[R] nlme graphics in a loop problem

[Liaw, Andy]

Could it be that you need print(plot(model)) inside the loop?  I believe
plot() methods in nlme are mostly lattice graphics, which needs to be
explicitly print()ed inside functions and loops.

Andy

> From: Chris Knight
> 
> Hi, I'm fitting mixed effects models using the lme function 
> of the nlme
> package. This involves using the various associated plot functions.
> However, when I attempt to fit a number of models using an 
> loop, whilst
> the models work, the plot functions fail. As a trivial example, the
> following works:
> 
> library(nlme)
> 
> graphics.off()
> x<-c(1:10)
> y<-c(1:4,7:12)
> b<-as.factor(c(rep("A",5),rep("B",5)))
> model<-lme(y~x, random=~1|b)
> plot(model)
> 
> however the following, identical code in a loop, doesn't:
> 
> graphics.off()
> for(i in 1:2){
> x<-c(1:10)
> y<-c(1:4,7:12)
> b<-as.factor(c(rep("A",5),rep("B",5)))
> model<-lme(y~x, random=~1|b)
> plot(model)
> }
> 
> Mostly this is only inconvenient, since a similar plot may be created
> successfully within the loop using plot(fitted(model),resid(model)),
> however, I'd be keen to find out whether this is a general 
> problem/sign
> of something deeper or I'm just missing something easy that could sort
> it out.
> 
> Thanks,
> Chris
> -- 
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