[R-sig-ME] [R] lme4 : lmer : convergence problem and other errors
yufeng at nsm.umass.edu
yufeng at nsm.umass.edu
Thu Jul 3 15:30:16 CEST 2008
Dear R-user,
I am trying to use the R "lmer" function in lme4 package to fit a non linear
mixed effects model. The model I wand to fit is at an individual level with 4
parameters. For all parameters both fixed and random effects have to be
estimated, as well as their covariance matrix (see the formula bellow).
y~x1+x1^2+x2+x2^2.
I tried to fit the model with my data sets, but most of the time, R returns an
error message.
there are three main types of errors :
- In mer_finalize(ans, verbose) :
function evaluation limit reached without convergence (9)
- there are false convergence (8)
-there are singular convergence (7)
Do you know how to resolve these problems. Is there a way to modify the
parameters of the maximization algorithm to avoid these error messages?
Thank you for your help and answers.
Regards,
Yufeng Zhang
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