Package org.nlpub.watset.util

Class Maximizer

java.lang.Object

org.nlpub.watset.util.Maximizer

public final class Maximizer
extends Object

Utilities for searching arguments of the maxima of the function.

Method Summary

Modifier and Type	Method	Description
static <T> Predicate<T>	alwaysFalse()	A predicate that is always false.
static <T> Predicate<T>	alwaysTrue()	A predicate that is always true.
static <V,S extends Comparable<S>> Optional<V>	argmax(Iterator<V> it, Function<V,S> scorer)	Find the first argument of the maximum (argmax) of the function.
static <V,S extends Comparable<S>> Optional<V>	argmax(Iterator<V> it, Predicate<V> checker, Function<V,S> scorer)	Find the first argument of the maximum (argmax) of the function.
static <V,S extends Comparable<S>> Optional<V>	argmaxRandom(Iterator<V> it, Function<V,S> scorer, Random random)	Find the arguments of the maxima (argmax) of the function and randomly choose any of them.

Methods inherited from class java.lang.Object

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

Method Detail

alwaysTrue

public static <T> Predicate<T> alwaysTrue()

A predicate that is always true.

Type Parameters:

T - the type

Returns:

the absolute truth

alwaysFalse

public static <T> Predicate<T> alwaysFalse()

A predicate that is always false.

Type Parameters:

T - the type

Returns:

the absolute non-truth

argmax

public static <V,S extends Comparable<S>> Optional<V> argmax(Iterator<V> it,
                                                                   Predicate<V> checker,
                                                                   Function<V,S> scorer)

Find the first argument of the maximum (argmax) of the function.

Type Parameters:

V - the argument type

S - the score type

Parameters:

it - the finite iterator

checker - the predicate that evaluates the suitability of the argument

scorer - the scoring function

Returns:

a non-empty optional that contains the first found argmax, otherwise the empty one

argmax

public static <V,S extends Comparable<S>> Optional<V> argmax(Iterator<V> it,
                                                                   Function<V,S> scorer)

Find the first argument of the maximum (argmax) of the function.

Type Parameters:

V - the argument type

S - the score type

Parameters:

it - the finite iterator

scorer - the scoring function

Returns:

a non-empty optional that contains the first found argmax, otherwise the empty one

See Also:

argmax(Iterator, Predicate, Function)

argmaxRandom

public static <V,S extends Comparable<S>> Optional<V> argmaxRandom(Iterator<V> it,
                                                                         Function<V,S> scorer,
                                                                         Random random)

Find the arguments of the maxima (argmax) of the function and randomly choose any of them.

Type Parameters:

V - the argument type

S - the score type

Parameters:

it - the finite iterator

scorer - the scoring function

random - the random number generator

Returns:

a non-empty optional that contains the randomly chosen argmax, otherwise the empty one