Re: [Caml-list] Comparing floats

[Boris Yakobowski <boris@yakobowski.org>]

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Hi Sébastien,

I feel obligated to point out that the _semantics_ of floating-point
comparison is a bit tricky. IEEE 754 mandates that NaN == NaN should return
false (as well as NaN != NaN), breaking all algebraic laws known to mankind
:-). OCaml's operators '=' and '!=' follow this convention, but  'compare
nan nan' returns 0, which is usually the desired behavior. However,
'compare 0. (-0.)' also returns 0, while you might want to distinguish
those two values.

HTH,

On Thu, Jul 23, 2015 at 10:35 AM, Sébastien Hinderer <
Sebastien.Hinderer@inria.fr> wrote:

> Dear all,
>
> What's the most efficient way to compare floats, please?
> Is it the polymorphic compare function, or is there a more specialized
> version of it?
>
> I saw Float.compare mentionned on the web but that does not seem to exist
> any longer?
>
> Thanks,
>
> Sébastien.
>
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-- 
Boris

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