AMReX-Astro / AMReX-Astro/Castro

Question About Subcycles

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C++
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Description

On a few of the science codes I've seen failure due to "Error: too many subcycles. !!!" For a couple of them I've simply added castro.max_subcycles=20 for example and that fixed the problem, but now I'm getting it on subchandra. I suppose this is a message related to convergence. I'm concerned that perhaps I'm doing something wrong.

My execution in my Slurm job looks like this

mpirun -n 64 Castro2d.gnu.MPI.SMPLSDC.ex inputs_2d.NSE
castro.max_subcycles=30
amr.plot_file=<project_folder>/subchandra/plt
amr.check_file=<project_folder>/subchandra/chk

Also I changed the tolerance for the tol_hse to 1.e-8 in the _prob_params file.

I guess I can increase the maximum subcycles and/or modify more tolerances, but before I waste a bunch of time I'm wondering if there is something else I should do.

I'm using Castro v26.07.

Thanks.

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Research direction

Start with the shown Slurm mpirun command, the subchandra case, and the Castro v26.07 version, then examine how the reported subcycle error relates to the changed tol_hse setting. Done means determining whether the failure needs a specific configuration change; the issue names no source file or test.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
hpc
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
25/100

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