On Sat, 10 Nov 2007, Anders Schwartz Corr wrote: > I'm getting an error message using polr(): > > Error in optim(start, fmin, gmin, method = "BFGS", hessian = Hess, ...) : > initial value in 'vmmin' is not finite > > The outcome variable is ordinal and factored, and the independant variable > is continuous. I've checked the source code for both polr() and optim() > and can't find any variable called "vmmin" as referenced in the error > message.
vmmin is the C code for optim(method="BFGS"), so I don't know how you could have missed it. See line 304 of src/main/optim.c! What you did not say is that you were using polr(method="cauchit"), where finding starting values is notoriously difficult. Either supply starting values or call polr(..., Hess=TRUE) if you know you are going to be calling summary() on the result. > > Any suggestions welcome. > > Thanks, > > Anders > > >> summary(data$ordaodb) > 0 1 2 3 4 > 8228 3505 1755 559 1757 >> summary(data$gpconc) > Min. 1st Qu. Median Mean 3rd Qu. Max. > 0.138 0.280 0.313 0.305 0.332 0.515 >> formula<-data$ordaodb~data$gpconc >> propensityordaodb.plr <- polr(formula, method="cauchit") >> propensityordaodb.plr > Call: > polr(formula = formula, method = "cauchit") > > Coefficients: > data$gpconc > 8.508 > > Intercepts: > 0|1 1|2 2|3 3|4 > 2.651 3.569 4.593 5.304 > > Residual Deviance: 40009.85 > AIC: 40019.85 >> summary(propensityordaodb.plr) > > Re-fitting to get Hessian > > Error in optim(start, fmin, gmin, method = "BFGS", hessian = Hess, ...) : > initial value in 'vmmin' is not finite -- 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@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
