Dear R-help list readers,
I am fitting a mixed model using the lme function (R V 2.3.1 for
Windows). This is an example:
dep<-c(25,40,33.33,60,70.83,72,71.43,50,40,53.33,64,54.17,60,53.57)
yes<-c(0,1,2,3,4,5,6,0,1,2,3,4,5,6)
treat<-c(1,1,1,1,1,1,1,0,0,0,0,0,0,0) #factor
If I now fit a model with random slopes as well as intercepts:
model1<-lme(dep~yes,random=yes|treat)
R encounters the following problem:
Fehler in lme.formula(dep ~ yes, random = ~yes | treat) :
iteration limit reached without convergence (9)
Following other instructions on that problem, I tried to adjust the
iteration limits and tolerances using lmeControl(), however this did not
work.
Can someone help me?
Best regards,
Ralf
On 2/28/07, Ralf Sommerfeld <sommerfeld at mpil-ploen.mpg.de> wrote:> Dear R-help list readers, > > I am fitting a mixed model using the lme function (R V 2.3.1 for > Windows). This is an example: > > dep<-c(25,40,33.33,60,70.83,72,71.43,50,40,53.33,64,54.17,60,53.57) > yes<-c(0,1,2,3,4,5,6,0,1,2,3,4,5,6) > treat<-c(1,1,1,1,1,1,1,0,0,0,0,0,0,0) #factor > > If I now fit a model with random slopes as well as intercepts: > > model1<-lme(dep~yes,random=yes|treat) > > R encounters the following problem: > > Fehler in lme.formula(dep ~ yes, random = ~yes | treat) : > iteration limit reached without convergence (9) > > Following other instructions on that problem, I tried to adjust the > iteration limits and tolerances using lmeControl(), however this did not > work. > > Can someone help me?Not really. You're trying to estimate three variance-covariance parameters from two groups and just about any way you try to do that will encounter difficulties.