ceph/src/boost/boost/math/special_functions/hypergeometric_1F0.hpp

   1
   2 ///////////////////////////////////////////////////////////////////////////////
   3 //  Copyright 2014 Anton Bikineev
   4 //  Copyright 2014 Christopher Kormanyos
   5 //  Copyright 2014 John Maddock
   6 //  Copyright 2014 Paul Bristow
   7 //  Distributed under the Boost
   8 //  Software License, Version 1.0. (See accompanying file
   9 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  10
  11 #ifndef BOOST_MATH_HYPERGEOMETRIC_1F0_HPP
  12 #define BOOST_MATH_HYPERGEOMETRIC_1F0_HPP
  13
  14 #include <boost/math/policies/policy.hpp>
  15 #include <boost/math/policies/error_handling.hpp>
  16
  17
  18 namespace boost { namespace math { namespace detail {
  19
  20 template <class T, class Policy>
  21 inline T hypergeometric_1F0_imp(const T& a, const T& z, const Policy& pol)
  22 {
  23    static const char* function = "boost::math::hypergeometric_1F0<%1%,%1%>(%1%, %1%)";
  24    BOOST_MATH_STD_USING // pow
  25
  26    if (z == 1)
  27       return policies::raise_pole_error<T>(
  28          function,
  29          "Evaluation of 1F0 with z = %1%.",
  30          z,
  31          pol);
  32    if (1 - z < 0)
  33    {
  34       if (floor(a) != a)
  35          return policies::raise_domain_error<T>(function,
  36             "Result is complex when a is non-integral and z > 1, but got z = %1%", z, pol);
  37    }
  38    // more naive and convergent method than series
  39    return pow(T(1 - z), T(-a));
  40 }
  41
  42 } // namespace detail
  43
  44 template <class T1, class T2, class Policy>
  45 inline typename tools::promote_args<T1, T2>::type hypergeometric_1F0(T1 a, T2 z, const Policy&)
  46 {
  47    BOOST_FPU_EXCEPTION_GUARD
  48    typedef typename tools::promote_args<T1, T2>::type result_type;
  49    typedef typename policies::evaluation<result_type, Policy>::type value_type;
  50    typedef typename policies::normalise<
  51       Policy,
  52       policies::promote_float<false>,
  53       policies::promote_double<false>,
  54       policies::discrete_quantile<>,
  55       policies::assert_undefined<> >::type forwarding_policy;
  56    return policies::checked_narrowing_cast<result_type, Policy>(
  57       detail::hypergeometric_1F0_imp<value_type>(
  58          static_cast<value_type>(a),
  59          static_cast<value_type>(z),
  60          forwarding_policy()),
  61       "boost::math::hypergeometric_1F0<%1%>(%1%,%1%)");
  62 }
  63
  64 template <class T1, class T2>
  65 inline typename tools::promote_args<T1, T2>::type hypergeometric_1F0(T1 a, T2 z)
  66 {
  67    return hypergeometric_1F0(a, z, policies::policy<>());
  68 }
  69
  70
  71   } } // namespace boost::math
  72
  73 #endif // BOOST_MATH_HYPERGEOMETRIC_1F0_HPP