[R] Another loop - deloop question

[Talbot Katz]

Hi.

You folks are so clever, I thought perhaps you could help me make another 
procedure more efficient.

Right now I have the following setup:

p is a vector of length m
g is a list of length n, g[[i]] is a vector whose elements are indices of p, 
i.e., integers between 1 and m inclusive); the g[[i]] cover the full set 
1:m, but they don't have to constitute an exact partition, theycan overlap 
members.
y is another list of length n, each y[[i]] is a vector of the same length as 
g[[i]].

Now I build up the vector p as follows:

p=rep(0,m)
for(i in 1:n){p[g[[i]]]=p[g[[i]]]+y[[i]]}

Can this loop be vectorized?

Thanks!

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