Extract part of a sparse matrix
6 views (last 30 days)
Show older comments
Pedro Montenegro
on 2 May 2014
Commented: Azzi Abdelmalek
on 2 May 2014
Dear users,
I'm trying to find a way to extract a block from a big sparse matrix without being computationally costly. Here what I have
A - sparse matrix n*n i - a vector with the indices I want to extract (i = [5556 68424 85345 925325], for example)
I can do what I want like this:
A_new = A(i,i).
However, this indexing that is used in full matrices is not effective for sparse. how can I do this operation in an effective way?
Thank you in advance,
Pedro Montenegro University of Porto, Portugal
0 Comments
Accepted Answer
Azzi Abdelmalek
on 2 May 2014
i = [5556 68424 85345 925325];
ii=sub2ind(size(A),i,i)
A_new = A(ii)
More Answers (0)
See Also
Categories
Find more on Sparse Matrices in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!