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Re: floor problems

  • To: mathgroup at
  • Subject: [mg8288] Re: [mg8140] [mg8113] floor problems
  • From: "P.J. Hinton" <paulh>
  • Date: Sun, 24 Aug 1997 04:46:28 -0400
  • Organization: Wolfram Research, Inc.
  • Sender: owner-wri-mathgroup at

Sean Ross wrote:

> Will Self wrote:
> >
> > Hi Sean, I just resubscribed.  I think that any reasonable human being
> > should reasonably expect that Mathematica should give the correct
> > answers for *both* of those Floor expressions, as indeed my old
> > version 2.0 does.  It is all very well to exhort people to be careful
> > and be extra-aware, but if one has to go around walking on eggs, then
> > what becomes of the usefulness of Mathematica?  I say, let the blame
> > rest where it should, on WRI.
> I always "walk on eggshells" and never trust a numerical coprocessor or
> a compiler further than I can spit.  We just had a post where someone
> with a Unix based system does not have the error that your powerPC chip
> and my Pentium chip do.  I don't think this kind of error has anything
> to do with mathematica, but with the way the numeric coproccessor
> handles floating point and integer conversions.  I think the wolfram
> people were just talented in exposing the error in the numeric
> coprocessor.

Anyone who would ever totally and blindly accept the results that come
from a numerical algorithm deserve what he or she gets.  For an interesting
discussion on this, read the book _Real Computing Made Real_ by 
Forman Acton (except that section in the Exhortation titled "Should
I use Mathematica to solve my problem?" :-) ).  Very enlightening
stuff, indeed.

P.J. Hinton	
Mathematica Programming Group		paulh at
Wolfram Research, Inc.
Disclaimer: Opinions expressed herein are those of the author alone.

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