[Haskell-beginners] How to improve the accuracy of floating point calculation?

KC kc1956 at gmail.com
Wed Feb 6 00:08:43 CET 2013


0.1 cannot be represented exactly in floating point.

0.5 can be represented exactly.  Why?


On Tue, Feb 5, 2013 at 2:41 PM, yi lu <zhiwudazhanjiangshi at gmail.com> wrote:
> Hi,
>
> I found that in ghci, I input
> [0.1,0.2..2]
> and run, I get a result of
>
> [0.1,0.2,0.30000000000000004,0.4000000000000001,0.5000000000000001,0.6000000000000001,0.7000000000000001,0.8,0.9,1.0,1.1,1.2000000000000002,1.3000000000000003,1.4000000000000004,1.5000000000000004,1.6000000000000005,1.7000000000000006,1.8000000000000007,1.9000000000000008,2.000000000000001]
>
> But, as you know, it is not the exact answer.
>
> So, I wonder if there is something I can do to achieve a better performance
> and get [0.1,0.2,0.3,0.4..] as the result.
>
> Thanks.
>
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-- 
--
Regards,
KC



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