How to get the diagonal and a subdiagonal in the same matrix?
33 views (last 30 days)
Show older comments
Jose
on 15 Oct 2014
Commented: Mohammad Abouali
on 15 Oct 2014
I'm trying to get matrix that only has the diagonal and the first subdiagonal values only. Say I have a 4x4 matrix
A=[ 1 2 3 4;
5 6 7 8;
9 10 11 12;
13 14 15 16]
I want to get a matrix
B=[1 2 0 0;
0 6 7 0;
0 0 11 12;
0 0 0 16].
I know using
diag(diag(A))
will give me a 4x4 matrix with the diagonal but the part I'm hung up on is getting the subdiagonal in the form of a 4x4 matrix, I used
diag(diag(A,1))
and it gave me a 3x3 matrix of the subdiagonal. To conclude, is there a way of getting a subdiagonal in the original matrix dimensions?
0 Comments
Accepted Answer
Mohammad Abouali
on 15 Oct 2014
A=[ 1 2 3 4;
5 6 7 8;
9 10 11 12;
13 14 15 16]
B=triu(A)-triu(A,2)
B =
1 2 0 0
0 6 7 0
0 0 11 12
0 0 0 16
More Answers (0)
See Also
Categories
Find more on Matrices and Arrays 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!