the operation A == B produces a logical array of the same dimensions as A and B, with Is in locations where the corresponding elements of A and B match, and Os elsewhere.
Consider the following illustration
>> A = [1 2 3; 9 6 3; 3 1 6] A = 1 2 3 9 6 3 3 1 6 >> B = [1 3 6; 6 6 3; 3 6 9] B = 1 3 6 6 6 3 3 6 9 >> A==B ans = 1 0 0 0 1 1 1 0 0