We have detected a problem running Interactive graphics. We suspect that to correct the error we will have to update the grid slurm, which will take some time. However, we have an alternative solution that will allow you to use the grid interactively, until the problem is resolved.

## login with -X (or -Y):
ssh -X -l up201xxxxxx submit.grid.fe.up.pt
ou
ssh -X up201xxxxxx@submit.grid.fe.up.pt

## Execute salloc:
salloc bash -c 'ssh -Y $(scontrol show hostnames | head -n 1)'

## Once in the terminal:
module load ansys
fluent

#####
## More information at https://slurm.schedmd.com/salloc.html
## Extra options:
–mem
–mem-per-cpu
–partition
–nodes
–ntasks-per-node
…

## example:
salloc –nodes=2 –ntasks-per-node=2 bash -c 'ssh -Y $(scontrol show hostnames | head -n 1)'

It is possible to use graphical programs on the cluster. However, the speed of the interface will be very slow, their use is limited to interactive jobs (and so your workstation needs to maintain a connection to the cluster at all times) and requires several components:

1. Installation and configuration of a X11 server on your workstation
2. Configuring your SSH client
3. Running the qsub command with an extra argument

The X11 server is a piece of software which displays graphical interfaces, it also includes a protocol for rendering these interfaces across networks. It's normally already installed on Linux workstations, but Microsoft Windows and Mac OS X users will need to install one

The SSH client and qsub need to be called with arguments which tell them to forward a connection from the X11 server on your workstation to the cluster. It's over this connection that the graphical display will be transmitted. Unfortunately, because this connection has to travel over two hops (the SSH connection between your workstation and the submit host, and between the submit host and the cluster node) this usually makes the graphical interface very slow and difficult to use.

After describing how to install a X11 server and configure the SSH client to do X11 forwarding for Windows and Linux, we will show you how to forward X11 connections to the compute nodes using qsub.

You first need to download an X11 server. We recommend the free utility Xming (the latest version is