On Tue, Jan 19, 2010 at 4:50 PM, DIETER ENSSLEN <[email protected]> wrote: > the regular 'pi' by two significant digits?! ..5862 vs > ..5898 , the last figures to 14 places. A > difference of -3.6e-12. J gives ..5897 931.
http://www.eveandersson.com/pi/digits/1000000 claims this should be 5897 9328 Meanwhile, J uses 64 bit IEEE floating point numbers, which are described at http://en.wikipedia.org/wiki/IEEE_754-2008 In the context of pi, this means that J has 51 bits to represent the fractional part of pi. (I think it is important to realize that J's numbers do not use decimal fractions but use binary fractions instead. Thus, for example, 0.2 can only be represented approximately, even though 0.0009765625 can be represented exactly.) Anyways, 10^.2^51 15.3525 We should expect pi in J to be accurate to 15 digits to the right of the decimal point, and its sixteenth digit should not be too inaccurate. x:<.o.10^17 314159265358979328 Ironically, J itself is more accurate in this case than the routine it uses to display fractional numbers. This might be a coincidence (since those last two digits are somewhat spurious) but probably also has something to do with the architecture of J's implementation.. FYI, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
