Hi Steven,

Thank you for your reply.

But I need to this to prevent the error from stopping the iteration. I need
to count how many time the model fits without error.

cahn



On Thu, Feb 4, 2010 at 3:29 PM, Steven McKinney <smckinney@bccrc.ca> wrote:

>
> > -----Original Message-----
> > From: r-sig-mixed-models-bounces@r-project.org [mailto:r-sig-mixed-
> > models-bounces@r-project.org] On Behalf Of Chaehyung Ahn
> > Sent: Thursday, February 04, 2010 9:36 AM
> > To: r-sig-mixed-models@r-project.org
> > Subject: [R-sig-ME] nonlinear models with warnOnly
> >
> > Dear list,
> >
> > I need to make nls() or gnls() function to return something like "NA"
> > when
> > it fails to fit. I found I can use "warnOnly", but I cannot make it
> > work.
> >
> > In the following program. I intentionally make it fail by making very
> > wrong
> > initial values, but the "out" is empty. What is wrong with my approach?
> >
> > Many thanks in advance!
> >
> > library(nlme)
> > out<- gnls(conc~SSbiexp(time,A,lalpha,B,lbeta),
> >           start=list(A=-1,lalpha=2,B=20,lbeta=4),
> >           weights=varPower(fixed=1),control=list(warnOnly=TRUE),
> >           data=Indometh,subset=Subject==1)
>
> Have you explored using the "try()" or "tryCatch()"
> strategies?
>
>
>  out <- try(gnls(conc~SSbiexp(time,A,lalpha,B,lbeta),
>            start=list(A=-1,lalpha=2,B=20,lbeta=4),
>           weights=varPower(fixed=1),
>            data=Indometh,subset=Subject==1))
>
> Then if the fit fails, variable "out" will have class "try-error"
> so you can check the class of out and decide what to do etc.
>
>
> (I tried your example in R 2.10.1 on a Mac and R 2.9.2 on a PC and
> get an error that I haven't been able to track down yet.
> > require("nlme")
> Loading required package: nlme
> > out<- gnls(conc~SSbiexp(time,A,lalpha,B,lbeta),
> +            start=list(A=-1,lalpha=2,B=20,lbeta=4),
> +            weights=varPower(fixed=1),control=list(warnOnly=TRUE),
> +            data=Indometh,subset=Subject==1)
> Error: object 'convIter' not found
> >
> >
> >  out<- try(gnls(conc~SSbiexp(time,A,lalpha,B,lbeta),
> +            start=list(A=-1,lalpha=2,B=20,lbeta=4),
> +            weights=varPower(fixed=1),
> +            data=Indometh,subset=Subject==1))
> Error : object 'convIter' not found
> >
> )
>
> Best
>
> Steve McKinney
>
>
> >
> >
> >
> >
> > --
> > Chaehyung Ahn, Ph.D.
> > 4033 Remington Oaks Circle
> > Cary, NC 27519
> > Daum Cafe: http://cafe.daum.net/biometrika
> > Blog: http://cahn88.blogspot.com/
> >
> >       [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-mixed-models@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models
>
>
>
>
> Steven McKinney, Ph.D.
>
> Statistician
> Molecular Oncology and Breast Cancer Program
> British Columbia Cancer Research Centre
>
> email: smckinney -at-  bccrc +dot+ ca
> tel: 604-675-8000 x7561
>
> BCCRC
> Molecular Oncology
> 675 West 10th Ave, Floor 4
> Vancouver B.C.
> V5Z 1L3
>
> Canada
>
>


-- 
Chaehyung Ahn, Ph.D.
4033 Remington Oaks Circle
Cary, NC 27519
Daum Cafe: http://cafe.daum.net/biometrika
Blog: http://cahn88.blogspot.com/

	[[alternative HTML version deleted]]


