Running sum

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Sean Davis
Sent: Friday, November 19, 2004 1:09 PM
To: r-help
Subject: [R] Running sum


I have vector X of length N that I want to have a running sum for 
(called Y).  I just need max(Y).  I do this with a "for" loop like so:

     Y <- vector(length=N)
     Y[1] <- X[1]
     for (i in 2:N) {
       Y[i] <- Y[i-1]+X[i]
     }
     return(max(Y))

Is there a faster way to do this?

Thanks,
Sean