lme4 and cholmod warning
On Mon, 2 Aug 2010, Marie-Agnes wrote:
Dears, I encoutered the following message, when using lme4 : Warning messages: 1: In mer_finalize(ans) : Cholmod warning 'not positive definite' at file:../Cholesky/t_cholmod_rowfac.c, line 432 2: In mer_finalize(ans) : Cholmod warning 'not positive definite' at file:../Cholesky/t_cholmod_rowfac.c, line 432 3: In mer_finalize(ans) : singular convergence (7) I saw the same kind of message on your mailing list, but then I could not follow up the reply. My model was:
ga1p<-glmer(A1P~T131006+typop*mr+(1|pop/fam), family= poisson)
The dataset is unbalanced: there are 16 "pop", with a varying number of "fam" within pop. In one population, there is only one family. The problem is related to T131006 (when omitted, glmer works). When I replace this covariate by another one, I have the same message, except in one particular case.
Is T131006 continuous or categorical? If the latter, what do table(T131006) and table(pop,T131006) look like? Cheers, David Duffy
| David Duffy (MBBS PhD) ,-_|\ | email: davidD at qimr.edu.au ph: INT+61+7+3362-0217 fax: -0101 / * | Epidemiology Unit, Queensland Institute of Medical Research \_,-._/ | 300 Herston Rd, Brisbane, Queensland 4029, Australia GPG 4D0B994A v