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From: =?UTF-8?Q?J=c3=b6rg_Buchholz?= <bookwood4news@freenet.de>
Newsgroups: comp.graphics.apps.gnuplot
Subject: Re: incorrect arithmetik?
Date: Tue, 12 Jan 2016 18:50:29 +0100
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On 12.01.2016 14:19, Karl Ratzsch wrote:
> Am 12.01.2016 um 11:40 schrieb J=C3=B6rg Buchholz:
>> I can not found the solution to the following problem:
>>
>> b=3D7.2-6.9
>> c=3D8.2-7.9
>>
>> show variables
>
>> b =3D 0.3
>> c =3D 0.299999999999999
>>
>> Why is c not 0.3?
>
> Floating point arithmetics. Most decimal fractions cannot be represente=
d
> exactly by a binary float variable.
>
> 8.2 is 1000.00110011....
> 7.2 is 111.11100110011....
>
> If the two errors add up in one direction, the result of your
> subtraction will be closer to a value that is in fact off by 1 in the
> least significant digit.

Thanks for the explanation, I think I understand it.

J=C3=B6rg