How to read elements of a matrix diagonally in MATLAB?

Suppose A is a 3X3 matrix
A=[2,5,7; 3,0,1; 9,17,23]
I want to read the elements in this fashion.
2
5 3
9 0 7
1 17
23

 채택된 답변

Andrei Bobrov
Andrei Bobrov 2013년 9월 18일
편집: Andrei Bobrov 2013년 9월 18일
A=[2,5,7; 3,0,1; 9,17,23]
k = spdiags(rot90(A));
s = size(k);
nns = nan(s);
ptr = tril(triu(ones(s)),s(1)-1);
nns(ptr>0) = k(ptr>0);
nns(:,1:2:end) = nns(end:-1:1,1:2:end);
out = sort(ptr,'descend');
out(out>0) = nns(~isnan(nns));
out = out';
or
A=[2,5,7; 3,0,1; 9,17,23];
ds = spdiags(rot90(A));
l = spdiags(ones(size(A)));
ds(:,1:2:end) = flipud(ds(:,1:2:end));
l(:,1:2:end) = flipud(l(:,1:2:end));
l2 = sort(l,'descend');
l2(l2>0) = ds(l>0);
out = l2';

댓글 수: 4

Febin Benjamin
Febin Benjamin 2013년 9월 18일
편집: Febin Benjamin 2013년 9월 18일
Thanx Andrei! It worked! And what if I had to read the same matrix as shown below?
7
5 1
23 0 2
3 17
9
Jan
Jan 2013년 9월 18일
@Andrei: I'm impressed. After reading the question I do not have the faintest idea what "reading a matrix in a specific fashion" could mean and what the shown list of value is.
@Jan: I tried hard to frame the question in a comprehensive way but that's what I managed to come up with. :) Fortunately, Andrei got it! hehe :)
B = [2,5,7; 3,0,1; 9,17,23];
A = fliplr(B); % and etc

댓글을 달려면 로그인하십시오.

추가 답변 (0개)

카테고리

도움말 센터File Exchange에서 Operating on Diagonal Matrices에 대해 자세히 알아보기

제품

태그

Community Treasure Hunt

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

Start Hunting!

Translated by