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Posted to dev@commons.apache.org by "matic@nimp.co.uk" <ma...@nimp.co.uk> on 2012/08/06 03:44:13 UTC

[math] MATH-841 gcd speed up

Hello,

The gcd(int,int) method of ArithmeticUtils seems 2 times slower than the
naive approach using modulo operator.
Gilles tested the patch separately and found similar performance penalty.
Please check it out: 
https://issues.apache.org/jira/browse/MATH-841?page=com.atlassian.jira.plugi
n.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428944#comment-1
3428944

Anyone aware of an environment were the modulo operator is painfully slow ?

Gilles pointed out that my patch don't conform to CM formating style, I
will correct that as well as the javadoc (its mention of the binary gcd
algorithm) if the code change is basically approved here. Please let me
know.
 
Sebastien

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Re: [math] MATH-841 gcd speed up

Posted by sebb <se...@gmail.com>.
On 6 August 2012 04:58, Phil Steitz <ph...@gmail.com> wrote:
> On 8/5/12 6:44 PM, matic@nimp.co.uk wrote:
>> Hello,
>>
>> The gcd(int,int) method of ArithmeticUtils seems 2 times slower than the
>> naive approach using modulo operator.
>> Gilles tested the patch separately and found similar performance penalty.
>> Please check it out:
>> https://issues.apache.org/jira/browse/MATH-841?page=com.atlassian.jira.plugi
>> n.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428944#comment-1
>> 3428944
>>
>> Anyone aware of an environment were the modulo operator is painfully slow ?
>>
>> Gilles pointed out that my patch don't conform to CM formating style, I
>> will correct that as well as the javadoc (its mention of the binary gcd
>> algorithm) if the code change is basically approved here. Please let me
>> know.
>
> It is probably worth doing some research in the archives on this
> function.  I suspect there are reasons for the implementation
> choices made in the current impl.  Could be bad reasons / bad impl,
> but IIRC there was a fair amount of discussion on this.

And then please add the details to the code itself for future
readers/maintainers.

> Phil
>>
>> Sebastien
>>
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>>
>>
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>>
>
>
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Re: [math] MATH-841 gcd speed up

Posted by Phil Steitz <ph...@gmail.com>.
On 8/5/12 6:44 PM, matic@nimp.co.uk wrote:
> Hello,
>
> The gcd(int,int) method of ArithmeticUtils seems 2 times slower than the
> naive approach using modulo operator.
> Gilles tested the patch separately and found similar performance penalty.
> Please check it out: 
> https://issues.apache.org/jira/browse/MATH-841?page=com.atlassian.jira.plugi
> n.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428944#comment-1
> 3428944
>
> Anyone aware of an environment were the modulo operator is painfully slow ?
>
> Gilles pointed out that my patch don't conform to CM formating style, I
> will correct that as well as the javadoc (its mention of the binary gcd
> algorithm) if the code change is basically approved here. Please let me
> know.

It is probably worth doing some research in the archives on this
function.  I suspect there are reasons for the implementation
choices made in the current impl.  Could be bad reasons / bad impl,
but IIRC there was a fair amount of discussion on this.

Phil
>  
> Sebastien
>
> --------------------------------------------------------------------
> mail2web.com - Microsoft® Exchange solutions from a leading provider -
> http://link.mail2web.com/Business/Exchange
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
> For additional commands, e-mail: dev-help@commons.apache.org
>
>


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