Hi, I am using Splus to run a multiphase mixed-effects model. The quations of the models are as below: gf[ij]=b0[i]+b1[i]*age[ij]+b2[i]*max(0,(age[ij]-tau[i]))^2+e[ij] b0[i]=b00+e[i0] b1[i]=b10+e[i1] b2[i]=b20+e[i2] tau[i]=tau+e[i3] i: 1,2,...,100 subjects j: 1,2,...,6 occasions The main scripts of Splus 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
"Lijuan Wang" <lw7s at cms.mail.virginia.edu> writes:> I am using Splus ...So why post to an R list? best, -tony -- Anthony Rossini Research Associate Professor rossini at u.washington.edu http://www.analytics.washington.edu/ Biomedical and Health Informatics University of Washington Biostatistics, SCHARP/HVTN Fred Hutchinson Cancer Research Center UW (Tu/Th/F): 206-616-7630 FAX=206-543-3461 | Voicemail is unreliable FHCRC (M/W): 206-667-7025 FAX=206-667-4812 | use Email CONFIDENTIALITY NOTICE: This e-mail message and any attachme...{{dropped}}
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