make_monideal()

MonomialIdeal * Matrix::make_monideal	(	int	n,
		bool	use_only_monomials_with_unit_coeffs = false ) const

Definition at line 1925 of file matrix.cpp.

{
  const PolynomialRing *P = get_ring()->cast_to_PolynomialRing();
  if (P == nullptr)
    {
      ERROR("expected polynomial ring");
      return nullptr;
    }
  bool coeffsZZ = (P->coefficient_type() == Ring::COEFF_ZZ &&
                   use_only_monomials_with_unit_coeffs);
  const Monoid *M = P->getMonoid();
  VECTOR(Bag *) new_elems;
  for (int i = 0; i < n_cols(); i++)
    {
      vec v = elem(i);
      if (v == nullptr) continue;
      const vecterm *w = P->vec_locate_lead_term(rows(), v);
      if (w->comp != n) continue;
      if (coeffsZZ && !globalZZ->is_unit(P->lead_flat_coeff(w->coeff)))
        continue;
      Bag *b = new Bag(i);
      M->to_varpower(P->lead_flat_monomial(w->coeff), b->monom());
      new_elems.push_back(b);
    }
 
  // If the base ring is a quotient ring, include these lead monomials.
  for (int i = 0; i < P->n_quotients(); i++)
    {
      Nterm *f = P->quotient_element(i);
      if (coeffsZZ && !globalZZ->is_unit(f->coeff)) continue;
      Bag *b = new Bag(-1);
      M->to_varpower(f->monom, b->monom());
      new_elems.push_back(b);
    }
 
  // If the base ring has skew commuting variables, include their squares
  if (P->is_skew_commutative())
    {
      for (int i = 0; i < M->n_vars(); i++)
        if (P->is_skew_var(i))
          {
            Bag *b = new Bag(-1);
            varpower::var(i, 2, b->monom());
            new_elems.push_back(b);
          }
    }
 
  MonomialIdeal *result = new MonomialIdeal(P, new_elems);
  return result;
}

References Nterm::coeff, vec::coeff, Ring::COEFF_ZZ, PolynomialRing::coefficient_type(), vec::comp, elem(), ERROR, get_ring(), PolynomialRing::getMonoid(), globalZZ, PolynomialRing::is_skew_commutative(), PolynomialRing::is_skew_var(), PolynomialRing::lead_flat_coeff(), PolynomialRing::lead_flat_monomial(), make_monideal(), int_bag::monom(), Nterm::monom, n_cols(), PolynomialRing::n_quotients(), Monoid::n_vars(), PolynomialRing::quotient_element(), result(), rows(), Monoid::to_varpower(), ExponentList< int, true >::var(), PolynomialRing::vec_locate_lead_term(), and VECTOR.

Referenced by dimension1(), IM2_MonomialIdeal_make(), and make_monideal().