title: AUC of a Precision Recall Curve by using package ROCR
body: <p>How to obtain AUC (area under curve) of a Precision Recall Curve by using package ROCR..? </p>
  
  <pre><code>library(ROCR)
  data(ROCR.simple)
  pred &lt;- prediction( ROCR.simple$predictions, ROCR.simple$labels)
  perf &lt;- performance(pred,"tpr","fpr")
  plot(perf)
  ## precision/recall curve (x-axis: recall, y-axis: precision)
  perf1 &lt;- performance(pred, "prec", "rec")
  plot(perf1)
  </code></pre>