you could try the following:
# here with 10 instead of 50
ind <- t(combn(10, 5))
nind <- nrow(ind)
cbn <- rep(0, 10 * nind)
dim(cbn) <- c(nind, 10)
for (i in 1:nind) {
cbn[cbind(i, ind[i, ])] <- 1
}
cbn
rowSums(cbn)
I hope it helps.
Best,
Dimitris
----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
----- Original Message -----
From: "francogrex" <[EMAIL PROTECTED]>
To: <r-help@r-project.org>
Sent: Friday, November 16, 2007 12:35 PM
Subject: [R] expand.grid overflows?
>
>>cbn<-as.matrix(expand.grid( rep( list(0:1), 50)))
>
> Error in rep.int(rep.int(seq_len(nx), rep.int(rep.fac, nx)), orep) :
> invalid 'times' value
> In addition: Warning message:
> In rep.int(rep.int(seq_len(nx), rep.int(rep.fac, nx)), orep) :
> NAs introduced by coercion
>
> But I'm only interested in cbn matrix rows where:
> cbn<- cbn[rowSums(cbn)==5,]
>
> Is there a way to evaluate it row by row and only store where the
> sum is
> equal to 5, maybe it reduces cost of computation?
> --
> View this message in context:
> http://www.nabble.com/expand.grid-overflows--tf4820635.html#a13791428
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
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