| // (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 |
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