[MRG] add seeds when n_jobs=1 and use seed as random_state

[bryanyang0528]

Reference Issue

Fixes #9287, Fixes #9784

What does this implement/fix? Explain your changes.

no matter how many n_jobs, the random_state in kmeans_single should be the same.
So I added seeds = random_state.randint(np.iinfo(np.int32).max, size=n_init if n_jobs=1
and use seed instead original random_state in the for loop.

Any other comments?

I didn't revise test cases for this change yet. I'll update them if you think this change is good.

[jnothman]

This seems reasonable except insofar as KMeans with a fixed random state might have been returning the same model for a long time. I'm not sure it's worth breaking users' clusterings,

[lesteve]

You can move the seeds assignment outside of the if clause since it used both for n_job == 1 and n_jobs != 1.

[bryanyang0528]

@jnothman Even though creating seeds for n_jobs =1, seeds will be the same with the fixed random_state which might return the same model. But the model might be not the same as the model generated by the current method.

[amueller]

some duplication with #9785

[adrinjalali]

This looks good to me. It can take the test from the other PR and I'd say it's almost good to go.

@jnothman you still worried about backward compatibility here?

[amueller]

I think it's a good fix.

[adrinjalali]

@bryanyang0528 would you have time to address the comments, and rebase on the latest master here?

[bryanyang0528]

@adrinjalali no problem. Thanks!

[jnothman]

Any chance you can add a test?

[bryanyang0528]

@jnothman no problem.

[adrinjalali]

@bryanyang0528 tests failing :)

[bryanyang0528]

@adrinjalali I'm not sure why tests failed only on py35_conda_openblas and pylatest_conda_mkl_pandas. And No module named 'sklearn.__check_build._check_build' happened in circleci:doc. Are there any suggestions or hints for figuring out the issues?

p.s. I notice that recent PRs in sklearn are failed in these tests steps either.

[thomasjpfan]

Merge with master should fix the issue.

[adrinjalali]

@bryanyang0528 please avoid force pushing. The errors are not related to you, you can ignore the ones which fail to create the environment.

[adrinjalali]

or merge master as @thomasjpfan suggests.

[bryanyang0528]

@adrinjalali @thomasjpfan Thank you for suggestions.

[bryanyang0528]

@adrinjalali Thank you for help, all tests passed. What should I do for next step?

[adrinjalali]

This LGTM, ping @jnothman since I know he had some reservations about this solution. To me this is a fix, and therefore I wouldn't mind the change.

[amueller]

happy to wait for @jnothman but looks good to me.

[NicolasHug]

LGTM as a bug-fix, thanks @bryanyang0528

[jnothman]

I'm happy with the fix.

[jnothman]

I'm happy with the fix.
Please add an entry to the change log at doc/whats_new/v0.22.rst. Like the other entries there, please reference this pull request with :pr: and credit yourself (and other contributors if applicable) with :user:

Please also note the change at the top of that file under Changed Models

[amueller]

thanks!

[bryanyang0528]

Thanks!