From rossini@blindglobe.net  Fri Sep 15 04:26:33 2000
From: rossini@blindglobe.net (A.J. Rossini)
Date: 14 Sep 2000 20:26:33 -0700
Subject: [Rd] Projects
In-Reply-To: <39c38587.1708646@julian.uwo.ca>
 (Duncan Murdoch's message of "Fri, 15 Sep 2000 02:15:52 GMT")
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>
 <87og1qlviu.fsf@jeeves.blindglobe.net> <39c38587.1708646@julian.uwo.ca>
Message-ID: <87n1ha1gk6.fsf@jeeves.blindglobe.net>

>>>>> "DM" == Duncan Murdoch <dmurdoch@pair.com> writes:


    DM> On 14 Sep 2000 10:43:05 -0700, you wrote:
    >> 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.

    DM> I'm not sure if this is what Tony has in mind, but something I
    DM> always do when working with optimizers that take a supplied
    DM> derivative is to write a little numerical derivative routine
    DM> to check that my calculus and programming were done correctly.
    DM> Putting that into a single function which took arguments just
    DM> like the ones you pass to the optimizer would be very
    DM> convenient.

That's exactly it.  (but perhaps have at least the 3 basic forms --
f(point + eps) - f(point), f(point + eps/2) - f(point - eps/2),
f(point) - f(point - eps)).

best,
-tony

-- 
A.J. Rossini				Rsrch. Asst. Prof. of Biostatistics
BlindGlobe Networks (home/default)	rossini@blindglobe.net	
UW Biostat/Center for AIDS Research	rossini@u.washington.edu	
FHCRC/SCHARP/HIV Vaccine Trials Net	rossini@scharp.org

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[Rd] Projects
A.J. Rossini