Message-ID: <Pine.LNX.4.61.0411191857240.3190@gannet.stats>
Date: 2004-11-19T18:58:14Z
From: Brian Ripley
Subject: Running sum
In-Reply-To: <09151670-3A56-11D9-AD50-000A95D7BA10@mail.nih.gov>
?cumsum
On Fri, 19 Nov 2004, 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?
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595