Package a5.ai

Class TranspositionTable<GameState>

java.lang.Object

a5.ai.TranspositionTable<GameState>

Type Parameters:

GameState - A type representing the state of a game.

public class TranspositionTable<GameState>
extends Object

A transposition table for an arbitrary game. It maps a game state to a search depth and a heuristic evaluation of that state to the recorded depth. Unlike a conventional map abstraction, a state is associated with a depth, so that clients can look for states whose entry has at least the desired depth.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	TranspositionTable.StateInfo	Information about a game state, for use by clients.

Method Summary

Modifier and Type	Method	Description
void	add(GameState state, int depth, int value)	Effect: Add a new entry in the transposition table for a given state and depth, or overwrite the existing entry for this state with the new depth and value.
Maybe<TranspositionTable.StateInfo>	getInfo(GameState state)	Returns: the information in the transposition table for a given game state, package in an Optional.
int	size()	The number of entries in the transposition table.

Methods inherited from class java.lang.Object

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

Method Details

size

public int size()

The number of entries in the transposition table.

getInfo

public Maybe<TranspositionTable.StateInfo> getInfo(GameState state)

Returns: the information in the transposition table for a given game state, package in an Optional. If there is no information in the table for this state, returns an empty Optional.

add

public void add(GameState state,
 int depth,
 int value)

Effect: Add a new entry in the transposition table for a given state and depth, or overwrite the existing entry for this state with the new depth and value. Requires: if overwriting an existing entry, the new depth must be greater than the old one.