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:phil.ste...@gmail.com]
> 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
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