"eli5.show_weights"显示的标准偏差与"feature_importances_std_"中的值不一致 [英] `eli5.show_weights` displayed standard deviation does not agree with the values in `feature_importances_std_`

问题描述

PermutationImportance对象具有一些不错的属性，例如feature_importances_和feature_importances_std_.

The PermutationImportance object has some nice attributes such as feature_importances_ and feature_importances_std_.

为了以HTML样式可视化此属性，我使用了eli5.show_weights函数.但是，我注意到显示的标准偏差与feature_importances_std_中的值不一致.

To visualize in an HTML style this attributes I used eli5.show_weights function. However, I noticed that the displayed standard deviation does not agree with the values in feature_importances_std_.

更具体地说，我可以看到显示的HTML值等于feature_importances_std_ * 2.为什么会这样?

代码:

from sklearn import datasets
import eli5
from eli5.sklearn import PermutationImportance
from sklearn.svm import SVC, SVR

# import some data to play with
iris = datasets.load_iris()
X = iris.data[:, :2]  # we only take the first two features.
y = iris.target

clf = SVC()
perms = PermutationImportance(clf, n_iter=1000, cv=10, random_state=0).fit(X, y)

print(perms.feature_importances_)
# this is the actual SD
print(perms.feature_importances_std_)
# These are the displayed values
print(perms.feature_importances_std_* 2)

[0.39527333 0.17178   ] # the actual mean
[0.13927548 0.11061278] # the actual SD
[0.27855095 0.22122556] # the displayed values by `show_weights()`

eli5.show_weights(perms)

我们可以看到显示的标准偏差成倍增加，即2 * perms.feature_importances_std_.

We can see that the diplayed standard deviation is doupled i.e. 2 * perms.feature_importances_std_.

这可能是错误吗?

推荐答案

找到了*2:
在模板中，该页面将在下一页中生成功能重要性html表

Found the *2 :
It's in the template generating the feature importances html table in the following page

https://github.com/TeamHG -Memex/eli5/blob/63e99182dc682bbf225355c80a24807396a747b6/eli5/templates/feature_importances.html

        {% if not fw.std is none %}
            ± {{ "%0.4f"|format(2 * fw.std) }}
        {% endif %}

显然是手工放置的

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