Thank you very much Peter, I'm going to dig deeper into the code of the functions you've listed.
On Wed, Aug 3, 2011 at 6:57 AM, Peter Ehlers <ehl...@ucalgary.ca> wrote: > On 2011-08-02 11:51, Sébastien Bihorel wrote: > >> Hi, >> >> This might be a simple problem but I don't know how to calculate a random >> variable density the way panel.histogram does it before it creates the >> actual density rectangles. The documentation says that it uses the density >> function but the actual code suggests that the hist.constructor function >> (which does not seem to be easily accessible). >> > > The documentation in ?histogram is misleading. I think that the intent > is that density() is used in panel.densityplot but panel.histogram uses > hist(), as is clear in ?panel.histogram. > > So you'll find the code for the density rectangles in hist.default > where 'counts' is computed and followed with > > dens <- counts/(n * diff(breaks)) > > You might find the code for truehist() in the MASS package easy to > follow. > > To see how hist.constructor calls hist(): > > lattice:::hist.constructor > > Peter Ehlers > > >> Any suggestion for computing the density values of foo$x in the following >> example will be welcome. >> >> >> require(lattice) >> set.seed(12345) >> >> foo1<- >> data.frame(x=rnorm(100,0,0.1),**grp=1,by=rep(1:2,each=50),by2=** >> rep(1:2,times=50)) >> foo2<- >> data.frame(x=rnorm(100,2,1),**grp=2,by=rep(1:2,each=50),by2=** >> rep(1:2,times=50)) >> foo<- rbind(foo1,foo2) >> >> xplot<- histogram(~x,data=foo, type='density') >> >> >> PS: the present question relates to a workaround for another problem >> previously submitted to the list ( >> https://stat.ethz.ch/**pipermail/r-help/attachments/** >> 20110727/5f0a8853/attachment.**pl<https://stat.ethz.ch/pipermail/r-help/attachments/20110727/5f0a8853/attachment.pl> >> ). >> >> [[alternative HTML version deleted]] >> >> ______________________________**________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> >> PLEASE do read the posting guide http://www.R-project.org/** >> posting-guide.html <http://www.R-project.org/posting-guide.html> >> and provide commented, minimal, self-contained, reproducible code. >> > > [[alternative HTML version deleted]]
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