libgfortran/generated/bessel_r4.c

   1 /* Implementation of the BESSEL_JN and BESSEL_YN transformational
   2    function using a recurrence algorithm.
   3    Copyright 2010 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 #include <stdlib.h>
  29 #include <assert.h>
  30
  31
  32
  33 #define MATHFUNC(funcname) funcname ## f
  34
  35 #if defined (HAVE_GFC_REAL_4)
  36
  37
  38
  39 #if defined (HAVE_JNF)
  40 extern void bessel_jn_r4 (gfc_array_r4 * const restrict ret, int n1,
  41                                      int n2, GFC_REAL_4 x);
  42 export_proto(bessel_jn_r4);
  43
  44 void
  45 bessel_jn_r4 (gfc_array_r4 * const restrict ret, int n1, int n2, GFC_REAL_4 x)
  46 {
  47   int i;
  48   index_type stride;
  49
  50   GFC_REAL_4 last1, last2, x2rev;
  51
  52   stride = GFC_DESCRIPTOR_STRIDE(ret,0);
  53
  54   if (ret->data == NULL)
  55     {
  56       size_t size = n2 < n1 ? 0 : n2-n1+1;
  57       GFC_DIMENSION_SET(ret->dim[0], 0, size-1, 1);
  58       ret->data = internal_malloc_size (sizeof (GFC_REAL_4) * size);
  59       ret->offset = 0;
  60     }
  61
  62   if (unlikely (n2 < n1))
  63     return;
  64
  65   if (unlikely (compile_options.bounds_check)
  66       && GFC_DESCRIPTOR_EXTENT(ret,0) != (n2-n1+1))
  67     runtime_error("Incorrect extent in return value of BESSEL_JN "
  68                   "(%ld vs. %ld)", (long int) n2-n1,
  69                   GFC_DESCRIPTOR_EXTENT(ret,0));
  70
  71   stride = GFC_DESCRIPTOR_STRIDE(ret,0);
  72
  73   if (unlikely (x == 0))
  74     {
  75       ret->data[0] = 1;
  76       for (i = 1; i <= n2-n1; i++)
  77         ret->data[i*stride] = 0;
  78       return;
  79     }
  80
  81   ret->data = ret->data;
  82   last1 = MATHFUNC(jn) (n2, x);
  83   ret->data[(n2-n1)*stride] = last1;
  84
  85   if (n1 == n2)
  86     return;
  87
  88   last2 = MATHFUNC(jn) (n2 - 1, x);
  89   ret->data[(n2-n1-1)*stride] = last2;
  90
  91   if (n1 + 1 == n2)
  92     return;
  93
  94   x2rev = GFC_REAL_4_LITERAL(2.)/x;
  95
  96   for (i = n2-n1-2; i >= 0; i--)
  97     {
  98       ret->data[i*stride] = x2rev * (i+1+n1) * last2 - last1;
  99       last1 = last2;
 100       last2 = ret->data[i*stride];
 101     }
 102 }
 103
 104 #endif
 105
 106 #if defined (HAVE_YNF)
 107 extern void bessel_yn_r4 (gfc_array_r4 * const restrict ret,
 108                                      int n1, int n2, GFC_REAL_4 x);
 109 export_proto(bessel_yn_r4);
 110
 111 void
 112 bessel_yn_r4 (gfc_array_r4 * const restrict ret, int n1, int n2,
 113                          GFC_REAL_4 x)
 114 {
 115   int i;
 116   index_type stride;
 117
 118   GFC_REAL_4 last1, last2, x2rev;
 119
 120   stride = GFC_DESCRIPTOR_STRIDE(ret,0);
 121
 122   if (ret->data == NULL)
 123     {
 124       size_t size = n2 < n1 ? 0 : n2-n1+1;
 125       GFC_DIMENSION_SET(ret->dim[0], 0, size-1, 1);
 126       ret->data = internal_malloc_size (sizeof (GFC_REAL_4) * size);
 127       ret->offset = 0;
 128     }
 129
 130   if (unlikely (n2 < n1))
 131     return;
 132
 133   if (unlikely (compile_options.bounds_check)
 134       && GFC_DESCRIPTOR_EXTENT(ret,0) != (n2-n1+1))
 135     runtime_error("Incorrect extent in return value of BESSEL_JN "
 136                   "(%ld vs. %ld)", (long int) n2-n1,
 137                   GFC_DESCRIPTOR_EXTENT(ret,0));
 138
 139   stride = GFC_DESCRIPTOR_STRIDE(ret,0);
 140
 141   if (unlikely (x == 0))
 142     {
 143       for (i = 0; i <= n2-n1; i++)
 144 #if defined(GFC_REAL_4_INFINITY)
 145         ret->data[i*stride] = -GFC_REAL_4_INFINITY;
 146 #else
 147         ret->data[i*stride] = -GFC_REAL_4_HUGE;
 148 #endif
 149       return;
 150     }
 151
 152   ret->data = ret->data;
 153   last1 = MATHFUNC(yn) (n1, x);
 154   ret->data[0] = last1;
 155
 156   if (n1 == n2)
 157     return;
 158
 159   last2 = MATHFUNC(yn) (n1 + 1, x);
 160   ret->data[1*stride] = last2;
 161
 162   if (n1 + 1 == n2)
 163     return;
 164
 165   x2rev = GFC_REAL_4_LITERAL(2.)/x;
 166
 167   for (i = 2; i <= n1+n2; i++)
 168     {
 169 #if defined(GFC_REAL_4_INFINITY)
 170       if (unlikely (last2 == -GFC_REAL_4_INFINITY))
 171         {
 172           ret->data[i*stride] = -GFC_REAL_4_INFINITY;
 173         }
 174       else
 175 #endif
 176         {
 177           ret->data[i*stride] = x2rev * (i-1+n1) * last2 - last1;
 178           last1 = last2;
 179           last2 = ret->data[i*stride];
 180         }
 181     }
 182 }
 183 #endif
 184
 185 #endif
 186