| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of Daniel Frey | Sent: 15 May 2005 23:21 | To: boost@lists.boost.org | Subject: [boost] Re: Math constants - updated. | | Paul A Bristow wrote: | > | rationale.html. cubeRootFour is called two_pow_two_thirds in the | > | documentation. | > | > Sorry I have not updated this much after the discussion | during review. | > I'll do some tidying up - thanks for noting this. | | Another typo: sqrt32 is commented as sqrt(10) in the source. Thanks - corrected in my version and will upload some time. | | And a question: Sometimes, you omit the trailing 0(s) from some | constants. Could you change the scripts to not do this? I | could make use | of it, the current version of my library (not yet published) | includes a | "port" of your constants, that is also capable of retrieving the | original value (that is, the string in the source!) and pass it on to | generic mappers to initialize e.g. RWDecimal<RWMP3Int> or other types | with a ctor taking const char*. Having the trailing zeros would make a | better statement about the real value-range it represents. Example: | | 1.23 specifies a number from the range [1.225-1.235) | | while | | 1.230 specifies a number from the range [1.2295-1.2305) | | and thus the latter yields more information. Not easily, I fear, as NTL's RR type does NOT provide all the formatting like double. I'll look into this - ask the author - but I fear not. | BTW: In case you don't like me to port your header, let me know. Of | course, credit will be given if you don't have any objections. You are welcome to the values - they are hardly secret or novel - But CONVENIENT and ACCURATE (I hope!) Paul PS Oh and don't forget the final desiderata for Boost "Doing The Right Thing" - handling smallest intervals, (floating-point format dependent) for example: pi float, radix = 2, digits = 24 pi is 3.141592653589793238462643383279502884197169400753 to 50 decimal digits. float pi to 9 significant digits 3.14159265 static const float v_l = 13176794.0f/(1 << 22); // One representation. static const float v_u = 13176795.0f/(1 << 22); static const float pi_l = 3.141592502593994140625F; // Exactly representables. static const float pi_u = 3.1415927410125732421875F; pi double, radix = 2, digits = 53 pi is 3.141592653589793238462643383279502884197169400753 to 50 decimal digits. double pi to 17 significant digits 3.1415926535897932 static const double v_l = 7074237752028440.0f/(1 << 51) static const double v_u = 7074237752028441.0f/(1 << 51); static const double pi_l = 3.141592653589793115997963468544185161590576171875; // Exactly representables. static const double pi_u = 3.141592653589793560087173318606801331043243408203125; Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow@hetp.u-net.com