Function redRing_S

kernel/GBEngine/kstd2.cc:1047–1100

}

static int redRing_S (LObject* h,kStrategy strat)
{
  if (strat->sl<0) return 1;
  if (h->IsNull()) return 0; // spoly is zero (can only occur with zero divisors)

  int j = 0;
  int pass = 0;
  // poly zeroPoly = NULL;

  h->SetpFDeg();
  assume(h->pFDeg() == h->FDeg);
  int max_ind;

  h->SetShortExpVector();
  loop
  {
    max_ind=strat->sl;
    j = kFindDivisibleByInS(strat, &max_ind, h);
    if (j < 0)
    {
      // over ZZ: cleanup coefficients by complete reduction with monomials
      postReduceByMon(h, strat);
      if(h->p == NULL)
      {
        h->Clear();
        return 0;
      }
      if(nIsZero(pGetCoeff(h->p))) return 2;
      max_ind=strat->sl;
      j = kFindDivisibleByInS(strat, &max_ind,h);
      if(j < 0)
      {
        if (h->GetLmTailRing() == NULL)
        {
          h->Clear();
          return 0;
        }
        return 1;
      }
    }
    //printf("\nFound one: ");pWrite(strat->T[j].p);
    //enterT(*h, strat);
    TObject tj(strat->S[j]);
    ksReducePoly(h, &tj, NULL, NULL, NULL, strat); // with debug output
    //printf("\nAfter small red: ");pWrite(h->p);
    if (h->GetLmTailRing() == NULL)
    {
      h->Clear();
      return 0;
    }
    h->SetShortExpVector();
    /*- try to reduce the s-polynomial -*/
    pass++;
  }
}

/*2