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From "Wilhelm Burger (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MATH-1397) Complex.ZERO.pow(2.0) is NaN
Date Thu, 27 Apr 2017 20:22:04 GMT

    [ https://issues.apache.org/jira/browse/MATH-1397?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15987584#comment-15987584
] 

Wilhelm Burger commented on MATH-1397:
--------------------------------------

Hello Eric, 

thanks for this update. I have used Eclipse for all my projects over many years with good
success. However, I agree that Maven support is brittle, so I have been considering to switch
to IntelliJ as an alternative for quite a while now. As a first test, I tried it on the 'commons-number'
project and it importet without any glitch. Looks good!

Thanks for the invitation to participate in this project, I'll be happy to look into it and
see where I can help. Note however that, while I do have a CS background, I am not a mathematician
(hobbyist at best) ...

--Wilhelm

> 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
>             Fix For: 4.0
>
>
> ```
> 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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