From dmurdoch at pair.com  Thu Aug 14 19:50:17 2003
From: dmurdoch at pair.com (dmurdoch@pair.com)
Date: Thu Aug 14 18:50:12 2003
Subject: [Rd] Bug in numericDeriv (was: [R] nls confidence intervals)
	(PR#3746)
Message-ID: <200308141650.h7EGoHJH016759@pubhealth.ku.dk>

Moved from r-help:

On Thu, 14 Aug 2003 09:08:26 -0700, Spencer Graves
<spencer.graves@pdf.com> wrote :

>p.s.  The following command in S-Plus 6.1 seems to work fine but 
>produces an error in R 1.7.1:
>
>nls(y~a, data=tstDf, start=list(a=1))
>Error in nlsModel(formula, mf, start) : singular gradient matrix at 
>initial parameter estimates

This looks like a bug in numericDeriv, which finds a derivative of 0
rather than 1 for da/da.  I've cc'd the author.

Duncan


[Rd] Bug in numericDeriv (was: [R] nls confidence intervals) (PR#3746)
dmurdoch@pair.com