Contour presenting rendering artifacts, as the number of ranks increases

[mvictoras]

We have instrumented NekRS with ASCENT, and found that as the number of ranks increases, so are various rendering artifacts. Is this expected behavior?

We are on v0.8.0.

My ascent_actions.yaml:

-
  action: "add_pipelines"
  pipelines:
    pl1:
      f3:
        type: "contour"
        params:
          field: "temperature"
          iso_values: [40, 50, 60]
-
  action: "add_scenes"
  scenes:
    s1:
      plots:
        p1:
          type: "pseudocolor"
          field: "pressure"
          pipeline: "pl1"
      renders:
        r1:
          camera:
            position: [-30.32, -30.99, 34.63]
            look_at: [-0.006, -0.006, 0.932]
            up: [0.146, 0.659, 0.737]
            zoom: 2.0
          image_prefix: "pb_%04d"

Resulting images:

4 ranks:

40 ranks:

[cyrush]

@mvictoras -- does the simulations have embedded ghost or halo zones?

If so, we need to make sure to provide a field that identifies those so Ascent can handle them properly.

By default, ascent will look for an element-associated field named ascent_ghosts. It will assume 0 == normal elements, 1 == ghost elements, other == garbage elements -- and will filter things out using this info.

[cyrush]

@mvictoras where you able to check if ghost zones help with this issue?

[mvictoras]

I apologize for the late response, I have been busy and did not.

This week I am at VIS, so I will probably get back to this in 1-2 weeks. Is 1 level of ghosts assumed, or can we increase it?

[cyrush]

@mvictoras no worries, enjoy VIS!

Ghosts are presented by the sim code itself, not generated in Ascent -- we can work out the details later.

[cyrush]

@mvictoras I believe we solved this mystery -- so I am closing the issue. Feel free to reopen or add a new ticket if we are still missing something.

[mvictoras]

Yes we did, I was able to pass them! Thanks for all the help.

[cyrush]

Awesome, thanks for confirming!