Sum over cell array of sparse matrices error: Dimension for sparse matrix concatenation must be <= 2.

Question

Xiaohan Du 2017-11-3

评论： Xiaohan Du 2017-11-3

Hi all,

I have a cell contains sparse matrices,

K>> a
a =
  2×1 cell array
    [12×12 double]
    [12×12 double]

Now I'd like to sum these 2 sparse matrices into 1. I tried:

K>> sum(cat(3, a{:}), 3)

which gave me error:

Error using cat
  Dimension for sparse matrix concatenation must be <= 2.

This line works for non-sparse matrices, but not for sparse matrices. Any idea how to do it?

Thanks!

Answer 1

Andrei Bobrov 2017-11-3

a = cellfun(@full,a,'un',0);
sum(cat(3,a{:}),3);

Xiaohan Du 2017-11-3

Nah, here a is 12 by 12 only for testing, in my real code it could be very large, so can only deal with sparse matrices, no back to full matrices.