Add stacking param tuning

[jrbourbeau]

Description

Currently the parameters in StackingClassifier, StackingCVClassifier, StackingRegressor, StackingCVRegressor, and EnsembleVoteClassifier can't be tuned in GridSearchCV. This PR fixes that bug.

Related issues or pull requests

Fixes #253

Pull Request requirements

• Added appropriate unit test functions in the ./mlxtend/*/tests directories
• Ran nosetests ./mlxtend -sv and make sure that all unit tests pass
• Checked the test coverage by running nosetests ./mlxtend --with-coverage
• Checked for style issues by running flake8 ./mlxtend
• Added a note about the modification or contribution to the ./docs/sources/CHANGELOG.md file
• Modify documentation in the appropriate location under mlxtend/docs/sources/ (optional)
• Checked that the Travis-CI build passed at https://travis-ci.org/rasbt/mlxtend

[pep8speaks]

Hello @jrbourbeau! Thanks for updating the PR.

Cheers ! There are no PEP8 issues in this Pull Request. 🍻

Comment last updated on September 20, 2017 at 03:24 Hours UTC

[coveralls]

Coverage increased (+0.03%) to 89.649% when pulling 67df542 on jrbourbeau:add_stacking_param_tuning into edb96f1 on rasbt:master.

[coveralls]

Coverage increased (+0.04%) to 89.657% when pulling 16c7772 on jrbourbeau:add_stacking_param_tuning into edb96f1 on rasbt:master.

[coveralls]

Coverage increased (+0.04%) to 89.657% when pulling 16c7772 on jrbourbeau:add_stacking_param_tuning into edb96f1 on rasbt:master.

[jrbourbeau]

@rasbt I think this PR might be good to go. Let me know if you see any issues!

Note: I didn't make any additions to the tests for StackingRegressor because there aren't any additional parameters other than verbose! But if there more parameters are added in the future, they should be able to work in GridSearchCV.

[rasbt]

Thanks a lot, I really appreciate that! The PR looks perfect, and I think that although StackingRegressor doesn't have any additional parameters, it's good to made the mod already (even though there's no unit test for that yes).

[jrbourbeau]

No problem, thanks for all your work on mlxtend!