title: Akima interpolation of an array of doubles
body: <p>Assuming I have an array of doubles, what's a good algorithm to sample this series using <a href="http://www.iue.tuwien.ac.at/phd/rottinger/node60.html" rel="noreferrer">Akima interpolation</a>? I'm too stupid to translate that mathematical description into code.</p>
  
  <pre><code>// values is an array of doubles
  // idx is the index of the left-hand value for the current interpolation
  // t is the normalized parameter between values[idx] and values[idx+1]
  // Don't worry about array bounds, I'll handle that separately.
  public double InterpolateAkima(double[] values, int idx, double t)
  {
    ...?
  }
  </code></pre>