product of sum of the elements along the fourth dimension in a 4D matrix

Hi, I've a 4D matrix. I want to take the product of sum of the elements along the fourth dimension. Basically i want to do this "ΠΣ" operation.

For example, a(i,j,k,l) is a 4D matrix. I want the sum along fourth dimension for all i,j,k values and store it to a 3D matrix b(i,j,k). Then I want to find the product of all elements along the third dimension in b for all i,j values and store it to a 2D matrix c(i,j).

How to do this? Thanks in advance.

Answer 1

[Adam]

a = ones( 3, 4, 5, 6 );
b = sum( a, 4 );
c = prod( b, 3 );

seems to do the job