aim4.util
Class Util

java.lang.Object
  aim4.util.Util

public class Util
extends Object

This class provides helper methods that are used throughout the code.

Field Summary

static Random	random The global random number generator
static long	randSeed The random seed for all random number generators in the simulation

Method Summary

static String	concatenate(List<String> strings, String sep) Concatenate a list of strings.
static String	concatenate(String[] strings, String sep) Concatenate an array of strings.
static double	constrain(double inputValue, double minValue, double maxValue) Constrain a double value between a lower and upper bound.
static boolean	isDoubleEqual(double a, double b) Whether two floating-point numbers (doubles) are equal.
static boolean	isDoubleEqual(double a, double b, double precision) Whether two floating-point numbers (doubles) are equal.
static boolean	isDoubleEqualOrGreater(double a, double b) Whether two floating-point numbers (doubles) are greater than or equal to another.
static boolean	isDoubleEqualOrLess(double a, double b) Whether two floating-point numbers (doubles) are less than or equal to another.
static boolean	isDoubleNotEqual(double a, double b) Whether two floating-point numbers (doubles) are not equal.
static boolean	isDoubleNotEqual(double a, double b, double precision) Whether two floating-point numbers (doubles) are not equal.
static boolean	isDoubleNotZero(double a) Whether a floating-point numbers (doubles) is not zero.
static boolean	isDoubleZero(double a) Whether a floating-point numbers (doubles) is zero.
static boolean	nearlyEqual(double a, double b, double epsilon) Check whether two double values are "nearly" equal.
static int	randomIndex(double[] distribution) Choose a number according to a finite probability distribution.
static int	randomIndex(List<Double> distribution) Choose a number according to a finite probability distribution.
static List<String>	readFileToStrArray(String inFileName) Read the content of a file into a list of strings.
static double	recenter(double inputValue, double minValue, double maxValue) Recenter a double value between a lower and upper bound.
static double	sum(double[] as) The sum of an array of floating-point numbers
static double	sum(Iterable<Double> as) The sum of a sequence of floating-point numbers

Methods inherited from class java.lang.Object

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

Field Detail

randSeed

public static long randSeed

The random seed for all random number generators in the simulation

random

public static final Random random

The global random number generator

Method Detail

nearlyEqual

public static boolean nearlyEqual(double a,
                                  double b,
                                  double epsilon)

Check whether two double values are "nearly" equal.

Parameters:

a - the first double value

b - the second double value

epsilon - the precision

Returns:

whether the two values are nearly equal.

isDoubleZero

public static boolean isDoubleZero(double a)

Whether a floating-point numbers (doubles) is zero.

Parameters:

a - a double value

Returns:

whether the floating-point number is zero.

isDoubleNotZero

public static boolean isDoubleNotZero(double a)

Whether a floating-point numbers (doubles) is not zero.

Parameters:

a - a double value

Returns:

whether the floating-point number is not zero.

isDoubleEqual

public static boolean isDoubleEqual(double a,
                                    double b)

Whether two floating-point numbers (doubles) are equal.

Parameters:

a - a double value

b - a double value

Returns:

whether the two floating-point numbers are equal.

isDoubleNotEqual

public static boolean isDoubleNotEqual(double a,
                                       double b)

Whether two floating-point numbers (doubles) are not equal.

Parameters:

a - a double value

b - a double value

Returns:

whether the two floating-point numbers are not equal.

isDoubleEqual

public static boolean isDoubleEqual(double a,
                                    double b,
                                    double precision)

Whether two floating-point numbers (doubles) are equal.

Parameters:

a - a double value

b - a double value

precision - the bound on of the difference between a and b that is considered equal.

Returns:

whether the two floating-point numbers are equal.

isDoubleNotEqual

public static boolean isDoubleNotEqual(double a,
                                       double b,
                                       double precision)

Whether two floating-point numbers (doubles) are not equal.

Parameters:

a - a double value

b - a double value

precision - the bound on of the difference between a and b that is considered equal.

Returns:

whether the two floating-point numbers are not equal.

isDoubleEqualOrGreater

public static boolean isDoubleEqualOrGreater(double a,
                                             double b)

Whether two floating-point numbers (doubles) are greater than or equal to another.

Parameters:

a - a double value

b - a double value

Returns:

whether a >= b.

isDoubleEqualOrLess

public static boolean isDoubleEqualOrLess(double a,
                                          double b)

Whether two floating-point numbers (doubles) are less than or equal to another.

Parameters:

a - a double value

b - a double value

Returns:

whether a <= b.

constrain

public static double constrain(double inputValue,
                               double minValue,
                               double maxValue)

Constrain a double value between a lower and upper bound. If it is below the minimum value, return the minimum value. If it is above the maximum value, return the maximum value. Otherwise, return the original value.

Parameters:

inputValue - the value to constrain

minValue - the lower bound

maxValue - the upper bound

Returns:

a value between the lower and upper bounds

recenter

public static double recenter(double inputValue,
                              double minValue,
                              double maxValue)

Recenter a double value between a lower and upper bound. This means that if a number is between the two bounds, it is returned unchanged, but if it falls out of bounds, it is adjusted by the size of the interval until it fits. For example, it can be used for for recentering angles between 0 and 2π or 0 and 180.

Parameters:

inputValue - the value to recenter

minValue - the lower bound

maxValue - the upper bound

Returns:

a value between the lower and upper bounds

sum

public static double sum(Iterable<Double> as)

The sum of a sequence of floating-point numbers

Parameters:

as - an iterable of double values

Returns:

the sum of the double values

sum

public static double sum(double[] as)

The sum of an array of floating-point numbers

Parameters:

as - an array of double values

Returns:

the sum of the double values

randomIndex

public static int randomIndex(double[] distribution)

Choose a number according to a finite probability distribution.

Parameters:

distribution - the probability distribution

Returns:

an index of the distribution that is randomly chosen according to the distribution

randomIndex

public static int randomIndex(List<Double> distribution)

Choose a number according to a finite probability distribution.

Parameters:

distribution - the probability distribution

Returns:

an index of the distribution that is randomly chosen according to the distribution

concatenate

public static String concatenate(List<String> strings,
                                 String sep)

Concatenate a list of strings.

Parameters:

strings - a list of string

sep - the separator

Returns:

the concatenation of the list of string.

concatenate

public static String concatenate(String[] strings,
                                 String sep)

Concatenate an array of strings.

Parameters:

strings - an array of string

sep - the separator

Returns:

the concatenation of the list of string.

readFileToStrArray

public static List<String> readFileToStrArray(String inFileName)
                                       throws IOException

Read the content of a file into a list of strings.

Parameters:

inFileName - the name of the file

Returns:

the list of strings

Throws:

IOException