[MRG] EXA Improve example plot_svm_anova.py #11731
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what if you keep the old data and just scale the features? |
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@agramfort |
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ok thanks for giving it a try.
I agree now that Iris is more adapted.
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Not sure whether it's appropriate to use cv=5 for the iris dataset since we do not have enough data. |
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Wondering if someone can review it. The original example is wrong IMO. |
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thanks @adrinjalali I agree that your version is better. |
examples/svm/plot_svm_anova.py
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| transform = SelectPercentile(chi2) | ||
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| clf = Pipeline([('anova', transform), ('svc', SVC(gamma="auto"))]) | ||
| clf = Pipeline([('anova', transform), |
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the transform variable is only used here, I guess we can remove it and have SelectPercentile(chi2) directly in the pipeline. The comment above the pipeline also needs to change accordingly.
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ping @jnothman @agramfort |
This reverts commit d8214fe.
This reverts commit d8214fe.
I think the example plot_svm_anova.py is not good. It claims that
This example shows how to perform univariate feature selection to improve the classification scores.However, with some non-informative features, we actually get the worst result when we select number of features equal to the original dataset. The reason is that the features in digits dataset are either 0 or 1, so it seems not reasonable to add non-informative features with np.random.random.Related comment #11588 (review)
In the new example, I use the iris dataset (4 features) and add 36 non-informative features. We can find that our model achieves best performance when we select around 10% of features.
Before the PR:
After the PR: