Product of elementwise differences

As a part of a large function in my MATLAB code I have to calculate difference between elements of matrices and sum them up in a special way. Let me illustrate my case with sample matrices:

1     2     3     4
9    10    11    12

and

5     6     7     8
13    14    15    16

My calculations goes as follows:(Zeroes appear due to padding)

(1-2)(5-6)+(2-3)(6-7)+(3-4)(7-8)+(4-0)(8-0): This replaces 1 in initial matrix.
(2-3)(6-7)+(3-4)(7-8)+(4-0)(8-0)+(0-0)(0-0): This replaces 2 in initial matrix.
(3-4)(7-8)+(4-0)(8-0)+(0-0)(0-0)+(0-0)(0-0): This replaces 3 in initial matrix.
........

Coming to second row of matrices:

(9-10)(13-14)+(10-11)(14-15)+(11-12)(15-16)+(12-0)(16-0): This replaces 9 in initial matrix.
(10-11)(14-15)+(11-12)(15-16)+(12-0)(16-0)+(0-0)(0-0): This replaces 10 in initial matrix.
.........

As an inexperienced programmer I am finding this task really hard. Can someone please help me?

Answer 1

[Walter Roberson]

Not much too this one.

fliplr(cumsum(diff([zeros(size(A,1)),fliplr(A)],1,2) .* diff([zeros(size(B,1)),fliplr(B)],1,2),2))