[ceph.git] / ceph / src / boost / boost / math / special_functions / detail / bessel_j0.hpp

//  Copyright (c) 2006 Xiaogang Zhang
//  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_BESSEL_J0_HPP
#define BOOST_MATH_BESSEL_J0_HPP

#ifdef _MSC_VER
#pragma once
#endif

#include <boost/math/constants/constants.hpp>
#include <boost/math/tools/rational.hpp>
#include <boost/math/tools/big_constant.hpp>
#include <boost/assert.hpp>

#if defined(__GNUC__) && defined(BOOST_MATH_USE_FLOAT128)
//
// This is the only way we can avoid
// warning: non-standard suffix on floating constant [-Wpedantic]
// when building with -Wall -pedantic.  Neither __extension__
// nor #pragma dianostic ignored work :(
//
#pragma GCC system_header
#endif

// Bessel function of the first kind of order zero
// x <= 8, minimax rational approximations on root-bracketing intervals
// x > 8, Hankel asymptotic expansion in Hart, Computer Approximations, 1968

namespace boost { namespace math { namespace detail{

template <typename T>
T bessel_j0(T x);

template <class T>
struct bessel_j0_initializer
{
   struct init
   {
      init()
      {
         do_init();
      }
      static void do_init()
      {
         bessel_j0(T(1));
      }
      void force_instantiate()const{}
   };
   static const init initializer;
   static void force_instantiate()
   {
      initializer.force_instantiate();
   }
};

template <class T>
const typename bessel_j0_initializer<T>::init bessel_j0_initializer<T>::initializer;

template <typename T>
T bessel_j0(T x)
{
    bessel_j0_initializer<T>::force_instantiate();
    
    static const T P1[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -4.1298668500990866786e+11)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.7282507878605942706e+10)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -6.2140700423540120665e+08)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.6302997904833794242e+06)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -3.6629814655107086448e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0344222815443188943e+02)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2117036164593528341e-01))
    };
    static const T Q1[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.3883787996332290397e+12)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.6328198300859648632e+10)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.3985097372263433271e+08)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.5612696224219938200e+05)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 9.3614022392337710626e+02)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 0.0))
    };
    static const T P2[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.8319397969392084011e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2254078161378989535e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -7.2879702464464618998e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0341910641583726701e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.1725046279757103576e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.4176707025325087628e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 7.4321196680624245801e+02)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.8591703355916499363e+01))
    };
    static const T Q2[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -3.5783478026152301072e+05)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.4599102262586308984e+05)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.4055062591169562211e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.8680990008359188352e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.9458766545509337327e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.3307310774649071172e+02)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.5258076240801555057e+01)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0))
    };
    static const T PC[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2779090197304684302e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.1345386639580765797e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1170523380864944322e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.4806486443249270347e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.5376201909008354296e+02)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.8961548424210455236e-01))
    };
    static const T QC[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2779090197304684318e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.1370412495510416640e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1215350561880115730e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.5028735138235608207e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.5711159858080893649e+02)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0))
    };
    static const T PS[] = {
        static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.9226600200800094098e+01)),
        static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.8591953644342993800e+02)),
        static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.1183429920482737611e+02)),
        static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.2300261666214198472e+01)),
        static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2441026745835638459e+00)),
        static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.8033303048680751817e-03))
    };
    static const T QS[] = {
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.7105024128512061905e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.1951131543434613647e+04)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 7.2642780169211018836e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.4887231232283756582e+03)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 9.0593769594993125859e+01)),
         static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0))
    };
    static const T x1  =  static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.4048255576957727686e+00)),
                   x2  =  static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.5200781102863106496e+00)),
                   x11 =  static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.160e+02)),
                   x12 =  static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.42444230422723137837e-03)),
                   x21 =  static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.4130e+03)),
                   x22 =  static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.46860286310649596604e-04));

    T value, factor, r, rc, rs;

