Function pSubstPar

Singular/maps_ip.cc:265–379

2 * substitutes the parameter par (from 1..N) by image, * does not destroy p and image */

* does not destroy p and  image
*/
poly pSubstPar(poly p, int par, poly image)
{
  const ring R = currRing->cf->extRing;
  ideal theMapI = idInit(rPar(currRing),1);
  nMapFunc nMap = n_SetMap(R->cf, currRing->cf);
  int i;
  for(i = rPar(currRing);i>0;i--)
  {
    if (i != par)
      theMapI->m[i-1]= p_NSet(n_Param(i, currRing), currRing);
    else
      theMapI->m[i-1] = p_Copy(image, currRing);
    p_Test(theMapI->m[i-1],currRing);
  }
  //iiWriteMatrix((matrix)theMapI,"map:",1,currRing,0);

  map theMap=(map)theMapI;
  theMap->preimage=NULL;

  leftv v=(leftv)omAllocBin(sleftv_bin);
  sleftv tmpW;
  poly res=NULL;

  p_Normalize(p,currRing);
  if (currRing->cf->rep==n_rep_rat_fct )
  {
    while (p!=NULL)
    {
      memset(v,0,sizeof(sleftv));

      number d = n_GetDenom(pGetCoeff(p), currRing->cf);
      p_Test((poly)NUM((fraction)d), R);

      if ( n_IsOne (d, currRing->cf) )
      {
        n_Delete(&d, currRing->cf); d = NULL;
      }
      else if (!p_IsConstant((poly)NUM((fraction)d), R))
      {
        WarnS("ignoring denominators of coefficients...");
        n_Delete(&d, currRing->cf); d = NULL;
      }

      number num = n_GetNumerator(pGetCoeff(p), currRing->cf);
      memset(&tmpW,0,sizeof(sleftv));
      tmpW.rtyp = POLY_CMD;
      p_Test((poly)NUM((fraction)num), R);

      tmpW.data = NUM ((fraction)num); // a copy of this poly will be used

      p_Normalize(NUM((fraction)num),R);
      if (maApplyFetch(MAP_CMD,theMap,v,&tmpW,R,NULL,NULL,0,nMap))
      {
        WerrorS("map failed");
        v->data=NULL;
      }
      n_Delete(&num, currRing->cf);
      //TODO check for memory leaks