Package org.swtpra1.alphabetaplayer.transpositiontables

Class AlphaBetaSearchTreeWithTranspositionTables

java.lang.Object

org.swtpra1.alphabetaplayer.alphabeta.AlphaBetaSearchTree

org.swtpra1.alphabetaplayer.transpositiontables.AlphaBetaSearchTreeWithTranspositionTables

public class AlphaBetaSearchTreeWithTranspositionTables
extends AlphaBetaSearchTree

Implements the negamax search algorithm with alpha beta pruning and transposition table optimization.

Field Summary

Fields

Modifier and Type	Field	Description
java.util.concurrent.atomic.AtomicLong	transCount

Fields inherited from class org.swtpra1.alphabetaplayer.alphabeta.AlphaBetaSearchTree

evaluator, executor, parallelism

Constructor Summary

Constructors

Constructor	Description
AlphaBetaSearchTreeWithTranspositionTables(Evaluator evaluator, int parallelism)	Creates a search tree instance of negamax search with alpha beta pruning and transposition table optimization.

Method Summary

Modifier and Type	Method	Description
void	clearTranspositionTable()
protected ValuedTurn	negamax(Board board, int player, int depth, boolean presort, float alpha, float beta, java.util.List<Turn> blacklist)	Searches for the best turn using negamax search with alpha beta pruning and transposition tables.
ValuedTurn	negamax(Board board, int player, int depth, boolean presort, java.util.List<Turn> blacklist)	Searches for the best turn using negamax search with alpha beta pruning and transposition tables.

Methods inherited from class org.swtpra1.alphabetaplayer.alphabeta.AlphaBetaSearchTree

chooseMostPromisingTurns, negamax, negamax, parallelNegamax

Methods inherited from class java.lang.Object

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

Field Detail

transCount

public final java.util.concurrent.atomic.AtomicLong transCount

Constructor Detail

AlphaBetaSearchTreeWithTranspositionTables

public AlphaBetaSearchTreeWithTranspositionTables(Evaluator evaluator,
                                                  int parallelism)

Creates a search tree instance of negamax search with alpha beta pruning and transposition table optimization.

Parameters:

evaluator - the evaluator to use to evaluate board positions

parallelism - see AlphaBetaPlayer.parallelism

Method Detail

negamax

public ValuedTurn negamax(Board board,
                          int player,
                          int depth,
                          boolean presort,
                          java.util.List<Turn> blacklist)

Searches for the best turn using negamax search with alpha beta pruning and transposition tables.

Overrides:

negamax in class AlphaBetaSearchTree

Parameters:

board - the current state of the board

player - the id (0 or 1) of the player on this layer

depth - the maximum depth to be considered

presort - whether to presort the moves and cut off

blacklist - moves that should never be considered

Returns:

best possible turn with its evaluation

negamax

protected ValuedTurn negamax(Board board,
                             int player,
                             int depth,
                             boolean presort,
                             float alpha,
                             float beta,
                             java.util.List<Turn> blacklist)

Searches for the best turn using negamax search with alpha beta pruning and transposition tables.

Overrides:

negamax in class AlphaBetaSearchTree

Parameters:

board - the current state of the board

player - the id (0 or 1) of the player on this layer

depth - the maximum depth to be considered

presort - whether to presort the moves and cut off

alpha - to determine whether better moves can be found

beta - to determine whether better moves can be found

blacklist - moves that should never be considered

Returns:

best possible turn with its evaluation

clearTranspositionTable

public void clearTranspositionTable()