I have one qualm about next / prior / rep or discrete distance names: they do not indicate at all that the operation is tied to *floating-point* representation! Imho, a major omission. Especially discrete_distance is bad from that point of view. That is why I suggested and still prefer next_float / prior_float / floating_distance names. Perhaps next_float_distance is even better. Regarding ulp_distance, I might also work but the name is misleading, I think. It would likely be understood by someone relying on name rather than reading docs to mean: the number of times you have to add ulp to x to obtain y??? Regarding ulp(T), the comment is wrong: that is not the ulp_distance between x and next(x), that would be one. Or else I misunderstood ulp_distance. Back to square one... Just a few personal thoughts, please feel free to disregard. Sent via BlackBerry from T-Mobile -----Original Message----- From: John Maddock <john@johnmaddock.co.uk> Date: Mon, 05 May 2008 11:48:22 To:boost@lists.boost.org Subject: Re: [boost] [Math/nextafter] A question of naming functions... So, it looks like so far we have: next(val) prior(val) and either of representation_distance(a, b); discrete_distance(a, b); Whilst I'm normally all in favour of "long_meaningful_names_with_underscores", next() and prior() do look OK to me: especially so long as they're in namespace boost::math. Like Paul, I'm still looking for the right "killer name" for the *_distance function, I quite like "maddock_metric" but I doubt anyone will know what that means :-) Given that this function is inherently related to the "units in the last place" metric, I wonder if we can compose a name from that? Maybe extending the API slightly how about: T upl_distance(T, T); // "representation distance" T relative_distance(T, T); // AKA relative error. T ulp(T); // distance between arg and next(arg) Thoughts? Thanks, John. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost