title: pyenv+conda doesn't install packages
body: <p>I am trying to install packages using <code>conda</code> but nothing happens. <code>conda</code> doesn't find numpy:</p>
  
  <pre class="lang-py prettyprint-override"><code>$ python -c "import numpy"
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
      import numpy
  ModuleNotFoundError: No module named 'numpy'
  </code></pre>
  
  <p>But when I try to install <code>numpy</code> using <code>conda</code> I just get:</p>
  
  <pre><code>$ conda install numpy
  Collecting package metadata: done
  Solving environment: done
  
  # All requested packages already installed.
  </code></pre>
  
  <p>And there is no way to force <code>conda</code> to install it anyway:</p>
  
  <pre><code>$ conda install --force-reinstall numpy
  Collecting package metadata: done
  Solving environment: done
  
  ## Package Plan ##
  
    environment location: {HOME}/.pyenv/versions/miniconda3-latest
  
    added / updated specs:
      - numpy
  
  
  
  Proceed ([y]/n)? y
  
  Preparing transaction: done
  Verifying transaction: done
  Executing transaction: done
  </code></pre>
  
  <p>Is there a solution to make <code>conda</code> really install packages? Or do I really have to uninstall everything and install everything again? Or is there even a solution to install python (using <code>mkl</code>) that is less horrible than <code>conda</code>?</p>
  
  <hr>
  
  <p>My environment is set up (using <code>pyenv</code>), to use the <code>conda</code> installation:</p>
  
  <pre><code>$ which python
  {HOME}/.pyenv/shims/python
  </code></pre>
  
  <p>and e.g.</p>
  
  <pre><code>$ python -c "import tqdm; print(tqdm.__file__)"
  {HOME}/.pyenv/versions/miniconda3-latest/lib/python3.6/site-packages/tqdm/__init__.py
  </code></pre>