[gradsusr] How to define this formula?

[Jeff Duda]

That looks like standard deviation or RMSE.  Either way, assume your array
is VAR.  Then it's

C = sqrt(amean(asum(pow(VAR -
amean(VAR,x=x1,x=x2,y=y1,y=y2)),2),x=x1,x=x2,y=y1,y=y2))

OR

C = sqrt(asum(VAR - amean(VAR,x=x1,x=x2,y=y1,y=y2))/N), where N is the
number of grid points over which you're summing.

You'll have to insert values for x1, x2, y1, and y2 yourself.  You can use
lat and lon instead of y and x, though.

If that fails, try breaking it into parts:
'average = amean(VAR,x=x1,x=x2,y=y1,y=y2)'
'diffsquaredsum = asum(pow(VAR-average,2),x=x1,x=x2,y=y1,y=y2)'
'SD (or) RMSE = sqrt(diffsquaredsum/N)'

Jeff Duda

On Sat, Feb 2, 2013 at 11:24 PM, T. haghroosta <haghroosta at hotmail.com>wrote:

>  Dear All,
>
> Could you please tell me how can I define this equation which I have
> attached to the email. I got confused completely, I did somethings that
> don't work.
>
> Regards,
>
> T.
>
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-- 
Jeff Duda
Graduate research assistant
University of Oklahoma School of Meteorology
Center for Analysis and Prediction of Storms
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