From rossini@blindglobe.net  Thu Sep 14 18:43:05 2000
From: rossini@blindglobe.net (A.J. Rossini)
Date: 14 Sep 2000 10:43:05 -0700
Subject: [Rd] Projects
In-Reply-To: <qxpaeda6fzk.fsf@verdi.stat.wisc.edu>
 (Saikat DebRoy's message of "14 Sep 2000 12:27:43 -0500")
References: <6rk8cfkmru.fsf@franz.stat.wisc.edu>
 <14785.241.670605.528570@gargle.gargle.HOWL>
 <873dj2ncf3.fsf@jeeves.blindglobe.net> <qxpaeda6fzk.fsf@verdi.stat.wisc.edu>
Message-ID: <87og1qlviu.fsf@jeeves.blindglobe.net>

>>>>> "SD" == Saikat DebRoy <saikat@stat.wisc.edu> writes:


>>>>> "AJR" == A J Rossini <rossini@blindglobe.net> writes:
>>>>> "MM" == Martin Maechler <maechler@stat.math.ethz.ch> writes:
    MM> 2) For Computer Scientists : "Differentiation" / Symbolic
    MM> derivatives,..

    MM> Improve the possibilities of D() and deriv(), and document
    MM> them.  Make these user-extensible.

    MM> Think about the hessian in addition to the gradient.

    AJR> Even automating/specifications for numerical derivatives
    AJR> would be nice.

    SD> The nls package has a function called numericDeriv - with a
    SD> little modification it could be used elsewhere. An earlier
    SD> version of the underlying C code is used as an example in the
    SD> R Extensions manual.

Right, and it would be nice (necessary?) for testing and verification
of the "symbolic" side of the package as well as for "drop-in" or
"change a parameter" design functionality.  As well as being a
starting point for the interface for the symbolicDeriv package.

best,
-tony


-- 
A.J. Rossini				Rsrch. Asst. Prof. of Biostatistics
BlindGlobe Networks (home/default)	rossini@blindglobe.net	
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[Rd] Projects
A.J. Rossini