1 /* Implementation of the BESSEL_JN and BESSEL_YN transformational
2 function using a recurrence algorithm.
3 Copyright (C) 2010-2023 Free Software Foundation, Inc.
4 Contributed by Tobias Burnus <burnus@net-b.de>
5
6 This file is part of the GNU Fortran runtime library (libgfortran).
7
8 Libgfortran is free software; you can redistribute it and/or
9 modify it under the terms of the GNU General Public
10 License as published by the Free Software Foundation; either
11 version 3 of the License, or (at your option) any later version.
12
13 Libgfortran is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 Under Section 7 of GPL version 3, you are granted additional
19 permissions described in the GCC Runtime Library Exception, version
20 3.1, as published by the Free Software Foundation.
21
22 You should have received a copy of the GNU General Public License and
23 a copy of the GCC Runtime Library Exception along with this program;
24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 <http://www.gnu.org/licenses/>. */
26
27 #include "libgfortran.h"
28
29
30
31 #if defined(POWER_IEEE128)
32 #define MATHFUNC(funcname) __ ## funcname ## ieee128
33 #elif defined(GFC_REAL_17_USE_IEC_60559)
34 #define MATHFUNC(funcname) funcname ## f128
35 #else
36 #define MATHFUNC(funcname) funcname ## q
37 #endif
38
39 #if defined (HAVE_GFC_REAL_17)
40
41
42
43 #if 1 /* FIXME: figure this out later. */
44 extern void bessel_jn_r17 (gfc_array_r17 * const restrict ret, int n1,
45 int n2, GFC_REAL_17 x);
46 export_proto(bessel_jn_r17);
47
48 void
49 bessel_jn_r17 (gfc_array_r17 * const restrict ret, int n1, int n2, GFC_REAL_17 x)
50 {
51 int i;
52 index_type stride;
53
54 GFC_REAL_17 last1, last2, x2rev;
55
56 stride = GFC_DESCRIPTOR_STRIDE(ret,0);
57
58 if (ret->base_addr == NULL)
59 {
60 size_t size = n2 < n1 ? 0 : n2-n1+1;
61 GFC_DIMENSION_SET(ret->dim[0], 0, size-1, 1);
62 ret->base_addr = xmallocarray (size, sizeof (GFC_REAL_17));
63 ret->offset = 0;
64 }
65
66 if (unlikely (n2 < n1))
67 return;
68
69 if (unlikely (compile_options.bounds_check)
70 && GFC_DESCRIPTOR_EXTENT(ret,0) != (n2-n1+1))
71 runtime_error("Incorrect extent in return value of BESSEL_JN "
72 "(%ld vs. %ld)", (long int) n2-n1,
73 (long int) GFC_DESCRIPTOR_EXTENT(ret,0));
74
75 stride = GFC_DESCRIPTOR_STRIDE(ret,0);
76
77 if (unlikely (x == 0))
78 {
79 ret->base_addr[0] = 1;
80 for (i = 1; i <= n2-n1; i++)
81 ret->base_addr[i*stride] = 0;
82 return;
83 }
84
85 last1 = MATHFUNC(jn) (n2, x);
86 ret->base_addr[(n2-n1)*stride] = last1;
87
88 if (n1 == n2)
89 return;
90
91 last2 = MATHFUNC(jn) (n2 - 1, x);
92 ret->base_addr[(n2-n1-1)*stride] = last2;
93
94 if (n1 + 1 == n2)
95 return;
96
97 x2rev = GFC_REAL_17_LITERAL(2.)/x;
98
99 for (i = n2-n1-2; i >= 0; i--)
100 {
101 ret->base_addr[i*stride] = x2rev * (i+1+n1) * last2 - last1;
102 last1 = last2;
103 last2 = ret->base_addr[i*stride];
104 }
105 }
106
107 #endif
108
109 #if 1 /* FIXME: figure this out later. */
110 extern void bessel_yn_r17 (gfc_array_r17 * const restrict ret,
111 int n1, int n2, GFC_REAL_17 x);
112 export_proto(bessel_yn_r17);
113
114 void
115 bessel_yn_r17 (gfc_array_r17 * const restrict ret, int n1, int n2,
116 GFC_REAL_17 x)
117 {
118 int i;
119 index_type stride;
120
121 GFC_REAL_17 last1, last2, x2rev;
122
123 stride = GFC_DESCRIPTOR_STRIDE(ret,0);
124
125 if (ret->base_addr == NULL)
126 {
127 size_t size = n2 < n1 ? 0 : n2-n1+1;
128 GFC_DIMENSION_SET(ret->dim[0], 0, size-1, 1);
129 ret->base_addr = xmallocarray (size, sizeof (GFC_REAL_17));
130 ret->offset = 0;
131 }
132
133 if (unlikely (n2 < n1))
134 return;
135
136 if (unlikely (compile_options.bounds_check)
137 && GFC_DESCRIPTOR_EXTENT(ret,0) != (n2-n1+1))
138 runtime_error("Incorrect extent in return value of BESSEL_JN "
139 "(%ld vs. %ld)", (long int) n2-n1,
140 (long int) GFC_DESCRIPTOR_EXTENT(ret,0));
141
142 stride = GFC_DESCRIPTOR_STRIDE(ret,0);
143
144 if (unlikely (x == 0))
145 {
146 for (i = 0; i <= n2-n1; i++)
147 #if defined(GFC_REAL_17_INFINITY)
148 ret->base_addr[i*stride] = -GFC_REAL_17_INFINITY;
149 #else
150 ret->base_addr[i*stride] = -GFC_REAL_17_HUGE;
151 #endif
152 return;
153 }
154
155 last1 = MATHFUNC(yn) (n1, x);
156 ret->base_addr[0] = last1;
157
158 if (n1 == n2)
159 return;
160
161 last2 = MATHFUNC(yn) (n1 + 1, x);
162 ret->base_addr[1*stride] = last2;
163
164 if (n1 + 1 == n2)
165 return;
166
167 x2rev = GFC_REAL_17_LITERAL(2.)/x;
168
169 for (i = 2; i <= n2 - n1; i++)
170 {
171 #if defined(GFC_REAL_17_INFINITY)
172 if (unlikely (last2 == -GFC_REAL_17_INFINITY))
173 {
174 ret->base_addr[i*stride] = -GFC_REAL_17_INFINITY;
175 }
176 else
177 #endif
178 {
179 ret->base_addr[i*stride] = x2rev * (i-1+n1) * last2 - last1;
180 last1 = last2;
181 last2 = ret->base_addr[i*stride];
182 }
183 }
184 }
185 #endif
186
187 #endif
188