// (C) Copyright John Maddock 2006. | |
// Use, modification and distribution are 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) | |
#ifndef BOOST_MATH_POWM1 | |
#define BOOST_MATH_POWM1 | |
#ifdef _MSC_VER | |
#pragma once | |
#endif | |
#include <boost/math/special_functions/log1p.hpp> | |
#include <boost/math/special_functions/expm1.hpp> | |
#include <boost/math/special_functions/math_fwd.hpp> | |
#include <boost/assert.hpp> | |
namespace boost{ namespace math{ namespace detail{ | |
template <class T, class Policy> | |
inline T powm1_imp(const T a, const T z, const Policy& pol) | |
{ | |
BOOST_MATH_STD_USING | |
if((fabs(a) < 1) || (fabs(z) < 1)) | |
{ | |
T p = log(a) * z; | |
if(fabs(p) < 2) | |
return boost::math::expm1(p, pol); | |
// otherwise fall though: | |
} | |
return pow(a, z) - 1; | |
} | |
} // detail | |
template <class T1, class T2> | |
inline typename tools::promote_args<T1, T2>::type | |
powm1(const T1 a, const T2 z) | |
{ | |
typedef typename tools::promote_args<T1, T2>::type result_type; | |
return detail::powm1_imp(static_cast<result_type>(a), static_cast<result_type>(z), policies::policy<>()); | |
} | |
template <class T1, class T2, class Policy> | |
inline typename tools::promote_args<T1, T2>::type | |
powm1(const T1 a, const T2 z, const Policy& pol) | |
{ | |
typedef typename tools::promote_args<T1, T2>::type result_type; | |
return detail::powm1_imp(static_cast<result_type>(a), static_cast<result_type>(z), pol); | |
} | |
} // namespace math | |
} // namespace boost | |
#endif // BOOST_MATH_POWM1 | |