[jira] [Work logged] (NUMBERS-143) Investigate Math.hypot for computing the absolute of a complex number

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[jira] [Work logged] (NUMBERS-143) Investigate Math.hypot for computing the absolute of a complex number

Gilles Sadowski (Jira)

     [ https://issues.apache.org/jira/browse/NUMBERS-143?focusedWorklogId=388140&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-388140 ]

ASF GitHub Bot logged work on NUMBERS-143:
------------------------------------------

                Author: ASF GitHub Bot
            Created on: 17/Feb/20 00:09
            Start Date: 17/Feb/20 00:09
    Worklog Time Spent: 10m
      Work Description: coveralls commented on issue #76: NUMBERS-143: Added specialised hypot function to Complex.
URL: https://github.com/apache/commons-numbers/pull/76#issuecomment-586772181
 
 
   
   [![Coverage Status](https://coveralls.io/builds/28763900/badge)](https://coveralls.io/builds/28763900)
   
   Coverage increased (+0.02%) to 98.411% when pulling **f39fbe9e438dcea7df4f28f7c9c3e00921bc572f on aherbert:numbers-143-feature** into **81c2fd3d763afdae3cadc711b220e6ded9f7fd36 on apache:master**.
   
 
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Issue Time Tracking
-------------------

    Worklog Id:     (was: 388140)
    Time Spent: 20m  (was: 10m)

> Investigate Math.hypot for computing the absolute of a complex number
> ---------------------------------------------------------------------
>
>                 Key: NUMBERS-143
>                 URL: https://issues.apache.org/jira/browse/NUMBERS-143
>             Project: Commons Numbers
>          Issue Type: Task
>          Components: complex
>            Reporter: Alex Herbert
>            Priority: Minor
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> {{Math.hypot}} computes the value {{sqrt(x^2+y^2)}} to within 1 ULP. The function uses the [e_hypot.c|https://www.netlib.org/fdlibm/e_hypot.c] implementation from the Freely Distributable Math Library (fdlibm).
> Pre-java 9 this function used JNI to call an external implementation. The performance was slow. Java 9 ported the function to native java (see [JDK-7130085 : Port fdlibm hypot to Java|https://bugs.java.com/bugdatabase/view_bug.do?bug_id=7130085]).
> This function is used to define the absolute value of a complex number. It is also used in sqrt() and log(). This ticket is to investigate the performance and accuracy of \{{Math.hypot}} against alternatives for use in Complex.
>  



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