Re: [boost] [Test] BOOST_CHECK_CLOSE Feature request

From: Ian McCulloch (ianmcc_at_[hidden])
Date: 2005-11-12 10:56:21

Related to this, there is a very interesting article on comparing IEEE
floats at
http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm

This makes use of the property that IEEE floating point formats are
lexicographically ordered when reinterpreted as an appropriate length
signed integer.  It appears you can use this to define a closeness measure
based on how many units in the last place the two numbers differ by
(equivalently, if you enumerated all possible floats and counted how far
away one number is from the other in the enumeration).  I only just came
across it now so I havn't tried playing with it yet, but it looks like it
would make a useful closeness measure.

Cheers,
Ian McCulloch