[Haskell-cafe] Re: Double -> CDouble, realToFrac doesn't work

Lennart Augustsson lennart at augustsson.net
Mon Nov 8 09:38:47 EST 2004

Henning Thielemann wrote:
> On Fri, 5 Nov 2004, Robert Dockins wrote:
>>What IEEE has done is shoehorned in some values that aren't really 
>>numbers into their representation (NaN certainly; one could make a 
>>convincing argument that +Inf and -Inf aren't numbers).
> I wonder why Infinity has a sign in IEEE floating processing, as well as
> 0. To support this behaviour uniformly one would need a +0 or -0 offset
> for each number, which would lead straightforward to non-standard analysis
> ... 

IEEE floats support both affine (signed) and projective (unsigned)
infinity.  Projective is more natural in some circumstances (since
you can do a Möbius transformation from a circle to an infinite line).

Haskell, on the othet hand, does not let you specify the mode.

	-- Lennart

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