Re: [ferret_users] daily cumul to daily value

["Paulo B. Oliveira" <pboliveira@xxxxxxx>]

Hello,

Try pi[i=@shf:1]-pi, as in:

let ii = i
let pi = ii[i=@rsum]
list/i=1:10 i,pi,pi[i=@shf:1]-pi

Cheers,

Paulo
---------------------
On Thu, 2015-02-26 at 10:28 +0100, Delclaux Francois wrote:
> HI,
> I have a file containing daily cumulative data. For exemple, if  pi is 
> daily precipitation:
> day 1:  p1
> day 2 : p1 + p2
> day 3 : p1+ p2 +p3
> ...
> day i : p1 + p2 + ... + pi-1 + pi
> ...
> day 365 : p1 + p2 + ... + p365    = yearly precipitation
>
> Now, I would like to calculate pi the daily precipitation, i.e.
> day 1 : p1
> day 2 : p2
> day 3 : p3
> ...
> day i : pi
> ...
> day 365: p365
>
> So, for each day, I have to substract the pi-1 value to the pi value.
> Is it possible to do that with Ferret ?
>
> Thanks in advance for any help