Tip of the Month 25.08 - Ascent visualization tip

[jmusser]

Ascent allows you to set up multiple renders of the same scene, which can be useful for comparing different views.

This feature is only available if mfix is compiled with the Ascent and Conduit libraries. A few examples of building these tools on several high-performance systems are provided in the MFIX-Exa documentation.

We’ve observed that sometimes simulations appear to hang when multiple renders are used. To avoid this issue, we recommend configuring your YAML files to use only one render per scene.

Attached is a complete YAML file that you can run with benchmarks/01-HCS/Size0001 by including the following keywords in the inputs file.

mfix.ascent_int = 10
ascent.actions = ascent_actions.yaml

Key elements in the YAML file:

1. pipelines - Define the fluid and particle data to visualize:
   • We construct a fluid velocity vector field (vel_g) from the components u_g, v_g, and w_g, and compute its magnitude (vel_g_mag).
   • For particles, we build a velocity vector (V) from velx, vely, and velz, and compute the magnitude (vel).
2. scenes – Specify what to visualize and how:
   • plots – Select the data to display
     • p1: fluid velocity magnitude
     • p2: particle velocity magnitude
   • renders – Define camera views:
     • r1: isometric view
     • r2: isometric view, zoomed out

Avoid combining multiple renders (e.g., r1 and r2) under the same scene. Instead, define two separate scenes, each with a single render. This approach improves stability and prevents simulation hangs.

Example output from attached actions file

• Left: output of r1 - an isometric view of fluid slices and particles
• Left: output of r2 - same view as r1 but further aways

[Doug]

The ascent yaml file seems to be missing.

[jmusser]

I updated the post to include the correct link.
Thanks – JM