Dear all,
I am using the nlme package to find the best model using non-linear
mixed effects model.
After the all the other things needed, I did
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=B~1,start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
and it was ok.
However, the data showed to need random parameters at both the
intercept and the slope.
And I can not understand why do I always get an error message like:
Error in parse(text = paste("~", paste(nVal, collapse =
"/"))) :
unexpected end of input in "~ "
or
Error in nlme.formula(NShrubs ~ A * exp(-B * CED), data = DataSg,
fixed = list(A ~ :
random formula must be a formula or list of formulae
Could you please tell me where/what am I doing wrong (in any of the
following options I have uses)?
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=list(B~1),start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=list(B~1(SITE)),start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=~CED,start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=list(A~I,B~I),start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=~1,start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=~1|SITE,start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
> M1<- nlme(NShrubs~A*exp(-B*CED),data=DataSg,fixed=list
(A~SITE,B~1), random=~1|SITE/T,start=list(fixed=c
(1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,0.0038)),control=lmc)
I would be really greatful if you can please help me on this.
Best regards,
Sara Maltez Mouro
Centro de Ecologia Funcional
Departamento de Botânica
Universidade de Coimbra
sara@gmesintra.com
www.uc.pt/ecology/saramaltezmouro
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