Displaying 2 results from an estimated 2 matches for "th2b".
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2007 Jul 18
0
multicollinearity in nlme models
I am working on a nlme model that has multiple fixed effects (linear and nonlinear) with a nonlinear (asymptotic) random effect.
asymporig<-function(x,th1,th2)th1*(1-exp(-exp(th2)*x))
asymporigb<-function(x,th1b,th2b)th1b*(1-exp(-exp(th2b)*x))
mod.vol.nlme<-nlme(fa20~(ah*habdiv+ads*ds+ads2*ds2+at*trout)+asymporig(da.p,th1,th2)+
asymporigb(vol,th1b,th2b),
fixed=ah+ads+ads2+at+th1+th2+th1b+th2b~1,
random=pdBlocked(list(th1~1,th2~1)),
start=c(ah=.5524,ads=.8,ads2=-.1,at=-1,th1=2.542,th2=-7.117,...
2009 Jun 25
2
crr - computationally singular
...les.
In case a:
> covaea <- cbind(sexa,fsha,fdra,nsigna,eega,th1a,th2a,stype1a,stype2a,stype3a,pgu1a,pgu2a,log(agea),firstinta/1000,totsezbasea)
> fita <- crr(snearma$with.Withtime,csaea,covaea,failcode=2,cencode=0)
and in case b:
> covaeb <- cbind(sexb,fshb,fdrb,nsignb,eegb,th1b,th2b,stype1b,stype2b,stype3b,stype4b,stype5b,pgu1b,pgu2b,(ageb/10)^(-1),firstintb,log(totsezbaseb))
> fitb <- crr(snearmb$with.Withtime,csaeb,covaeb,failcode=2,cencode=0)
csaea and csaeb are the censoring indicators for a and b respectively
which equal 1 for the event of interest, 2 for the compe...