import sklearn.base
import scipy.sparse
import numpy as np

class DiaEstimator(sklearn.base.BaseEstimator):
    def __init__(self, p=None):
        self.p = p

    def transform(self, X, y=None):
        return X

    def fit(self, X, y=None):
        return self

M = scipy.sparse.csr_matrix(np.diag([1,2,3]))
e = DiaEstimator(p=M)
# works fine
sklearn.base.clone(e)

M = scipy.sparse.dia_matrix(np.diag([1,2,3]))
e = DiaEstimator(p=M)
# fails
sklearn.base.clone(e)

"""
Traceback (most recent call last):
  File "diabug.py", line 23, in <module>
    sklearn.base.clone(e)
  File "/Users/elawrence/anaconda/lib/python2.7/site-packages/sklearn/base.py", line 90, in clone
    and param1.data[0] == param2.data[0]
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
"""