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<p>我尝试在scikit learn中使用gradientboostingclasifier,它可以很好地使用默认参数。但是,当我试图用另一个分类器替换BaseEstimator时,它不起作用,并给了我以下错误</p>
<pre><code>return y - np.nan_to_num(np.exp(pred[:, k] -
IndexError: too many indices
</code></pre>
<p>你有这个问题的解决办法吗。</p>
<p>可以使用以下代码段重新生成此错误:</p>
<pre><code>import numpy as np
from sklearn import <a href="https://www.cnpython.com/pypi/dataset" class="inner-link">dataset</a>s
from sklearn.ensemble import GradientBoostingClassifier
from sklearn.linear_model import LogisticRegression
from sklearn.utils import shuffle
mnist = datasets.fetch_mldata('MNIST original')
X, y = shuffle(mnist.data, mnist.target, random_state=13)
X = X.astype(np.float32)
offset = int(X.shape[0] * 0.01)
X_train, y_train = X[:offset], y[:offset]
X_test, y_test = X[offset:], y[offset:]
### works fine when init is None
clf_init = None
print 'Train with clf_init = None'
clf = GradientBoostingClassifier( (loss='deviance', learning_rate=0.1,
n_estimators=5, subsample=0.3,
min_samples_split=2,
min_samples_leaf=1,
max_depth=3,
init=clf_init,
random_state=None,
max_features=None,
verbose=2,
learn_rate=None)
clf.fit(X_train, y_train)
print 'Train with clf_init = None is done :-)'
print 'Train LogisticRegression()'
clf_init = LogisticRegression();
clf_init.fit(X_train, y_train);
print 'Train LogisticRegression() is done'
print 'Train with clf_init = LogisticRegression()'
clf = GradientBoostingClassifier(loss='deviance', learning_rate=0.1,
n_estimators=5, subsample=0.3,
min_samples_split=2,
min_samples_leaf=1,
max_depth=3,
init=clf_init,
random_state=None,
max_features=None,
verbose=2,
learn_rate=None)
clf.fit(X_train, y_train) # <------ ERROR!!!!
print 'Train with clf_init = LogisticRegression() is done'
</code></pre>
<p>以下是错误的完整回溯:</p>
<pre><code>Traceback (most recent call last):
File "/home/mohsena/Dropbox/programing/gbm/gb_with_init.py", line 56, in <module>
clf.fit(X_train, y_train)
File "/usr/local/lib/python2.7/dist-packages/sklearn/ensemble/gradient_boosting.py", line 862, in fit
return super(GradientBoostingClassifier, self).fit(X, y)
File "/usr/local/lib/python2.7/dist-packages/sklearn/ensemble/gradient_boosting.py", line 614, in fit random_state)
File "/usr/local/lib/python2.7/dist-packages/sklearn/ensemble/gradient_boosting.py", line 475, in _fit_stage
residual = loss.negative_gradient(y, y_pred, k=k)
File "/usr/local/lib/python2.7/dist-packages/sklearn/ensemble/gradient_boosting.py", line 404, in negative_gradient
return y - np.nan_to_num(np.exp(pred[:, k] -
IndexError: too many indices
</code></pre>