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MathGroup Archive 2005

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Re: Re: Re: Bug in 5.1??


Your response is very curious. Who told you you are not supposed to 
complain? I suggested you file a bug report. If you do not file one 
presumably you have a reason?? Is the reason that (you imagine) I told 
you not to complain? I am flattered to see that I now wield this sort 
of authority but really I do not seek it. I only told you that in the 
past people wrote write about such issues and, in the old days, someone 
(usually David Withoff) would respond. But even he never gave, as far 
as I can recall,  a clear reason why this happens, only a vague one 
like the one I have given: strange things happen if you use 
significance arithmetic at low precision,and try making comparisons 
like

10`2 ==0

True

or

100`2==0

True

or whatever. Don't do it.

So now please do file a bug report and demand an explanation. I will be 
very interested to read the response, if you get one of course. After 
all, I am just another user and have no better access to WRI's thinking 
than you have.

Andrzej Kozlowski




On 22 Feb 2005, at 10:23, DrBob wrote:

> It doesn't make sense to ANYBODY, as far as I can tell.
>
> But we're not supposed to complain, because somebody ALREADY 
> complained (some time or another).
>
> Bobby
>
> On Mon, 21 Feb 2005 03:44:38 -0500 (EST), Dana DeLouis 
> <delouis at bellsouth.net> wrote:
>
>> Seems to me that the loss of precision returns an "Interval", which 
>> is still
>> greater than zero.  It looks like the cutoff between True & False is 
>> a hair
>> above -1, which doesn't make sense to me either.
>>
>> Interval[N[5, 2]]
>> Interval[{4.9, 5.1}]
>>
>> N[5, 2] > -1
>> True
>>
>> N[5, 2] > -1 + $MachineEpsilon
>> False
>>
>
>
>
> -- 
> DrBob at bigfoot.com
> www.eclecticdreams.net
>
>


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