Chris@16: //  (C) Copyright Gennadiy Rozental 2001-2008.
Chris@16: //  Distributed under the Boost Software License, Version 1.0.
Chris@16: //  (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  See http://www.boost.org/libs/test for the library home page.
Chris@16: //
Chris@16: //  File        : $RCSfile$
Chris@16: //
Chris@101: //  Version     : $Revision$
Chris@16: //
Chris@16: //  Description : defines algoirthms for comparing 2 floating point values
Chris@16: // ***************************************************************************
Chris@16: 
Chris@16: #ifndef BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER
Chris@16: #define BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER
Chris@16: 
Chris@16: // Boost.Test
Chris@16: #include <boost/test/detail/global_typedef.hpp>
Chris@16: #include <boost/test/utils/class_properties.hpp>
Chris@16: #include <boost/test/predicate_result.hpp>
Chris@16: 
Chris@16: // Boost
Chris@16: #include <boost/limits.hpp>  // for std::numeric_limits
Chris@16: #include <boost/numeric/conversion/conversion_traits.hpp> // for numeric::conversion_traits
Chris@16: #include <boost/static_assert.hpp>
Chris@16: 
Chris@16: #include <boost/test/detail/suppress_warnings.hpp>
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: namespace test_tools {
Chris@16: 
Chris@16: using unit_test::readonly_property;
Chris@16: 
Chris@16: // ************************************************************************** //
Chris@16: // **************        floating_point_comparison_type        ************** //
Chris@16: // ************************************************************************** //
Chris@16: 
Chris@16: enum floating_point_comparison_type {
Chris@16:     FPC_STRONG, // "Very close"   - equation 1' in docs, the default
Chris@16:     FPC_WEAK    // "Close enough" - equation 2' in docs.
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: // ************************************************************************** //
Chris@16: // **************                    details                   ************** //
Chris@16: // ************************************************************************** //
Chris@16: 
Chris@16: namespace tt_detail {
Chris@16: 
Chris@16: // FPT is Floating-Point Type: float, double, long double or User-Defined.
Chris@16: template<typename FPT>
Chris@16: inline FPT
Chris@16: fpt_abs( FPT fpv ) 
Chris@16: {
Chris@16:     return fpv < static_cast<FPT>(0) ? -fpv : fpv;
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: template<typename FPT>
Chris@16: struct fpt_limits {
Chris@16:     static FPT    min_value()
Chris@16:     {
Chris@16:         return std::numeric_limits<FPT>::is_specialized
Chris@16:                     ? (std::numeric_limits<FPT>::min)()
Chris@16:                     : 0;
Chris@16:     }
Chris@16:     static FPT    max_value()
Chris@16:     {
Chris@16:         return std::numeric_limits<FPT>::is_specialized
Chris@16:                     ? (std::numeric_limits<FPT>::max)()
Chris@16:                     : static_cast<FPT>(1000000); // for the our purpuses it doesn't really matter what value is returned here
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: // both f1 and f2 are unsigned here
Chris@16: template<typename FPT>
Chris@16: inline FPT
Chris@16: safe_fpt_division( FPT f1, FPT f2 )
Chris@16: {
Chris@16:     // Avoid overflow.
Chris@16:     if( (f2 < static_cast<FPT>(1))  && (f1 > f2*fpt_limits<FPT>::max_value()) )
Chris@16:         return fpt_limits<FPT>::max_value();
Chris@16: 
Chris@16:     // Avoid underflow.
Chris@16:     if( (f1 == static_cast<FPT>(0)) ||
Chris@16:         ((f2 > static_cast<FPT>(1)) && (f1 < f2*fpt_limits<FPT>::min_value())) )
Chris@16:         return static_cast<FPT>(0);
Chris@16: 
Chris@16:     return f1/f2;
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: } // namespace tt_detail
Chris@16: 
Chris@16: // ************************************************************************** //
Chris@16: // **************         tolerance presentation types         ************** //
Chris@16: // ************************************************************************** //
Chris@16: 
Chris@16: template<typename FPT>
Chris@16: struct percent_tolerance_t {
Chris@16:     explicit    percent_tolerance_t( FPT v ) : m_value( v ) {}
Chris@16: 
Chris@16:     FPT m_value;
Chris@16: };
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: template<typename Out,typename FPT>
Chris@16: Out& operator<<( Out& out, percent_tolerance_t<FPT> t )
Chris@16: {
Chris@16:     return out << t.m_value;
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: template<typename FPT>
Chris@16: inline percent_tolerance_t<FPT>
Chris@16: percent_tolerance( FPT v )
Chris@16: {
Chris@16:     return percent_tolerance_t<FPT>( v );
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: template<typename FPT>
Chris@16: struct fraction_tolerance_t {
Chris@16:     explicit fraction_tolerance_t( FPT v ) : m_value( v ) {}
Chris@16: 
Chris@16:     FPT m_value;
Chris@16: };
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: template<typename Out,typename FPT>
Chris@16: Out& operator<<( Out& out, fraction_tolerance_t<FPT> t )
Chris@16: {
Chris@16:     return out << t.m_value;
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: template<typename FPT>
Chris@16: inline fraction_tolerance_t<FPT>
Chris@16: fraction_tolerance( FPT v )
Chris@16: {
Chris@16:     return fraction_tolerance_t<FPT>( v );
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: // ************************************************************************** //
Chris@16: // **************             close_at_tolerance               ************** //
Chris@16: // ************************************************************************** //
Chris@16: 
