Dear R users,
Would you plz tell me how to avoid this "for" loop blow??
I think there might be a better way to reduce running time.
----------------------------------------------------------------------------------------------
## y1 and y2 are n*1 vectors
for (k in 1:n){
ymax <- max( y1[k], y2[k] )
i <- 0:ymax
sums<- -lgamma(y1[k]-i+1)-lgamma(i+1)-lgamma(y2[k]-i+1)
maxsums <- max(sums)
sums <- sums - maxsums
lsum <- log( sum(exp(sums)) ) + maxsums
logbp[k] <- y1[k] + y2[k] + lsum
}
------------------------------------------------------------------------------------
Any suggestion will be greatly appreciated.
Regards,
Kathryn Lord
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efficient way to reduce running time
2 messages · Kathie, Dennis Murphy
Hi: Could you please provide a reproducible example? In your code, (i) n is undefined; (ii) logbp is undefined. A description of what you want to do and/or a reproducible example with an expected outcome would be useful. As the bottom of each e-mail to R-help says... PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Dennis
On Tue, Aug 2, 2011 at 4:05 AM, Kathie <kathryn.lord2000 at gmail.com> wrote:
Dear R users,
Would you plz tell me how to avoid this "for" loop blow??
I think there might be a better way to reduce running time.
----------------------------------------------------------------------------------------------
## y1 and y2 are n*1 vectors
? ? ? ?for (k in 1:n){
? ? ? ? ? ? ? ?ymax <- max( y1[k], y2[k] )
? ? ? ? ? ? ? ?i <- 0:ymax
? ? ? ? ? ? ? ?sums<- -lgamma(y1[k]-i+1)-lgamma(i+1)-lgamma(y2[k]-i+1)
? ? ? ? ? ? ? ?maxsums <- max(sums)
? ? ? ? ? ? ? ?sums <- sums - maxsums
? ? ? ? ? ? ? ?lsum <- log( sum(exp(sums)) ) + maxsums
? ? ? ? ? ? ? ?logbp[k] <- y1[k] ?+ y2[k] ?+ lsum
? ? ? ?}
------------------------------------------------------------------------------------
Any suggestion will be greatly appreciated.
Regards,
Kathryn Lord
--
View this message in context: http://r.789695.n4.nabble.com/efficient-way-to-reduce-running-time-tp3711985p3711985.html
Sent from the R help mailing list archive at Nabble.com.
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.