reduce()

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

private

Definition at line 1126 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);
 
  res2_pair *q;
  ring_elem rg;
  //  Bag *b;
 
  int count = 0;
  if (M2_gbTrace >= 4) emit_wrapped(",");
 
  while (f != nullptr)
    {
      M->divide(f->monom, f->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(f->monom, r->monom, REDUCE_mon);
          R->ring_subtract_multiple_to(f, f->coeff, REDUCE_mon, f->comp, rg);
          total_reduce_count++;
          count++;
        }
      //      else if (f->comp->mi.search_expvector(REDUCE_exp, b))
      else if (find_divisor(f->comp->mi, REDUCE_exp, q))
        {
          // q = (res2_pair *) (b->basis_ptr());
          lastterm->next = R->new_term(K->negate(f->coeff), f->monom, q);
          lastterm = lastterm->next;
          pivot = lastterm;
          if (q->syz_type == SYZ2_S_PAIR || q->syz_type == SYZ2_MAYBE_MINIMAL)
            {
              if (M2_gbTrace >= 4)
                {
                  buffer o;
                  o << count;
                  emit_wrapped(o.str());
                }
              return q;  // i.e. not computed yet
            }
          M->divide(f->monom, q->syz->monom, REDUCE_mon);
          R->subtract_multiple_to(f, f->coeff, REDUCE_mon, q->syz);
          total_reduce_count++;
          count++;
        }
      else
        {
          res2term *tmp = f;
          f = f->next;
          tmp->next = nullptr;
          R->remove(tmp);
        }
    }
  if (M2_gbTrace >= 4)
    {
      buffer o;
      o << count;
      emit_wrapped(o.str());
    }
  return nullptr;
}

References 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, res2term::next, R, buffer::str(), res2_pair::syz, SYZ2_MAYBE_MINIMAL, SYZ2_S_PAIR, res2_pair::syz_type, and total_reduce_count.

Referenced by handle_pair(), and handle_pair_by_level().