message: Update examples/ex26.cpp
diff: @@ -199,8 +199,10 @@ int main(int argc, char *argv[])
  // iterative solver.
  Array<int> ess_bdr(mesh->bdr_attributes.Max());
  ess_bdr = 1;
  +
  DiffusionMultigrid M(fespaces, ess_bdr);
  M.SetCycleType(Multigrid::CycleType::VCYCLE, 1, 1);
  +
  OperatorPtr A;
  Vector B, X;
  M.FormFineLinearSystem(x, *b, A, X, B);
  