find_divisors()

int MonomialTable::find_divisors	(	int	max,
		exponents_t	exp,
		int	comp,
		VECTOR(mon_term *) *	result = nullptr )

Definition at line 152 of file montable.cpp.

{
  assert(comp >= 1);
  assert(max != 0);
  if (comp >= static_cast<int>(_head.size())) return 0;
  if (max == 1 && comp == _last_match_comp && _last_match != nullptr &&
      exponents::divides(_nvars, _last_match->_lead, exp))
    {
      if (result != nullptr) result->push_back(_last_match);
      return 1;
    }
  mon_term *head = _head[comp];
  int nmatches = 0;
  unsigned long expmask = ~exponents::mask(_nvars, exp);
  //*DEBUG*/ long nviewed = 0;
  //*DEBUG*/ long nmasked = 0;
  for (mon_term *t = head->_next, *tnext = t->_next; t != head;
       t = tnext, tnext = t->_next)
    if ((expmask & t->_mask) == 0)
      {
        //*DEBUG*/   nviewed++;
        if (exponents::divides(_nvars, t->_lead, exp))
          {
            nmatches++;  // this doesn't happen very often
            _last_match = t;
            _last_match_comp = comp;
            // move_up(t,head);
            if (result != nullptr) result->push_back(t);
            if (max >= 0 && nmatches >= max) break;
          }
      }
  //*DEBUG*/    else
  //*DEBUG*/      nmasked++;
  //*DEBUG*/  fprintf(stderr, "nviewed %d nmasked %ld max %d nfound %ld\n",
  // nviewed, nmasked, max, nmatches);
  return nmatches;
}

References _last_match, _last_match_comp, MonomialTable::mon_term::_next, _nvars, ExponentVector< int, true >::divides(), max, and result().

Referenced by ReducedGB_Field_Local::find_good_divisor(), and gbA::minimalize_pairs_non_ZZ().