Prepartitioned grid import for massively parallel job - very slow time integration about gdtk HOT 2 CLOSED

Hi Manu,

It's good you started stepwise on your journey. Can I suggest a few more intermediate steps? For example 1M cells or 10M cells before in 3D before jumping to 150M. Perhaps just truncate your domain.

As for your specific import issue, there are two possible workflows with GridPro grids. I think you have mixed the two workflows.

1. Using GridPro grids in GridPro native format. There is an example in our collection that shows this approach. That is: gdtk/examples/eilmer/3D/gridpro-import. When you are using importGridproGrid() function call in your script, you are using this approach. This will read all elemental blocks from the original grid you built. You will need that same number of cores for your simulation.
2. Using GridPro grids in SU2 format. When we do this, we typically partition the SU2 grid using Metis. For this type of workflow, look at the example: gdtk/examples/eilmer/2D/sharp-cone-20-degrees/usg-su2

To answer your question about slow or not, I think you need to step up systematically in cell size to see if there's a scaling issue. It's hard for me to reason about an isolated 150M cell grid.

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Hi Rowan, thanks for your feedback.
There is a small correction to my previous comment : I meant to say that I am writing the grid out in format native to GridPro (.tmp), and not in SU2 format. My apologies for that. So no, I don't think I am mixing up the two workflows.

And as far as your suggestions on truncating the geometry is concerned : I shall try that. Perhaps I should also perform a test to see how the code scales.

Thanks again! I shall mark this issue as closed.

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