Question

I would like to vectorize the calculation of the sum

A{1} + A{2} + ... + A{end}

where A is a vector cell array and each A{i} is a nxn numeric matrix.

There are many ways to code my way through this but I was wondering if there was a clever one fitting in just one or two lines of code.

Answer 1

You can catenate first, then sum up along the 3rd dimension:

[A{1:3}] = deal(ones(4)); %# each element of the cell array contains a 4-by-4 array of ones

out = sum( cat(3,A{:}), 3); %# catenate, then sum