title: F# return sorting indices from array.sort
body: <p>For an F# array, is there an easy way to return sorting indices along with the sorted array?</p>
  
  <p>Like the <code>sort()</code> function from Matlab?</p>
  
  <p>Background: I came from matlab/R, where manipulating array on indices are essential.  </p>
  
  <p>I'd like to reproduce some index functions and trying to be able to pass indices array around as a variable in various functions. for this <code>sort()</code> function, one usage would be sorting several aligned arrays together based on any one of them.</p>
  
  <p>Maybe there are better ways to do this? </p>