Ben Bolker wrote: > At this point I'd just like to advertise the "bbmle" package > (on CRAN) for those who respectfully disagree, as I do, with Peter over > this issue. I have added a data= argument to my version > of the function that allows other variables to be passed > to the objective function. It seems to me that this is perfectly > in line with the way that other modeling functions in R > behave. > This is at least cleaner than abusing the "fixed" argument. As you know, I have reservations, one of which is that it is not a given that I want it to behave just like other modeling functions, e.g. a likelihood function might refer to more than one data set, and/or data that are not structured in the traditional data frame format. The design needs more thought than just adding arguments.
I still prefer a design based a plain likelihood function. Then we can discuss how to construct such a function so that the data are incorporated in a flexible way. There are many ways to do this, I've shown one, here's another: > f <- function(lambda) -sum(dpois(x, lambda, log=T)) > d <- data.frame(x=rpois(10000, 12.34)) > environment(f)<-evalq(environment(),d) > mle(f, start=list(lambda=10)) Call: mle(minuslogl = f, start = list(lambda = 10)) Coefficients: lambda 12.3402 It is not at all an unlikely design to have mle() as a generic function which works on many kinds of objects, the default method being function(object,...) mle(minuslogl(obj)) and minuslogl is an extractor function returning (tada!) the negative log likelihood function. > (My version also has a cool formula interface and other > bells and whistles, and I would love to get feedback from other > useRs about it.) > > cheers > Ben Bolker > > -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
