Sum of cross diagonals of a non symmetric matrix

Hi I need to calculate the sum of cross diagonals of a non symmetric matrix. if A=[ 1 2 3 4;5 6 7 8; 9 8 7 3]

I want to calculate the sum of all the diagonals from left to right and store it in an array such as:

B=[1 7 18 19 15 3] Can someone help me to find the logic for this calculation?

[Guillaume]

Note that the sums you've written are the sums of the antidiagonals, not the diagonals.

Answer 1

[Guillaume]

To calculate the sums of the diagonals:

A=[ 1 2 3 4;5 6 7 8; 9 8 7 3]
s = arrayfun(@(d) sum(diag(A, d)), 1-size(A, 1):size(A, 2)-1)

If you really want the antidiagonal sums, then you'll have to flip A.

Answer 2

[Andrei Bobrov]

sum(spdiags(A(end:-1:1,:)))