Chris@16
|
1 // Copyright (c) 2006 Xiaogang Zhang
|
Chris@16
|
2 // Use, modification and distribution are subject to the
|
Chris@16
|
3 // Boost Software License, Version 1.0. (See accompanying file
|
Chris@16
|
4 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
Chris@16
|
5
|
Chris@16
|
6 #ifndef BOOST_MATH_BESSEL_Y0_HPP
|
Chris@16
|
7 #define BOOST_MATH_BESSEL_Y0_HPP
|
Chris@16
|
8
|
Chris@16
|
9 #ifdef _MSC_VER
|
Chris@16
|
10 #pragma once
|
Chris@16
|
11 #endif
|
Chris@16
|
12
|
Chris@16
|
13 #include <boost/math/special_functions/detail/bessel_j0.hpp>
|
Chris@16
|
14 #include <boost/math/constants/constants.hpp>
|
Chris@16
|
15 #include <boost/math/tools/rational.hpp>
|
Chris@16
|
16 #include <boost/math/tools/big_constant.hpp>
|
Chris@16
|
17 #include <boost/math/policies/error_handling.hpp>
|
Chris@16
|
18 #include <boost/assert.hpp>
|
Chris@16
|
19
|
Chris@16
|
20 // Bessel function of the second kind of order zero
|
Chris@16
|
21 // x <= 8, minimax rational approximations on root-bracketing intervals
|
Chris@16
|
22 // x > 8, Hankel asymptotic expansion in Hart, Computer Approximations, 1968
|
Chris@16
|
23
|
Chris@16
|
24 namespace boost { namespace math { namespace detail{
|
Chris@16
|
25
|
Chris@16
|
26 template <typename T, typename Policy>
|
Chris@16
|
27 T bessel_y0(T x, const Policy&);
|
Chris@16
|
28
|
Chris@16
|
29 template <class T, class Policy>
|
Chris@16
|
30 struct bessel_y0_initializer
|
Chris@16
|
31 {
|
Chris@16
|
32 struct init
|
Chris@16
|
33 {
|
Chris@16
|
34 init()
|
Chris@16
|
35 {
|
Chris@16
|
36 do_init();
|
Chris@16
|
37 }
|
Chris@16
|
38 static void do_init()
|
Chris@16
|
39 {
|
Chris@16
|
40 bessel_y0(T(1), Policy());
|
Chris@16
|
41 }
|
Chris@16
|
42 void force_instantiate()const{}
|
Chris@16
|
43 };
|
Chris@16
|
44 static const init initializer;
|
Chris@16
|
45 static void force_instantiate()
|
Chris@16
|
46 {
|
Chris@16
|
47 initializer.force_instantiate();
|
Chris@16
|
48 }
|
Chris@16
|
49 };
|
Chris@16
|
50
|
Chris@16
|
51 template <class T, class Policy>
|
Chris@16
|
52 const typename bessel_y0_initializer<T, Policy>::init bessel_y0_initializer<T, Policy>::initializer;
|
Chris@16
|
53
|
Chris@16
|
54 template <typename T, typename Policy>
|
Chris@16
|
55 T bessel_y0(T x, const Policy& pol)
|
Chris@16
|
56 {
|
Chris@16
|
57 bessel_y0_initializer<T, Policy>::force_instantiate();
|
Chris@16
|
58
|
Chris@16
|
59 static const T P1[] = {
|
Chris@16
|
60 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0723538782003176831e+11)),
|
Chris@16
|
61 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.3716255451260504098e+09)),
|
Chris@16
|
62 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.0422274357376619816e+08)),
|
Chris@16
|
63 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.1287548474401797963e+06)),
|
Chris@16
|
64 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0102532948020907590e+04)),
|
Chris@16
|
65 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.8402381979244993524e+01)),
|
Chris@16
|
66 };
|
Chris@16
|
67 static const T Q1[] = {
|
Chris@16
|
68 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.8873865738997033405e+11)),
|
Chris@16
|
69 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.1617187777290363573e+09)),
|
Chris@16
|
70 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.5662956624278251596e+07)),
|
Chris@16
|
71 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.3889393209447253406e+05)),
|
Chris@16
|
72 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.6475986689240190091e+02)),
|
Chris@16
|
73 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
|
Chris@16
|
74 };
|
Chris@16
|
75 static const T P2[] = {
|
Chris@16
|
76 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.2213976967566192242e+13)),
|
Chris@16
|
77 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -5.5107435206722644429e+11)),
|
Chris@16
|
78 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.3600098638603061642e+10)),
|
Chris@16
|
79 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -6.9590439394619619534e+08)),
|
Chris@16
|
80 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.6905288611678631510e+06)),
|
Chris@16
|
81 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.4566865832663635920e+04)),
|
Chris@16
|
82 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.7427031242901594547e+01)),
