How can I sort data like this?

1 view (last 30 days)
Husni
Husni on 24 Nov 2012
I have data like this:
A= [6.5048 + 4.7841i
6.5048 - 4.7841i
1.2539 + 3.7939i
1.2539 - 3.7939i
-3.0305 + 3.2324i
-3.1216 + 5.9919i
-3.0305 - 3.2324i
-3.1216 - 5.9919i];
how can I sort to be following:
A= [6.5048 + 4.7841i
6.5048 - 4.7841i
1.2539 + 3.7939i
1.2539 - 3.7939i
-3.0305 + 3.2324i
-3.0305 - 3.2324i
-3.1216 + 5.9919i
-3.1216 - 5.9919i];
where all data are followed directly by the conjugates?
Best regard
Ali
  2 Comments
Azzi Abdelmalek
Azzi Abdelmalek on 24 Nov 2012
How are they sorted?
Husni
Husni on 24 Nov 2012
I am sorry it is not clear, they sorted based on this: first data is 6.5048 + 4.7841i, it then will be followed by its conjugate 6.5048 - 4.7841i which automatically becomes second data. the third data is 1.2539 + 3.7939i and will be followed by 1.2539 - 3.7939i (third & fourth data). The fifth data is -3.0305 + 3.2324i.but in the original data, the conjugate of fifth does not follow, therefore its should be reordered. I hope it is clear?

Sign in to comment.

Accepted Answer

Azzi Abdelmalek
Azzi Abdelmalek on 24 Nov 2012
  5 Comments
Husni
Husni on 24 Nov 2012
Sorry, I try to find good way to explain. Imagine that A is complex power. I want to sort this. The top element has energy 6.5048 + 4.7841i and its complex conjugate 6.5048 - 4.7841i. the second element has energy 1.2539 + 3.7939i and its conjugate 1.2539 - 3.7939i. the third element has energy -3.0305 + 3.2324i but the following data is not its conjugate. Its conjugate locates at data number 7. so the 7 th data is moved to 5 th data (since it is the conjugate of -3.0305 + 3.2324i ) and so on. hopefully it is quite clear :-)
many thanks anyway :-)
Matt Fig
Matt Fig on 24 Nov 2012
See my solution below.

Sign in to comment.

More Answers (2)

Matt Fig
Matt Fig on 24 Nov 2012
Edited: Matt Fig on 24 Nov 2012
You need more than to simply call SORT. The SORT function sorts complex arrays by magnitude, which is a problem for an array like this:
A = [2+3i;
3+2i;
sqrt(13/2)+sqrt(13/2)*i;
2-3i;
3-2i;
sqrt(13/2)-sqrt(13/2)*i]
% Note all(abs(A)==sqrt(13))
For problems like this you need to do something more involved.
[RA,J] = sort(real(A));
% Now we can put them together
newA = complex(RA,imag(A(J)))
  1 Comment
Husni
Husni on 24 Nov 2012
Thanks matt, I got idea from your code

Sign in to comment.


Azzi Abdelmalek
Azzi Abdelmalek on 24 Nov 2012
Edited: Azzi Abdelmalek on 24 Nov 2012
try this
B=A
while length(A)>0;
idx=find(A==conjug(A(1)));
B(ii)=A(1);
B(ii+1)=A(idx);
A(idx)=[];
A(1)=[];
ii=ii+2;
end

Categories

Find more on Shifting and Sorting Matrices in Help Center and File Exchange

Tags

Products

Community Treasure Hunt

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

Start Hunting!