How to Use Flux with PBS via Display Manager?

Introduction

Flux offered the possibility to use PBS Professional Compute Manager to compute distributed jobs.

With Flux, the possibility to post-process the solved projects located on your cluster is now available through Display Manager.

The integration of Flux enables you to open your solved projects to compute and display isovalues, isolines or arrows as usually. So, you won’t have to download those projects, potentially huge, to post-process on your local machine.

Other post-processing can also be computed as forces or flux computations. However, we recommend to not use it for heavy computations. If so, please refer to the section General access to Display Manager.

To get this feature, the administrator or IT of the cluster must install Flux 2019 (or newer) and then add the appDef directory of Flux-GUI. The appDef is located in the directory $INSTALLFLUX/Api/PBS, with $INSTALLFLUX the directory where Flux is install. The default install directory is /opt/altair/flux/Flux/.

Access from the Display Manager

You can access the Display Manager through any web browser with the next URL: <PBS_SERVER>/pbswork/. In the list of applications, the application Flux-GUI should be available as in the figure below:

Double-clicking Flux-GUI icon allows you to choose the version and application type to open thanks to the drop menu, as shown below:

Once your choice is selected, Flux will be run using the default configuration allocating:
  • One core
  • the RAM
    • 4 GB of Numerical memory (used for computations)
    • 1 GB of GUI memory (used for graphical display)

These default settings should be sufficient for small to medium sized 3D projects. To customize the other default settings, please refer to the next section General access to Display Manager.

General access to Display Manager

This section aims to show how to create and access a Display Manager session with user-defined settings. This is mandatory when the default settings do not satisfy one needs.

To change the default settings, first, go to the Compute Manager and select the Job Submission page. In the list of applications, the application Flux-GUI should be available. Select the application and the page below should be displayed:

Next, set the desired settings. Here we want to open Flux2D projects with a larger amount of memory. Once the memory is defined, click on the Submit button and the id of the created job should appear in a pop-up. Finally, go into the Monitoring page, select the job with the right id (here it is "13501") and click on the Connect button to access the session:

It will redirect you to the Display Manager page with your session. If the created job is not showing, please ensure that the filters (on the left panel with the checkboxes) are correctly set.

Once you are in the user-defined session, you can navigate on your cluster and open your projects as usual. Usually, the projects solved through the Compute Manager can be found in the stage directory (here, /stage/<yourname>).

For example, the 2D project below was solved using the parametric distribution and the Display Manager is used to study isolines on multiple steps:

Important: Please note that once a session has been created, its settings cannot be modified. Another session with the new settings will have to be created. Thus, it implies that one session is dedicated to one type of application, i.e. in the same session, Flux will be only able to open projects of the same type of application (2D, 3D, Skew or PEEC).