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noa
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calculating mean values of a 3D matrix

Asked by noa
on 9 Oct 2012
Latest activity Commented on by BBB
on 13 Nov 2019 at 12:23
hi.
I have a 3D matrix. size 79x63x100
I want to calc the mean of each of the 79x63 values so to get a 2D matrix the size of 79x63x1
but when i do mean(mat) i get it in the size of 1x63x100
how should I write it?
Thanks, Noa

  1 Comment

You can mention the dimension you want to take mean across. Something like this will work: x=mean(mat,3);

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2 Answers

Answer by Andrei Bobrov
on 9 Oct 2012
 Accepted Answer

out = mean(yourarray3D,3)

  5 Comments

I try to calclulate standard deviation with the same method:
out = std(yourarray3d,3);
But its not working in the same way as with the mean. What can I do to make it work?
out = std(yourarray3d,[],3)
BBB
about 22 hours ago
Hi,
I also have a similar question.
I have a 51x51 2D matrix that I need to take a mean off, but it has to give me back a 51x51 2D matrix as an output.
How can do this using the mean function. I need to put this in a loop as well. Please see code below for reference:
rand_image_stim = rand(10000,51,51);
kk = 1:length(rand_image_stim);
firing_rate_kk(kk) = 0;
gab_filt = z_cos.*z_gauss;
lp(kk) = 0;
for kk = 1:length(rand_image_stim)
output_kk = squeeze(rand_image_stim(kk,:,:)).*gab_filt;
firing_rate_kk(kk) = sum(output_kk,'all');
jk = squeeze(rand_image_stim(kk,:,:))*firing_rate_kk(kk);
lp = squeeze(mean(jk,2)); %Need help with this last bit!
end

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Answer by Zoe
on 28 Nov 2017

shape2 = reshape(yourarray,[100 79*64]);
meanArray = mean(shape2,2);

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