Another nitpick: don't use return() in the last statement. It isn't needed, it looks like some other language, and dropping it saves 8% of the time for the uncompiled code (the compiler seems to get of it).
Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Berend Hasselman > Sent: Tuesday, October 02, 2012 11:19 AM > To: Rui Barradas > Cc: r-help@r-project.org; Naser Jamil > Subject: Re: [R] Integration in R > > > On 02-10-2012, at 20:01, Rui Barradas <ruipbarra...@sapo.pt> wrote: > > > Hello, > > > > Yes, it's possible to remove the loop. Since the loop is used to compute a > > running > product and all we want is the final result, use the vectorized behavior of R > and a final > ?prod(). > > Seedup: another 2x. And 4x2 == 8 == 1 [decimal] order of magnitude. > > > > > > lf2 <-function (x) { > > v<-1 > > x1 <- x[1] > > x2 <- x[2] > > x3 <- x[3] > > x4 <- x[4] > > z1 <- exp(x1+x2*dose) > > z2 <- exp(x3+x4*dose) > > psi0<-1/((1+z1)*(1+z2)) > > psi1<-z1*psi0 > > v <- (psi0^y0)*(psi1^y1)*((1-psi0-psi1)^y2) > > return( prod(v) ) > > } > > > > lf2.c <- cmpfun(lf2) > > > > Hope this helps, > > > Wonderful. It certainly does help. > A single nitpick: the v <- 1 at the start of the function can now be removed. > > I got a speedup of 7.5 compared to the very first version lf1. > > Berend > > ______________________________________________ > 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. ______________________________________________ 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.
