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Kathie <kathryn.lord2...@gmail.com> wrote: Dear R users, I have two n*1 integer vectors, y1 and y2, where n is very very large. I'd like to compute elbp = 4^(y1) * 5^(y2) * sum_{i=0}^{max(y1, y2)} [{ (y1-i)! * (i)! * (y2-i)! }^(-1)]; that is, I need to compute "elbp" for each (y1, y2) pair. So I made R code like below, but I don't think it's efficient Would you plz tell me how to avoid this "for" loop blow?? _____________________________________________ 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 lbp[k] <- y1[k]*log(4) + y2[k]*log(5) + lsum } elbp <- exp(lbp) _____________________________________________ Any suggestion will be greatly appreciated. Regards, Kathryn Lord -- View this message in context: http://r.789695.n4.nabble.com/My-R-code-is-not-efficient-tp3712762p3712762.html Sent from the R help mailing list archive at Nabble.com. _____________________________________________ R-help@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. [[alternative HTML version deleted]] ______________________________________________ R-help@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.