Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-21 Thread Spencer Graves
I get upset when software dies and refuses to give me an answer. I'd much rather have a routine give me a wrong answer -- with an error message -- than just an error message. Maybe refuse to print standard errors when the hessian is singular, but at least give me a progress report

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-20 Thread Berton Gunter
May I interject a comment? When data is generated from a specified model with reasonable parameter values, it should be possible to fit such a model successful, or is this me being stupid? Let me take a turn at being stupid. Why should this be true? That is, why should it be possible

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-20 Thread Hans Julius Skaug
I agree that the model is not fitting the Lesaffre data well, but my point was to show that glmmADMB is numerically stable. Numerical stability is obviously a nice property, but becomes particularly important when one wants to do parametric bootstrappin, which I think is needed for these kinds of

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-20 Thread Roel de Jong
Of course it is generally possible to generate datasets for a perfectly well-defined model that are hard to fit, but in this particular case I feel it should be possible. In my observations, glmm.admb is far more numerically stable fitting GLMM's than other software I've seen. Further , I

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-19 Thread Hans Julius Skaug
Douglas Bates wrote: The Laplace method in lmer and the default method in glmm.admb, which according to the documentation is the Laplace approximation, produce essentially the same model fit. One difference is the reported value of the log-likelihood, which we should cross-check, and another

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-19 Thread Douglas Bates
On 12/19/05, Hans Julius Skaug [EMAIL PROTECTED] wrote: Douglas Bates wrote: The Laplace method in lmer and the default method in glmm.admb, which according to the documentation is the Laplace approximation, produce essentially the same model fit. One difference is the reported value of

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-17 Thread Douglas Bates
On 12/15/05, Roel de Jong [EMAIL PROTECTED] wrote: Dear R-users, because lme(r) glmmpql, which are based on Penalized Quasi Likelihood, are not very robust with Bernoulli responses, The current version of lmer takes method = PQL (the default) or Laplace or AGQ although AGQ is not available

Re: [R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-15 Thread Roel de Jong
Dear R-users, because lme(r) glmmpql, which are based on Penalized Quasi Likelihood, are not very robust with Bernoulli responses, I wanted to test glmmADMB. I run the following simulation study: 500 samples are drawn with the model specification: y =

[R] glmmADMB: Generalized Linear Mixed Models using AD Model Builder

2005-12-14 Thread Hans Julius Skaug
Dear R-users, Half a year ago we put out the R package glmmADMB for fitting overdispersed count data. http://otter-rsch.com/admbre/examples/glmmadmb/glmmADMB.html Several people who used this package have requested additional features. We now have a new version ready. The major new feature is