edu.umich.eecs.april.jmat

Class MathUtil

java.lang.Object

edu.umich.eecs.april.jmat.MathUtil

public class MathUtil
extends java.lang.Object

Miscellaneous math utilities like mod2pi and fast exp functions.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static double	epsilon
(package private) static double	twopi
(package private) static double	twopi_inv

Constructor Summary

Constructors

Constructor and Description
MathUtil()

Method Summary

Modifier and Type	Method and Description
protected static double	atan_mag1(double x)
static double	atan(double x) returns [-PI/2, PI/2] accurate within 0.014 degrees
static double	atan2(double y, double x)
static void	benchatan()
static void	benchexp()
static double	clamp(double v, double min, double max)
static int	clamp(int v, int min, int max)
static boolean	doubleEquals(double a, double b) Returns true if the two doubles are within a small epsilon of each other.
protected static double	exp_pos(double xin) Quickly compute e^x for positive x.
static double	exp(double xin) Quickly compute e^x for all x.
static void	inverse22(Matrix A)
static void	inverse33(Matrix A)
static void	main(java.lang.String[] args)
static double	mod2pi(double vin) Ensure that v is [-PI, PI]
static double	mod2pi(double ref, double v) Returns a value of v wrapped such that ref and v differ by no more +/-PI
static int	sign(double v)
static double	square(double x)

Methods inherited from class java.lang.Object

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

Field Detail

epsilon

static double epsilon

twopi_inv

static double twopi_inv

twopi

static double twopi

Constructor Detail

MathUtil

public MathUtil()

Method Detail

mod2pi

public static double mod2pi(double vin)

Ensure that v is [-PI, PI]

mod2pi

public static double mod2pi(double ref,
                            double v)

Returns a value of v wrapped such that ref and v differ by no more +/-PI

doubleEquals

public static boolean doubleEquals(double a,
                                   double b)

Returns true if the two doubles are within a small epsilon of each other.

clamp

public static int clamp(int v,
                        int min,
                        int max)

clamp

public static double clamp(double v,
                           double min,
                           double max)

square

public static final double square(double x)

sign

public static final int sign(double v)

exp

public static final double exp(double xin)

Quickly compute e^x for all x. Accuracy for x>0: x<0.5, absolute error > .0099 x<0.5, relative error 0.36% For x<0, we internally compute the reciprocal form; error is magnified. This approximation is also monotonic.

exp_pos

protected static final double exp_pos(double xin)

Quickly compute e^x for positive x.

atan2

public static final double atan2(double y,
                                 double x)

atan

public static final double atan(double x)

returns [-PI/2, PI/2] accurate within 0.014 degrees

atan_mag1

protected static final double atan_mag1(double x)

main

public static void main(java.lang.String[] args)

benchexp

public static void benchexp()

benchatan

public static void benchatan()

inverse22

public static void inverse22(Matrix A)

inverse33

public static void inverse33(Matrix A)