- Następna wiadomość (według wątku): [Cosmo-torun] cosmo workshop wt 14:00 27.01.09 B Roukema: 'a hint towards Poincare gravity?'
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hi cosmo-torun, This follows from a conversation some of us had recently. Debian stable (etch) includes GMP and MPFR - i ran a test program which quite nicely does e.g. 200-bit floating point operations, including trig functions, and gets reasonable answers. :) Source + doc: http://gmplib.org/ http://www.mpfr.org/ These are both under the LGPL instead of the GPL, so it turns out that... the non-free program Mathematica uses the free program GMP ! So apparently non-free software libraries are not good enough for Mathematica for this purpose. Or Mathematica is just "abusing the commons". [the commons: http://en.wikipedia.org/wiki/The_commons ] pozdr boud On Wed, 14 Jan 2009, Bartosz Lew wrote: >>>But within standard types long double is better than double etc.>>>>i assume this means you've experimented with this? Based on the>>wikipedia entries, i suggested to Zbyszek that this could be>>interesting, but i haven't tried it. My understanding is that it>>pushes to the limit of the machine you're using, which can be better>>than 64bit, but is nowhere near 128bit. :)>>mmm, don't remember which means that probably not much.>>But, I never experienced a need for such extremely super-duper high accuracy.>As far as the calculation is actually correct within the given precision it's cool.>Eg. CMBFast works in 4byte float numbers and it's sufficient.>AFAIK people still very often use 4byte floats.>My opinion is that is the code returns wrong numbers its an indication that it should be rewritten>in smarter way rather than going to long doubles or quadruple precisions.>>>>>Tomorrow Thursday i've got linux w IF so i'm very unlikely to be at>>KRA. But that's not an argument against both of you coming here and>>doing stuff. :)>>ok.>>B.>

- Następna wiadomość (według wątku): [Cosmo-torun] cosmo workshop wt 14:00 27.01.09 B Roukema: 'a hint towards Poincare gravity?'
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