|
Chris@16
|
83 };
|
Chris@16
|
84 static const T Q2[] = {
|
Chris@16
|
85 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.3386146580707264428e+14)),
|
Chris@16
|
86 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.4266824419412347550e+12)),
|
Chris@16
|
87 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.4015103849971240096e+10)),
|
Chris@16
|
88 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.3960202770986831075e+08)),
|
Chris@16
|
89 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.0669982352539552018e+05)),
|
Chris@16
|
90 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.3030857612070288823e+02)),
|
Chris@16
|
91 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
|
Chris@16
|
92 };
|
Chris@16
|
93 static const T P3[] = {
|
Chris@16
|
94 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.0728726905150210443e+15)),
|
Chris@16
|
95 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.7016641869173237784e+14)),
|
Chris@16
|
96 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2829912364088687306e+11)),
|
Chris@16
|
97 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.9363051266772083678e+11)),
|
Chris@16
|
98 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1958827170518100757e+09)),
|
Chris@16
|
99 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.0085539923498211426e+07)),
|
Chris@16
|
100 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1363534169313901632e+04)),
|
Chris@16
|
101 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.7439661319197499338e+01)),
|
Chris@16
|
102 };
|
Chris@16
|
103 static const T Q3[] = {
|
Chris@16
|
104 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.4563724628846457519e+17)),
|
Chris@16
|
105 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.9272425569640309819e+15)),
|
Chris@16
|
106 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2598377924042897629e+13)),
|
Chris@16
|
107 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.6926121104209825246e+10)),
|
Chris@16
|
108 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.4727219475672302327e+08)),
|
Chris@16
|
109 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.3924739209768057030e+05)),
|
Chris@16
|
110 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.7903362168128450017e+02)),
|
Chris@16
|
111 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
|
Chris@16
|
112 };
|
Chris@16
|
113 static const T PC[] = {
|
Chris@16
|
114 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2779090197304684302e+04)),
|
Chris@16
|
115 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.1345386639580765797e+04)),
|
Chris@16
|
116 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1170523380864944322e+04)),
|
Chris@16
|
117 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.4806486443249270347e+03)),
|
Chris@16
|
118 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.5376201909008354296e+02)),
|
Chris@16
|
119 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.8961548424210455236e-01)),
|
Chris@16
|
120 };
|
Chris@16
|
121 static const T QC[] = {
|
Chris@16
|
122 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.2779090197304684318e+04)),
|
Chris@16
|
123 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 4.1370412495510416640e+04)),
|
Chris@16
|
124 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.1215350561880115730e+04)),
|
Chris@16
|
125 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.5028735138235608207e+03)),
|
Chris@16
|
126 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.5711159858080893649e+02)),
|
Chris@16
|
127 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
|
Chris@16
|
128 };
|
Chris@16
|
129 static const T PS[] = {
|
Chris@16
|
130 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.9226600200800094098e+01)),
|
Chris@16
|
131 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.8591953644342993800e+02)),
|
Chris@16
|
132 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.1183429920482737611e+02)),
|
Chris@16
|
133 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -2.2300261666214198472e+01)),
|
Chris@16
|
134 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -1.2441026745835638459e+00)),
|
Chris@16
|
135 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, -8.8033303048680751817e-03)),
|
Chris@16
|
136 };
|
Chris@16
|
