libgfortran/generated/norm2_r8.c

   1 /* Implementation of the NORM2 intrinsic
   2    Copyright 2010 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->data == 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       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       else
 115         retarray->data = internal_malloc_size (alloc_size);
 116     }
 117   else
 118     {
 119       if (rank != GFC_DESCRIPTOR_RANK (retarray))
 120         runtime_error ("rank of return array incorrect in"
 121                        " NORM intrinsic: is %ld, should be %ld",
 122                        (long int) (GFC_DESCRIPTOR_RANK (retarray)),
 123                        (long int) rank);
 124
 125       if (unlikely (compile_options.bounds_check))
 126         bounds_ifunction_return ((array_t *) retarray, extent,
 127                                  "return value", "NORM");
 128     }
 129
 130   for (n = 0; n < rank; n++)
 131     {
 132       count[n] = 0;
 133       dstride[n] = GFC_DESCRIPTOR_STRIDE(retarray,n);
 134       if (extent[n] <= 0)
 135         return;
 136     }
 137
 138   base = array->data;
 139   dest = retarray->data;
 140
 141   continue_loop = 1;
 142   while (continue_loop)
 143     {
 144       const GFC_REAL_8 * restrict src;
 145       GFC_REAL_8 result;
 146       src = base;
 147       {
 148
 149         GFC_REAL_8 scale;
 150         result = 0;
 151         scale = 1;
 152         if (len <= 0)
 153           *dest = 0;
 154         else
 155           {
 156             for (n = 0; n < len; n++, src += delta)
 157               {
 158
 159           if (*src != 0)
 160             {
 161               GFC_REAL_8 absX, val;
 162               absX = MATHFUNC(fabs) (*src);
 163               if (scale < absX)
 164                 {
 165                   val = scale / absX;
 166                   result = 1 + result * val * val;
 167                   scale = absX;
 168                 }
 169               else
 170                 {
 171                   val = absX / scale;
 172                   result += val * val;
 173                 }
 174             }
 175               }
 176             result = scale * MATHFUNC(sqrt) (result);
 177             *dest = result;
 178           }
 179       }
 180       /* Advance to the next element.  */
 181       count[0]++;
 182       base += sstride[0];
 183       dest += dstride[0];
 184       n = 0;
 185       while (count[n] == extent[n])
 186         {
 187           /* When we get to the end of a dimension, reset it and increment
 188              the next dimension.  */
 189           count[n] = 0;
 190           /* We could precalculate these products, but this is a less
 191              frequently used path so probably not worth it.  */
 192           base -= sstride[n] * extent[n];
 193           dest -= dstride[n] * extent[n];
 194           n++;
 195           if (n == rank)
 196             {
 197               /* Break out of the look.  */
 198               continue_loop = 0;
 199               break;
 200             }
 201           else
 202             {
 203               count[n]++;
 204               base += sstride[n];
 205               dest += dstride[n];
 206             }
 207         }
 208     }
 209 }
 210
 211 #endif