// (C) Copyright 2007-2009 Andrew Sutton // // Use, modification and distribution are subject to the // Boost Software License, Version 1.0 (See accompanying file // LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) #ifndef BOOST_GRAPH_NUMERIC_VALUES_HPP #define BOOST_GRAPH_NUMERIC_VALUES_HPP #include namespace boost { #define BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(type) \ template <> struct numeric_values< type > \ { \ typedef type value_type; \ static type zero() { return 0.0; } \ static type infinity() \ { \ return std::numeric_limits< type >::infinity(); \ } \ }; /** * This generic type reports various numeric values for some type. In the * general case, numeric values simply treat their maximum value as infinity * and the default-constructed value as 0. * * Specializations of this template can redefine the notions of zero and * infinity for various types. For example, the class is specialized for * floating point types to use the built in notion of infinity. */ template < typename T > struct numeric_values { typedef T value_type; static T zero() { return T(); } static T infinity() { return (std::numeric_limits< T >::max)(); } }; // Specializations for floating point types refer to 0.0 and their infinity // value defined by numeric_limits. BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(float) BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(double) BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(long double) #undef BOOST_GRAPH_SPECIALIZE_NUMERIC_VALUE } #endif