search for: mixed_em

...ied to code this model in R using lmer(). It turned out that R has some issues with nesting levels with fixed effect. I changed and tried a few models just for diagnostic purpose. And I found whenever I included the nesting fixed effects, I got the following error message: "Problem in .C("mixed_EM",: Singularity in backsolve, while calling subroutine mixed_EM". I am wondering whether someone can help me set up this mixed model in R. Thanks Huiyan Zhao --------------------------------------------------------------------------------------------------------- This e-mail me...

...us is: simu1<-groupedData(gf~age|id) simu.nlme<-nlme(gf~(b0 + b1 * age + b2 * max(0,(age-tau))^2),data=simu1,fixed=list(b0~1,b1~1,b2~1,tau~1), + random=list(b0~1,b1~1,b2~1,tau~1),start=c(b0=4,b1=5.32,b2=-5.29,tau=14.8)) But it seems like that there are some errors in it. Error in .C("mixed_EM",: Singularity in backsolve at level 2, block 1 I think maybe there is something wrong in my scripts, could you help me to find it? Thanks a lot Peggy