How to average over a cell-array of arrays?

Question

I have a cell array c of equal-sized arrays, i.e. size(c{n}) = [ m l ... ] for any n. How can I get the mean values (averaging over the cell array index n) for all array elements in one sweep? I thought about using cell2mat and mean but the former does not add another dimension but changes l to l*n. And looping manually of course takes like forever...

Answer 1

If all of your arrays are the same size, it makes more sense to store them in a matrix rather than a cell array. That makes it easier to perform operations across them, like taking the mean. You can convert your data to a matrix using the functions NDIMS and CAT:

dim = ndims(c{1});          %# Get the number of dimensions for your arrays
M = cat(dim+1,c{:});        %# Convert to a (dim+1)-dimensional matrix
meanArray = mean(M,dim+1);  %# Get the mean across arrays