gb_insert()

void GBinhom_comp::gb_insert ( gbvector * f, gbvector * fsyz, int minlevel )

private

Definition at line 618 of file gb-sugarless.cpp.

{
  monomial f_m = M->make_one();
  minlevel = (minlevel == 0 ? MINGB_MASK : MINGEN_MASK | MINGB_MASK);
  gb_elem *p = new gb_elem(f, fsyz, minlevel);
  p->me = last_gb_num++;
  p->lead_exp = newarray_atomic(int, M->n_vars());
 
  GR->gbvector_get_lead_monomial(F, p->f, f_m);
  GR->gbvector_remove_content(p->f, p->fsyz);
 
  M->to_expvector(f_m, p->lead_exp);
  if (M->in_subring(1, f_m)) n_subring++;
 
  // Next determine the new s pairs.  This also deletes unneeded pairs
  find_pairs(p);
 
  // Insert into the Groebner basis
  minimal_gb_valid = false;
  gb_elem *q = gbLarge;
  gb_elem *prevmin = gb;
  for (;;)
    {
      if (q->next == nullptr || compare(p, q->next) == LT)
        {
          p->next = q->next;
          q->next = p;
          n_gb++;
          // Now place into the minimal list as well
          p->next_min = prevmin->next_min;
          prevmin->next_min = p;
          break;
        }
      else if (q->next->is_min & MINGB_MASK)
        prevmin = q->next;
      q = q->next;
    }
 
  M->remove(f_m);
 
  // At this point 'p' has been inserted.  Now we need to remove the
  // non-minimal elements.
  q = p;
  while (q->next_min != nullptr)
    // MES: this loop would be a good place to put in auto-reduction?
    if (p->f->comp == q->next_min->f->comp &&
        M->divides(p->f->monom, q->next_min->f->monom))
      {
        gb_elem *tmp = q->next_min;
        q->next_min = tmp->next_min;
        tmp->next_min = nullptr;
        tmp->is_min ^= MINGB_MASK;  // I.e. not in the minimal GB
        n_gb--;
      }
    else
      q = q->next_min;
}

References gbvector::comp, compare(), F, gb_elem::f, find_pairs(), gb, gbLarge, GR, gb_elem::is_min, last_gb_num, LT, M, MINGB_MASK, MINGEN_MASK, minimal_gb_valid, gbvector::monom, monomial, n_gb, n_subring, newarray_atomic, gb_elem::next, gb_elem::next_min, and p.

Referenced by s_pair_step().