    BOOST_MATH_STD_USING
    using namespace boost::math::tools;
    using namespace boost::math::constants;

    if (x < 0)
    {
        x = -x;                         // even function
    }
    if (x == 0)
    {
        return static_cast<T>(1);
    }
    if (x <= 4)                       // x in (0, 4]
    {
        T y = x * x;
        BOOST_ASSERT(sizeof(P1) == sizeof(Q1));
        r = evaluate_rational(P1, Q1, y);
        factor = (x + x1) * ((x - x11/256) - x12);
        value = factor * r;
    }
    else if (x <= 8.0)                  // x in (4, 8]
    {
        T y = 1 - (x * x)/64;
        BOOST_ASSERT(sizeof(P2) == sizeof(Q2));
        r = evaluate_rational(P2, Q2, y);
        factor = (x + x2) * ((x - x21/256) - x22);
        value = factor * r;
    }
    else                                // x in (8, \infty)
    {
        T y = 8 / x;
        T y2 = y * y;
        BOOST_ASSERT(sizeof(PC) == sizeof(QC));
        BOOST_ASSERT(sizeof(PS) == sizeof(QS));
        rc = evaluate_rational(PC, QC, y2);
        rs = evaluate_rational(PS, QS, y2);
        factor = constants::one_div_root_pi<T>() / sqrt(x);
        //
        // What follows is really just:
        //
        // T z = x - pi/4;
        // value = factor * (rc * cos(z) - y * rs * sin(z));
        //
        // But using the addition formulae for sin and cos, plus
        // the special values for sin/cos of pi/4.
        //
        T sx = sin(x);
        T cx = cos(x);
        value = factor * (rc * (cx + sx) - y * rs * (sx - cx));
    }

