/usr/include/boost/math/special_functions/detail
Edit: /usr/include/boost/math/special_functions/detail/hypergeometric_cf.hpp (5826B)
///////////////////////////////////////////////////////////////////////////////
// Copyright 2014 Anton Bikineev
// Copyright 2014 Christopher Kormanyos
// Copyright 2014 John Maddock
// Copyright 2014 Paul Bristow
// 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_DETAIL_HYPERGEOMETRIC_CF_HPP
#define BOOST_MATH_DETAIL_HYPERGEOMETRIC_CF_HPP
namespace boost { namespace math { namespace detail {
// primary template for term of continued fraction
template
struct hypergeometric_pFq_cf_term;
// partial specialization for 0F1
template
struct hypergeometric_pFq_cf_term
{
typedef std::pair result_type;
hypergeometric_pFq_cf_term(const T& b, const T& z):
n(1), b(b), z(z),
term(std::make_pair(T(0), T(1)))
{
}
result_type operator()()
{
const result_type result = term;
++b; ++n;
numer = -(z / (b * n));
term = std::make_pair(numer, 1 - numer);
return result;
}
private:
unsigned n;
T b;
const T z;
T numer;
result_type term;
};
// partial specialization for 1F0
template
struct hypergeometric_pFq_cf_term
{
typedef std::pair result_type;
hypergeometric_pFq_cf_term(const T& a, const T& z):
n(1), a(a), z(z),
term(std::make_pair(T(0), T(1)))
{
}
result_type operator()()
{
const result_type result = term;
++a; ++n;
numer = -((a * z) / n);
term = std::make_pair(numer, 1 - numer);
return result;
}
private:
unsigned n;
T a;
const T z;
T numer;
result_type term;
};
// partial specialization for 1F1
template
struct hypergeometric_pFq_cf_term
{
typedef std::pair result_type;
hypergeometric_pFq_cf_term(const T& a, const T& b, const T& z):
n(1), a(a), b(b), z(z),
term(std::make_pair(T(0), T(1)))
{
}
result_type operator()()
{
const result_type result = term;
++a; ++b; ++n;
numer = -((a * z) / (b * n));
term = std::make_pair(numer, 1 - numer);
return result;
}
private:
unsigned n;
T a, b;
const T z;
T numer;
result_type term;
};
// partial specialization for 1f2
template
struct hypergeometric_pFq_cf_term
{
typedef std::pair result_type;
hypergeometric_pFq_cf_term(const T& a, const T& b, const T& c, const T& z):
n(1), a(a), b(b), c(c), z(z),
term(std::make_pair(T(0), T(1)))
{
}
result_type operator()()
{
const result_type result = term;
++a; ++b; ++c; ++n;
numer = -((a * z) / ((b * c) * n));
term = std::make_pair(numer, 1 - numer);
return result;
}
private:
unsigned n;
T a, b, c;
const T z;
T numer;
result_type term;
};
// partial specialization for 2f1
template
struct hypergeometric_pFq_cf_term
{
typedef std::pair result_type;
hypergeometric_pFq_cf_term(const T& a, const T& b, const T& c, const T& z):
n(1), a(a), b(b), c(c), z(z),
term(std::make_pair(T(0), T(1)))
{
}
result_type operator()()
{
const result_type result = term;
++a; ++b; ++c; ++n;
numer = -(((a * b) * z) / (c * n));
term = std::make_pair(numer, 1 - numer);
return result;
}
private:
unsigned n;
T a, b, c;
const T z;
T numer;
result_type term;
};
template
inline T compute_cf_pFq(detail::hypergeometric_pFq_cf_term& term, const Policy& pol)
{
BOOST_MATH_STD_USING
boost::uintmax_t max_iter = policies::get_max_series_iterations();
const T result = tools::continued_fraction_b(
term,
boost::math::policies::get_epsilon(),
max_iter);
boost::math::policies::check_series_iterations(
"boost::math::hypergeometric_pFq_cf<%1%>(%1%,%1%,%1%)",
max_iter,
pol);
return result;
}
template
inline T hypergeometric_0F1_cf(const T& b, const T& z, const Policy& pol)
{
detail::hypergeometric_pFq_cf_term f(b, z);
T result = detail::compute_cf_pFq(f, pol);
result = ((z / b) / result) + 1;
return result;
}
template
inline T hypergeometric_1F0_cf(const T& a, const T& z, const Policy& pol)
{
detail::hypergeometric_pFq_cf_term f(a, z);
T result = detail::compute_cf_pFq(f, pol);
result = ((a * z) / result) + 1;
return result;
}
template
inline T hypergeometric_1F1_cf(const T& a, const T& b, const T& z, const Policy& pol)
{
detail::hypergeometric_pFq_cf_term f(a, b, z);
T result = detail::compute_cf_pFq(f, pol);
result = (((a * z) / b) / result) + 1;
return result;
}
template
inline T hypergeometric_1F2_cf(const T& a, const T& b, const T& c, const T& z, const Policy& pol)
{
detail::hypergeometric_pFq_cf_term f(a, b, c, z);
T result = detail::compute_cf_pFq(f, pol);
result = (((a * z) / (b * c)) / result) + 1;
return result;
}
template
inline T hypergeometric_2F1_cf(const T& a, const T& b, const T& c, const T& z, const Policy& pol)
{
detail::hypergeometric_pFq_cf_term f(a, b, c, z);
T result = detail::compute_cf_pFq(f, pol);
result = ((((a * b) * z) / c) / result) + 1;
return result;
}
} } } // namespaces
#endif // BOOST_MATH_DETAIL_HYPERGEOMETRIC_CF_HPP