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how to do average over third dimension?

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Lilya
Lilya on 26 Jul 2021
Commented: Star Strider on 26 Jul 2021
Hi all,
I have multiple 3D matrices with the dimension of 21*41*24 for each which 24 (third dimension) is 24 hours.
I wanted to calculate 6 hours average for the third dimension.
Where I am mistaken?
NHours=size(ucom,3);
NDays=NHours/6;
out = nanmean(permute(reshape(ucom,[6,NDays]),[2,1,3]),3);
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Accepted Answer

Star Strider
Star Strider on 26 Jul 2021
Taking a slightly shorter example, try something like this —
% ucom = randi(9,21,41,24);
ucom = randi(9, 3, 4, 24);
sz_ucom = size(ucom);
ucomr = reshape(ucom,sz_ucom(1),sz_ucom(2),[],6);
out = nanmean(ucomr,4)
out =
out(:,:,1) = 5.6667 5.5000 4.8333 3.1667 5.8333 4.5000 5.6667 4.0000 5.8333 5.1667 5.0000 4.5000 out(:,:,2) = 3.8333 6.0000 4.5000 6.0000 6.0000 5.1667 5.6667 2.5000 3.1667 6.0000 5.3333 5.3333 out(:,:,3) = 3.8333 3.6667 6.3333 5.3333 4.1667 6.0000 5.5000 5.6667 3.6667 5.0000 4.1667 6.3333 out(:,:,4) = 5.5000 5.5000 4.1667 2.6667 3.1667 3.6667 4.8333 4.8333 7.0000 3.8333 5.5000 6.3333
The ‘out’ variable now has 4 blocks of 6-hour averages
.
  8 Comments
Star Strider
Star Strider on 26 Jul 2021
As always, my pleasure!
(Sorry for the delay — I was off doing other things.)
.

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