Package org.djutils.complex.demo

Class PerformanceTests

java.lang.Object

org.djutils.complex.demo.PerformanceTests

public final class PerformanceTests
extends Object

PerformanceTests.java.

Copyright (c) 2020-2020 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://djutils.org. The DJUTILS project is distributed under a three-clause BSD-style license, which can be found at https://djutils.org/docs/license.html.

Author:

Alexander Verbraeck, Peter Knoppers

Method Summary

Modifier and Type	Method	Description
static double	hypotA(double x, double y)	Implementation of hypot taken from https://stackoverflow.com/questions/3764978/why-hypot-function-is-so-slow .
static double	hypotB(double x, double y)	hypot.
static double	hypotC(double x, double y)	Better implementation of the hypotenuse function (faster and more accurate than the one in the java Math library).
static void	main(String[] args)	Measure performance of atan2, hypot, sine and cosine.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

main

public static void main(String[] args)

Measure performance of atan2, hypot, sine and cosine.

Parameters:

args - String[]; the command line arguments (not used)

hypotA

public static double hypotA(double x,
                            double y)

Implementation of hypot taken from https://stackoverflow.com/questions/3764978/why-hypot-function-is-so-slow .

Parameters:

x - double; x

y - double; y

Returns:

double; the hypot of x, and y

hypotB

public static double hypotB(double x,
                            double y)

hypot.

Parameters:

x - double; x

y - double; y

Returns:

sqrt(x*x +y*y) without intermediate overflow or underflow. Note Math.hypot(double, double) is unnecessarily slow. This returns the identical result to Math.hypot with reasonable run times (~40 nsec vs. 800 nsec). The logic for computing z is copied from "Freely Distributable Math Library" fdlibm's e_hypot.c. This minimizes rounding error to provide 1 ulb accuracy.

hypotC

public static double hypotC(double x,
                            double y)

Better implementation of the hypotenuse function (faster and more accurate than the one in the java Math library).
Derived from An improved algorithm for hypot(a, b) by Carlos F. Borges.

Parameters:

x - double; the x value

y - double; the y value

Returns:

double; hypot(x, y)