Message-ID: <50d1c22d0612231336p4811fb8ct4862e98b3561bd2d@mail.gmail.com>
Date: 2006-12-23T21:36:09Z
From: ivo welch
Subject: simple NLS query
In-Reply-To: <Pine.LNX.4.64.0612231251140.8986@tajo.ucsd.edu>
duh! thanks.
summary(nls( y ~ 1/(1+b*x), data = d, start= list(b=0.5)))
works, of course.
/iaw
On 12/23/06, Charles C. Berry <cberry at tajo.ucsd.edu> wrote:
>
>
> See the nls help page:
>
> Arguments
>
> formula a nonlinear model formula including variables and parameters.
>
> and you have
>
> y ~ 1/(1+x)
>
> which does not seem to match the requirement of the help page.
>
> What are the unknowns for which you were hoping nls would solve??
>
> On Sat, 23 Dec 2006, ivo welch wrote:
>
> > dear R experts: I am trying to orient myself using nls(). so, I am
> > just trying to copy and adapt an example in the nls() function:
> >
> > > d= data.frame( y= runif(10), x= runif(10) )
> > > nls( y ~ 1/(1+x), data = d, start= list(x=0.5,y=0.5), trace=TRUE)
> > Error in n%%respLength : non-numeric argument to binary operator
> >
> > the error message seems internal, so it would be nicer if there was a
> > better error message. I presume my mistake is so basic that an R
> > expert sees the problem in 1 second.
> >
> > (if I manage to figure this one out, my next step will be to learn how
> > I can get [presumably asymptotic ML] standard errors on estimated
> > coefficients.
>
> Look at the help page for nls. Specifically under 'Details'.
>
>
> I hope I am looking in the right direction with the
> > nls() function.)
> >
> > advice appreciated.
> >
> > regards,
> >
> > /ivo
> >
> > ______________________________________________
> > R-help at 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
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
> Charles C. Berry (858) 534-2098
> Dept of Family/Preventive Medicine
> E mailto:cberry at tajo.ucsd.edu UC San Diego
> http://biostat.ucsd.edu/~cberry/ La Jolla, San Diego 92093-0717
>
>
>