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

[kst@aonix.com (Keith Thompson)]

In <E1uEEs.2xJ.0.-s@inmet.camb.inmet.com> stt@houdini.camb.inmet.com (Tucker Taft) writes:
> Are you also saying that X <= Y is somehow "better" than not (X > Y)?
> That is truly mysterious, if so.

Of course not.  Ignoring NaNs and readability, X <= Y is identical
to not (X > Y).

The original statement was that AQ&S recommends using "<=" rather than "<"
because it's more portable.  The general consensus (with which I agree)
is that that's absurd as a general statement.  I was merely speculating
on a possible rationale for the original (incorrect) statement by trying
to construct a specific case in which X <= Y might be safer than X < Y,
even if X is mathematically known to be less than Y.  (Even this is not
entirely safe, since roundoff errors could cause X to be greater than Y.)

This is tricky stuff.  I probably know just enough about numerical
analysis to be dangerous.

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