Error found: Index in position 1 is invalid. Array indices must be positive integers or logical values. Error in MyCost (line 25) z=z+w(i,j)*d(p(i),p(j)); Error

function z=MyCost(p,model)

n=model.n;
w=model.w;
d=model.d;

z=0;

for i=1:n-1
    for j=i+1:n
        
        z=z+w(i,j)*d(p(i),p(j));
        
    end
end

end

[Walter Roberson]

We do not know what data type p is. It could be a function, so p(i) an p(j) could be almost anything.

We do not know what data type model.d is.

But... if p is a vector and it does not happen to be positive integers, and if model.d is an array, then d(p(i), p(j)) could easily be an attempt to index d at something that is not an integer.

Answer 1

[Image Analyst]

See the FAQ for a thorough explanation.

https://matlab.fandom.com/wiki/FAQ#.22Subscript_indices_must_either_be_real_positive_integers_or_logicals..22

You'll find out that your p are either zero, negative, or some fractional number, not integers.

p(i) and p(j) need to be integers and they aren't.

They are the row and column index of d so they must be integers like 1,2,3,4, etc. Not -37, not 0, not 3.1415. There is no -37th row of any matrix.

Maybe you can just round them, but who knows -- you'll have to figure that out. Why did you expect them to be integers greater than 1? But for some reason, they are not that.