libgfortran/generated/norm2_r8.c

   1 /* Implementation of the NORM2 intrinsic
   2    Copyright (C) 2010-2015 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 = GFC_DESCRIPTOR_STRIDE(retarray,rank-1) * extent[rank-1];
 105
 106       retarray->base_addr = xmallocarray (alloc_size, sizeof (GFC_REAL_8));
 107       if (alloc_size == 0)
 108         {
 109           /* Make sure we have a zero-sized array.  */
 110           GFC_DIMENSION_SET(retarray->dim[0], 0, -1, 1);
 111           return;
 112
 113         }
 114     }
 115   else
 116     {
 117       if (rank != GFC_DESCRIPTOR_RANK (retarray))
 118         runtime_error ("rank of return array incorrect in"
 119                        " NORM intrinsic: is %ld, should be %ld",
 120                        (long int) (GFC_DESCRIPTOR_RANK (retarray)),
 121                        (long int) rank);
 122
 123       if (unlikely (compile_options.bounds_check))
 124         bounds_ifunction_return ((array_t *) retarray, extent,
 125                                  "return value", "NORM");
 126     }
 127
 128   for (n = 0; n < rank; n++)
 129     {
 130       count[n] = 0;
 131       dstride[n] = GFC_DESCRIPTOR_STRIDE(retarray,n);
 132       if (extent[n] <= 0)
 133         return;
 134     }
 135
 136   base = array->base_addr;
 137   dest = retarray->base_addr;
 138
 139   continue_loop = 1;
 140   while (continue_loop)
 141     {
 142       const GFC_REAL_8 * restrict src;
 143       GFC_REAL_8 result;
 144       src = base;
 145       {
 146
 147         GFC_REAL_8 scale;
 148         result = 0;
 149         scale = 1;
 150         if (len <= 0)
 151           *dest = 0;
 152         else
 153           {
 154             for (n = 0; n < len; n++, src += delta)
 155               {
 156
 157           if (*src != 0)
 158             {
 159               GFC_REAL_8 absX, val;
 160               absX = MATHFUNC(fabs) (*src);
 161               if (scale < absX)
 162                 {
 163                   val = scale / absX;
 164                   result = 1 + result * val * val;
 165                   scale = absX;
 166                 }
 167               else
 168                 {
 169                   val = absX / scale;
 170                   result += val * val;
 171                 }
 172             }
 173               }
 174             result = scale * MATHFUNC(sqrt) (result);
 175             *dest = result;
 176           }
 177       }
 178       /* Advance to the next element.  */
 179       count[0]++;
 180       base += sstride[0];
 181       dest += dstride[0];
 182       n = 0;
 183       while (count[n] == extent[n])
 184         {
 185           /* When we get to the end of a dimension, reset it and increment
 186              the next dimension.  */
 187           count[n] = 0;
 188           /* We could precalculate these products, but this is a less
 189              frequently used path so probably not worth it.  */
 190           base -= sstride[n] * extent[n];
 191           dest -= dstride[n] * extent[n];
 192           n++;
 193           if (n == rank)
 194             {
 195               /* Break out of the look.  */
 196               continue_loop = 0;
 197               break;
 198             }
 199           else
 200             {
 201               count[n]++;
 202               base += sstride[n];
 203               dest += dstride[n];
 204             }
 205         }
 206     }
 207 }
 208
 209 #endif