MATLAB: Compare each row of a matrix

Question

I would like to compare each row of the Matrix with the rest. 
For example if you have the matrix:

A = [1 1 1;2 2 2;3 3 3;4 4 4}

Compare first row with the second, third, fourth. And Automatically the Programme takes the second row and do the same process(first, third, fourth), third row with first, second, fourth, and the fourth row with first, second and third.

If someone could help me I would be very greatful

Answer 1

I would use the pdist function, and define your own distance metric if it is not one of those already provided.