Re: More problems with SetPrecision[] and/or $MinPrecision,...
- To: mathgroup at smc.vnet.net
- Subject: [mg56991] Re: [mg56954] More problems with SetPrecision[] and/or $MinPrecision,...
- From: Chris Chiasson <chris.chiasson at gmail.com>
- Date: Thu, 12 May 2005 02:32:28 -0400 (EDT)
- References: <200505110924.FAA24004@smc.vnet.net>
- Reply-to: Chris Chiasson <chris.chiasson at gmail.com>
- Sender: owner-wri-mathgroup at wolfram.com
On my Mathematica 5.0 for Windows XP sp2, the output of your code is: From In[11]:= 0``20.85065878472074 From In[11]:= 0``20.85065878472074 On 5/11/05, terryisnow at yahoo.com <terryisnow at yahoo.com> wrote: > Dear Mathematica Guru's, > > Lately I seem to be finding a lot of SetPrecision[]/$MinPrecision bugs. > This appears to be another one: > > In[1]:= $MinPrecision = 20; > > savedData1 = 669151541.9328941107875; > savedData2 = 0.99960472897267246018765; > savedData3 = Log[savedData1^savedData2/savedData1^savedData2]; > > Print[Apply[Plus, savedData3 - > Log[savedData1^savedData2/savedData1^savedData2]] ]; > > x = 0.99960472897267245645; > y = 669151541.932894110712; > Do[ > z = SetPrecision[y,24]^x; > ,{50000}]; > > Print[Apply[Plus, savedData3 - > Log[savedData1^savedData2/savedData1^savedData2]] ]; > > The output looks like this on my Mathematica 3.0 system: > > 0 > 1.9586707534418188626 x 10^-30 > > Obviously the question is why is the second Print statement not > also returning a 0, after all the code that runs between the two > Print statements neither changes any of the variables referenced > by the two Print statements, nor even references any of the same > variables. > > The problem maybe reproducible without the $MinPrecision but with > this specific test case it is needed (there might however be other > constants that can reproduce the problem without $MinPrecision). > > Can someone also run this on a more recent version of Mathematica > to see if it reproduces? All help is very much appreciated! > > Terry > > -- Chris Chiasson http://chrischiasson.com/ 1 (810) 265-3161
- References:
- More problems with SetPrecision[] and/or $MinPrecision,...
- From: terryisnow@yahoo.com
- More problems with SetPrecision[] and/or $MinPrecision,...