Re: differences between implementations of IEEE-754 basic operators
David Hough 754R work <754r@xxxxxxxxxxx> wrote:
one can validly argue that it is silly to expect absolute
repeatable floating-point behavior
It might be unrealistic to expect it at the current time, but as a
general proposition one might well wonder why "standard" arithmetic
is so unpredictable.
One might. And, once upon a time, the experts in the field did
so wonder. They investigated why, and found out that it was a
fundamental and irremovable property of the floating-point model
when used in the context of any normal programming language and
programming methodology. And that was 40 years ago ....
And many inexperienced people do so wonder. I wouldn't call
I would call them ignorant, because they have been misinformed
by the so-called experts. What I would call those experts is
rather stronger than 'silly'.
Yes, getting reproducible results IS possible. But you CAN'T do
it without defining a programming methodology intended to deliver
that property. And that has FAR more drastic consequences than
any of its proponents admit - in particular, it is effectively
incompatible with most forms of parallelism.
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