From p.dalgaard@biostat.ku.dk  Mon Apr 26 15:54:51 1999
From: p.dalgaard@biostat.ku.dk (Peter Dalgaard BSA)
Date: 26 Apr 1999 16:54:51 +0200
Subject: [S] uniroot -- doesn't work recursively
In-Reply-To: Adelchi Azzalini's message of "Mon, 26 Apr 1999 10:12:35 +0100"
References: <199904220944.LAA10647@gwen.stat.unipd.it.> <199904231713.TAA15277@sophie.ethz.ch> <x2yajhh9in.fsf@blueberry.kubism.ku.dk> <37242E03.63BEAB06@jrc.it>
Message-ID: <x2n1zvv3d0.fsf@blueberry.kubism.ku.dk>

Adelchi Azzalini <adelchi.azzalini@jrc.it> writes:

> Martin Maechler wrote:
> 
> ) However, note that R currently has the same problem as S-plus:
> 
> ) Uniroot() doesn't work reliably, recursively.
> ) When you found it to be better, you were just lucky.
> 
> Right.  I realised later on that R seemed to behave better but 
> it could not work properly since it calls a Fortran (66? 77?) routine.
> It just happen to produce less obviously wrong answers than Splus.
> In fact more tests confirm wrong answers, but not as non-sensical 
> as those from Splus.

The development version now has a reentrant uniroot(). Those of you
outside R-core who are interested can get it in the next development
snapshot. (and perhaps remind me what is the proper typecast to avoid
the following error message...)

optimize.c: In function `do_zeroin':
optimize.c:205: warning: passing arg 3 of `zeroin' from incompatible pointer type

Binaries are a bit further into the future, I'm afraid.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907
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[S] uniroot -- doesn't work recursively
Peter Dalgaard BSA