74 lines
2.3 KiB
C++
74 lines
2.3 KiB
C++
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///////////////////////////////////////////////////////////////////////////////
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// Copyright 2014 Anton Bikineev
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// Copyright 2014 Christopher Kormanyos
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// Copyright 2014 John Maddock
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// Copyright 2014 Paul Bristow
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// Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_MATH_HYPERGEOMETRIC_1F0_HPP
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#define BOOST_MATH_HYPERGEOMETRIC_1F0_HPP
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#include <boost/math/policies/policy.hpp>
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#include <boost/math/policies/error_handling.hpp>
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namespace boost { namespace math { namespace detail {
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template <class T, class Policy>
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inline T hypergeometric_1F0_imp(const T& a, const T& z, const Policy& pol)
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{
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static const char* function = "boost::math::hypergeometric_1F0<%1%,%1%>(%1%, %1%)";
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BOOST_MATH_STD_USING // pow
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if (z == 1)
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return policies::raise_pole_error<T>(
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function,
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"Evaluation of 1F0 with z = %1%.",
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z,
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pol);
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if (1 - z < 0)
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{
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if (floor(a) != a)
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return policies::raise_domain_error<T>(function,
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"Result is complex when a is non-integral and z > 1, but got z = %1%", z, pol);
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}
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// more naive and convergent method than series
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return pow(T(1 - z), T(-a));
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}
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} // namespace detail
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template <class T1, class T2, class Policy>
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inline typename tools::promote_args<T1, T2>::type hypergeometric_1F0(T1 a, T2 z, const Policy&)
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{
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BOOST_FPU_EXCEPTION_GUARD
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typedef typename tools::promote_args<T1, T2>::type result_type;
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typedef typename policies::evaluation<result_type, Policy>::type value_type;
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typedef typename policies::normalise<
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Policy,
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policies::promote_float<false>,
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policies::promote_double<false>,
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policies::discrete_quantile<>,
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policies::assert_undefined<> >::type forwarding_policy;
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return policies::checked_narrowing_cast<result_type, Policy>(
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detail::hypergeometric_1F0_imp<value_type>(
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static_cast<value_type>(a),
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static_cast<value_type>(z),
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forwarding_policy()),
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"boost::math::hypergeometric_1F0<%1%>(%1%,%1%)");
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}
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template <class T1, class T2>
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inline typename tools::promote_args<T1, T2>::type hypergeometric_1F0(T1 a, T2 z)
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{
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return hypergeometric_1F0(a, z, policies::policy<>());
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}
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} } // namespace boost::math
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#endif // BOOST_MATH_HYPERGEOMETRIC_1F0_HPP
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