diagonal matrix with ones

Question

0 个投票

Hello I am trying to do a diagonal inferior matrix with a diagonal of ones but my diagonal have differentes valors. How do i do a matrix with diagonal of ones? Here is my code:

if true
  % code
a=[6,9,7;6,2,0;1,8,3]
a=tril(a)
end

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Daniel Shub 2013-3-8

What would be really helpful is if in addition to your example input you could tell us what you want the output to be.

请先登录，再进行评论。

请先登录，再回答此问题。

Follow Question

Answer 1

Sean de Wolski 2013-3-8

编辑：Sean de Wolski 2013-3-8

在 MATLAB Online 中打开

0 个投票

eye(5)

?

more per clarification:

a = tril(magic(3));
a(logical(eye(size(a,1)))) = 1

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Cristian 2013-3-8

0 个投票

Hello Thanks for the answers but the firs answer just create a matriz of 5x5 with diagonal of ones and I need my matrix "a" but with diagonal of ones. The second answer has an error say: ??? Undefined function or variable 'n'.

Error in ==> Untitled2 at 3 [ii,jj]=ind2sub(size(a),1:n*m)

What should I do?

Thanks

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Sean de Wolski 2013-3-8

see more in my answer above.

请先登录，再进行评论。

Answer 3

Leah 2013-3-8

在 MATLAB Online 中打开

0 个投票

a(eye(3))=1;

like that?

3 个评论
显示 1更早的评论隐藏 1更早的评论

Leah 2013-3-8

thanks Sean, I'm waiting on my license at my new job :)

Sean de Wolski 2013-3-8

I'm sure your friendly sales rep would be happy to set you up with a trial :) !

请先登录，再进行评论。

Answer 4

Cristian 2013-3-8

0 个投票

Well thaks Azzi Abdelmalek but now with your code matlab give me a triangular matrix with ones down of the diagonal and I need my diagonal just of ones. I could divide the last coefficent each row, and so have my diagonal with ones but I dont know manipulate rows and how I do that. Example I want that my triangular matrix: A=[6,9,7;6,2,0;1,8,3] A=tril(A)

A=[6,0,0;6,2,0;1,8,3]---->A=[1,0,0;3,1,0;1/3,8/3,1] This I want to do, having any matrix.