Calculating median along specific dimension of 3D array

Hi,

I have a 3D array (S) of size 75x31253x1523. If I was to calculate the median along the second axis (for each row) it would be median(S,2) which would result in a 75x1x1523 array.

However, because the array is large, I run out of memory when I try to calculate the median of the whole array with one line. Therefore, I want to calculate the median in chunks. The problem is that each chunk will be of size Ax1xB. When stacking them together, they will be of size AxNxB. How can I calculate it in chunks and still end with size Ax1xB (75x1x1523)?

Thanks!

[Stephen23]

Check your available memory, it works when I tried it (32 bit R2012b):

>> S = randi(75,31253,1523);
>> M = median(S,2);
>>

You might be able to increase your swap space, which although slow can be effective in avoiding such errors.

[Uerm]

Sorry, I wrote the dimensions wrong. They are 90x38021x1633. However, they are from other calculations and take up approximately 22.5 gb of space.

Can I increase the swap space when I use a mac?

Answer 1

[Matt J]

M=nan(90,1,1633);

for i=1:90
    
    M(i,:,:)=median(S(i,:,:),2);
    
end

[Uerm]

Works like a charm. Thank you!