title: 'Inverse' cumprod in pandas
body: <p>I have a data frame which contains dates as index and a value column storing growth percentage between consecutive dates (i.e. dates in the index). Suppose I want to compute 'real' values by setting a 100 basis at the first date of the index and then iteratively applying the % of growth. It is easy with the cumprod method.</p>
  
  <p>Now, I want to set as 100 basis the laste date in the index. I thus need to compute for each date in the index the 'inverse' growth. Is there an easy way (and pythonic) to do this with pandas?</p>
  
  <p>Regards,</p>
  
  <p>Allia</p>