# Re: Calculation for pattern correlation

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Tue Oct 18 2011 - 22:51:07 MDT

You can see the 'pattern_cor' => "pattern_cor2"
The latter does the actual computations.

%> less \$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl

On 10/18/11 10:06 PM, Ivanna Mo wrote:
> Hi,
> I use the built-in function pattern_cor to calculate the pattern
> correlation coefficient of my result. I find that the r is strange and
> different from the result I compute myself. Here is the script that I use:
>
> r_x = pattern_cor(X,O,1.0,1) ; r_x = 0.9998
> r_y = pattern_cor(Y,O,1.0,1) ; r_y= 0.99996
>
>
> Avg_X = avg(X)
> Avg_Y = avg(Y)
> Avg_O = avg(O)
>
> Sum_X = 0.0
> Sum_y = 0.0
> Sum_dev_X = 0.0
> Sum_dev_Y = 0.0
> Sum_dev_O = 0.0
>
> do i=0, 67
> do j=0, 67
>
> Sum_x = Sum_x + (X(i,j) - Avg_X)*(O(i,j) - Avg_O)
> Sum_y = Sum_y + (Y(i,j) - Avg_Y)*(O(i,j) - Avg_O)
> Sum_dev_X = Sum_dev_X + (X(i,j) - Avg_X)*(X(i,j) - Avg_X)
> Sum_dev_Y = Sum_dev_Y +(Y(i,j) - Avg_Y)*(Y(i,j) - Avg_Y)
> Sum_dev_O = Sum_dev_O +(O(i,j) - Avg_O)*(O(i,j) - Avg_O)
>
> end do
> end do
>
> R_x = Sum_x/(sqrt(Sum_dev_X)*sqrt(Sum_dev_O)) ; R_x = 0.70
>
> R_y = Sum_y/(sqrt(Sum_dev_Y)*sqrt(Sum_dev_O)) ; R_y = 0.98
>
>
>
>
>
>
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Received on Tue Oct 18 22:51:12 2011

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