libgfortran/generated/norm2_r8.c

   1 /* Implementation of the NORM2 intrinsic
   2    Copyright (C) 2010-2013 Free Software Foundation, Inc.
   3    Contributed by Tobias Burnus  <burnus@net-b.de>
   4
   5 This file is part of the GNU Fortran runtime library (libgfortran).
   6
   7 Libgfortran is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU General Public
   9 License as published by the Free Software Foundation; either
  10 version 3 of the License, or (at your option) any later version.
  11
  12 Libgfortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "libgfortran.h"
  27 #include <stdlib.h>
  28 #include <math.h>
  29 #include <assert.h>
  30
  31
  32
  33 #if defined (HAVE_GFC_REAL_8) && defined (HAVE_GFC_REAL_8) && defined (HAVE_SQRT) && defined (HAVE_FABS)
  34
  35 #define MATHFUNC(funcname) funcname
  36
  37
  38 extern void norm2_r8 (gfc_array_r8 * const restrict,
  39         gfc_array_r8 * const restrict, const index_type * const restrict);
  40 export_proto(norm2_r8);
  41
  42 void
  43 norm2_r8 (gfc_array_r8 * const restrict retarray,
  44         gfc_array_r8 * const restrict array,
  45         const index_type * const restrict pdim)
  46 {
  47   index_type count[GFC_MAX_DIMENSIONS];
  48   index_type extent[GFC_MAX_DIMENSIONS];
  49   index_type sstride[GFC_MAX_DIMENSIONS];
  50   index_type dstride[GFC_MAX_DIMENSIONS];
  51   const GFC_REAL_8 * restrict base;
  52   GFC_REAL_8 * restrict dest;
  53   index_type rank;
  54   index_type n;
  55   index_type len;
  56   index_type delta;
  57   index_type dim;
  58   int continue_loop;
  59
  60   /* Make dim zero based to avoid confusion.  */
  61   dim = (*pdim) - 1;
  62   rank = GFC_DESCRIPTOR_RANK (array) - 1;
  63
  64   len = GFC_DESCRIPTOR_EXTENT(array,dim);
  65   if (len < 0)
  66     len = 0;
  67   delta = GFC_DESCRIPTOR_STRIDE(array,dim);
  68
  69   for (n = 0; n < dim; n++)
  70     {
  71       sstride[n] = GFC_DESCRIPTOR_STRIDE(array,n);
  72       extent[n] = GFC_DESCRIPTOR_EXTENT(array,n);
  73
  74       if (extent[n] < 0)
  75         extent[n] = 0;
  76     }
  77   for (n = dim; n < rank; n++)
  78     {
  79       sstride[n] = GFC_DESCRIPTOR_STRIDE(array, n + 1);
  80       extent[n] = GFC_DESCRIPTOR_EXTENT(array, n + 1);
  81
  82       if (extent[n] < 0)
  83         extent[n] = 0;
  84     }
  85
  86   if (retarray->base_addr == NULL)
  87     {
  88       size_t alloc_size, str;
  89
  90       for (n = 0; n < rank; n++)
  91         {
  92           if (n == 0)
  93             str = 1;
  94           else
  95             str = GFC_DESCRIPTOR_STRIDE(retarray,n-1) * extent[n-1];
  96
  97           GFC_DIMENSION_SET(retarray->dim[n], 0, extent[n] - 1, str);
  98
  99         }
 100
 101       retarray->offset = 0;
 102       retarray->dtype = (array->dtype & ~GFC_DTYPE_RANK_MASK) | rank;
 103
 104       alloc_size = sizeof (GFC_REAL_8) * GFC_DESCRIPTOR_STRIDE(retarray,rank-1)
 105                    * extent[rank-1];
 106
 107       retarray->base_addr = xmalloc (alloc_size);
 108       if (alloc_size == 0)
 109         {
 110           /* Make sure we have a zero-sized array.  */
 111           GFC_DIMENSION_SET(retarray->dim[0], 0, -1, 1);
 112           return;
 113
 114         }
 115     }
 116   else
 117     {
 118       if (rank != GFC_DESCRIPTOR_RANK (retarray))
 119         runtime_error ("rank of return array incorrect in"
 120                        " NORM intrinsic: is %ld, should be %ld",
 121                        (long int) (GFC_DESCRIPTOR_RANK (retarray)),
 122                        (long int) rank);
 123
 124       if (unlikely (compile_options.bounds_check))
 125         bounds_ifunction_return ((array_t *) retarray, extent,
 126                                  "return value", "NORM");
 127     }
 128
 129   for (n = 0; n < rank; n++)
 130     {
 131       count[n] = 0;
 132       dstride[n] = GFC_DESCRIPTOR_STRIDE(retarray,n);
 133       if (extent[n] <= 0)
 134         return;
 135     }
 136
 137   base = array->base_addr;
 138   dest = retarray->base_addr;
 139
 140   continue_loop = 1;
 141   while (continue_loop)
 142     {
 143       const GFC_REAL_8 * restrict src;
 144       GFC_REAL_8 result;
 145       src = base;
 146       {
 147
 148         GFC_REAL_8 scale;
 149         result = 0;
 150         scale = 1;
 151         if (len <= 0)
 152           *dest = 0;
 153         else
 154           {
 155             for (n = 0; n < len; n++, src += delta)
 156               {
 157
 158           if (*src != 0)
 159             {
 160               GFC_REAL_8 absX, val;
 161               absX = MATHFUNC(fabs) (*src);
 162               if (scale < absX)
 163                 {
 164                   val = scale / absX;
 165                   result = 1 + result * val * val;
 166                   scale = absX;
 167                 }
 168               else
 169                 {
 170                   val = absX / scale;
 171                   result += val * val;
 172                 }
 173             }
 174               }
 175             result = scale * MATHFUNC(sqrt) (result);
 176             *dest = result;
 177           }
 178       }
 179       /* Advance to the next element.  */
 180       count[0]++;
 181       base += sstride[0];
 182       dest += dstride[0];
 183       n = 0;
 184       while (count[n] == extent[n])
 185         {
 186           /* When we get to the end of a dimension, reset it and increment
 187              the next dimension.  */
 188           count[n] = 0;
 189           /* We could precalculate these products, but this is a less
 190              frequently used path so probably not worth it.  */
 191           base -= sstride[n] * extent[n];
 192           dest -= dstride[n] * extent[n];
 193           n++;
 194           if (n == rank)
 195             {
 196               /* Break out of the look.  */
 197               continue_loop = 0;
 198               break;
 199             }
 200           else
 201             {
 202               count[n]++;
 203               base += sstride[n];
 204               dest += dstride[n];
 205             }
 206         }
 207     }
 208 }
 209
 210 #endif