I'm trying to improve a perfectly working Bernoulli Naive Bayes model with bagging.
But when I try to cross-validate the BaggingClassifier
, I get a very unexpected ZeroDivisionError
coming from parallel.py.
I've tried to change all the parameters I know, rebooted python but nothing worked.
Here is a reproducible example with a binary-modified iris
dataset:
#%% run
import numpy as np
from sklearn.model_selection import GridSearchCV
from sklearn.ensemble import BaggingClassifier
from sklearn.naive_bayes import BernoulliNB
from sklearn.datasets import load_iris
data = load_iris()
data.targetbin = (data.target!=0).astype("int")
param_grid2={'max_samples' : np.linspace(0.5,1.0,3),
'base_estimator__alpha':np.linspace(0.1,1,3),
'base_estimator__binarize':[*np.linspace(0.0,1,3)],
'base_estimator__fit_prior':[True,False]}
param_grid2={'max_samples' :[0.7]}
clf = GridSearchCV(
BaggingClassifier(
BernoulliNB(),
n_estimators = 10, max_features = 0.5),
param_grid2,
scoring = "accuracy",
verbose=-1)
clf.fit(data.data, data.targetbin)
And here is the stacktrace of my error:
[Parallel(n_jobs=1)]: Using backend SequentialBackend with 1 concurrent workers. Traceback (most recent call last):
File "<ipython-input-1-dc4eaed2671b>", line 33, in <module>
clf.fit(data.data, data.targetbin)
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\model_selection\_search.py", line 722, in fit
self._run_search(evaluate_candidates)
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\model_selection\_search.py", line 1191, in _run_search
evaluate_candidates(ParameterGrid(self.param_grid))
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\model_selection\_search.py", line 711, in evaluate_candidates
cv.split(X, y, groups)))
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\externals\joblib\parallel.py", line 917, in __call__
if self.dispatch_one_batch(iterator):
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\externals\joblib\parallel.py", line 759, in dispatch_one_batch
self._dispatch(tasks)
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\externals\joblib\parallel.py", line 716, in _dispatch
job = self._backend.apply_async(batch, callback=cb)
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\externals\joblib\_parallel_backends.py", line 184, in apply_async
callback(result)
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\externals\joblib\parallel.py", line 306, in __call__
self.parallel.print_progress()
File "C:\Users\Dan\Anaconda3\lib\site-packages\sklearn\externals\joblib\parallel.py", line 806, in print_progress
if (is_last_item or cursor % frequency):
ZeroDivisionError: integer division or modulo by zero
What am I doing wrong?
I tried to debug the lib and found self.verbose
for sklearn/externals/joblib/parallel.py
is -1
, however it's supposed to be at least 0
by default. So I think it's a bug.