Function ksReducePoly

kernel/GBEngine/kspoly.cc:187–341

#endif

int ksReducePoly(LObject* PR,
                 TObject* PW,
                 poly spNoether,
                 number *coef,
                 poly *mon,
                 kStrategy strat,
                 BOOLEAN reduce)
{
#ifdef KDEBUG
  red_count++;
#ifdef TEST_OPT_DEBUG_RED
//  if (TEST_OPT_DEBUG)
//  {
//    Print("Red %d:", red_count); PR->wrp(); Print(" with:");
//    PW->wrp();
//    //printf("\necart(PR)-ecart(PW): %i\n",PR->ecart-PW->ecart);
//    //pWrite(PR->p);
//  }
#endif
#endif
  int ret = 0;
  ring tailRing = PR->tailRing;
  if (strat!=NULL)
  {
    kTest_L(PR,strat);
    kTest_T(PW,strat);
  }

  poly p1 = PR->GetLmTailRing();   // p2 | p1
  poly p2 = PW->GetLmTailRing();   // i.e. will reduce p1 with p2; lm = LT(p1) / LM(p2)
  poly t2 = pNext(p2), lm = p1;    // t2 = p2 - LT(p2); really compute P = LC(p2)*p1 - LT(p1)/LM(p2)*p2
  assume(p1 != NULL && p2 != NULL);// Attention, we have rings and there LC(p2) and LC(p1) are special
  p_CheckPolyRing(p1, tailRing);
  p_CheckPolyRing(p2, tailRing);

  pAssume1(p2 != NULL && p1 != NULL &&
           p_DivisibleBy(p2,  p1, tailRing));

  pAssume1(p_GetComp(p1, tailRing) == p_GetComp(p2, tailRing) ||
           (p_GetComp(p2, tailRing) == 0 &&
            p_MaxComp(pNext(p2),tailRing) == 0));

#ifdef HAVE_PLURAL
  if (rIsPluralRing(currRing))
  {
    // for the time being: we know currRing==strat->tailRing
    // no exp-bound checking needed
    // (only needed if exp-bound(tailring)<exp-b(currRing))
    if (PR->bucket!=NULL)  nc_kBucketPolyRed_Z(PR->bucket, p2,coef,reduce);
    else
    {
      poly _p = (PR->t_p != NULL ? PR->t_p : PR->p);
      assume(_p != NULL);
      nc_PolyPolyRed(_p, p2,coef, currRing);
      if (PR->t_p!=NULL) PR->t_p=_p; else PR->p=_p;
      PR->pLength=0; // usually not used, GetpLength re-computes it if needed
    }
    return 0;