I want to do a least squares fit to the values around a matrix diagonal including the diagonal itself.

Suggestions?

[Stephen23]

"Suggestions?"

https://www.mathworks.com/help/matlab/ref/mldivide.html

https://www.mathworks.com/help/matlab/ref/mrdivide.html

[John D'Errico]

Suggestions? Well, first I'd suggest you explain CLEARLY what you mean, because the words you wrote make no sense in terms of mathematics.

Give an example, if necessary, of what you have, what you hope to do.

[Walter Roberson]

covariance matrix maybe?

[Stephen23]

Douglas Brenner's "Answer" moved here:

Actually the post went out prematurely. But it help me get a clearer picture of what I want to do. So let me ask another question. How do I query the values in a matrix surrounding the diagonal? That is for each row and column such that sqrt(p^2 + q^2) < n^2 elements from the diagonal besides a loop.

[Walter Roberson]

? You are looking for a quarter-circle centered just outside the upper left corner, with radius n ?

Answer 1

[Stephen23]

"How do I query the values in a matrix surrounding the diagonal?"

https://www.mathworks.com/help/matlab/ref/diag.html

[Stephen23]

Douglas Brenner's "Answer" moved here:

Thanks Steve.

[Stephen23]

@Douglas Brenner: please accept my answer if it helped you.