[Rd] Bug in numericDeriv (was: [R] nls confidence intervals) (PR#3746)

dmurdoch at pair.com dmurdoch at pair.com
Thu Aug 14 19:50:17 MEST 2003

Moved from r-help:

On Thu, 14 Aug 2003 09:08:26 -0700, Spencer Graves
<spencer.graves at 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.


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