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From Luc Maisonobe <Luc.Maison...@free.fr>
Subject Re: svn commit: r1166099 - /commons/proper/math/trunk/src/main/java/org/apache/commons/math/linear/LUDecompositionImpl.java
Date Wed, 07 Sep 2011 12:59:04 GMT
Le 07/09/2011 14:46, Gilles Sadowski a écrit :
> On Wed, Sep 07, 2011 at 01:16:03PM +0100, Mark Thomas wrote:
>> On 07/09/2011 12:49, Gilles Sadowski wrote:
>>> On Wed, Sep 07, 2011 at 11:39:37AM +0100, Mark Thomas wrote:
>>>> On 07/09/2011 11:34, erans@apache.org wrote:
>>>>> Author: erans
>>>>> Date: Wed Sep  7 10:34:49 2011
>>>>> New Revision: 1166099
>>>>>
>>>>> URL: http://svn.apache.org/viewvc?rev=1166099&view=rev
>>>>> Log:
>>>>> Added "final".
>>>>> Moved declaration of "sum" where it is used.
>>>>
>>>> You might want to re-consider that. I suspect sum was declared outside
>>>> of the inner loops to save allocating memory for a new double on every
>>>> iteration of the loop. It may be worth moving the declaration outside
>>>> the outer loop too.
>>>
>>> Reducing scope makes for clearer code and can lead to _more_ optimized code.
>>
>> Cleaner code, certainly.
>>
>> As far as optimisation goes I'm not so sure with a primitive. On further
>> research it looks like the performance should be identical. For an
>> "interesting" discussion on what exactly is going on I found this:
>> http://www.javalobby.org/java/forums/t16730.html?start=0
>
> So:
>   - Cleaner code: Yes
>   - Faster code: Maybe
>   - Higher memory usage: No
>
> Do we agree that the change is fine?

Yes, I prefer to have a smaller scope too.

Luc

>
>
> Gilles
>
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