Re: [Q] Portability of <= and >= with real operands

[kst@aonix.com (Keith Thompson)]

In <dewar.849320173@merv> dewar@merv.cs.nyu.edu (Robert Dewar) writes:
[...]
> The idea that the use of <= is more portable than either < or =
> is particular rubbish, I see no possible justification for such a
> statement, and, unlike the old rule about avoiding equality, I cannot
> even guess the thought behind this misunderstanding.

Suppose you've computed two quantities, X and Y, such that X is
mathematically known to be less than Y, but it may be arbitrarily close.
Since floating-point is of finite precision, the representations of X
and Y may be equal.  (For example, X = 0.0, Y = some tiny value which
underflows to 0.0).  Then X <= Y may reflect the relationship more
accurately than X < Y.

Of course, in real life you should analyze the particular case, and you
may well reach the opposite conclusion, but I'd bet that the original
rationale for the statement was something like the above.

-- 
Keith Thompson (The_Other_Keith) kst@aonix.com <http://www.aonix.com> <*>
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