AMReX-Astro / AMReX-Astro/Microphysics

lower the default ode_max_steps

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integrator
Dominant language
C++
Stars
43
Forks
46
Avg merge
2d 18h
Merged PRs (30d)
15

Description

Right now, integrator.ode_max_steps = 150000 by default. This is very high, and if we need this many steps, we most likely have a problem (like a bad Jacobian). In many problems, lowering this to 10000 or so and then turning on integrator.use_burn_retry speeds up the execution a lot.

We should lower this default to something smaller like 25000. This will force retries (either at the burner or application code level) and should perform better on GPUs where the divergence in the number of steps different zones needs can be a big slowdown.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by locating the default assignment for integrator.ode_max_steps and the handling of integrator.use_burn_retry. Review nearby tests or configuration examples, then verify that the proposed lower default triggers the intended retry behavior without breaking existing cases; the issue does not name specific files or tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
performance
Issue type
Feature
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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