Efficient sparse matrix operation

I have a 900 x 900 sparse matrix 'S' which contains alot of zeros, when i perform the following operation

S./sum(S,2)

It takes too long because it is operating on the zeros too and resulting in alot of NaN values. Is there a more efficient way to do this

Answer 1

[Stephan]

Hi,

if you precalculate the sum and then calculate you can save some time:

N = sum(S,2);
S./N;

I tried using sparse matrices of 900x900 with about 10k non zero elements, which was more time consuming then this operation.

Best regards

Stephan