Chris@16: template<typename FPT>
Chris@16: class close_at_tolerance {
Chris@16: public:
Chris@16:     // Public typedefs
Chris@16:     typedef bool result_type;
Chris@16: 
Chris@16:     // Constructor
Chris@16:     template<typename ToleranceBaseType>
Chris@16:     explicit    close_at_tolerance( percent_tolerance_t<ToleranceBaseType>  tolerance, 
Chris@16:                                     floating_point_comparison_type          fpc_type = FPC_STRONG ) 
Chris@16:     : p_fraction_tolerance( tt_detail::fpt_abs( static_cast<FPT>(0.01)*tolerance.m_value ) )
Chris@16:     , p_strong_or_weak( fpc_type ==  FPC_STRONG )
Chris@16:     , m_report_modifier( 100. )
Chris@16:     {}
Chris@16:     template<typename ToleranceBaseType>
Chris@16:     explicit    close_at_tolerance( fraction_tolerance_t<ToleranceBaseType> tolerance, 
Chris@16:                                     floating_point_comparison_type          fpc_type = FPC_STRONG ) 
Chris@16:     : p_fraction_tolerance( tt_detail::fpt_abs( tolerance.m_value ) )
Chris@16:     , p_strong_or_weak( fpc_type ==  FPC_STRONG )
Chris@16:     , m_report_modifier( 1. )
Chris@16:     {}
Chris@16: 
Chris@16:     predicate_result        operator()( FPT left, FPT right ) const
Chris@16:     {
Chris@16:         FPT diff = tt_detail::fpt_abs( left - right );
Chris@16:         FPT d1   = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( right ) );
Chris@16:         FPT d2   = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( left ) );
Chris@16:         
Chris@16:         predicate_result res( p_strong_or_weak 
Chris@16:             ? (d1 <= p_fraction_tolerance.get() && d2 <= p_fraction_tolerance.get()) 
Chris@16:             : (d1 <= p_fraction_tolerance.get() || d2 <= p_fraction_tolerance.get()) );
Chris@16: 
Chris@16:         if( !res )
Chris@16:             res.message() << (( d1 <= p_fraction_tolerance.get() ? d2 : d1 ) * m_report_modifier);
Chris@16: 
Chris@16:         return res;
Chris@16:     }
Chris@16: 
Chris@16:     // Public properties
Chris@16:     readonly_property<FPT>  p_fraction_tolerance;
Chris@16:     readonly_property<bool> p_strong_or_weak;
Chris@16: private:
Chris@16:     // Data members
Chris@16:     FPT                     m_report_modifier;
Chris@16: };
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: // ************************************************************************** //
Chris@16: // **************               check_is_close                 ************** //
Chris@16: // ************************************************************************** //
Chris@16: 
Chris@16: struct BOOST_TEST_DECL check_is_close_t {
Chris@16:     // Public typedefs
Chris@16:     typedef bool result_type;
Chris@16: 
Chris@16:     template<typename FPT1, typename FPT2, typename ToleranceBaseType>
Chris@16:     predicate_result
Chris@16:     operator()( FPT1 left, FPT2 right, percent_tolerance_t<ToleranceBaseType> tolerance, 
Chris@16:                 floating_point_comparison_type fpc_type = FPC_STRONG ) const
Chris@16:     {
Chris@16:         // deduce "better" type from types of arguments being compared
Chris@16:         // if one type is floating and the second integral we use floating type and 
Chris@16:         // value of integral type is promoted to the floating. The same for float and double
Chris@16:         // But we don't want to compare two values of integral types using this tool.
Chris@16:         typedef typename numeric::conversion_traits<FPT1,FPT2>::supertype FPT;
Chris@16:         BOOST_STATIC_ASSERT( !is_integral<FPT>::value );
Chris@16: 
Chris@16:         close_at_tolerance<FPT> pred( tolerance, fpc_type );
Chris@16: 
Chris@16:         return pred( left, right );
Chris@16:     }
Chris@16:     template<typename FPT1, typename FPT2, typename ToleranceBaseType>
Chris@16:     predicate_result
Chris@16:     operator()( FPT1 left, FPT2 right, fraction_tolerance_t<ToleranceBaseType> tolerance, 
Chris@16:                 floating_point_comparison_type fpc_type = FPC_STRONG ) const
Chris@16:     {
Chris@16:         // same as in a comment above
Chris@16:         typedef typename numeric::conversion_traits<FPT1,FPT2>::supertype FPT;
Chris@16:         BOOST_STATIC_ASSERT( !is_integral<FPT>::value );
Chris@16: 
Chris@16:         close_at_tolerance<FPT> pred( tolerance, fpc_type );
Chris@16: 
Chris@16:         return pred( left, right );
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: namespace {
Chris@16: check_is_close_t const& check_is_close = unit_test::ut_detail::static_constant<check_is_close_t>::value;
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: // ************************************************************************** //
Chris@16: // **************               check_is_small                 ************** //
Chris@16: // ************************************************************************** //
Chris@16: 
Chris@16: struct BOOST_TEST_DECL check_is_small_t {
Chris@16:     // Public typedefs
Chris@16:     typedef bool result_type;
Chris@16: 
Chris@16:     template<typename FPT>
Chris@16:     bool
Chris@16:     operator()( FPT fpv, FPT tolerance ) const
Chris@16:     {
Chris@16:         return tt_detail::fpt_abs( fpv ) < tt_detail::fpt_abs( tolerance );
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: namespace {
Chris@16: check_is_small_t const& check_is_small = unit_test::ut_detail::static_constant<check_is_small_t>::value;
Chris@16: }
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: } // namespace test_tools
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: //____________________________________________________________________________//
Chris@16: 
Chris@16: #include <boost/test/detail/enable_warnings.hpp>
Chris@16: 
Chris@16: #endif // BOOST_FLOATING_POINT_COMAPARISON_HPP_071894GER