
Hi, I am running a model with lmer and I had this message from R (2.12)
> Model<-lmer(freq ~ ln_age_rel + ppt_vis + gps_dec + tempsq + (1|espece/nestid), family=poisson)Messages d'avis :1: In mer_finalize(ans) :  Cholmod warning 'not positive definite' at file:../Cholesky/t_cholmod_rowfac.c, line 4322: In mer_finalize(ans) :  Cholmod warning 'not positive definite' at file:../Cholesky/t_cholmod_rowfac.c, line 4323: In mer_finalize(ans) : singular convergence (7)> summary (Model)Erreur dans asMethod(object) : matrix is not symmetric [1,2]
Can anyone give me a clue about what the message means?> I noticed that it appears most of the time when I try to include the (temperature^2). 
Thank you
Marie-Helene 		 	   		  
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