libgfortran/generated/norm2_r8.c

   1 /* Implementation of the NORM2 intrinsic
   2    Copyright (C) 2010-2018 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 #ifdef HAVE_BACK_ARG
  58   assert(back == 0);
  59 #endif
  60
  61   /* Make dim zero based to avoid confusion.  */
  62   rank = GFC_DESCRIPTOR_RANK (array) - 1;
  63   dim = (*pdim) - 1;
  64
  65   if (unlikely (dim < 0 || dim > rank))
  66     {
  67       runtime_error ("Dim argument incorrect in NORM intrinsic: "
  68                      "is %ld, should be between 1 and %ld",
  69                      (long int) dim + 1, (long int) rank + 1);
  70     }
  71
  72   len = GFC_DESCRIPTOR_EXTENT(array,dim);
  73   if (len < 0)
  74     len = 0;
  75   delta = GFC_DESCRIPTOR_STRIDE(array,dim);
  76
  77   for (n = 0; n < dim; n++)
  78     {
  79       sstride[n] = GFC_DESCRIPTOR_STRIDE(array,n);
  80       extent[n] = GFC_DESCRIPTOR_EXTENT(array,n);
  81
  82       if (extent[n] < 0)
  83         extent[n] = 0;
  84     }
  85   for (n = dim; n < rank; n++)
  86     {
  87       sstride[n] = GFC_DESCRIPTOR_STRIDE(array, n + 1);
  88       extent[n] = GFC_DESCRIPTOR_EXTENT(array, n + 1);
  89
  90       if (extent[n] < 0)
  91         extent[n] = 0;
  92     }
  93
  94   if (retarray->base_addr == NULL)
  95     {
  96       size_t alloc_size, str;
  97
  98       for (n = 0; n < rank; n++)
  99         {
 100           if (n == 0)
 101             str = 1;
 102           else
 103             str = GFC_DESCRIPTOR_STRIDE(retarray,n-1) * extent[n-1];
 104
 105           GFC_DIMENSION_SET(retarray->dim[n], 0, extent[n] - 1, str);
 106
 107         }
 108
 109       retarray->offset = 0;
 110       GFC_DTYPE_COPY_SETRANK(retarray,array,rank);
 111
 112       alloc_size = GFC_DESCRIPTOR_STRIDE(retarray,rank-1) * extent[rank-1];
 113
 114       retarray->base_addr = xmallocarray (alloc_size, sizeof (GFC_REAL_8));
 115       if (alloc_size == 0)
 116         {
 117           /* Make sure we have a zero-sized array.  */
 118           GFC_DIMENSION_SET(retarray->dim[0], 0, -1, 1);
 119           return;
 120
 121         }
 122     }
 123   else
 124     {
 125       if (rank != GFC_DESCRIPTOR_RANK (retarray))
 126         runtime_error ("rank of return array incorrect in"
 127                        " NORM intrinsic: is %ld, should be %ld",
 128                        (long int) (GFC_DESCRIPTOR_RANK (retarray)),
 129                        (long int) rank);
 130
 131       if (unlikely (compile_options.bounds_check))
 132         bounds_ifunction_return ((array_t *) retarray, extent,
 133                                  "return value", "NORM");
 134     }
 135
 136   for (n = 0; n < rank; n++)
 137     {
 138       count[n] = 0;
 139       dstride[n] = GFC_DESCRIPTOR_STRIDE(retarray,n);
 140       if (extent[n] <= 0)
 141         return;
 142     }
 143
 144   base = array->base_addr;
 145   dest = retarray->base_addr;
 146
 147   continue_loop = 1;
 148   while (continue_loop)
 149     {
 150       const GFC_REAL_8 * restrict src;
 151       GFC_REAL_8 result;
 152       src = base;
 153       {
 154
 155         GFC_REAL_8 scale;
 156         result = 0;
 157         scale = 1;
 158         if (len <= 0)
 159           *dest = 0;
 160         else
 161           {
 162             for (n = 0; n < len; n++, src += delta)
 163               {
 164
 165           if (*src != 0)
 166             {
 167               GFC_REAL_8 absX, val;
 168               absX = MATHFUNC(fabs) (*src);
 169               if (scale < absX)
 170                 {
 171                   val = scale / absX;
 172                   result = 1 + result * val * val;
 173                   scale = absX;
 174                 }
 175               else
 176                 {
 177                   val = absX / scale;
 178                   result += val * val;
 179                 }
 180             }
 181               }
 182             result = scale * MATHFUNC(sqrt) (result);
 183             *dest = result;
 184           }
 185       }
 186       /* Advance to the next element.  */
 187       count[0]++;
 188       base += sstride[0];
 189       dest += dstride[0];
 190       n = 0;
 191       while (count[n] == extent[n])
 192         {
 193           /* When we get to the end of a dimension, reset it and increment
 194              the next dimension.  */
 195           count[n] = 0;
 196           /* We could precalculate these products, but this is a less
 197              frequently used path so probably not worth it.  */
 198           base -= sstride[n] * extent[n];
 199           dest -= dstride[n] * extent[n];
 200           n++;
 201           if (n >= rank)
 202             {
 203               /* Break out of the loop.  */
 204               continue_loop = 0;
 205               break;
 206             }
 207           else
 208             {
 209               count[n]++;
 210               base += sstride[n];
 211               dest += dstride[n];
 212             }
 213         }
 214     }
 215 }
 216
 217 #endif