# [rrd-users] Re: Is is possible to get short term average directly in RRD tool ?

Alex van den Bogaerdt alex at ergens.op.het.net
Sun May 2 23:53:01 MEST 2004

```On Sun, May 02, 2004 at 10:34:21AM +0200, Didier wrote:
> Is is possible to get short term average directly in RRD tool ?

Just do this using your front end.  Also, values in RRDtool _are_
short term averages.  You're after the average of averages!
I'll use the phrase "moving average" for what you asked for.

>     For example if we have  5 minutes  between   (t-1)  and  (t)     ==>  20 minutes represent 5 intervals of time

5 times 5 is 25 , not 20.

>            With    A=average of  v(t-7), v(t-6) , v(t-5)  , v(t-4) , v(t-3)
>                       B=average of  v(t-6), v(t-5)  , v(t-4) , v(t-3), v(t-2)
>                       C=average of  v(t-5), v(t-4)  , v(t-3) , v(t-2), v(t-1)

In the front end:

A = B
B = C
C = D
D = E
E = current value from device
F = (A+B+C+D+E)/5

rrdtool update your.rrd N:E:F

To graph the current average, use E. To graph the moving average, graph F.

HTH
Alex
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