| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of John Maddock | Sent: 02 December 2005 12:22 | To: boost@lists.boost.org | Subject: Re: [boost] [math] floating point classification - | testinghelpwanted | | but there's at least one | problem case: | long double's on Darwin. I can't find any information on | these after a | quick google search, but I believe they're effectively a sum | of two doubles. | If so this is exceptionally bad form because it violates the most | fundamental principal of IEEE arithmatic that a number is n*2^k. | (Background: epsilon is very small for this type, it's | possible to add a | number "delta" to 1.0L and still get a distict value when | "delta" is much | smaller than the number of bit's in a long double would | otherwise indicate. | This makes a *lot* of IEEE based reasoning invalid. If | anyone has more | information on this type I'd appreciate a reference). Is the the same as doubledouble by Keith Briggs http://keithbriggs.info/xrc.html and NTL http://www.shoup.net/ntl/ ? Paul -- Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB Phone and SMS text +44 1539 561830, Mobile and SMS text +44 7714 330204 mailto: pbristow@hetp.u-net.com http://www.hetp.u-net.com/index.html http://www.hetp.u-net.com/Paul%20A%20Bristow%20info.html