Homework Statement
I want to change the order of triple summation. it follows:
$$\sum^N_{k=0} f(k) \sum^k_{n=0}\sum^{N-k}_{m=0} g(k,n)h(k,m)A(n+m)$$
=>
I need to set the variable x(=n+m) go from 0 to N firstly, and then further go on...
$$\sum^N_{x=0} A(x) \cdots \cdots$$
But, I...