On Fri, 21 Sep 2012 15:23:41 -0700, Paul Rubin wrote: > Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> writes: >> Have I got this right? Is there a way to work out the gap between one >> float and the next? > > Yes, 53-bit mantissa as people have mentioned. That tells you what ints > can be exactly represented. But, arithmetic in some situations can have > a 1-ulp error. So I wonder if it's possible that if n is large enough, > you might have something like n+1==n even if the integers n and n+1 have > distinct floating point representations.
I don't think that is possible for IEEE 754 floats, where integer arithmetic is exact. But I'm not entirely sure, which is why I asked. For non IEEE 754 floating point systems, there is no telling how bad the implementation could be :( -- Steven -- http://mail.python.org/mailman/listinfo/python-list