libgfortran/generated/norm2_r8.c

   1 /* Implementation of the NORM2 intrinsic
   2    Copyright (C) 2010-2017 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
  28
  29
  30 #if defined (HAVE_GFC_REAL_8) && defined (HAVE_GFC_REAL_8) && defined (HAVE_SQRT) && defined (HAVE_FABS)
  31
  32 #define MATHFUNC(funcname) funcname
  33
  34
  35 extern void norm2_r8 (gfc_array_r8 * const restrict,
  36         gfc_array_r8 * const restrict, const index_type * const restrict);
  37 export_proto(norm2_r8);
  38
  39 void
  40 norm2_r8 (gfc_array_r8 * const restrict retarray,
  41         gfc_array_r8 * const restrict array,
  42         const index_type * const restrict pdim)
  43 {
  44   index_type count[GFC_MAX_DIMENSIONS];
  45   index_type extent[GFC_MAX_DIMENSIONS];
  46   index_type sstride[GFC_MAX_DIMENSIONS];
  47   index_type dstride[GFC_MAX_DIMENSIONS];
  48   const GFC_REAL_8 * restrict base;
  49   GFC_REAL_8 * restrict dest;
  50   index_type rank;
  51   index_type n;
  52   index_type len;
  53   index_type delta;
  54   index_type dim;
  55   int continue_loop;
  56
  57   /* Make dim zero based to avoid confusion.  */
  58   dim = (*pdim) - 1;
  59   rank = GFC_DESCRIPTOR_RANK (array) - 1;
  60
  61   len = GFC_DESCRIPTOR_EXTENT(array,dim);
  62   if (len < 0)
  63     len = 0;
  64   delta = GFC_DESCRIPTOR_STRIDE(array,dim);
  65
  66   for (n = 0; n < dim; n++)
  67     {
  68       sstride[n] = GFC_DESCRIPTOR_STRIDE(array,n);
  69       extent[n] = GFC_DESCRIPTOR_EXTENT(array,n);
  70
  71       if (extent[n] < 0)
  72         extent[n] = 0;
  73     }
  74   for (n = dim; n < rank; n++)
  75     {
  76       sstride[n] = GFC_DESCRIPTOR_STRIDE(array, n + 1);
  77       extent[n] = GFC_DESCRIPTOR_EXTENT(array, n + 1);
  78
  79       if (extent[n] < 0)
  80         extent[n] = 0;
  81     }
  82
  83   if (retarray->base_addr == NULL)
  84     {
  85       size_t alloc_size, str;
  86
  87       for (n = 0; n < rank; n++)
  88         {
  89           if (n == 0)
  90             str = 1;
  91           else
  92             str = GFC_DESCRIPTOR_STRIDE(retarray,n-1) * extent[n-1];
  93
  94           GFC_DIMENSION_SET(retarray->dim[n], 0, extent[n] - 1, str);
  95
  96         }
  97
  98       retarray->offset = 0;
  99       retarray->dtype = (array->dtype & ~GFC_DTYPE_RANK_MASK) | rank;
 100
 101       alloc_size = GFC_DESCRIPTOR_STRIDE(retarray,rank-1) * extent[rank-1];
 102
 103       retarray->base_addr = xmallocarray (alloc_size, sizeof (GFC_REAL_8));
 104       if (alloc_size == 0)
 105         {
 106           /* Make sure we have a zero-sized array.  */
 107           GFC_DIMENSION_SET(retarray->dim[0], 0, -1, 1);
 108           return;
 109
 110         }
 111     }
 112   else
 113     {
 114       if (rank != GFC_DESCRIPTOR_RANK (retarray))
 115         runtime_error ("rank of return array incorrect in"
 116                        " NORM intrinsic: is %ld, should be %ld",
 117                        (long int) (GFC_DESCRIPTOR_RANK (retarray)),
 118                        (long int) rank);
 119
 120       if (unlikely (compile_options.bounds_check))
 121         bounds_ifunction_return ((array_t *) retarray, extent,
 122                                  "return value", "NORM");
 123     }
 124
 125   for (n = 0; n < rank; n++)
 126     {
 127       count[n] = 0;
 128       dstride[n] = GFC_DESCRIPTOR_STRIDE(retarray,n);
 129       if (extent[n] <= 0)
 130         return;
 131     }
 132
 133   base = array->base_addr;
 134   dest = retarray->base_addr;
 135
 136   continue_loop = 1;
 137   while (continue_loop)
 138     {
 139       const GFC_REAL_8 * restrict src;
 140       GFC_REAL_8 result;
 141       src = base;
 142       {
 143
 144         GFC_REAL_8 scale;
 145         result = 0;
 146         scale = 1;
 147         if (len <= 0)
 148           *dest = 0;
 149         else
 150           {
 151             for (n = 0; n < len; n++, src += delta)
 152               {
 153
 154           if (*src != 0)
 155             {
 156               GFC_REAL_8 absX, val;
 157               absX = MATHFUNC(fabs) (*src);
 158               if (scale < absX)
 159                 {
 160                   val = scale / absX;
 161                   result = 1 + result * val * val;
 162                   scale = absX;
 163                 }
 164               else
 165                 {
 166                   val = absX / scale;
 167                   result += val * val;
 168                 }
 169             }
 170               }
 171             result = scale * MATHFUNC(sqrt) (result);
 172             *dest = result;
 173           }
 174       }
 175       /* Advance to the next element.  */
 176       count[0]++;
 177       base += sstride[0];
 178       dest += dstride[0];
 179       n = 0;
 180       while (count[n] == extent[n])
 181         {
 182           /* When we get to the end of a dimension, reset it and increment
 183              the next dimension.  */
 184           count[n] = 0;
 185           /* We could precalculate these products, but this is a less
 186              frequently used path so probably not worth it.  */
 187           base -= sstride[n] * extent[n];
 188           dest -= dstride[n] * extent[n];
 189           n++;
 190           if (n >= rank)
 191             {
 192               /* Break out of the loop.  */
 193               continue_loop = 0;
 194               break;
 195             }
 196           else
 197             {
 198               count[n]++;
 199               base += sstride[n];
 200               dest += dstride[n];
 201             }
 202         }
 203     }
 204 }
 205
 206 #endif