Thanks for the prompt reply. This is truly a great alternative. I have followed the instructions, and it worked for me by using -display frontend:10.0 option.
I understand that the Petsc graphic output is mainly for debugging (which should probably be done just on my laptop), but I guess it is helpful to have the functionale of dumping output on multiple processors, even just for a fun demo. Aron: In the original setup, my DISPLAY variable is set to $DISPLAY=localhost:0.0. This works indeed when I only use -np 1 (I guess it only start the work on the master node n0000). Cheers, Jianing > Different clusters have different 'scripts' for job submission. > So > you'll have to figureout how to 'sneak' in the ssh-x11 > connections in > here during the job startup. [i.e this not easy to automate] > > And then there are issues of x11 authentication & ssh > authentication > to worry about [if we are opening sockets connectins across > machines] > > However there is a simple alternative to get this working - it > the > following are true for your cluster: > - all compute-nodes share home filesystem with the frontend-node > [i.e > everyone can read the same ~/.Xauthority file for x11 > permissions] > - a willing sys-admin who can change sshd config on the > front-end. The > change is to add the following to /etc/ssh/sshd_config and > restart sshd > > >>> > X11UseLocalhost no > << > > With the above config - one can get X11 working as follows: > - compute nodes directly talk via x11 to the front-end > - the frontend forwards this x11 communication to the users > desktop > via ssh. > > i.e you would do the following: > - login to frontend node from your desktop with ssh-x11 [ssh -Y > frontend]. > - Check what the display is [echo $DISPLAY]. It should be > frontend:10.0 or something equivalent. > - Now run the PETSc executable with the option [-display > frontend:10.0] > > There might be some firewall issues that need to be taken canre > of > [the x11 connections from compute-nodes to front-end should not > be > blocked by the firewall] > > Satish > >