message: Do not get an FESpace from a nullptr
diff: @@ -153,7 +153,7 @@ int main(int argc, char *argv[])
  ParGridFunction *u_gf = nullptr;
  ParGridFunction *p_gf = nullptr;
  - ParGridFunction p_ex_gf(p_gf->ParFESpace());
  + ParGridFunction p_ex_gf(flowsolver.GetCurrentPressure()->ParFESpace());
  GridFunctionCoefficient p_ex_gf_coeff(&p_ex_gf);
  for (int step = 0; !last_step; ++step)
  