top_coefficients()

Matrix * Matrix::top_coefficients

(

Matrix *&

monoms

)

const

Definition at line 994 of file matrix.cpp.

{
  const PolynomialRing *R = get_ring()->cast_to_PolynomialRing();
  if (R == nullptr)
    {
      ERROR("expected polynomial ring");
      return nullptr;
    }
  MatrixConstructor result(rows(), 0);
  MatrixConstructor cons_monoms(R->make_FreeModule(1), 0);
  for (int i = 0; i < n_cols(); i++)
    {
      int var, exp;
      vec u = elem(i);
      vec v = R->vec_top_coefficient(u, var, exp);
      result.append(v);
      if (v == nullptr)
        cons_monoms.append(v);
      else
        {
          ring_elem b;
          if (var < R->n_vars())
            {
              ring_elem a = R->var(var);
              b = R->power(a, exp);
            }
          else
            {
              b = R->from_long(1);
            }
          vec w = R->make_vec(0, b);
          cons_monoms.append(w);
        }
    }
  monoms = cons_monoms.to_matrix();
  return result.to_matrix();
}

References MatrixConstructor::append(), elem(), ERROR, Ring::from_long(), get_ring(), Ring::make_FreeModule(), Ring::make_vec(), Matrix(), MatrixConstructor, n_cols(), Ring::power(), result(), rows(), MatrixConstructor::to_matrix(), top_coefficients(), PolynomialRing::var(), and PolynomialRing::vec_top_coefficient().

Referenced by rawTopCoefficients(), and top_coefficients().