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