Re: Re: Bug in 5.1??

*To*: mathgroup at smc.vnet.net*Subject*: [mg54482] Re: [mg54448] Re: [mg54349] Bug in 5.1??*From*: DrBob <drbob at bigfoot.com>*Date*: Mon, 21 Feb 2005 03:44:49 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Duly noted. Bobby On Sun, 20 Feb 2005 22:04:51 +0100, Andrzej Kozlowski <akoz at mimuw.edu.pl> wrote: > I never wrote this makes sense. I only pointed out that if you think it > is a bug you should report it. On the other hand it has been a part of > Mathematica since the first version I used, which was version 1.2, I > think. Since then this issue has been discussed almost every year. From > what has been explained, both on this list and in other places, it is a > consequence of certain shortcuts that Significance arithmetic makes to > achieve reasonable speed. It is harmless because nobody ever needs to > compute anything with two digits of precision. > > Andrzej Kozlowski > > > On 20 Feb 2005, at 17:58, DrBob wrote: > >> N[50000,2] should represent something between, say, 49500 and 50500, >> both of which are positive. If it means something other than that, >> please enlighten us!! >> >> Meanwhile, perhaps we can use Interval to interpret it: >> >> Interval[N[50000, 2]]//InputForm >> Interval[ >> {49488.`1.9955298983230858, >> 50512.`2.0044245602121236}] >> >> Interval@N[50000,2]>0 >> True >> >> So I don't see how this makes sense: >> >> N[50000,2]>0 >> False >> >> Bobby >> >> On Sun, 20 Feb 2005 10:53:16 +0100, Andrzej Kozlowski >> <akoz at mimuw.edu.pl> wrote: >> >>> *This message was transferred with a trial version of CommuniGate(tm) >>> Pro* >>> Then surely you must have filed a bug report as it would be >>> irresponsible not to! >>> >>> Andrzej Kozlowski >>> >>> On 20 Feb 2005, at 06:10, DrBob wrote: >>> >>>> This behavior will find defenders, I'm sure, but it certainly looks >>>> like a bug to ME. >>>> >>>> Bobby >>>> >>>> On Sat, 19 Feb 2005 02:31:49 -0500 (EST), Gehrmann, James E >>>> <jgehrman at saclink.csus.edu> wrote: >>>> >>>>> I'm running Mathematica v. 5.1 under WinXP and had the following >>>>> interaction with Mathematica: >>>>> 5>0 >>>>> >>>>> True >>>>> >>>>> 5.>0 >>>>> >>>>> True >>>>> >>>>> N[5]>0 >>>>> >>>>> True >>>>> >>>>> N[5,3]>0 >>>>> >>>>> True >>>>> >>>>> N[5,2]>0 >>>>> >>>>> False >>>>> >>>>> N[50000,2]>0 >>>>> >>>>> False >>>>> >>>>> Are the last two results a bug or am I not understanding the N >>>>> function? >>>>> >>>>> Thanks for you help. >>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> -- >>>> DrBob at bigfoot.com >>>> www.eclecticdreams.net >>>> >>>> >>> >>> >>> >>> >> >> >> >> -- >> DrBob at bigfoot.com >> www.eclecticdreams.net >> >> > > > > -- DrBob at bigfoot.com www.eclecticdreams.net