[Rd] how to use update if method for formula is not in namesp ace?

[Liaw, Andy]

> From: Prof Brian Ripley 
> 
> On Tue, 14 Sep 2004, Liaw, Andy wrote:
> 
> > Dear R-devel,
> > 
> > I've noticed that if the method for formula is not exported 
> in NAMESPACE,
> > then update() would fail.  As an example:
> > 
> > > library(e1071)
> > > data(iris)
> > > iris.svm <- svm(Species ~ ., data=iris)
> > > update(iris.svm)
> > Error in eval(expr, envir, enclos) : couldn't find function 
> "svm.formula"
> > 
> > The same thing happens with randomForest, because 
> randomForest.formula() was
> > not exported.  Is this the intended behavior of update()?  
> What would be the
> > preferred work-around?
> 
> It is.   randomForest.formula should be written to report its 
> call as to 
> randomForest.  Take a look at e.g. rlm.formula.

Got it!  Works now.  Many thanks!

Best,
Andy

 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> 
> 
>