MATLAB Answers

Circulant Matrix [Column Wise Traversal]

9 views (last 30 days)
Tarek Hajj Shehadi
Tarek Hajj Shehadi on 18 Sep 2020
Commented: Rena Berman on 8 Oct 2020 at 15:46
Below is the row wise circulant matrix algorithm :
function C= circulant(x)
n=length(x);
C=zeros(n,n);
C(1,:)=x;
for i=2:n
C(i, :)=[C(i-1, n) C(i-1, 1:n-1)];
end
How can I compute the circulant matrix column wise based on what I wrote for the circulant matrix computed row wise?

  4 Comments

Show 1 older comment
Rik
Rik on 20 Sep 2020
Original question by Tarek Hajj Shehadi retrieved from Google cache:
Circulant Matrix [Column Wise Traversal]
Below is the row wise circulant matrix algorithm :
function C= circulant(x)
n=length(x);
C=zeros(n,n);
C(1,:)=x;
for i=2:n
C(i, :)=[C(i-1, n) C(i-1, 1:n-1)];
end
How can I compute the circulant matrix column wise based on what I wrote for the circulant matrix computed row wise?
Rik
Rik on 20 Sep 2020
Tarek, removing you question and comments is very rude. I have restored some of your posts from the cache that Google creates. Why did you remove it? Are you afraid to be caught cheating? There is a reason you can't delete a question once you get an answer: people put in time to understand your problem, find a solution, and post it. The curteous thing to is to leave it up so future people with a similar problem can benefit from that time investment as well.
Rena Berman
Rena Berman on 8 Oct 2020 at 15:46
(Answers Dev) Restored edit

Sign in to comment.

Accepted Answer

Bruno Luong
Bruno Luong on 19 Sep 2020
function C= circulant(x)
n=length(x);
C=zeros(n,n);
C(:,1)=x;
for j=2:n
C(:,j)=[C(n,j-1); C(1:n-1,j-1)];
end

  1 Comment

Rik
Rik on 20 Sep 2020
Deleted comment by by Tarek Hajj Shehadi:
I have accepted your answer as it is the one I am looking for, I would also like to thank Matt J for also putting an effort in helping me. As for your answer its entirley what I was looking for just that I added C=C'; to transpose this matrix as required.

Sign in to comment.

More Answers (3)

Matt J
Matt J on 18 Sep 2020
function C= circulant(x)
n=length(x);
C=zeros(n,n);
C(1,:)=x;
for i=2:n
C(i, :)=[C(i-1, n) C(i-1, 1:n-1)];
end
C=C.';

  1 Comment

Rik
Rik on 20 Sep 2020
Deleted comment by by Tarek Hajj Shehadi:
Hello, The thing I was trying to make columnwise computation and the rowwise computation of the circulant matrix output the same matrix where in both cases, the entries are in same position so the problem I am encountering is perhaps in the for loop.

Sign in to comment.


Bruno Luong
Bruno Luong on 18 Sep 2020
function C= circulant(x)
toeplitz(x,circshift(flip(x),1))
end

  1 Comment

Rik
Rik on 20 Sep 2020
Deleted comment by by Tarek Hajj Shehadi:
I wish to write the algorithm using for loops and not use the builtin function.

Sign in to comment.


Bruno Luong
Bruno Luong on 19 Sep 2020
function C= circulant(x)
n = length(x);
C = x(mod((1:n)'-(1:n),n)+1);

  0 Comments

Sign in to comment.

Community Treasure Hunt

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

Start Hunting!