find_good_monomial_divisor_ZZ()

int gbA::find_good_monomial_divisor_ZZ ( mpz_srcptr c, exponents_t e, int x, int degf, int & result_gap )

private

Definition at line 1606 of file gb-default.cpp.

{
  // Get all of the term divisors.
  // Choose one with the smallest gap.
  int i, gap, newgap, egap;
  int n = 0;
 
  (void) c;
  VECTOR(MonomialTableZZ::mon_term *) divisors;
  egap = degf - weightInfo_->exponents_weight(e, x);
 
  /* First search for ring divisors */
  if (ringtableZZ)
    n += ringtableZZ->find_monomial_divisors(-1, e, 1, &divisors);
 
  /* Next search for GB divisors */
  n += lookupZZ->find_monomial_divisors(-1, e, x, &divisors);
 
  /* Now find the minimal gap value */
  if (n == 0) return -1;
  int result = divisors[0]->_val;
  gbelem *tg = gb[result];
  gap = tg->gap - egap;
  if (gap <= 0)
    gap = 0;
  else
    for (i = 1; i < n; i++)
      {
        int new_val = divisors[i]->_val;
        tg = gb[new_val];
        newgap = tg->gap - egap;
        if (newgap <= 0)
          {
            gap = 0;
            result = new_val;
            break;
          }
        else if (newgap < gap)
          {
            result = new_val;
            gap = newgap;
          }
      }
  result_gap = gap;
  return result;
}

References gbA::gbelem::gap, gb(), lookupZZ, result(), ringtableZZ, VECTOR, weightInfo_, and x.

Referenced by remainder_ZZ(), and tail_remainder_ZZ().