[R] warning message for lmer model with poisson family

2008-06-04 Thread arams

Hello,

I'm trying to run an lmer model with family poisson but receive the
following
warning message: 

model<-lmer(count~tem+dat+alt+year+tem:dat+tem:alt+tem:year+dat:alt+dat:year+alt:year+(1|id),family=poisson)
Error in objective(.par, ...) : 
  Leading minor of order 2 in downdated X'X is not positive definite

I'm using the newest version of R and recently installed the following
libraries: (lme4, matrix, lattice).
I don't understand what the warning message means or know how to fix it,
please help!
My response variable is a count variable (n=551); 212 with value = 0, and
the rest range between 1-3.
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Re: [R] warning message for lmer model with poisson family

2008-06-04 Thread Steven McKinney

Looks like you have some independent
variables in your model that correlate
perfectly so your design matrix is
not of full rank, probably because
your independent variable data is not
balanced.

Does a simpler fit such as
  model<-lmer(count~tem+(1|id),family=poisson)
give you a result?

You might need to build up your model from such
a simple one, adding one new term at a time
until you find the one that causes the issue.

You probably do not have enough balanced
data to allow fitting such a complex
model.

HTH

Steve McKinney

-Original Message-
From: [EMAIL PROTECTED] on behalf of arams
Sent: Wed 6/4/2008 5:18 PM
To: r-help@r-project.org
Subject: [R]  warning message for lmer model with poisson family
 

Hello,

I'm trying to run an lmer model with family poisson but receive the
following
warning message: 

model<-lmer(count~tem+dat+alt+year+tem:dat+tem:alt+tem:year+dat:alt+dat:year+alt:year+(1|id),family=poisson)
Error in objective(.par, ...) : 
  Leading minor of order 2 in downdated X'X is not positive definite

I'm using the newest version of R and recently installed the following
libraries: (lme4, matrix, lattice).
I don't understand what the warning message means or know how to fix it,
please help!
My response variable is a count variable (n=551); 212 with value = 0, and
the rest range between 1-3.
-- 
View this message in context: 
http://www.nabble.com/warning-message-for-lmer-model-with-poisson-family-tp17659512p17659512.html
Sent from the R help mailing list archive at Nabble.com.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.