message: Write intermediate gf only when visualization = true
diff: @@ -272,6 +272,7 @@ int main(int argc, char *argv[])
  // TODO: Need the radius of the smallest circle that encompasses
  // the element, which this method does not quite provide.
  +
  double hmin;
  if (cfl > 0)
  {
  @@ -312,6 +313,8 @@ int main(int argc, char *argv[])
  {
  cout << "time step: " << ti << ", time: " << t << endl;
  + if (visualization)
  + {
  // Write out the grid function, since GLvis cannot yet
  // visualize vector grid functions over the socket.
  ofstream osol(string("vortex-") + to_string(ti) + string(".gf"));
  @@ -319,6 +322,7 @@ int main(int argc, char *argv[])
  u.Save(osol);
  }
  }
  + }
  // 9. Save the final solution. This output can be viewed later using GLVis:
  // "glvis -m vortex.mesh -g vortex-final.gf -gc 1".
  