Function fast_map_common_subexp

kernel/maps/fast_maps.cc:354–427

*/

ideal fast_map_common_subexp(const ideal map_id,const ring map_r,const ideal image_id,const ring image_r)
{
  ring src_r, dest_r;
  ideal dest_id/*, res_id*/;
  int length = 0;
  BOOLEAN no_sort;

  // construct rings we work in:
  // src_r: Wp with Weights set to length of poly in image_id
  // dest_r: Simple ring without degree ordering and short exponents
  maMap_CreateRings(map_id, map_r, image_id, image_r, src_r, dest_r, no_sort);

  // construct dest_id
  if (dest_r != image_r)
  {
    dest_id = idrShallowCopyR(image_id, image_r, dest_r);
  }
  else
    dest_id = image_id;

  // construct mpoly and mideal
  mapoly mp;
  maideal mideal;
  maMap_CreatePolyIdeal(map_id, map_r, src_r, dest_r, mp, mideal);

  if (TEST_OPT_PROT)
  {
    maPoly_GetLength(mp, length);
    Print("map[%ld:%d]{%d:", dest_r->bitmask, dest_r->ExpL_Size, length);
  }

  // do the optimization step
#if HAVE_MAP_OPTIMIZE > 0
  if (mp!=NULL) maPoly_Optimize(mp, src_r);
#endif
  if (TEST_OPT_PROT)
  {
    maPoly_GetLength(mp, length);
    Print("%d}", length);
  }

  // do the actual evaluation
  maPoly_Eval(mp, src_r, dest_id, dest_r, length);
  if (TEST_OPT_PROT) PrintS(".");

  // collect the results back into an ideal, clean up mideal
  ideal res_dest_id = maIdeal_2_Ideal(mideal, dest_r);
  if (TEST_OPT_PROT) PrintS(".");

  // convert result back to image_r
  ideal res_image_id;
  if (dest_r != image_r)
  {
    //if (no_sort) see Old/m134si.tst
    //  res_image_id = idrShallowCopyR_NoSort(res_dest_id, dest_r, image_r);
    //else
      res_image_id = idrShallowCopyR(res_dest_id, dest_r, image_r);
    id_ShallowDelete(&res_dest_id, dest_r);