[R-sig-ME] Alternatives to lmer

[Iker Vaquero Alba]

   Yes, that could be a good idea, I definitely have to learn how to use the function "try()". But it's especially annoying this is not working because I have implemented a few similar models before with other dependent variables and all of them worked fine.  

   I have attached the data set I am using, hope that helps.

   Thank you very much.

   Iker

--- El dom, 16/1/11, Murray Jorgensen <maj at waikato.ac.nz> escribió:

De: Murray Jorgensen <maj at waikato.ac.nz>
Asunto: Re: [R-sig-ME] Alternatives to lmer
Para: "Iker Vaquero Alba" <karraspito at yahoo.es>
CC: r-sig-mixed-models at r-project.org
Fecha: domingo, 16 de enero, 2011 21:53

Hi Iker,

you don't give us information about your data set or the number of 
levels of your factors. Although you have removed some of the 
interactions from the model it would seem that you are trying to 
estimate a very large number of parameters in the fixed part of the 
model. I would guess that many would be unidentifiable. Any software 
that you might try could have trouble fitting this model. Why don't you 
start off more slowly with main effects only and then use try() to 
identify interactions that would be worth adding to your model?

Murray Jorgensen

On 17/01/2011 9:15 a.m., Iker Vaquero Alba wrote:
>
>     Hello:
>
>     As I posted several days ago, I was trying to implement this model:
>
> fledgecoltailmodel1<-lmer(nfledge~sex*briventral*inslarge*weatherpc1*tlength-sex:briventral:inslarge:weatherpc1:tlength-sex:briventral:inslarge:weatherpc1-sex:briventral:inslarge:tlength-sex:briventral:weatherpc1:tlength-sex:inslarge:weatherpc1:tlength-briventral:inslarge:weatherpc1:tlength-sex:briventral:inslarge-sex:briventral:weatherpc1-sex:briventral:tlength-sex:inslarge:weatherpc1-sex:inslarge:tlength-sex:weatherpc1:tlength-briventral:inslarge:weatherpc1-briventral:inslarge:tlength-briventral:weatherpc1:tlength-inslarge:weatherpc1:tlength+(site|pair),family=poisson)
>
>     but I got the error message:
>
>     Error in asMethod(object) : matrix is not symmetric [1,2]
>
>    as no one seems to know what could be the reason for that or how to find a solution, I was thinking that maybe I could try using another function. Starting with the one which seems more similar to "lmer", I tried with "GLMM", which I read in some post it could be taken from "lme4" package. However, when I try to use it (either "glmm" or "GLMM"), R tells me such function doesn't exist.
>
>     Do you know why this could be happening? Do you know of any other functions I could use to fit my model? I was thinking as well of "MCMCglmm", but I'm not sure I can apply it to my model and I don't think I'm expert enough as to deal with its syntax or the overdispersion problems.
>
>     I am using R 2.12.0
>
>     Thank you very much for your help!
>
>
>
>     Iker Vaquero-Alba
>
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-- 
Dr Murray Jorgensen      http://www.stats.waikato.ac.nz/Staff/maj.html
Department of Statistics, University of Waikato, Hamilton, New Zealand
Email: maj at waikato.ac.nz    majorgensen at ihug.co.nz      Fax 7 838 4155
Phone  +64 7 838 4773 wk    Home +64 7 825 0441   Mobile 021 0200 8350



      
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