double summation of an equation with four variables

i need some help using symbolic variables. i have a equation with double summation

f(x,y)=sigma(i=1:4)sigma(j=1:5)g(x,y,i,j)*w(i,j) where g() is a function but w is a matrix, x and y are vectors. i need to multiply the element corresponding to w(i,j) while doing the summation. how can i do it considering four variables.

thanking you in advance