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

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.

-- 
Brian D. Ripley,                  ripley@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