    return value;
}

}}} // namespaces

#endif // BOOST_MATH_BESSEL_J0_HPP
Commit	Line	Data
7c673cae FG	1	// Copyright (c) 2006 Xiaogang Zhang
	2	// Use, modification and distribution are subject to the
	3	// Boost Software License, Version 1.0. (See accompanying file
	4	// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
	5
	6	#ifndef BOOST_MATH_BESSEL_J0_HPP
	7	#define BOOST_MATH_BESSEL_J0_HPP
	8
	9	#ifdef _MSC_VER
	10	#pragma once
	11	#endif
	12
	13	#include <boost/math/constants/constants.hpp>
	14	#include <boost/math/tools/rational.hpp>
	15	#include <boost/math/tools/big_constant.hpp>
	16	#include <boost/assert.hpp>
	17
92f5a8d4 TL	18	#if defined(__GNUC__) && defined(BOOST_MATH_USE_FLOAT128)
	19	//
	20	// This is the only way we can avoid
	21	// warning: non-standard suffix on floating constant [-Wpedantic]
	22	// when building with -Wall -pedantic. Neither __extension__
	23	// nor #pragma dianostic ignored work :(
	24	//
	25	#pragma GCC system_header
	26	#endif
	27
7c673cae FG	28	// Bessel function of the first kind of order zero
	29	// x <= 8, minimax rational approximations on root-bracketing intervals
	30	// x > 8, Hankel asymptotic expansion in Hart, Computer Approximations, 1968
	31
	32	namespace boost { namespace math { namespace detail{
	33
	34	template <typename T>
	35	T bessel_j0(T x);
	36
	37	template <class T>
	38	struct bessel_j0_initializer
	39	{
	40	struct init
	41	{
	42	init()
	43	{
	44	do_init();
	45	}
	46	static void do_init()
	47	{
	48	bessel_j0(T(1));
	49	}
	50	void force_instantiate()const{}
	51	};
	52	static const init initializer;
	53	static void force_instantiate()
	54	{
	55	initializer.force_instantiate();
	56	}
	57	};
	58
	59	template <class T>
	60	const typename bessel_j0_initializer<T>::init bessel_j0_initializer<T>::initializer;
	61
	62	template <typename T>
	63	T bessel_j0(T x)
	64	{
	65	bessel_j0_initializer<T>::force_instantiate();
	66
	67	static const T P1[] = {
	68	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -4.1298668500990866786e+11)),
	69	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.7282507878605942706e+10)),
	70	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -6.2140700423540120665e+08)),
	71	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.6302997904833794242e+06)),
	72	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -3.6629814655107086448e+04)),
	73	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0344222815443188943e+02)),
	74	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2117036164593528341e-01))
	75	};
	76	static const T Q1[] = {
	77	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.3883787996332290397e+12)),
	78	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.6328198300859648632e+10)),
	79	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.3985097372263433271e+08)),
	80	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.5612696224219938200e+05)),
	81	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 9.3614022392337710626e+02)),
	82	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
	83	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 0.0))
	84	};
	85	static const T P2[] = {
	86	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.8319397969392084011e+03)),
	87	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2254078161378989535e+04)),
	88	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -7.2879702464464618998e+03)),
	89	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0341910641583726701e+04)),
	90	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.1725046279757103576e+04)),
	91	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.4176707025325087628e+03)),
92	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 7.4321196680624245801e+02)),
93	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.8591703355916499363e+01))
94	};
95	static const T Q2[] = {
96	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -3.5783478026152301072e+05)),
97	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.4599102262586308984e+05)),
98	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.4055062591169562211e+04)),
99	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.8680990008359188352e+04)),
100	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.9458766545509337327e+03)),
101	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.3307310774649071172e+02)),
102	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.5258076240801555057e+01)),
103	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0))
104	};
105	static const T PC[] = {
106	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2779090197304684302e+04)),
107	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.1345386639580765797e+04)),
108	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1170523380864944322e+04)),
109	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.4806486443249270347e+03)),
110	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.5376201909008354296e+02)),
111	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.8961548424210455236e-01))
112	};
113	static const T QC[] = {
114	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2779090197304684318e+04)),
115	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.1370412495510416640e+04)),
116	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1215350561880115730e+04)),
117	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.5028735138235608207e+03)),
118	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.5711159858080893649e+02)),
119	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0))
120	};
121	static const T PS[] = {
122	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.9226600200800094098e+01)),
123	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.8591953644342993800e+02)),
124	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.1183429920482737611e+02)),
125	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.2300261666214198472e+01)),
126	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2441026745835638459e+00)),
127	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.8033303048680751817e-03))
128	};
129	static const T QS[] = {
130	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.7105024128512061905e+03)),
131	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.1951131543434613647e+04)),
132	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 7.2642780169211018836e+03)),
133	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.4887231232283756582e+03)),
134	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 9.0593769594993125859e+01)),
135	static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0))
136	};
137	static const T x1 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.4048255576957727686e+00)),
138	x2 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.5200781102863106496e+00)),
139	x11 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.160e+02)),
140	x12 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.42444230422723137837e-03)),
141	x21 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.4130e+03)),
142	x22 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.46860286310649596604e-04));
143
144	T value, factor, r, rc, rs;
145
146	BOOST_MATH_STD_USING
147	using namespace boost::math::tools;
148	using namespace boost::math::constants;
149
150	if (x < 0)
151	{
152	x = -x; // even function
153	}
154	if (x == 0)
155	{
156	return static_cast<T>(1);
157	}
158	if (x <= 4) // x in (0, 4]
159	{
160	T y = x * x;
161	BOOST_ASSERT(sizeof(P1) == sizeof(Q1));
162	r = evaluate_rational(P1, Q1, y);
163	factor = (x + x1) * ((x - x11/256) - x12);
164	value = factor * r;
165	}
166	else if (x <= 8.0) // x in (4, 8]
167	{
168	T y = 1 - (x * x)/64;
169	BOOST_ASSERT(sizeof(P2) == sizeof(Q2));
170	r = evaluate_rational(P2, Q2, y);
171	factor = (x + x2) * ((x - x21/256) - x22);
172	value = factor * r;
173	}
174	else // x in (8, \infty)
175	{
176	T y = 8 / x;
177	T y2 = y * y;
178	BOOST_ASSERT(sizeof(PC) == sizeof(QC));
179	BOOST_ASSERT(sizeof(PS) == sizeof(QS));
180	rc = evaluate_rational(PC, QC, y2);
181	rs = evaluate_rational(PS, QS, y2);
182	factor = constants::one_div_root_pi<T>() / sqrt(x);
183	//
184	// What follows is really just:
185	//
186	// T z = x - pi/4;
187	// value = factor * (rc * cos(z) - y * rs * sin(z));
188	//
189	// But using the addition formulae for sin and cos, plus
190	// the special values for sin/cos of pi/4.
191	//
192	T sx = sin(x);
193	T cx = cos(x);
194	value = factor * (rc * (cx + sx) - y * rs * (sx - cx));
195	}
196
197	return value;
198	}
199
200	}}} // namespaces
201
202	#endif // BOOST_MATH_BESSEL_J0_HPP
203