either color. The default color is white. |
| */ |
| template<> |
| struct property_reduce<vertex_color_t> |
| { |
| template<typename Color> |
| class apply |
| { |
| typedef color_traits<Color> traits; |
| |
| public: |
| BOOST_STATIC_CONSTANT(bool, non_default_resolver = true); |
| |
| template<typename Key> |
| Color operator()(const Key&) const { return traits::white(); } |
| |
| template<typename Key> |
| Color operator()(const Key&, Color local, Color remote) const { |
| if (local == traits::white()) return remote; |
| else if (remote == traits::black()) return remote; |
| else return local; |
| } |
| }; |
| }; |
| |
| /** |
| * Reduction of a distance always takes the shorter distance. The |
| * default distance value is the maximum value for the data type. |
| */ |
| template<> |
| struct property_reduce<vertex_distance_t> |
| { |
| template<typename T> |
| class apply |
| { |
| public: |
| BOOST_STATIC_CONSTANT(bool, non_default_resolver = true); |
| |
| template<typename Key> |
| T operator()(const Key&) const { return (std::numeric_limits<T>::max)(); } |
| |
| template<typename Key> |
| T operator()(const Key&, T x, T y) const { return x < y? x : y; } |
| }; |
| }; |
| |
| template<> |
| struct property_reduce<vertex_predecessor_t> |
| { |
| template<typename T> |
| class apply |
| { |
| public: |
| BOOST_STATIC_CONSTANT(bool, non_default_resolver = true); |
| |
| T operator()(T key) const { return key; } |
| T operator()(T key, T, T y) const { return y; } |
| }; |
| }; |
| |
| template<typename Property, typename PropertyMap> |
| inline void set_property_map_role(Property p, PropertyMap pm) |
| { |
| typedef typename property_traits<PropertyMap>::value_type value_type; |
| typedef property_reduce<Property> property_red; |
| typedef typename property_red::template apply<value_type> reduce; |
| |
| pm.set_reduce(reduce()); |
| } |
| |
| } // end namespace boost |
| #endif // BOOST_GRAPH_PARALLEL_PROPERTIES_HPP |