// (C) Copyright Gennadiy Rozental 2001-2008. | |
// Distributed under 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) | |
// See http://www.boost.org/libs/test for the library home page. | |
// | |
// File : $RCSfile$ | |
// | |
// Version : $Revision: 57992 $ | |
// | |
// Description : defines algoirthms for comparing 2 floating point values | |
// *************************************************************************** | |
#ifndef BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER | |
#define BOOST_TEST_FLOATING_POINT_COMPARISON_HPP_071894GER | |
// Boost.Test | |
#include <boost/test/detail/global_typedef.hpp> | |
#include <boost/test/utils/class_properties.hpp> | |
#include <boost/test/predicate_result.hpp> | |
// Boost | |
#include <boost/limits.hpp> // for std::numeric_limits | |
#include <boost/numeric/conversion/conversion_traits.hpp> // for numeric::conversion_traits | |
#include <boost/static_assert.hpp> | |
#include <boost/test/detail/suppress_warnings.hpp> | |
//____________________________________________________________________________// | |
namespace boost { | |
namespace test_tools { | |
using unit_test::readonly_property; | |
// ************************************************************************** // | |
// ************** floating_point_comparison_type ************** // | |
// ************************************************************************** // | |
enum floating_point_comparison_type { | |
FPC_STRONG, // "Very close" - equation 1' in docs, the default | |
FPC_WEAK // "Close enough" - equation 2' in docs. | |
}; | |
// ************************************************************************** // | |
// ************** details ************** // | |
// ************************************************************************** // | |
namespace tt_detail { | |
// FPT is Floating-Point Type: float, double, long double or User-Defined. | |
template<typename FPT> | |
inline FPT | |
fpt_abs( FPT fpv ) | |
{ | |
return fpv < static_cast<FPT>(0) ? -fpv : fpv; | |
} | |
//____________________________________________________________________________// | |
template<typename FPT> | |
struct fpt_limits { | |
static FPT min_value() | |
{ | |
return std::numeric_limits<FPT>::is_specialized | |
? (std::numeric_limits<FPT>::min)() | |
: 0; | |
} | |
static FPT max_value() | |
{ | |
return std::numeric_limits<FPT>::is_specialized | |
? (std::numeric_limits<FPT>::max)() | |
: static_cast<FPT>(1000000); // for the our purpuses it doesn't really matter what value is returned here | |
} | |
}; | |
//____________________________________________________________________________// | |
// both f1 and f2 are unsigned here | |
template<typename FPT> | |
inline FPT | |
safe_fpt_division( FPT f1, FPT f2 ) | |
{ | |
// Avoid overflow. | |
if( (f2 < static_cast<FPT>(1)) && (f1 > f2*fpt_limits<FPT>::max_value()) ) | |
return fpt_limits<FPT>::max_value(); | |
// Avoid underflow. | |
if( (f1 == static_cast<FPT>(0)) || | |
((f2 > static_cast<FPT>(1)) && (f1 < f2*fpt_limits<FPT>::min_value())) ) | |
return static_cast<FPT>(0); | |
return f1/f2; | |
} | |
//____________________________________________________________________________// | |
} // namespace tt_detail | |
// ************************************************************************** // | |
// ************** tolerance presentation types ************** // | |
// ************************************************************************** // | |
template<typename FPT> | |
struct percent_tolerance_t { | |
explicit percent_tolerance_t( FPT v ) : m_value( v ) {} | |
FPT m_value; | |
}; | |
//____________________________________________________________________________// | |
template<typename Out,typename FPT> | |
Out& operator<<( Out& out, percent_tolerance_t<FPT> t ) | |
{ | |
return out << t.m_value; | |
} | |
//____________________________________________________________________________// | |
template<typename FPT> | |
inline percent_tolerance_t<FPT> | |
percent_tolerance( FPT v ) | |
{ | |
return percent_tolerance_t<FPT>( v ); | |
} | |
//____________________________________________________________________________// | |
template<typename FPT> | |
struct fraction_tolerance_t { | |
explicit fraction_tolerance_t( FPT v ) : m_value( v ) {} | |
FPT m_value; | |
}; | |
//____________________________________________________________________________// | |
template<typename Out,typename FPT> | |
Out& operator<<( Out& out, fraction_tolerance_t<FPT> t ) | |
{ | |
return out << t.m_value; | |
} | |
//____________________________________________________________________________// | |
template<typename FPT> | |
inline fraction_tolerance_t<FPT> | |
fraction_tolerance( FPT v ) | |
{ | |
return fraction_tolerance_t<FPT>( v ); | |
} | |
