Extract the diagonal element of the matrix

Question

I need to extract the elements of the main diagonal of the matrix:

I have tried the following solution:

[U S V]= svd (T)
lambda= reshape(S',[],1);

But I have got the column vector with all elements but I need only the elements of the main diagonal

I also have tried:

[U S V]= svd (T)
lambda = diag(S);

But It doesn't"t work

Can someone help me to extract the elements of the diagonal?

`lambda = diag(S)`? Why the cell-indexing with `n` (which you don't show us how you defined it)? — Adriaan, Aug 29 '19 at 09:11
@Adriaan it was only a part of the code. this operation is only a part — Noel Miller, Aug 29 '19 at 09:38

Wolfie · Accepted Answer · 2019-08-29T09:44:51.163

1

You should just be able to use diag directly on S

lambda = diag(S);

From the docs:

D = diag(v) returns a square diagonal matrix with the elements of vector v on the main diagonal.

edited Aug 29 '19 at 09:44

answered Aug 29 '19 at 09:14

Wolfie

if I write diag (T), I get the diagonal element of the T. But I need the diagonal element of the S matrix from svd of T – Noel Miller Aug 29 '19 at 09:39
I need to extract only the elements of the ain diagonal of the matrix – Noel Miller Aug 29 '19 at 09:40
1

@Noel then you need to edit your question to include a [mcve], because "it doesn't work" is not a clear enough problem statement, `lambda = diag(S)` will return the diagonal elements of `S`. – Wolfie Aug 29 '19 at 09:44

1 Answers1