| -----Original Message----- | From: boost-bounces@lists.boost.org | [mailto:boost-bounces@lists.boost.org] On Behalf Of John Maddock | Sent: 11 February 2006 18:01 | To: boost@lists.boost.org | Subject: Re: [boost] Using BOOST_ASSERT to check | numeric_limits<FPT>::epsilon | | Yep. I don't think you'll ever find a value of | numeric_limits<>::epsilon() <= 0 If not specialized or not done sensibly, it would be 0 (as if NOT specialized), I thought it might be zero on Darwin. | BTW, it's a very small positive value very close to zero on Darwin. epsilon() = 4.94065645841246544176568792868221e-324 == denorm_min() = 4.94065645841246544176568792868221e-324 I don't think that is helpful/useful. It certainly needs a lot of justification and documentation. I think it should be based on bits used in significand. | BTW I added a useful little helper program to Boost.Config (called | math_info) that prints out this kind of information - see | http://engineering.meta-comm.com/boost-regression/CVS-HEAD/dev | eloper/output/dmcgrath-bin-boost-status-math_info-test-gcc-4_0 | -darwin-debug.html | for the Darwin results. Nice - though Firefox would not print it :-(( | As well as checking numeric_limits, it also looks for a | couple of other | gotchas I've fallen into: Hmmm. Not sure I'd rather not have long double at all than have it half done. Thanks. Paul