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MathGroup Archive 2005

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Re: Re: Re: Bug in 5.1??

  • To: mathgroup at smc.vnet.net
  • Subject: [mg54534] Re: [mg54489] Re: [mg54448] Re: [mg54349] Bug in 5.1??
  • From: János <janos.lobb at yale.edu>
  • Date: Tue, 22 Feb 2005 04:24:10 -0500 (EST)
  • References: <200502210845.DAA27260@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Taking into account those $billions missing from the US budget from 
year to year, minimum the US government must be using 2 digit precision 
or less :)

Smile,

János

On Feb 21, 2005, at 3:45 AM, Andrzej Kozlowski 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

------------------------------------------------
``Our enemies are innovative and resourceful, and so are we. They never 
stop thinking about new ways to harm our country and our people, and 
neither do we.''       -- George W. Bush


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