There's at least one package that can do zero-inflated gamma regression (Rfast2::zigamma). I'm not sure it's ML, though.
On Thu, Jan 19, 2023 at 10:17 AM Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > Beware of adding a constant... the magnitude of the constant used can have > an outsized impact on the answer obtained. See e.g. > https://gist.github.com/jdnewmil/99301a88de702ad2fcbaef33326b08b4 > > On January 19, 2023 3:49:29 AM PST, peter dalgaard <pda...@gmail.com> > wrote: > >Not necessarily homework, Bert. There's a generic issue with MLE and > rounded data, in that gamma densities may be 0 at the boundary but small > numbers are represented as 0, making the log-likelihood -Inf. > > > >The cleanest way out is to switch to a discretized distribution in the > likelihood, so that instead of log(dgamma(0,...)) you use > log(pgamma(.005,..) - pgamma(0,...)) == pgamma(.005,..., log=TRUE). (For > data rounded to nearest .01, that is). Cruder techniques would be to just > add, like, .0025 to all the zeros. > > > >-pd > > > >> On 10 Jan 2023, at 18:42 , Bert Gunter <bgunter.4...@gmail.com> wrote: > >> > >> Is this homework? This list has a no-homework policy. > >> > >> > >> -- Bert > >> > >> On Tue, Jan 10, 2023 at 8:13 AM Nyasha <kahuninyasha13...@gmail.com> > wrote: > >>> > >>> Please how can one go about this one? I don't know how to go about it. > >>> > >>> [[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. > >> > >> ______________________________________________ > >> 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. > > > > -- > Sent from my phone. Please excuse my brevity. > > ______________________________________________ > 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. > [[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.