/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/q2_feature_classifier/classifier.py:101: UserWarning: The TaxonomicClassifier artifact that results from this method was trained using scikit-learn version 0.20.2. It cannot be used with other versions of scikit-learn. (While the classifier may complete successfully, the results will be unreliable.)
  warnings.warn(warning, UserWarning)
Traceback (most recent call last):
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/q2cli/commands.py", line 311, in __call__
    results = action(**arguments)
  File "</home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/decorator.py:decorator-gen-349>", line 2, in fit_classifier_naive_bayes
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/qiime2/sdk/action.py", line 231, in bound_callable
    output_types, provenance)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/qiime2/sdk/action.py", line 365, in _callable_executor_
    output_views = self._callable(**view_args)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/q2_feature_classifier/classifier.py", line 318, in generic_fitter
    pipeline)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/q2_feature_classifier/_skl.py", line 32, in fit_pipeline
    pipeline.fit(X, y)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/sklearn/pipeline.py", line 267, in fit
    self._final_estimator.fit(Xt, y, **fit_params)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/q2_feature_classifier/custom.py", line 41, in fit
    classes=classes)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/sklearn/naive_bayes.py", line 555, in partial_fit
    self._count(X, Y)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/sklearn/naive_bayes.py", line 715, in _count
    self.feature_count_ += safe_sparse_dot(Y.T, X)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/sklearn/utils/extmath.py", line 168, in safe_sparse_dot
    ret = a * b
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/scipy/sparse/base.py", line 552, in __rmul__
    return (self.transpose() * tr).transpose()
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/scipy/sparse/base.py", line 473, in __mul__
    return self._mul_multivector(other)
  File "/home/qiime2/miniconda/envs/qiime2-2019.4/lib/python3.6/site-packages/scipy/sparse/compressed.py", line 477, in _mul_multivector
    dtype=upcast_char(self.dtype.char, other.dtype.char))
MemoryError