Function maApplyFetch

Singular/maps_ip.cc:45–259

2 * maps the expression w to res, * switch what: MAP_CMD: use theMap for mapping, N for preimage ring * //FETCH_CMD: use pOrdPoly for mapping * IMAP_CMD: use perm for mapping, N for preimage ring * default: map only poly-structures, * use perm and par_perm, N and P, */

*                       use perm and par_perm, N and P,
*/
BOOLEAN maApplyFetch(int what,map theMap,leftv res, leftv w, ring preimage_r,
                     int *perm, int *par_perm, int P, nMapFunc nMap)
{
  BOOLEAN use_mult=FALSE;
#ifdef HAVE_PLURAL
  if ((what==IMAP_CMD)
  && rIsPluralRing(currRing)
  && rIsPluralRing(preimage_r))
  {
    assume(perm!=NULL);
    int i=1;
    while((i<preimage_r->N)&&(perm[i]==0)) i++;
    if (i<preimage_r->N)
    {
      int prev_nonnull=i;
      i++;
      for(;i<=preimage_r->N;i++)
      {
        if (perm[prev_nonnull] > perm[i])
        {
          if (TEST_V_ALLWARN)
          {
            Warn("imap not usable for permuting variables, use map (%s <-> %s)",                 preimage_r->names[prev_nonnull-1],preimage_r->names[i-1]);
          }
          use_mult=TRUE;
          break;
        }
        else
          prev_nonnull=i;
      }
    }
  }
#endif
  int i;
  int N = preimage_r->N;
#if 0
  Print("N=%d what=%s ",N,Tok2Cmdname(what));
  if (perm!=NULL) for(i=1;i<=N;i++) Print("%d -> %d ",i,perm[i]);
  PrintS("\n");
  Print("P=%d ",P);
  if (par_perm!=NULL) for(i=0;i<P;i++) Print("%d -> %d ",i,par_perm[i]);
  PrintS("\n");
#endif

  void *data=w->Data();
  res->rtyp = w->rtyp;
  switch (w->rtyp)
  {
    case NUMBER_CMD:
      if (P!=0)
      {
// poly n_PermNumber(const number z, const int *par_perm, const int OldPar, const ring src, const ring dst);
        res->data= (void *) n_PermNumber((number)data, par_perm, P, preimage_r, currRing);
        res->rtyp=POLY_CMD;
        if (nCoeff_is_algExt(currRing->cf))
          res->data=(void *)p_MinPolyNormalize((poly)res->data, currRing);
        pTest((poly) res->data);
      }