[Cfp-interest 2215] Re: quantum

[David Hough CFP]

A problem with "ulp" is deciding what the ulp of an exact power of the
base should be - and thus ulp depends on the format; a real number doesn't
have an "ulp".     Then there's the question about what it means for
logarithmic formats.

But for conventional floating-point formats, the "ulp"  mostly arises
in terms of error bounds stated as ulps of the computed result.