create() [1/3]

SchreyerOrder * SchreyerOrder::create ( const GBMatrix * m )

static

Definition at line 80 of file schorder.cpp.

{
#ifdef DEVELOPMENT
#warning "the logic in SchreyerOrder creation is WRONG!"
#endif
  int i;
  const FreeModule *F = m->get_free_module();
  const Ring *R = F->get_ring();
  const SchreyerOrder *S = F->get_schreyer_order();
  const PolynomialRing *P = R->cast_to_PolynomialRing();
  const Monoid *M = P->getMonoid();
  SchreyerOrder *result = new SchreyerOrder(M);
  int rk = INTSIZE(m->elems);
  if (rk == 0) return result;
 
  monomial base = M->make_one();
  int *tiebreaks = newarray_atomic(int, rk);
  int *ties = newarray_atomic(int, rk);
  for (i = 0; i < rk; i++)
    {
      gbvector *v = m->elems[i];
      if (v == nullptr || S == nullptr)
        tiebreaks[i] = i;
      else
        tiebreaks[i] = i + rk * S->compare_num(v->comp - 1);
    }
  // Now sort tiebreaks in increasing order.
  std::sort<int *>(tiebreaks, tiebreaks + rk);
  for (i = 0; i < rk; i++) ties[tiebreaks[i] % rk] = i;
  for (i = 0; i < rk; i++)
    {
      gbvector *v = m->elems[i];
      if (v == nullptr)
        M->one(base);
      else  // if (S == NULL)
        M->copy(v->monom, base);
#ifdef DEVELOPMENT
#warning "Schreyer unencoded case not handled here"
#endif
#if 0
//       else
//      M->mult(v->monom, S->base_monom(i), base);
#endif
      result->append(ties[i], base);
    }
 
  intern_SchreyerOrder(result);
  M->remove(base);
  freemem(tiebreaks);
  freemem(ties);
  return result;
}

References base, Ring::cast_to_PolynomialRing(), gbvector::comp, compare_num(), GBMatrix::elems, freemem(), GBMatrix::get_free_module(), FreeModule::get_ring(), FreeModule::get_schreyer_order(), PolynomialRing::getMonoid(), intern_SchreyerOrder(), INTSIZE, M, gbvector::monom, monomial, newarray_atomic, result(), and SchreyerOrder().