Issue 1:
======================================================================
ERROR: check_transformer(WardAgglomeration)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/nose/case.py", line 197, in runTest
self.test(*self.arg)
File "/home/andy/checkout/scikit-learn/sklearn/tests/test_common.py", line 233, in check_transformer
transformer.fit(X, y_)
File "/home/andy/checkout/scikit-learn/sklearn/cross_decomposition/pls_.py", line 333, in fit
linalg.inv(np.dot(self.y_loadings_.T, self.y_weights_)))
File "/home/andy/.local/lib/python2.7/site-packages/scipy-0.11.0-py2.7-linux-x86_64.egg/scipy/linalg/basic.py", line 348, in inv
raise LinAlgError("singular matrix")
LinAlgError: singular matrix

Issue 2:
nosetests sklearn --exe
.............................................................../usr/local/lib/python2.7/site-packages/scikit_learn-0.13.1-py2.7-linux-x86_64.egg/sklearn/manifold/spectral_embedding.py:225: UserWarning: Graph is not fully connected, spectral embedding may not works as expected.
warnings.warn("Graph is not fully connected, spectral embedding"
...........SS....../usr/local/lib/python2.7/site-packages/scikit_learn-0.13.1-py2.7-linux-x86_64.egg/sklearn/datasets/tests/test_base.py:124: UserWarning: Could not load sample images, PIL is not available.
warnings.warn("Could not load sample images, PIL is not available.")
.../usr/local/lib/python2.7/site-packages/scikit_learn-0.13.1-py2.7-linux-x86_64.egg/sklearn/datasets/tests/test_base.py:145: UserWarning: Could not load sample images, PIL is not available.
warnings.warn("Could not load sample images, PIL is not available.")
./usr/local/lib/python2.7/site-packages/scikit_learn-0.13.1-py2.7-linux-x86_64.egg/sklearn/datasets/tests/test_base.py:161: UserWarning: Could not load sample images, PIL is not available.
warnings.warn("Could not load sample images, PIL is not available.")
.....SS................................................S.........................................................S.........................................SSS....................../usr/local/lib/python2.7/site-packages/scikit_learn-0.13.1-py2.7-linux-x86_64.egg/sklearn/externals/joblib/test/test_func_inspect.py:122: UserWarning: Cannot inspect object <functools.partial object at 0x6e36f18>, ignore list will not work.
nose.tools.assert_equal(filter_args(ff, ['y'], (1, )),
............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................S...........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................F............................................................................SSS....S....S...................................................................................................................................
======================================================================
FAIL: sklearn.tests.test_common.test_regressors_train
----------------------------------------------------------------------
Traceback (most recent call last):
File "/usr/local/lib/python2.7/site-packages/nose-1.2.1-py2.7.egg/nose/case.py", line 197, in runTest
self.test(*self.arg)
File "/usr/local/lib/python2.7/site-packages/scikit_learn-0.13.1-py2.7-linux-x86_64.egg/sklearn/tests/test_common.py", line 655, in test_regressors_train
assert_true(succeeded)
AssertionError: False is not true
-------------------- >> begin captured stdout << ---------------------
CCA(copy=True, max_iter=500, n_components=2, scale=True, tol=1e-06)
singular matrix

--------------------- >> end captured stdout << ----------------------

----------------------------------------------------------------------
Ran 1598 tests in 81.829s

FAILED (SKIP=15, failures=1)

Is the failures a big deal ? Can I use it anyway ? I want to use sklearn to do logistic regression . Thanks.