Wang, Yun <ywang <at> med.wayne.edu> writes: > > > Dear R users, > > Please help me on using "mix" function under package "mixdist". > > My data distribution shows there are two components for the mixture distribution: left part is an > exponential and right part is a normal. So I plan to use "gamma" mixture distribution to estimate the > parameters. Here is what I am using for the "mix" function. > > Test<-mix(x, mixparam(mu=c(1,125),sigma=c(1,11.18)),"gamma") > > However, one error message shows up as: > "Error in nlm(function(x) f(x, ...), p, hessian, typsize, fscale, msg, : missing value in parameter" > > Does anybody know what that means and how to fix it to get the estimation? Your help will be much appreciated. > > Yun >
You haven't given us enough to go on. First of all, mixdist is a contributed package -- not part of base R, and not even on CRAN (but not too hard to find: http://www.math.mcmaster.ca/peter/mix/mix.html ). You might consider asking the author/maintainer: see help(package="mixdist"). Second, please do as the posting guide suggests and give us a simple, reproducible example. If your data are small enough, you can just post them, or post them to a web site and send the URL -- or make up a small data set that also displays the problem (you will often discover the answer for yourself in the process of doing this!) Staring at the C code for nlm (in src/main/optimize.c) suggests that nlm is being passed an NA in a parameter set somewhere -- you might try options(error=recover) to start diagnosing, or change print.level in your mix() call. But your best bet is to find a reproducible example for us to look at. cheers Ben Bolker ______________________________________________ R-help@stat.math.ethz.ch 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.