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Message-ID: <419E43DE.8000308@jhsph.edu>
Date: 2004-11-19T19:05:02Z
From: Roger D. Peng
Subject: Running sum
In-Reply-To: <09151670-3A56-11D9-AD50-000A95D7BA10@mail.nih.gov>

You could try using embed(), but I doubt it's faster.

-roger

Sean Davis wrote:
> 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
> 
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> 

-- 
Roger D. Peng
http://www.biostat.jhsph.edu/~rpeng/