Re: Re: Re: Bug in 5.1??

*To*: mathgroup at smc.vnet.net*Subject*: [mg54571] Re: [mg54528] Re: [mg54469] Re: Bug in 5.1??*From*: DrBob <drbob at bigfoot.com>*Date*: Wed, 23 Feb 2005 03:11:42 -0500 (EST)*References*: <200502210844.DAA27157@smc.vnet.net> <200502220923.EAA10793@smc.vnet.net> <03d46b8e970e9ccc74c8324d28644629@mimuw.edu.pl>*Reply-to*: drbob at bigfoot.com*Sender*: owner-wri-mathgroup at wolfram.com

I don't file bug reports because (a) I don't usually have real applications that warrant it (certainly not in this case) and (b) reporting bugs is a pretty fruitless endeavor -- even if WRI _is_ a hundred times more responsive than Microsoft (for instance) in that regard. Nothing gets fixed until the next release, and many bugs have already survived five years or more. I am likely to get a work-around from tech support, but I can come up with work-arounds on my own. Anyway, WRI can't claim to be unaware of this problem, or anything else we discuss in this forum -- regardless of whether anybody files a bug report. I do understand that developmental priorities and theoretical issues make it impractical to fix some of these things. Generally, I'm not really asking anyone to fix them; I just want to understand, to whatever extent I can. Possibly you think I'm far more concerned than I actually am. As for 2-digit significance arithmetic in particular, if I want an explanation and you don't have one, and you clearly don't care about the issue, why answer? Bobby On Tue, 22 Feb 2005 15:37:35 +0100, Andrzej Kozlowski <akozlowski at gmail.com> wrote: > 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 >> >> > > > > -- DrBob at bigfoot.com www.eclecticdreams.net

**References**:**Re: Bug in 5.1??***From:*"Dana DeLouis" <delouis@bellsouth.net>

**Re: Re: Bug in 5.1??***From:*DrBob <drbob@bigfoot.com>