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Groups > comp.lang.java.programmer > #35820
| From | Eric Sosman <esosman@comcast-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: double == double |
| Date | 2016-10-19 09:32 -0400 |
| Organization | A noiseless patient Spider |
| Message-ID | <nu7sl4$h0a$1@dont-email.me> (permalink) |
| References | <double-20161012130409@ram.dialup.fu-berlin.de> <nu7quv$aur$1@dont-email.me> |
On 10/19/2016 9:03 AM, Mike Amling wrote:
> On 10/12/16 7:15 AM, Stefan Ram wrote:
>> Sometimes it is taught that it makes no sense to compare
>> two double values with »==«.
>>
>> But what about this function?
>>
>> public static double max( final double a, final double b)
>> { return
>> a == 0.0 && b == 0.0 && java.lang.Double.doubleToRawLongBits( a )
>> == Double.doubleToRawLongBits( -0.0d )? b : a >= b ? a : b; }
>>
>> which tries to return positive zero if one argument is
>> positive zero and the other one negative zero?
>>
>> It seems that there are special cases when a comparison
>> of double values with »==« is appropriate. I have observed
>> that this is usually the case when comparing with »0.0« -
>> another example would be avoiding to divide by 0.0.
>
> If a==0.0 and b==0.0, there's no need to test whether either is -0.0.
> The function could be simplified to
>
> public static double max(final double a, final double b) {
> return a==0.0 && b==0.0 ? 0.0 : (a>=b ? a : b);
> }
This would return +0.0 for max(-0.0, -0.0).
--
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM
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Re: double == double Mike Amling <mamling@chaff.us> - 2016-10-19 08:03 -0500
Re: double == double Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-10-19 09:32 -0400
Re: double == double Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-19 10:26 -0400
Re: double == double Jake Jarvis <pig_in_shoes@yahoo.com> - 2016-10-19 16:36 +0200
Re: double == double Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-19 16:50 -0400
Re: double == double Jake Jarvis <pig_in_shoes@yahoo.com> - 2016-10-20 01:08 +0200
Re: double == double Arne Vajhøj <arne@vajhoej.dk> - 2016-10-19 21:16 -0400
Re: double == double Arne Vajhøj <arne@vajhoej.dk> - 2016-10-19 21:19 -0400
Re: double == double Jerry Stuckle <jstucklex@attglobal.net> - 2016-10-19 21:47 -0400
Re: double == double Arne Vajhøj <arne@vajhoej.dk> - 2016-10-19 21:52 -0400
Re: double == double Michael Jung <miju@golem.phantasia.org> - 2016-10-19 19:39 +0200
Re: double == double Mike Amling <mamling@chaff.us> - 2016-10-22 07:15 -0500
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