title: What is the inverse of the numpy cumsum function?
body: <p>If I have <code>z = cumsum( [ 0, 1, 2, 6, 9 ] )</code>, which gives me <code>z = [ 0, 1, 3, 9, 18 ]</code>, how can I get back to the original array <code>[ 0, 1, 2, 6, 9 ]</code> ?</p>