137 static const T QS[] = {
|
Chris@16
|
138 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 5.7105024128512061905e+03)),
|
Chris@16
|
139 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.1951131543434613647e+04)),
|
Chris@16
|
140 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 7.2642780169211018836e+03)),
|
Chris@16
|
141 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.4887231232283756582e+03)),
|
Chris@16
|
142 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 9.0593769594993125859e+01)),
|
Chris@16
|
143 static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0)),
|
Chris@16
|
144 };
|
Chris@16
|
145 static const T x1 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 8.9357696627916752158e-01)),
|
Chris@16
|
146 x2 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 3.9576784193148578684e+00)),
|
Chris@16
|
147 x3 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 7.0860510603017726976e+00)),
|
Chris@16
|
148 x11 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.280e+02)),
|
Chris@16
|
149 x12 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 2.9519662791675215849e-03)),
|
Chris@16
|
150 x21 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.0130e+03)),
|
Chris@16
|
151 x22 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 6.4716931485786837568e-04)),
|
Chris@16
|
152 x31 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.8140e+03)),
|
Chris@16
|
153 x32 = static_cast<T>(BOOST_MATH_BIG_CONSTANT(T, 64, 1.1356030177269762362e-04))
|
Chris@16
|
154 ;
|
Chris@16
|
155 T value, factor, r, rc, rs;
|
Chris@16
|
156
|
Chris@16
|
157 BOOST_MATH_STD_USING
|
Chris@16
|
158 using namespace boost::math::tools;
|
Chris@16
|
159 using namespace boost::math::constants;
|
Chris@16
|
160
|
Chris@16
|
161 static const char* function = "boost::math::bessel_y0<%1%>(%1%,%1%)";
|
Chris@16
|
162
|
Chris@16
|
163 if (x < 0)
|
Chris@16
|
164 {
|
Chris@16
|
165 return policies::raise_domain_error<T>(function,
|
Chris@16
|
166 "Got x = %1% but x must be non-negative, complex result not supported.", x, pol);
|
Chris@16
|
167 }
|
Chris@16
|
168 if (x == 0)
|
Chris@16
|
169 {
|
Chris@16
|
170 return -policies::raise_overflow_error<T>(function, 0, pol);
|
Chris@16
|
171 }
|
Chris@16
|
172 if (x <= 3) // x in (0, 3]
|
Chris@16
|
173 {
|
Chris@16
|
174 T y = x * x;
|
Chris@16
|
175 T z = 2 * log(x/x1) * bessel_j0(x) / pi<T>();
|
Chris@16
|
176 r = evaluate_rational(P1, Q1, y);
|
Chris@16
|
177 factor = (x + x1) * ((x - x11/256) - x12);
|
Chris@16
|
178 value = z + factor * r;
|
Chris@16
|
179 }
|
Chris@16
|
180 else if (x <= 5.5f) // x in (3, 5.5]
|
Chris@16
|
181 {
|
Chris@16
|
182 T y = x * x;
|
Chris@16
|
183 T z = 2 * log(x/x2) * bessel_j0(x) / pi<T>();
|
Chris@16
|
184 r = evaluate_rational(P2, Q2, y);
|
Chris@16
|
185 factor = (x + x2) * ((x - x21/256) - x22);
|
Chris@16
|
186 value = z + factor * r;
|
Chris@16
|
187 }
|
Chris@16
|
188 else if (x <= 8) // x in (5.5, 8]
|
Chris@16
|
189 {
|
Chris@16
|
190 T y = x * x;
|
Chris@16
|
191 T z = 2 * log(x/x3) * bessel_j0(x) / pi<T>();
|
Chris@16
|
192 r = evaluate_rational(P3, Q3, y);
|
Chris@16
|
193 factor = (x + x3) * ((x - x31/256) - x32);
|
Chris@16
|
194 value = z + factor * r;
|
Chris@16
|
195 }
|
Chris@16
|
196 else // x in (8, \infty)
|
Chris@16
|
197 {
|
Chris@16
|
198 T y = 8 / x;
|
Chris@16
|
199 T y2 = y * y;
|
Chris@16
|
200 rc = evaluate_rational(PC, QC, y2);
|
Chris@16
|
201 rs = evaluate_rational(PS, QS, y2);
|
Chris@16
|
202 factor = constants::one_div_root_pi<T>() / sqrt(x);
|
Chris@16
|
203 //
|
Chris@16
|
204 // The following code is really just:
|
Chris@16
|
205 //
|
Chris@16
|
206 // T z = x - 0.25f * pi<T>();
|
Chris@16
|
207 // value = factor * (rc * sin(z) + y * rs * cos(z));
|
Chris@16
|
208 //
|
Chris@16
|
209 // But using the sin/cos addition formulae and constant values for
|
Chris@16
|
210 // sin/cos of PI/4 which then cancel part of the "factor" term as they're all
|
Chris@16
|
211 // 1 / sqrt(2):
|
Chris@16
|
212 //
|
Chris@16
|
213 T sx = sin(x);
|
Chris@16
|
214 T cx = cos(x);
|
Chris@16
|
215 value = factor * (rc * (sx - cx) + y * rs * (cx + sx));
|
Chris@16
|
216 }
|
Chris@16
|
217
|
Chris@16
|
218 return value;
|
Chris@16
|
219 }
|
Chris@16
|
220
|
Chris@16
|
221 }}} // namespaces
|
Chris@16
|
222
|
Chris@16
|
223 #endif // BOOST_MATH_BESSEL_Y0_HPP
|
Chris@16
|
224
|