Re: Off by 0.00000001, Why?

*To*: mathgroup at smc.vnet.net*Subject*: [mg37386] Re: [mg37378] Off by 0.00000001, Why?*From*: Murray Eisenberg <murraye at attbi.com>*Date*: Sat, 26 Oct 2002 02:03:12 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200210250648.CAA18199@smc.vnet.net>*Reply-to*: murray at math.umass.edu*Sender*: owner-wri-mathgroup at wolfram.com

Under Mathematica 4.2, I obtain the same result as you -- off by 1 in the last decimal place displayed from what is shown in Maeder's book. That was on a Pentium 4 PC. Could it be that Maeder was using a different hardware platform, and that that alone would account for the difference? Actually, I'd be surprised if that were the reason, because I applied NumberForm[%, 15] to the result and obtained: 0.00157908413803032 Steven T. Hatton wrote: > 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 MÃ¤der 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? > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street Amherst, MA 01375

**References**:**Off by 0.00000001, Why?***From:*"Steven T. Hatton" <hattons@globalsymmetry.com>