direct_sum()

Matrix * Matrix::direct_sum

(

const Matrix *

m

)

const

const_monomial deg; if (EQ == R->degree_monoid()->compare(degree_shift(), m->degree_shift())) deg = degree_shift(); else deg = nullptr;

Definition at line 629 of file matrix.cpp.

{
  auto R = get_ring();
  if (R != m->get_ring())
    {
      ERROR("concat: different base rings");
      return nullptr;
    }
 
  // direct_sum ignores the degree shift of each summand.
 
  const FreeModule *F = rows()->direct_sum(m->rows());
  const FreeModule *G = cols()->direct_sum(m->cols());
 
  MatrixConstructor mat(F, G, nullptr);
 
  int i;
  int nr = n_rows();
  int nc = n_cols();
  for (i = 0; i < nc; i++) mat.set_column(i, R->copy_vec(elem(i)));
  for (i = 0; i < m->n_cols(); i++)
    mat.set_column(nc + i, R->component_shift(nr, m->elem(i)));
  return mat.to_matrix();
}

References cols(), direct_sum(), elem(), ERROR, FreeModule, G, get_ring(), Matrix(), MatrixConstructor, n_cols(), n_rows(), rows(), MatrixConstructor::set_column(), and MatrixConstructor::to_matrix().

Referenced by direct_sum().