The method of setting the initial values given lambda, alpha1, etc. should not depend on the exact values of lambda, alpha1, etc. in my situation, i.e. it does not depend on my data.
On Mar 22, 2017 04:30, "David Winsemius" <dwinsem...@comcast.net> wrote: > On Mar 21, 2017, at 5:04 AM, Michael Dayan <mdayan.resea...@gmail.com> wrote: > > Hi, > > I would like to fit a mixture of two beta distributions with parameters > (alpha1, beta1) for the first component, (alpha2, beta2) for the second > component, and lambda for the mixing parameter. I also would like to set a > maximum of 200 iterations and a tolerance of 1e-08. > > My question is: how to use the betareg package to run the fit with initial > values for the parameters alpha1, beta1, alpha2, beta2 and lambda? I saw in > the documentation that I would need to use the 'start' option of the > betareg function, with start described as "an optional vector with starting > values for all parameters (including phi)". However I could not find how to > define this list given my alpha1, beta1, alpha2, beta2 and lambda. > > The current code I have is: > mydata$y <- <my_data> > bmix <- betamix(y ~ 1 | 1, data = mydata, k = 2, fstol = 1e-08, maxit = > 200, fsmaxit = 200) > > > And I suspect I would need to do something along the lines: > > initial.vals <- c(?, ?, ?, ?, ?) > bmix <- betamix(y ~ 1 | 1, data = mydata, k = 2, fstol = 1e-08, maxit = > 200, fsmaxit = 200, control=betareg.control(start=initial.vals))) > > But I do not know what to use for initial.vals. If there were sensitivity to data, then wouldn't that depend on your (unprovided) data? > > Best wishes, > > Michael > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. David Winsemius Alameda, CA, USA [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
