How can I apply a function to each column pair of a matrix?

Hi, I have a function that uses two vectors as inputs and gives an output as scalar. I want to apply this function to each pair of the matrix columns. For example, think about I have a matrix "x" with 5 columns. I want to apply my function to pairs of x(:,1)-x(:,2) + x(:,1)-x(:,3) + x(:,1)-x(:,4) + x(:,1)-x(:,5) + x(:,2)-x(:,3) + x(:,2)-x(:,4) + x(:,2)-x(:,5) + x(:,3)-x(:,4) + x(:,3)-x(:,5) + x(:,4)-x(:,5) +

And also I want store the resulting scalars in a symmetric 5x5 matrix with a diagonal of ones like correlation matrix.

Thanks,

Answer 1

[Chad Greene]

You can use nchoosek to get the permutations, then loop to call your function for each permutation.

[Chad Greene]

For example,

n = nchoosek(1:5,2)

gives you all the unique pairs from 1 to 5. To complete the list for your project you'd need to follow that with

n = [n;fliplr(n)];