Dear Peter, It's hard to know from your message what the source of the problem might be, but a good guess is that data are ill-conditioned in some way. Some things to check: What's the distribution of the response variable? (Are there many categories, some with very few observations?) How ill-conditioned is the model matrix?
I hope this helps, John > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Peter Flom > Sent: Friday, October 08, 2004 9:18 AM > To: [EMAIL PROTECTED] > Subject: [R] polr and optim question > > Hello again > > I am trying to fit an ordinal logistic model using the polr > function from MASS. When I run > > model.loan.ordinal <- polr(loancat~age + sex + racgp + > yrseduc + needlchg + gallery + sniffball + smokeball + > sniffher + smokeher + nicocaine + inject + > poly(year.of.int,3) + druginj + > inj.years) > > > I get an error > > Error in optim(start, fmin, gmin, method = "BFGS", hessian = > Hess, ...) > : > non-finite value supplied by optim > > > I checked in the MASS book, and in John Fox's book An R and > S-Plus Companion to Applied Regression, I also checked in > R-help, where a similar problem was solved by using > as.ordered, but that did not help here. > > Any help appreciated > > Thanks > > > > Peter L. Flom, PhD > Assistant Director, Statistics and Data Analysis Core Center > for Drug Use and HIV Research National Development and > Research Institutes > 71 W. 23rd St > www.peterflom.com > New York, NY 10010 > (212) 845-4485 (voice) > (917) 438-0894 (fax) > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
