Message-ID: <B9D1301370916C44B5874AF340C18B9B7F911B5389@VMAILB.uoa.abdn.ac.uk>
Date: 2009-02-10T16:54:30Z
From: Renwick, A. R.
Subject: CHOLMOD warning with GLMM
Dear All
I am trying to model the burden of fleas on field voles using a GLMM with poisson error and a nested random effect.
The random effect is (1|Farm/Margin) I have 7 farms and 14 margins (2 margins per farm) and have sampled each margin 4 times.
However, I continually get an error message even when I simplify the model. The model I am trying to run is:
bin<-lmer(fleaburden ~ sex + width + month + vole abundance + alternative host abunandance +(1|Farm/Margin), family=poisson, data=flea, REML=FALSE)
The error message:
CHOLMOD warning: ?e
Error in mer_finalize(ans) :
Cholmod error `not positive definite' at file:../Cholesky/t_cholmod_rowfac.c, line 432
Any help in understanding this error would be much appreciated.
Thanks,
Anna
Anna Renwick
Institute of Biological & Environment Sciences
University of Aberdeen
Zoology Building
Tillydrone Avenue
Aberdeen
AB24 2TZ
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