Matlab sparse matrix does not come out as I would expect

3 views (last 30 days)
This is my code:
S=sparse([1 3 2 1 4],[3 1 4 1 4],[1 2 3 4 5],4,4)
full(s)
However, when I run it, I get:
'S =
(1,1) 4
(3,1) 2
(1,3) 1
(2,4) 3
(4,4) 5
ans=
0 0 0 1
0 1 0 0
1 2 0 0
0 0 3 0'
Please tell me why ans is not [4 0 1 0;0 0 0 3; 2 0 0 0; 0 0 0 5]?

Accepted Answer

John D'Errico
John D'Errico on 3 Feb 2025
Edited: John D'Errico on 3 Feb 2025
S=sparse([1 3 2 1 4],[3 1 4 1 4],[1 2 3 4 5],4,4)
S = 4x4 sparse double matrix (5 nonzeros)
(1,1) 4 (3,1) 2 (1,3) 1 (2,4) 3 (4,4) 5
full(S)
ans = 4×4
4 0 1 0 0 0 0 3 2 0 0 0 0 0 0 5
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>
It works just fine.
What did you do wrong? LOOK CAREFULLY AT WHAT YOU WROTE. MATLAB is case sensitive in variable names.
You created the matrix S. Then you looked at full(s). Should MATLAB know that you wanted to see what was in the variable S, and not in the variable s? The mind reading toolbox never works correctly. ;-)

More Answers (0)

Tags

Products


Release

R2024a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!