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Off by 0.00000001, Why?

• To: mathgroup at smc.vnet.net
• Subject: [mg37378] Off by 0.00000001, Why?
• From: "Steven T. Hatton" <hattons at globalsymmetry.com>
• Date: Fri, 25 Oct 2002 02:48:38 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

I'm going through Dr. Maeder's book, _Compute Science with Mathematica_, 
entering the examples into Mathematica and evaluating them.  Here is my 
current notebook:
http://baldur.globalsymmetry.com/proprietary/com/wri/notebooks/csm-examples.nb

I've Noticed that in a few instances my results differ slightly from his.  I'm 
wondering why this is happeneing.  One would expect that the same algorithm 
would produce identical results regardless of the system on which it was run.  
I'm running on 4.2, and it's certain Dr Mäder was using an earlier version.  
Could that be the cause of the descrepency?  

One example is the very last evaluation in section 1.1.6.  His book shows 
0.00157909, whereas I get 0.00157908.  This may not seem like a big deal, but 
I heard of one company immediately losing a banking contract for accumulated 
errors of this magnitude in their software.  It sounds like a good way to 
lose a space probe as well.

Any thoughts on this?

-- 
STH
Hatton's Law: 
"There is only One inviolable Law."

• Follow-Ups:
  • Re: Off by 0.00000001, Why?
    • From: Murray Eisenberg <murraye@attbi.com>