On 2012-02-03 22:57:31 +0000, James Courtier-Dutton wrote: > On 3 February 2012 16:24, Vincent Lefevre <vincent+...@vinc17.org> wrote: > > But 1.0e22 cannot be handled correctly. > > Of course it can't. > You only have 52 bits of precision in double floating point numbers.
Wrong. 53 bits of precision. And 10^22 is the last power of 10 exactly representable in double precision (FYI, this example has been chosen because of this property). In case you don't know, I've participated in the revision of the IEEE 754 standard, giving the current IEEE 754-2008. And our team works on computer arithmetic (as my signature says), mainly floating-point arithmetic. So, I know what I'm talking about (though I can also make mistakes, as everyone...). > So, although you can have 1.0e22, you cannot represent (1.0e22 + 1) [...] The constant is 1.0e22. Whether you can represent 1.0e22 + 1 or not doesn't matter. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <http://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
