Flipping a matrix diagonally
83 views (last 30 days)
Show older comments
I would like to flip a matrix that I have diagonally from left to right as shown in the image. Is there a command or a simple way to do this? The other two ends of my matrices have the correct values so I do not want them to move![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/676633/image.jpeg)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/676633/image.jpeg)
0 Comments
Accepted Answer
DGM
on 7 Jul 2021
Edited: DGM
on 7 Jul 2021
I'm assuming you want to flip the whole matrix diagonally
To flip about the southeast-northwest diagonal is just transpose:
A = magic(5)
A.'
So then flipping about the opposite diagonal is just a matter of flipping one axis:
fliplr(fliplr(A).')
2 Comments
DGM
on 8 Jul 2021
I don't see how that's possible with any rigid transformation like a flip/transpose/rotation. The fact that adjacent corners become opposite corners leads me to question what you expect the interior of the array to look like.
Consider:
A = [147 278;
457 13];
becomes
B = [457 147;
278 13];
B is basically A' with the top row flipped. What if there were more rows?
A = [147 156 278;
124 456 583;
457 46 13];
We could transpose and then ...? How do you half-flip a row?
B = [457 124 147;
??? ??? ???;
278 583 13];
I'm not really sure what this transformation is supposed to do. I mean anything is possible with interpolation, but the question is what it means.
More Answers (1)
KSSV
on 7 Jul 2021
A = rand(5) ;
n = size(A,1) ;
v = A(1:n+1:end) ;
A(1:n+1:end) = fliplr(A(1:n+1:end))
Also read about diag.
1 Comment
See Also
Categories
Find more on Matrix Indexing 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!