Use Optuna v4 in Optuna Sweeper by himkt · Pull Request #3211 · facebookresearch/hydra

himkt · 2026-06-13T06:26:56Z

Motivation

Use a newer versions of Optuna (v4) to use new sampling algorithms and more latest APIs.

Have you read the Contributing Guidelines on pull requests?

Yes

For non-trivial features, API changes, or behavior changes: is there an issue or design discussion where maintainers agreed on the direction?

Behavior is not change from users' perspective. But this PR will let users install additional dependencies (cmaes, torch, and scipy). Would it be better to make them as optional dependencies?

Test Plan

Just run on a local environment and check the result on CI.

Related Issues and PRs

Modernize Optuna Sweeper #3210

I added my patch on #2995 by @michaelriedl to include his contributions on the update.

himkt · 2026-06-13T06:52:39Z

Successfully ran the example (https://hydra.cc/docs/plugins/optuna_sweeper/) on my local environment.

himkt · 2026-06-13T07:02:29Z

+        "cmaes>=0.12.0",  # Required for `optuna.samplers.CmaEsSampler`
+        "torch",  # Required for `optuna.samplers.GPSampler`
+        "scipy",  # Required for `optuna.samplers.GPSampler`


Not sure if it is acceptable to add them to requirements (it might be OK since it is a plugin, rather than hydra core itself?).

Give me more context here.
Is this optional for Optuna? which components wants those?
I strongly prefer not pull those in by default.

…na 4.x

himkt · 2026-06-13T09:33:46Z

  error
  ; SQLAlchemy imported by old Optuna on Python 3.12+
  ignore:datetime.datetime.utcfromtimestamp\(\) is deprecated.*:DeprecationWarning:sqlalchemy.sql.sqltypes
+  ; Optuna's sqlite connections are finalized by the GC; ignore the ResourceWarning so it isn't escalated to an unraisable error on Python 3.12+


Python 3.13+ started to warn when a connection to SQLite3 DB is not closed (🔗 lektor/lektor#1227, it is the issue of a third-party project though).

This potential problem already happens with old versions of Python and it might not be a critical immediately (https://docs.python.org/3.14/library/exceptions.html#ResourceWarning).

It is difficult to fix at this time, is it possible to add this warning filter for a workaround until a future upstream (Optuna-side) fix is introduced...?

https://github.com/facebookresearch/hydra/actions/runs/27461106520/job/81174946488

ok. can you check if some other ignores here can be removed?
The one with hydra changing working directory seems stale for sure.

himkt · 2026-06-13T09:35:22Z

@omry I think tests that I should make happy are now working well (with one concern #3211 (comment)).

Can I ask your review and opinion for the change?

omry · 2026-06-13T11:01:15Z

-    consider_prior: bool = True
-    prior_weight: float = 1.0
-    consider_magic_clip: bool = True
-    consider_endpoints: bool = False
    n_startup_trials: int = 10
    n_ei_candidates: int = 24
    multivariate: bool = False
-    warn_independent_sampling: bool = True


Can you explain the config changes?
those will change existing user configs so I want to make sure we are being deliberate.

omry · 2026-06-13T11:02:16Z

-    https://optuna.readthedocs.io/en/stable/reference/generated/optuna.samplers.MOTPESampler.html
+    https://optuna.readthedocs.io/en/stable/reference/samplers/generated/optuna.samplers.GPSampler.html


is this the same sampler just renamed, or are you changing the default sampler?

omry · 2026-06-13T11:04:21Z

+from optuna.exceptions import ExperimentalWarning
+
+warnings.filterwarnings("ignore", category=ExperimentalWarning)


why is the default example using experimental features?

omry · 2026-06-13T11:11:14Z

+
+### API Change (Renames, deprecations and removals)
+
+- Removed the `consider_prior`, `prior_weight`, `consider_magic_clip`, `consider_endpoints`, and `warn_independent_sampling` options from the TPE sampler config, as they are deprecated in Optuna 4.x


if they are just deprecated, we should not remove them but deprecate them.
What are users supposed to use instead?

