Adai, using traceback() helps, as does giving a reproducible example when reporting a problem.
However, the problem is I think the line d.glm <- update(glmfit, data = data[j.in, , drop = FALSE]) in cv.glm. I think that should be d.glm <- eval.parent(update(glmfit, data = data[j.in, , drop = FALSE], evaluate = FALSE)) as in add.default and many other places. Could you please confirm that is the cause? Brian On Mon, 25 Jul 2005, Adaikalavan Ramasamy wrote: > I am trying to write a wrapper for the last example in help(cv.glm) that > deals with leave-one-out-cross-validation (LOOCV) for a logistic model. > This wrapper will be used as part of a bigger program. > > Here is my wrapper funtion : > > logistic.LOOCV.err <- function( formu=NULL, data=NULL ){ > > cost.fn <- function(cl, pred) mean( abs(cl-pred) > 0.5 ) > > glmfit <- glm( formula=formu, data=data, family="binomial" ) > print("glmfit is OK") > > err <- cv.glm( data=data, glmfit=glmfit, > cost=cost.fn, K=nrow(data) )$delta[2] > print("cv.glm OK") > } > > > When I run the above function line by line with the arguments from > below, it works fine. But when I call it as function, I get this : > > rm( glmfit, formu, cv.err ) # cleanup if required > logistic.LOOCV.err( formu=as.formula(r~stage+xray+acid), data=nodal ) > > logistic.LOOCV.err( formu=as.formula(r~stage+xray+acid), data=nodal ) > [1] "glmfit is OK" > Error in model.frame(formula = formu, data = data[j.in, , drop = > FALSE], : > Object "formu" not found > > > I think this has something to do with formula and environments but I do > not know enough to solve it myself. I searched the archive without much > help (perhaps I was using the wrong keywords). > > Any help would be very much appreciated. Thank you. > > Regards, > -- > Adaikalavan Ramasamy [EMAIL PROTECTED] > Centre for Statistics in Medicine http://www.ihs.ox.ac.uk/csm/ > Wolfson College Annexe Tel : 01865 284 408 > Linton Road, Oxford OX2 6UD Fax : 01865 284 424 > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html