avarage of diagonal elements

Write a Matlab function that calculates the average of the elements of the diagonal of a matrix M.

Be careful, before doing this calculation, your function must check if M is a scalar, a vector or a

matrix. In case it is a scalar or a vector, it must return 0

[Mustafa Ahmed]

i did like that ,,,, but it is not enough and did not work

function ave = average(A)

if ismatrix(A)
    [r,c] = size(A);
    for i=1:r
        for j=1:c
            
            b = diag(A)
            ave=b./size(A)
        end
    end
end

Answer 1

[Adam Danz]

Since this appears to be an assignment I can help by explaining what's wrong and nudging you in the right direction.

Two errors in this line:

 ave=b./size(A)

1) The size function returns the number of rows in the first output. If A is a square matrix, that's OK but if A is not square, it's very wrong. A is probablly square since you need the diagonal buy why not play it safer by using the number of elements in b instead of the number of rows in A? See numel().

2. That line is computing element-wise division instead of the computing the mean. "./" vs "/"

Also, you don't need any of the loops.

[Mustafa Ahmed]

then how should i do it using Function like

function ave=myave(A)

[Adam Danz]

Like I said, I can point you in the right direction but I won't do it for you.

You don't need the loops. You only need the lines within the loops.

Look at what this line does, look at the output

b = diag(A)

That's what you need to average.

[Mustafa Ahmed]

thank you