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[Caml-list] Finding the sign of a float
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Date: 2003-02-01 (13:08)
From: John Carr <jfc@M...>
Subject: Re: [Caml-list] Finding the sign of a float

> I'm looking for a way, in pure ocaml without having to bail out to C, to
> tell if a float is negative or not.
> Just using x < 0.0 won't work, as I need to be able to tell the difference
> between -0.0 and +0.0. This is for ocaml versions of the C copysign and
> signbit functions. Any suggestions?

x < 0.0 || (x = 0.0 && 1.0/.x < 0.0)

may be faster than converting the bits to integer, or slower,
depending on platform and context, and how often you encounter -0.

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