[NUMBERS-143] Investigate Math.hypot for computing the absolute of a complex number

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Implemented
• Fix Version/s: 1.0-beta1
• Component/s: complex
• Assignee: Unassigned
• Reporter: Alex Herbert
• Created: 02/Feb/20 12:27
• Updated: 08/Apr/20 11:59
• Resolved: 24/Mar/20 23:32

Description

Math.hypot computes the value sqrt(x^2+y^2) to within 1 ULP. The function uses the 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).

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.

 

Issue Links

• relates to: GEOMETRY-50 Overflow in Vector norm and distance
• links to: GitHub Pull Request #76