I have a cell matrix with arrays. Each row has a certain size matrix. I would like to add the matrices along the rows

Given r={rand(3), rand(3);rand(2),rand(2)}, I want to get a row-wise sum of each size. cellfun and @sum lets you add arrays like that but seemingly, not matrices.

Is there a vectorized solution?

Also --- is it possible that sparse matrices make the operation slower?

[Stephen23]

What is "a row-wise sum of each size" ?

Do you wish to sum each matrix along columns or rows?