On Dec 31, 11:15 am, "Dr. David Kirkby" <david.kir...@onetel.net> wrote:
> > RJF > > The point you are missing is that we want to compare the output what Sage > prints > to a human. > The point you are missing is that the following item, which presumably could be printed by Sage, is perfectly readable to a human: 6121026514868073 * 2^(-51). It exactly dictates the bits in an IEEE double-float, and does not require any conversion from binary to decimal. It does not need rounding. This kind of representation does not have any hidden unprinted digits. It does not ever need to be longer because of delicate edge conditions of certain numbers. It happens to evaluate to APPROXIMATELY 2.718281828459045 a more accurate rendition of that same number, again in decimal is 2.7182818284590450907955982984.... although a more accurate rendition of exp(1) looks like this. 2.7182818284590452353602874713.... If you want to compare the results of 2 numerical computations for exact identical bits, then I suggest you look at the bits. The fact that two different systems get slightly different answers is not necessarily an indication of an error. RJF > Comparing the bits of a floating point number would not help as a test suite. > If > two systems have the same 64 bits to indicate the number, a bug in the code > which converts that to ASCII would not be detected. The tests compare ASCII > text, not numbers. > > I would accept for some randomised testing, it might be better to bypaass the > binary to ASCII conversion, as it would allow for more tests to be conducted > in > less time. But not in general would that be a good idea. > > It's 20+ years since I done any assembly language programming - that was on an > 386/387 chip, then later on a VAX - never SPARC. So I'd be at a loss really. > (BTW, after programming on a VAX, you realise how limited the x86 series was). > > Dave -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
