title: conda update scikit-learn (also scipy and numpy)
body: <p>I think I have made a mess using pip install when I am supposed to use conda. As a result I couldn't update the scikit-learn package to the latest version. I uninstalled scikit-learn with both conda and pip, and then installed again using conda but now I have issue import sklearn:</p>
  
  <pre><code>Python 2.7.11 |Anaconda custom (x86_64)| (default, Dec  6 2015, 18:57:58) 
  [GCC 4.2.1 (Apple Inc. build 5577)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  Anaconda is brought to you by Continuum Analytics.
  Please check out: http://continuum.io/thanks and https://anaconda.org
  
  from sklearn import metrics
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/Users/bowang/anaconda/lib/python2.7/site-packages/sklearn/metrics/__init__.py", line 7, in &lt;module&gt;
      from .ranking import auc
  ImportError: No module named ranking 
  </code></pre>
  
  <p>Also there seems to be confusions with which version of sklearn/numpy/scipy it actually uses:</p>
  
  <pre><code>$ conda update scikit-learn
  Using Anaconda Cloud api site https://api.anaconda.org
  Fetching package metadata: ......
  Solving package specifications: .........
  
  # All requested packages already installed.
  # packages in environment at /Users/bowang/anaconda:
  #
  scikit-learn              0.15.2               np18py27_0    http://repo.continuum.io/pkgs/free/osx-64/scikit-learn-0.15.2-np18py27_0.tar.bz2
  
  $ conda update scipy
  Using Anaconda Cloud api site https://api.anaconda.org
  Fetching package metadata: ......
  Solving package specifications: .........
  
  # All requested packages already installed.
  # packages in environment at /Users/bowang/anaconda:
  #
  scipy                     0.14.0               np18py27_0    http://repo.continuum.io/pkgs/free/osx-64/scipy-0.14.0-np18py27_0.tar.bz2
  </code></pre>
  
  <p>Above shows I still can't update to the latest versions but:</p>
  
  <pre><code>$ python
  Python 2.7.11 |Anaconda custom (x86_64)| (default, Dec  6 2015, 18:57:58) 
  [GCC 4.2.1 (Apple Inc. build 5577)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  Anaconda is brought to you by Continuum Analytics.
  Please check out: http://continuum.io/thanks and https://anaconda.org
  &gt;&gt;&gt; import scipy
  &gt;&gt;&gt; scipy.__version__
  '0.17.0'
  &gt;&gt;&gt; import numpy
  &gt;&gt;&gt; numpy.__version__
  '1.11.0'
  &gt;&gt;&gt; import sklearn
  &gt;&gt;&gt; sklearn.__version__
  '0.17.1'
  </code></pre>
  
  <p>Is there a way to clean up and resolve all the confusions here and allow me to update and thus use the latest versions of sklearn/numpy/scipy? Thanks!</p>