[R] convergence in polr
Hello splus-users, I am trying to fit a regression model for an ordered response factor. So I am using the function polr in library(MASS). My data is a matrix of 1665 rows and 63 columns (one of the column is the dependent variable). The code I use is polr(as.ordered(q23p)~.,data=newdatap) but I am getting the following warning message singularity encountered in: nlminb.1(temp, p, liv, lv, objective, gradient, bounds, scale) I looked in the MASS help for nlminb and I found that for the function nlminb(start, objective, gradient=NULL, hessian=NULL, scale=1, control=NULL, lower=-Inf, upper=Inf) when returning a warning message of singularity means that the optimization algorithm thinks it can't make any further progress because it has too many degrees of freedom. It usually means that the objective function is either not differentiable, or it may not have an optimum. So for my data an optimum can't be obtained. Is this true? Can I ignore this warning message since what I want to find is values for the boundaries? Will the values for the boundaries be accurate even though I get the warning message? __ [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
Re: [R] convergence in polr
I am really sorry. I was supposed to send it to the Splus users but by mistake I sent to the R-users. Sorry once again On Feb 24 2004, Prof Brian Ripley wrote: Why have you sent a message about S-PLUS to R-help, one that has already been answered on S-news? There is no function nlminb in R. On 24 Feb 2004, C. Spanou wrote: Hello splus-users, I am trying to fit a regression model for an ordered response factor. So I am using the function polr in library(MASS). My data is a matrix of 1665 rows and 63 columns (one of the column is the dependent variable). The code I use is polr(as.ordered(q23p)~.,data=newdatap) but I am getting the following warning message singularity encountered in: nlminb.1(temp, p, liv, lv, objective, gradient, bounds, scale) I looked in the MASS help for nlminb and I found that for the function nlminb(start, objective, gradient=NULL, hessian=NULL, scale=1, control=NULL, lower=-Inf, upper=Inf) when returning a warning message of singularity means that the optimization algorithm thinks it can't make any further progress because it has too many degrees of freedom. It usually means that the objective function is either not differentiable, or it may not have an optimum. So for my data an optimum can't be obtained. Is this true? Can I ignore this warning message since what I want to find is values for the boundaries? Will the values for the boundaries be accurate even though I get the warning message? __ [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 __ [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
[R] polr warning message optim
Hello R-users, I am using polr function in library(MASS). The code I use is the following: polr(as.ordered(q23p)~.,data=as.data.frame(datapr2)) where datapr2 is a matrix of 63 columns (together with the dependent variable) and 1665 rows. But I am receiving the warning message Error in optim(start, fmin, gmin, method = BFGS, hessian = Hess, ...) I would be very greatfull if anyone could suggest something. Thank you __ [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
[R] (no subject)
Hello I am doing a project on ordered logit/probit models using Splus. I am using the polr function in library(MASS) which is exactly the same code as in R. Unfortunatelly I am not very succesfull with it. The code I used was: polr(factor(resp)~.,data=data3) # data3 does not consist the resp variable But I am getting the same warning message 21 times. The message is the following: 1: singularity encountered in: nlminb.1(temp, p, liv, lv, objective, gradient, bounds, scale) I guess the corresponding warning message in R is: Error in optim(start, fmin, gmin, method = BFGS, hessian = Hess) I would be very greatfull if someone could suggest what it might be wrong with my model anh how I can overcome it. Thanking you in advance Charis Spanou __ [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
