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Re: RE: Re: Re: Accuracy and Precision

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  • Subject: [mg37117] Re: [mg37090] RE: [mg37076] Re: [mg37058] Re: Accuracy and Precision
  • From: Selwyn Hollis <selwynh at>
  • Date: Thu, 10 Oct 2002 03:20:56 -0400 (EDT)
  • References: <>
  • Sender: owner-wri-mathgroup at

DrBob wrote:
> Let's be realistic.  If you want 60 digits of precision, too bad! -- in
> the real world.  There's nothing we can measure that closely.  Drug
> concentrations in clinical trials are generally measured within 15%, for
> instance.  Even machine precision is more than can be realistically
> expected in any application I can think of.  Even getting a satellite to
> Jupiter probably involves more error in the final result than machine
> precision.  (If not, it's because we rely on ongoing corrections and
> natural factors that put the satellite where it should be, such as
> gravity drawing it toward each rendezvous -- not on that kind of
> precision in propulsion or guidance.)
> So... unless all numerics in a problem have a theoretical origin, and
> could be represented in Mathematica as Infinite precision expressions...
> all this talk of higher-precision computation seems futile.

...Except in the very rare instance when one needs to do intermediate 
calculations with, e.g., 60 digits of precision in order to get only a 
few correct digits of the final answer.

The length of this thread is surely proof of the need for a definitive 
reference on the topic. Has there been a Mathematica-centered numerical 
analysis book published since Skeel & Keiper?

Selwyn Hollis

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