//____________________________________________________________________________// | |
// ************************************************************************** // | |
// ************** close_at_tolerance ************** // | |
// ************************************************************************** // | |
template<typename FPT> | |
class close_at_tolerance { | |
public: | |
// Public typedefs | |
typedef bool result_type; | |
// Constructor | |
template<typename ToleranceBaseType> | |
explicit close_at_tolerance( percent_tolerance_t<ToleranceBaseType> tolerance, | |
floating_point_comparison_type fpc_type = FPC_STRONG ) | |
: p_fraction_tolerance( tt_detail::fpt_abs( static_cast<FPT>(0.01)*tolerance.m_value ) ) | |
, p_strong_or_weak( fpc_type == FPC_STRONG ) | |
, m_report_modifier( 100. ) | |
{} | |
template<typename ToleranceBaseType> | |
explicit close_at_tolerance( fraction_tolerance_t<ToleranceBaseType> tolerance, | |
floating_point_comparison_type fpc_type = FPC_STRONG ) | |
: p_fraction_tolerance( tt_detail::fpt_abs( tolerance.m_value ) ) | |
, p_strong_or_weak( fpc_type == FPC_STRONG ) | |
, m_report_modifier( 1. ) | |
{} | |
predicate_result operator()( FPT left, FPT right ) const | |
{ | |
FPT diff = tt_detail::fpt_abs( left - right ); | |
FPT d1 = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( right ) ); | |
FPT d2 = tt_detail::safe_fpt_division( diff, tt_detail::fpt_abs( left ) ); | |
predicate_result res( p_strong_or_weak | |
? (d1 <= p_fraction_tolerance.get() && d2 <= p_fraction_tolerance.get()) | |
: (d1 <= p_fraction_tolerance.get() || d2 <= p_fraction_tolerance.get()) ); | |
if( !res ) | |
res.message() << (( d1 <= p_fraction_tolerance.get() ? d2 : d1 ) * m_report_modifier); | |
return res; | |
} | |
// Public properties | |
readonly_property<FPT> p_fraction_tolerance; | |
readonly_property<bool> p_strong_or_weak; | |
private: | |
// Data members | |
FPT m_report_modifier; | |
}; | |
//____________________________________________________________________________// | |
// ************************************************************************** // | |
// ************** check_is_close ************** // | |
// ************************************************************************** // | |
struct BOOST_TEST_DECL check_is_close_t { | |
// Public typedefs | |
typedef bool result_type; | |
template<typename FPT1, typename FPT2, typename ToleranceBaseType> | |
predicate_result | |
operator()( FPT1 left, FPT2 right, percent_tolerance_t<ToleranceBaseType> tolerance, | |
floating_point_comparison_type fpc_type = FPC_STRONG ) const | |
{ | |
// deduce "better" type from types of arguments being compared | |
// if one type is floating and the second integral we use floating type and | |
// value of integral type is promoted to the floating. The same for float and double | |
// But we don't want to compare two values of integral types using this tool. | |
typedef typename numeric::conversion_traits<FPT1,FPT2>::supertype FPT; | |
BOOST_STATIC_ASSERT( !is_integral<FPT>::value ); | |
close_at_tolerance<FPT> pred( tolerance, fpc_type ); | |
return pred( left, right ); | |
} | |
template<typename FPT1, typename FPT2, typename ToleranceBaseType> | |
predicate_result | |
operator()( FPT1 left, FPT2 right, fraction_tolerance_t<ToleranceBaseType> tolerance, | |
floating_point_comparison_type fpc_type = FPC_STRONG ) const | |
{ | |
// same as in a comment above | |
typedef typename numeric::conversion_traits<FPT1,FPT2>::supertype FPT; | |
BOOST_STATIC_ASSERT( !is_integral<FPT>::value ); | |
close_at_tolerance<FPT> pred( tolerance, fpc_type ); | |
return pred( left, right ); | |
} | |
}; | |
namespace { | |
check_is_close_t const& check_is_close = unit_test::ut_detail::static_constant<check_is_close_t>::value; | |
} | |
//____________________________________________________________________________// | |
// ************************************************************************** // | |
// ************** check_is_small ************** // | |
// ************************************************************************** // | |
struct BOOST_TEST_DECL check_is_small_t { | |
// Public typedefs | |
typedef bool result_type; | |
template<typename FPT> | |
bool | |
operator()( FPT fpv, FPT tolerance ) const | |
{ | |
return tt_detail::fpt_abs( fpv ) < tt_detail::fpt_abs( tolerance ); | |
} | |
}; | |
namespace { | |
check_is_small_t const& check_is_small = unit_test::ut_detail::static_constant<check_is_small_t>::value; | |
} | |
//____________________________________________________________________________// | |
} // namespace test_tools | |
} // namespace boost | |
//____________________________________________________________________________// | |
#include <boost/test/detail/enable_warnings.hpp> | |
#endif // BOOST_FLOATING_POINT_COMAPARISON_HPP_071894GER |