Parametric sweep module

[bburke38]

Summary

New funtofem.sweep submodule: a reusable, callback-driven parameter sweep framework that replaces case-specific sweep scripts. Purely additive: everything lives in a new subpackage, and the only change to existing code is the export line in funtofem/__init__.py.

Marked experimental: the API may change without a deprecation cycle. Deliberately not re-exported into the top-level funtofem namespace. Users must import explicitly:

from funtofem.sweep import ParameterSweep

What's in it

• SweepStrategy ABC with CartesianStrategy (full product) and ZipStrategy (element-wise) built in; subclass for LHS/Sobol.
• MeshMode enum controls which mesh callbacks fire per design point (FULL_REGEN / CFD_ONLY / STRUCT_ONLY / NONE).
• ParameterSweep orchestrates the lifecycle: point enumeration, per-point directory isolation, mesh regeneration, model/solver construction, forward and adjoint solves, result extraction, and incremental CSV output. All set_* callbacks validate their signature at registration time and return self for chaining.
• SlurmSweepSubmitter generates and submits one SLURM job per design point, with dry_run and skip_completed modes. Jobs re-enter the user's script through the --point-file CLI path (cli_main → run_single).

Robustness

Per-point failures are caught and recorded as status = "failed" rather than aborting the sweep, and CSV rows are written incrementally so partial results survive an interruption. resume=True skips points already recorded as successful.

Output layout

Design keys default to a SHA-256 hash of the JSON-serialized point, truncated to pt_ + 12 hex chars, so key length is independent of parameter count. key_fn overrides this for readable keys on small sweeps.

cfd_root and struct_root share a <root>/<key>/<kind> template, so with the defaults everything for a design point lands in one directory:

sweep_output/<key>/point.json
sweep_output/<key>/cfd/
sweep_output/<key>/struct/

Setting them to different roots splits the two trees instead (e.g., for clusters where CFD output belongs on scratch while structural results stay on a backed-up filesystem).

Experimental marking

ParameterSweep and SlurmSweepSubmitter carry a .. warning:: **Experimental.** block at the top of their class docstrings, in the numpydoc slot after the short summary, so Sphinx renders it as a callout and it shows in help() and IDE hover.

Testing

tests/unit_tests/sweep/ — tests across six modules covering point execution, CSV writing, resume logic, the --point-file CLI, the SLURM submitter, and the per-point output layout. They import the sweep modules directly rather than through funtofem, so they run without native TACS or FUN3D.