aima.core.util

Class Util

java.lang.Object

aima.core.util.Util

public class Util
extends java.lang.Object

Author:

Ravi Mohan

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	NO
static java.lang.String	YES

Constructor Summary

Constructors

Constructor and Description
Util()

Method Summary

Modifier and Type	Method and Description
static double	calculateMean(java.util.List<java.lang.Double> lst)
static double	calculateStDev(java.util.List<java.lang.Double> values, double mean)
static void	checkForNanOrInfinity(double d)
static boolean	compareDoubles(double a, double b) Compares two doubles for equality.
static boolean	compareFloats(float a, float b) Compares two floats for equality.
static <K,V> java.util.Map<K,V>	create(java.util.Collection<K> keys, V value) Create a Map with the passed in keys having their values initialized to the passed in value.
static <V> java.util.Set<V>	createSet(V... values) Create a set for the provided values.
static <T> T	first(java.util.List<T> l) Get the first element from a list.
static double	generateRandomDoubleBetween(double lowerLimit, double upperLimit) Generates a random double between two limits.
static float	generateRandomFloatBetween(float lowerLimit, float upperLimit) Generates a random float between two limits.
static double	information(double[] probabilities)
static double	log2(double d)
static int	max(int i, int j)
static int	max(int i, int j, int k)
static int	min(int i, int j)
static int	min(int i, int j, int k)
static <T> T	mode(java.util.List<T> l)
static double[]	normalize(double[] probDist)
static java.util.List<java.lang.Double>	normalize(java.util.List<java.lang.Double> values)
static java.util.List<java.lang.Double>	normalizeFromMeanAndStdev(java.util.List<java.lang.Double> values, double mean, double stdev)
static java.lang.String	ntimes(java.lang.String s, int n)
static boolean	randomBoolean()
static int	randomNumberBetween(int i, int j)
static <T> java.util.List<T>	removeFrom(java.util.List<T> list, T member)
static <T> java.util.List<T>	rest(java.util.List<T> l) Get a sublist of all of the elements in the list except for first.
static <T> T	selectRandomlyFromList(java.util.List<T> l) Randomly select an element from a list.
static <T extends java.lang.Number> double	sumOfSquares(java.util.List<T> list)
static java.lang.String[]	yesno()

Methods inherited from class java.lang.Object

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

Field Detail

NO

public static final java.lang.String NO

See Also:

Constant Field Values

YES

public static final java.lang.String YES

See Also:

Constant Field Values

Constructor Detail

Util

public Util()

Method Detail

first

public static <T> T first(java.util.List<T> l)

Get the first element from a list.

Parameters:

l - the list the first element is to be extracted from.

Returns:

the first element of the passed in list.

rest

public static <T> java.util.List<T> rest(java.util.List<T> l)

Get a sublist of all of the elements in the list except for first.

Parameters:

l - the list the rest of the elements are to be extracted from.

Returns:

a list of all of the elements in the passed in list except for the first element.

create

public static <K,V> java.util.Map<K,V> create(java.util.Collection<K> keys,
                                              V value)

Create a Map with the passed in keys having their values initialized to the passed in value.

Parameters:

keys - the keys for the newly constructed map.

value - the value to be associated with each of the maps keys.

Returns:

a map with the passed in keys initialized to value.

createSet

@SafeVarargs
public static <V> java.util.Set<V> createSet(V... values)

Create a set for the provided values.

Parameters:

values - the sets initial values.

Returns:

a Set of the provided values.

selectRandomlyFromList

public static <T> T selectRandomlyFromList(java.util.List<T> l)

Randomly select an element from a list.

Type Parameters:

T - the type of element to be returned from the list l.

Parameters:

l - a list of type T from which an element is to be selected randomly.

Returns:

a randomly selected element from l.

randomBoolean

public static boolean randomBoolean()

normalize

public static double[] normalize(double[] probDist)

normalize

public static java.util.List<java.lang.Double> normalize(java.util.List<java.lang.Double> values)

min

public static int min(int i,
                      int j)

max

public static int max(int i,
                      int j)

max

public static int max(int i,
                      int j,
                      int k)

min

public static int min(int i,
                      int j,
                      int k)

mode

public static <T> T mode(java.util.List<T> l)

yesno

public static java.lang.String[] yesno()

log2

public static double log2(double d)

information

public static double information(double[] probabilities)

removeFrom

public static <T> java.util.List<T> removeFrom(java.util.List<T> list,
                                               T member)

sumOfSquares

public static <T extends java.lang.Number> double sumOfSquares(java.util.List<T> list)

ntimes

public static java.lang.String ntimes(java.lang.String s,
                                      int n)

checkForNanOrInfinity

public static void checkForNanOrInfinity(double d)

randomNumberBetween

public static int randomNumberBetween(int i,
                                      int j)

calculateMean

public static double calculateMean(java.util.List<java.lang.Double> lst)

calculateStDev

public static double calculateStDev(java.util.List<java.lang.Double> values,
                                    double mean)

normalizeFromMeanAndStdev

public static java.util.List<java.lang.Double> normalizeFromMeanAndStdev(java.util.List<java.lang.Double> values,
                                                                         double mean,
                                                                         double stdev)

generateRandomDoubleBetween

public static double generateRandomDoubleBetween(double lowerLimit,
                                                 double upperLimit)

Generates a random double between two limits. Both limits are inclusive.

Parameters:

lowerLimit - the lower limit.

upperLimit - the upper limit.

Returns:

a random double bigger or equals lowerLimit and smaller or equals upperLimit.

generateRandomFloatBetween

public static float generateRandomFloatBetween(float lowerLimit,
                                               float upperLimit)

Generates a random float between two limits. Both limits are inclusive.

Parameters:

lowerLimit - the lower limit.

upperLimit - the upper limit.

Returns:

a random float bigger or equals lowerLimit and smaller or equals upperLimit.

compareDoubles

public static boolean compareDoubles(double a,
                                     double b)

Compares two doubles for equality.

Parameters:

a - the first double.

b - the second double.

Returns:

true if both doubles contain the same value or the absolute deviation between them is below EPSILON.

compareFloats

public static boolean compareFloats(float a,
                                    float b)

Compares two floats for equality.

Parameters:

a - the first floats.

b - the second floats.

Returns:

true if both floats contain the same value or the absolute deviation between them is below EPSILON.