reduce3()

res2_pair * res2_comp::reduce3 ( res2term *& f, res2term *& fsyz, res2term *& pivot, res2_pair * p )

private

Definition at line 1308 of file res-a0.cpp.

{
  // 'lastterm' is used to append the next monomial to fsyz->syz
  exponents_t REDUCE_exp = ALLOCATE_EXPONENTS(exp_size);
  monomial REDUCE_mon = ALLOCATE_MONOMIAL(monom_size);
 
  res2term *lastterm = (fsyz->next == nullptr ? fsyz : fsyz->next);
  res2term head;
  res2term *red = &head;
  res2_pair *result = nullptr;
  res2_pair *q;
  ring_elem rg;
  respolyHeap fb(R);  // No bucket is needed for fsyz, since we
                      // only append elements to the end of fsyz.
  fb.add(f);
  f = nullptr;
  res2term *lead;
  //  Bag *b;
 
  int count = 0;
  if (M2_gbTrace >= 4) emit_wrapped(",");
 
  while ((lead = fb.remove_lead_term()) != nullptr)
    {
      M->divide(lead->monom, lead->comp->syz->monom, REDUCE_mon);
      M->to_expvector(REDUCE_mon, REDUCE_exp);
      if (find_ring_divisor(REDUCE_exp, rg))
        {
          // Subtract off f, leave fsyz alone
          Nterm *r = rg;
          M->divide(lead->monom, r->monom, REDUCE_mon);
          ring_elem c = K->negate(lead->coeff);
          res2term *h =
              R->ring_mult_by_term(r->next, c, REDUCE_mon, lead->comp);
          R->remove(lead);
          K->remove(c);
          fb.add(h);
          total_reduce_count++;
          count++;
        }
      else if (find_divisor(lead->comp->mi, REDUCE_exp, q))
        {
          // q = (res2_pair *) (b->basis_ptr());
          if (q->syz_type == SYZ2_S_PAIR || q->syz_type == SYZ2_MAYBE_MINIMAL)
            {
              if (result == nullptr)
                {
                  lastterm->next =
                      R->new_term(K->negate(lead->coeff), lead->monom, q);
                  lastterm = lastterm->next;
                  pivot = lastterm;
                  result = q;
                }
              red->next = lead;
              red = red->next;
              continue;
            }
          else
            {
              ring_elem c = K->negate(lead->coeff);
              M->divide(lead->monom, q->syz->monom, REDUCE_mon);
              res2term *h = R->mult_by_term(q->syz->next, c, REDUCE_mon);
              lastterm->next = R->new_term(c, lead->monom, q);
              lastterm = lastterm->next;
              R->remove(lead);
              fb.add(h);
              total_reduce_count++;
              count++;
            }
        }
      else
        {
          red->next = lead;
          red = red->next;
        }
    }
  red->next = nullptr;
  f = head.next;
  if (M2_gbTrace >= 4)
    {
      buffer o;
      o << count;
      emit_wrapped(o.str());
    }
  return result;
}

References geobucket< FREEMODULETYPE, VECTYPE >::add(), ALLOCATE_EXPONENTS, ALLOCATE_MONOMIAL, res2term::coeff, res2term::comp, emit_wrapped(), exp_size, find_divisor(), find_ring_divisor(), K, M, M2_gbTrace, res2_pair::mi, Nterm::monom, res2term::monom, monom_size, monomial, Nterm::next, res2term::next, R, geobucket< FREEMODULETYPE, VECTYPE >::remove_lead_term(), result(), buffer::str(), res2_pair::syz, SYZ2_MAYBE_MINIMAL, SYZ2_S_PAIR, res2_pair::syz_type, and total_reduce_count.

Referenced by handle_pair().