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From "Gilles (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MATH-1397) Complex.ZERO.pow(2.0) is NaN
Date Mon, 02 Jan 2017 23:31:58 GMT

    [ https://issues.apache.org/jira/browse/MATH-1397?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15793695#comment-15793695
] 

Gilles commented on MATH-1397:
------------------------------

Hello Mario and Raymond.

Having complex numbers (and related functionality) in their own component was on the roadmap;
an effort led by Eric Barnhill (to whom I've just assigned this issue).
If you'd like to help move the code out of Commons Math, please post to the "dev" ML.

Thanks for the report.


> Complex.ZERO.pow(2.0) is NaN
> ----------------------------
>
>                 Key: MATH-1397
>                 URL: https://issues.apache.org/jira/browse/MATH-1397
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 3.6.1
>         Environment: Linux, Java1.7/Java1.8
>            Reporter: Mario Wenzel
>            Assignee: Eric Barnhill
>            Priority: Minor
>
> ```
> package complextest;
> import org.apache.commons.math3.complex.Complex;
> public class T {
> 	public static void main(String[] args) {
> 		System.out.println(Complex.ZERO.pow(2.0));
> 	}
> }
> ```
> This is the code and the readout is `(NaN, NaN)`. This surely isn't right. For one, it
should actually be zero (https://www.wolframalpha.com/input/?i=(0%2B0i)%5E2) and second of
all, the documentation doesn't state that anything could go wrong from a Complex number that
has no NaNs and Infs.
> The other definition states that it doesn't work when the base is Zero, but it surely
should. This strange corner case destroys any naive implementation of stuff wrt the mandelbrot
set.
> It would be nice to not have to implement this exception myself.



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