Le 15/03/2013 22:36, Luc Maisonobe a écrit :
> Le 15/03/2013 21:21, Becksfort, Jared a écrit :
>>
>>
>> -----Original Message----- From: Becksfort, Jared Sent: Monday, March
>> 11, 2013 12:28 PM To: Commons Developers List Subject: RE: [math]
>> Scaling arrays. .
>>
>> On 3/11/13 8:21 AM, Becksfort, Jared wrote:
>>> Hi Phil,
>>>
>>>> What exactly *is* it and what are the use cases?
>>> Just a method to multiply each element in an array by a number and
>>> return either a copy of the array or do it in place. Maybe there
>>> can be one method for either way:
>>>
>>> public static double[] scale(double val, final double[] arr) {
>>> double[] newArr = new double[arr.length]; for (int i = 0; i <
>>> arr.length; i++) { newArr[i] = arr[i] * val; } return newArr; }
>>>
>>> public static void scaleInPlace(double val, final double[] arr) {
>>> for (int i = 0; i < arr.length; i++) { arr[i] *= val; } }
>>>
>>>> ...use cases
>>> I imagine they are pretty varied. These methods could be used any
>>> time you want to multiply all elements in an array by a number
>>> without writing a loop each time. I am using this in some
>>> optimization code that I am submitting but figured it would be
>>> broadly applicable enough to just be put in the MathArrays class.
>>>
>>> Jared
>>>
>>> -----Original Message----- From: Phil Steitz
>>> [mailto:[email protected]] Sent: Sunday, March 10, 2013 2:19
>>> PM To: Commons Developers List Subject: Re: [math] Scaling arrays.
>>> .
>>>
>>> On 3/8/13 12:14 PM, Becksfort, Jared wrote:
>>>> Hello,
>>>>
>>>> I may be missing it somewhere, but I am surprised there is no
>>>> function for scaling arrays in MathArrays.java or somewhere
>>>> else.
>>>>
>>>> - Am I stupidly missing it?
>>> Probably not. Closest thing is probably normalize in MathArrays.
>>>> - Is there a reason it is not in there?
>>> Probably no; though you will find that most vector / array
>>> algebraic operations are implemented on the objects in the linear
>>> package, rather than directly on double[]s.
>>>> - Shall I add it?
>>
>>> +1 to add this
>>
>>> Created an issue and submitted patches for MathArrays.java and
>>> MathArraysTest.java
>>
>>> https://issues.apache.org/jira/browse/MATH-946
>>
>>> Jared
>>
>>> Phil What exactly *is* it and what are the use cases?
>>>
>>> Phil
>>>> Thanks, Jared
>>
>> Hello,
>>
>
> Hi Jared,
>
>> Does anyone know if these changes might be committed to the
>> repository? Some upcoming changes I am submitting for another issue
>> rely on it. It is not too much trouble for me to remove the
>> dependencies, but if this is going in then I may as well use it.
>
> I will look at this tomorrow morning (European time) and will probably
> commit it if nobody does it before.
Well, it seems Phil did it just a few minutes ago ;-)
Luc
>
> best regards,
> Luc
>
>>
>> https://issues.apache.org/jira/browse/MATH-946
>>
>> Thanks, Jared
>>
>>
>>
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