I wrote a function for a math formula, may I ask you please check my code?

Hey all,

For my research, I needed to calculate some formula, So I searched everywhere, including Matlab file exchange and find nothing about the formula that I needed. Hence I decided to write a function for them and use them in my code. This is the very first time for me to write a function and also the first time to write a math formula. May I please ask you to check if where I do wrong?

Here is the formula:

And here is the function I wrote (I considered O as x and M as y):

function index_agreement = indexagreement(x,y) 
%In the name of God - This function calculate
%   Detailed explanation goes here
A = sum((y-x).^2);
B = abs(y - (mean(x)));
C = x - abs((mean(x)));
D = sum((B+C).^2);
index_agreement = 1 - (D);
end

Description: I run this function successfully, but I'm not sure about results because I believe they are not reasonable.

I want to thank you all.

Best Regards

Answer 1

[Image Analyst]

Assuming vertical bars mean absolute value and not modulus...

You got C wrong. Try

C = abs(x - abs((mean(x)));

then you need

index_agreement = 1 - abs(A / D);

There may be more errors, but I stopped looking once I found those errors.

[BN]

Dear Image Analyst,

I really appreciate you for fixing the first function. Now I get the right results from the aforementioned function.

[Image Analyst]

You're welcome. You can thank people by clicking the link to Accept the answer, and by voting for their answer. Thanks in advance.

[BN]

Thank you, Yes I voted and accepted ???

[BN]

I'm sorry it's my bad, jsut one thing in this line:

index_agreement = 1 - abs(A / D);

why we should add an abs?

the formula is 1-(fraction) not 1-|fraction|. in fact, in the image, they used [] as a parenthesis.

is still should be :

index_agreement = 1 - abs(A / D);

%or now I should use:
index_agreement = 1 - (A / D);

?

Thank you

[Image Analyst]

I thought it was weird because it should be positive already, but I just saw the vertical lines on either side of the fraction so I just said to do abs. If they are brackets, then I didn't notice the little "feet" on the bottom of the brackets, and the top ones are missing because your image clipped them off. But, no, you do not need the abs().