This is might be an opportunity to try oc.deprecated. But I think its only a fit if we have another key to point people at.

omry · 2026-06-13T11:12:11Z

+- Removed MOTPESampler support, as it has been removed in Optuna 4.x
+


Gotcha. this is a big change.
Maybe we should try to detect people trying to use the old one and give them a better error than "Not found".

omry · 2026-06-13T11:13:33Z

+        "cmaes>=0.12.0",  # Required for `optuna.samplers.CmaEsSampler`
+        "torch",  # Required for `optuna.samplers.GPSampler`
+        "scipy",  # Required for `optuna.samplers.GPSampler`


Give me more context here.
Is this optional for Optuna? which components wants those?
I strongly prefer not pull those in by default.

omry · 2026-06-13T11:14:48Z

+### Experimental Samplers
+
+GASampler and QMCSampler are experimental features in Optuna.
+When you use these samplers, you might want to suppress the warnings from Optuna.
+You can do this by adding the following code to your script:
+
+```python
+import warnings
+from optuna.exceptions import ExperimentalWarning
+
+warnings.filterwarnings("ignore", category=ExperimentalWarning)
+```
+


It would be better if we default to the non experimental sampler.
documented workaround for experimental is probably not the business of the plugin (unless to chooses to make experimental the default)

omry · 2026-06-13T11:18:35Z

  error
  ; SQLAlchemy imported by old Optuna on Python 3.12+
  ignore:datetime.datetime.utcfromtimestamp\(\) is deprecated.*:DeprecationWarning:sqlalchemy.sql.sqltypes
+  ; Optuna's sqlite connections are finalized by the GC; ignore the ResourceWarning so it isn't escalated to an unraisable error on Python 3.12+


ok. can you check if some other ignores here can be removed?
The one with hydra changing working directory seems stale for sure.

michaelriedl and others added 9 commits February 4, 2025 20:06

Changes necessary to use the newest version of Optuna

8563bb7

Updated README

837f3b8

Updated docs and version

05049d7

Added requested comments

90701fb

Added requested comments

e012c26

chore: require optuna 4.7.0 or later

19c097d

chore: add QMCSampler

93901e1

chore: add missing args to GPSampler

8945b58

chore: add cmaes since it is needed CmaEsSampler

1b68f3d

meta-cla Bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Jun 13, 2026

himkt added 2 commits June 13, 2026 15:27

chore: add upper bound of Optuna

2681f00

Merge branch 'main' into optuna-v4

bb73090

himkt marked this pull request as ready for review June 13, 2026 06:52

fix: isort .

c9a7209

himkt commented Jun 13, 2026

View reviewed changes

himkt added 4 commits June 13, 2026 16:09

chore: update docs about ExperimentalWarning

678f627

fix: drop deprecated TPESampler args and remove MOTPESampler for Optu…

7f3cb76

…na 4.x

fix: ignore Optuna sqlite unraisable ResourceWarning on Python 3.12+

ece772e

fix: narrow Optuna sqlite ResourceWarning ignore to the source warning

3263e1b

himkt commented Jun 13, 2026

View reviewed changes

himkt changed the title ~~(WIP) Use Optuna v4 in Optuna Sweeper~~ Use Optuna v4 in Optuna Sweeper Jun 13, 2026

omry reviewed Jun 13, 2026

View reviewed changes

		https://optuna.readthedocs.io/en/stable/reference/generated/optuna.samplers.MOTPESampler.html
		https://optuna.readthedocs.io/en/stable/reference/samplers/generated/optuna.samplers.GPSampler.html

		from optuna.exceptions import ExperimentalWarning

		warnings.filterwarnings("ignore", category=ExperimentalWarning)


		### API Change (Renames, deprecations and removals)

		- Removed the `consider_prior`, `prior_weight`, `consider_magic_clip`, `consider_endpoints`, and `warn_independent_sampling` options from the TPE sampler config, as they are deprecated in Optuna 4.x

		- Removed MOTPESampler support, as it has been removed in Optuna 4.x

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himkt commented Jun 13, 2026

Motivation

Have you read the Contributing Guidelines on pull requests?

For non-trivial features, API changes, or behavior changes: is there an issue or design discussion where maintainers agreed on the direction?

Test Plan

Related Issues and PRs

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himkt commented Jun 13, 2026

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himkt commented Jun 13, 2026

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