reduce()

Matrix * gbres_comp::reduce	(	const Matrix *	m,
		Matrix *&	lift )

Definition at line 239 of file res-a2.cpp.

{
  const FreeModule *F = nodes[0]->output_free_module();
  if (m->n_rows() != F->rank())
    {
      ERROR("expected matrices to have same number of rows");
      return nullptr;
    }
  MatrixConstructor mat_red(m->rows(), m->cols(), m->degree_shift());
  MatrixConstructor mat_lift(nodes[1]->output_free_module(), m->cols(), nullptr);
 
  for (int i = 0; i < m->n_cols(); i++)
    {
      const FreeModule *Fsyz = nodes[1]->output_free_module();
 
      ring_elem denom;
      gbvector *f = originalR->translate_gbvector_from_vec(F, (*m)[i], denom);
      gbvector *fsyz = GR->gbvector_zero();
 
      nodes[1]->reduce(f, fsyz);
 
      vec fv = originalR->translate_gbvector_to_vec_denom(F, f, denom);
      GR->get_flattened_coefficients()->negate_to(denom);
      vec fsyzv = originalR->translate_gbvector_to_vec_denom(Fsyz, fsyz, denom);
      mat_red.set_column(i, fv);
      mat_lift.set_column(i, fsyzv);
    }
  lift = mat_lift.to_matrix();
  return mat_red.to_matrix();
}

References Matrix::cols(), Matrix::degree_shift(), ERROR, GR, Matrix, Matrix::n_cols(), Matrix::n_rows(), nodes, originalR, FreeModule::rank(), Matrix::rows(), MatrixConstructor::set_column(), and MatrixConstructor::to_matrix().