title: Matplotlib: plot x/y coordinates with Two x-Axis with inverse scaling
body: <p>I want to create a special plot with two x axis and one y axis. The bottom X axis increases in value, and the top X axis decreases in value.  I have an <code>x-y</code> pair, for which I want to plot y over one x-axes and on the top <code>x'</code> axes with different scale: <code>(x' = f(x))</code>. </p>
  
  <p>In my case, the conversion between <code>x</code> and <code>x'</code> is <code>x' = c/x</code>, where c is a constant. I found an example <a href="http://matplotlib.1069221.n5.nabble.com/Dual-x-axes-with-transformation-td10865.html" rel="nofollow noreferrer">here</a>, which deals with transformations of this kind. Unfortunately this example doesn't work for me (no error message, the output is just not transformed).</p>
  
  <p>I am using <code>python 3.3</code> and <code>matplotlib 1.3.0rc4 (numpy 1.7.1)</code></p>
  
  <p>Does anybody know a convenient way to do this with matplotlib?</p>
  
  <p><strong>EDIT:</strong>
  I found an answer on stackoverflow (<a href="https://stackoverflow.com/a/10517481/2586950">https://stackoverflow.com/a/10517481/2586950</a>) which helped me to get to the desired plot.  As soon as I can post Images (due to Reputation-Limit), I will post the answer here, if anyone is interested.</p>