NCCoefficientMatrix() [2/2]

Matrix * NCCoefficientMatrix	(	ModuleMonomialSet &	H,
		const Matrix *	M )

Definition at line 1639 of file matrix.cpp.

{
  const M2FreeAlgebraOrQuotient* Q = dynamic_cast<const M2FreeAlgebraOrQuotient*>(M->get_ring());
  if (Q == nullptr)
    {
      ERROR("expected NC polynomial algebra");
      return nullptr;
    }
 
  // should not get here unless 'M' is a matrix over a M2FreeAlgebraOrQuotient
 
  MatrixConstructor mat(Q->make_FreeModule(H.size()), M->cols());
  for (int c = 0; c < M->n_cols(); c++)
    {
      vec v = M->elem(c);
      for (; v != nullptr; v = v->next)
        {
          int comp = v->comp;
          auto f = Q->toPoly(v->coeff);
          for (auto i = f->cbegin(); i != f->cend(); ++i)
            {
              auto result = H.find(i.monom(), comp);
              if (result.second)
                {
                  ring_elem cf = Q->from_coefficient(i.coeff());
                  mat.set_entry(result.first, c, cf);
                }
            }
        }
    }
  return mat.to_matrix();
}

References Matrix::cols(), Matrix::elem(), ERROR, IntsSet< Configuration >::find(), M2FreeAlgebraOrQuotient::from_coefficient(), Matrix::get_ring(), Ring::make_FreeModule(), Matrix, Matrix::n_cols(), result(), MatrixConstructor::set_entry(), IntsSet< Configuration >::size(), MatrixConstructor::to_matrix(), and M2FreeAlgebraOrQuotient::toPoly().

Referenced by Matrix::coeffs().