title: scikit_learn-0.14.1 RuntimeWarning: invalid value encountered in sqrt freezes on test
body: <p>I just installed scikit_learn on my MINT-15 linux following the instructions at <a href="http://scikit-learn.org/0.11/install.html" rel="nofollow">http://scikit-learn.org/0.11/install.html</a></p>
  
  <p>When I run the test: nosetests sklearn --exe  I get the follow output and my terminal freezes:</p>
  
  <p>/usr/local/lib/python2.7/dist-packages/scikit_learn-0.14.1-py2.7-linux-i686.egg/sklearn/pls.py:7: DeprecationWarning: This module has been moved to cross_decomposition and will be removed in 0.16
    "removed in 0.16", DeprecationWarning)
  ......./usr/lib/python2.7/dist-packages/scipy/sparse/linalg/eigen/arpack/arpack.py:1610: RuntimeWarning: invalid value encountered in sqrt
    s = np.sqrt(eigvals)</p>
  
  <p>Appreciate your assistance.
  ...........................</p>