Package org.djutils.float128

Class TestHypotAtan

java.lang.Object

org.djutils.float128.TestHypotAtan

public final class TestHypotAtan
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
(package private) static double	atan(double x)	atan from http://www.netlib.org/fdlibm/.
(package private) static double	fastAtan(double x)
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)	hypot.
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)

hypot. C.F. Borges, An Improved Algorithm for hypot(a, b). arXiv:1904.09481v6 [math.NA] 14 Jun 2019.

Parameters:

x - double; x

y - double; y

Returns:

sqrt(x*x +y*y) without intermediate overflow or underflow.

atan

static double atan(double x)

atan from http://www.netlib.org/fdlibm/.

Parameters:

x - double

Returns:

atan(x)

fastAtan

static double fastAtan(double x)

Parameters:

x - param

Returns:

atan(x)