On Thu, 10 Jun 2004, Prof Brian Ripley wrote: > On Thu, 10 Jun 2004, Prof Brian Ripley wrote: > > > Around R 1.2.x the notion was introduced that variables should be looked > > for in the environment of a formula. Functions using model.frame got > > converted to do that, but nls did not. I guess that the best way forward > > is to ensure that nls (and nlsModel) does search the environment of the > > formula for functions. > > It transpires that is rather easy to achieve. At the top of nlsModel and > nlsModel.plinear use > > env <- new.env(parent=environment(form)) > > instead of > > env <- new.env() > > This then automatically searches for objects used in the formula > > Notes > > 1) nls is in a namespace, so you need to fix the copy in the namespace or > fix the source code and rebuild. > > 2) This will add to the baggage needed when you save() a nls fit in a > workspace. I think that is inevitable as we cannot just identify the > funtions used in the formula (as they might call other functions in the > local environment), and it is necessary to capture the objects needed to > evaluate the formula for the predict() method to be reliable. > > We could call all.names() to get the names of functions used directly in > the formula, but that seems not good enough (previous para). > > Question to the cognescenti: is the price in 2) too great for this to be > done for 1.9.1? I will put the change in R-devel for now.
I don't think so. The fit objects already contain the formula (via the environment of the functions in the structure). Since environment sharing is preserved within a serialization, this means the change would only alter the parent of the env environment, not add anything extra. Best, luke -- Luke Tierney University of Iowa Phone: 319-335-3386 Department of Statistics and Fax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: [EMAIL PROTECTED] Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
