Function ksCreateShortSpoly

kernel/GBEngine/kspoly.cc:1447–1766

2 * creates the leading term of the S-polynomial of p1 and p2 * do not destroy p1 and p2 * remarks: * 1. the coefficient is 0 (p_Init) * 1. a) in the case of coefficient ring, the coefficient is calculated * 2. pNext is undefined */ static void bbb() { int i=0; }

*/
//static void bbb() { int i=0; }
poly ksCreateShortSpoly(poly p1, poly p2, ring tailRing)
{
  poly a1 = pNext(p1), a2 = pNext(p2);
#ifdef HAVE_SHIFTBBA
  int shift1, shift2;
  if (tailRing->isLPring)
  {
    // assume: LM is shifted, tail unshifted
    assume(p_FirstVblock(a1, tailRing) <= 1);
    assume(p_FirstVblock(a2, tailRing) <= 1);
    // save the shift of the LM so we can shift the other monomials on demand
    shift1 = p_mFirstVblock(p1, tailRing) - 1;
    shift2 = p_mFirstVblock(p2, tailRing) - 1;
  }
#endif
  long c1=p_GetComp(p1, currRing),c2=p_GetComp(p2, currRing);
  long c;
  poly m1,m2;
  number t1 = NULL,t2 = NULL;
  int cm,i;
  BOOLEAN equal;

  BOOLEAN is_Ring=rField_is_Ring(currRing);
  number lc1 = pGetCoeff(p1), lc2 = pGetCoeff(p2);
  if (is_Ring)
  {
    ksCheckCoeff(&lc1, &lc2, currRing->cf); // gcd and zero divisors
    if (a1 != NULL) t2 = nMult(pGetCoeff(a1),lc2);
    if (a2 != NULL) t1 = nMult(pGetCoeff(a2),lc1);
    while (a1 != NULL && nIsZero(t2))
    {
      pIter(a1);
      nDelete(&t2);
      if (a1 != NULL) t2 = nMult(pGetCoeff(a1),lc2);
    }
    while (a2 != NULL && nIsZero(t1))
    {
      pIter(a2);
      nDelete(&t1);
      if (a2 != NULL) t1 = nMult(pGetCoeff(a2),lc1);
    }
  }

#ifdef HAVE_SHIFTBBA
  // shift the next monomial on demand
  if (tailRing->isLPring)
  {
    a1 = p_LPCopyAndShiftLM(a1, shift1, tailRing);
    a2 = p_LPCopyAndShiftLM(a2, shift2, tailRing);
  }
#endif
  if (a1==NULL)
  {
    if(a2!=NULL)
    {
      m2=p_Init(currRing);
x2:
      for (i = (currRing->N); i; i--)