Re: A bug with Sum (as in Monoid)

Imprecise calculation shouldn't be considered as a bug. Topologically speaking, floating point types are regarded as if they had countably infinite precision. So the elements in domain are positive reals, negative reals, the zeros, the infinities, and the NaN. 2019년 11월 7일 (목) 07:29, Brent Yorgey 님이 작성:

Hint: the problem has nothing to do with zeros.

λ> 0.1 + (0.2 + 0.3) == (0.1 + 0.2) + 0.3 False

On Wed, Nov 6, 2019 at 4:20 PM Dannyu NDos wrote:

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Omg, addition is not even associative? The zeros truly ruined everything.

2019년 11월 7일 (목) 06:58, Brent Yorgey 님이 작성:

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How is that worse than the fact that addition is already not associative for floating point types? At least +0 is really the identity up to (==).

On Wed, Nov 6, 2019, 3:49 PM Dannyu NDos wrote:

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Sum has bug with floating points. Current definition states +0 as the identity element, while the actual identity is -0 since +0 + -0 = +0. _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries