/usr/include/boost/math/special_functions/detail
Edit: /usr/include/boost/math/special_functions/detail/hypergeometric_1F1_cf.hpp (1830B)
///////////////////////////////////////////////////////////////////////////////
// Copyright 2018 John Maddock
// 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)
//
#ifndef BOOST_MATH_HYPERGEOMETRIC_1F1_CF_HPP
#define BOOST_MATH_HYPERGEOMETRIC_1F1_CF_HPP
#include
//
// Evaluation of 1F1 by continued fraction
// see http://functions.wolfram.com/HypergeometricFunctions/Hypergeometric1F1/10/0002/
//
// This is not terribly useful, as like the series we're adding a something to 1,
// so only really useful when we know that the result will be > 1.
//
namespace boost { namespace math { namespace detail {
template
struct hypergeometric_1F1_cf_func
{
typedef std::pair result_type;
hypergeometric_1F1_cf_func(T a_, T b_, T z_) : a(a_), b(b_), z(z_), k(0) {}
std::pair operator()()
{
++k;
return std::make_pair(-(((a + k) * z) / ((k + 1) * (b + k))), 1 + ((a + k) * z) / ((k + 1) * (b + k)));
}
T a, b, z;
unsigned k;
};
template
T hypergeometric_1F1_cf(const T& a, const T& b, const T& z, const Policy& pol, const char* function)
{
hypergeometric_1F1_cf_func func(a, b, z);
boost::uintmax_t max_iter = boost::math::policies::get_max_series_iterations();
T result = boost::math::tools::continued_fraction_a(func, boost::math::policies::get_epsilon(), max_iter);
boost::math::policies::check_series_iterations(function, max_iter, pol);
return 1 + a * z / (b * (1 + result));
}
} } } // namespaces
#endif // BOOST_MATH_HYPERGEOMETRIC_1F1_BESSEL_HPP