aima.core.environment.connectfour

Class ConnectFourAIPlayer

java.lang.Object

aima.core.search.adversarial.IterativeDeepeningAlphaBetaSearch<ConnectFourState,java.lang.Integer,java.lang.String>

aima.core.environment.connectfour.ConnectFourAIPlayer

All Implemented Interfaces:

AdversarialSearch<ConnectFourState,java.lang.Integer>

public class ConnectFourAIPlayer
extends IterativeDeepeningAlphaBetaSearch<ConnectFourState,java.lang.Integer,java.lang.String>

Implements an iterative deepening Minimax search with alpha-beta pruning and a special action ordering optimized for the Connect Four game.

Author:

Ruediger Lunde

Field Summary

Fields inherited from class aima.core.search.adversarial.IterativeDeepeningAlphaBetaSearch

currDepthLimit, game, METRICS_MAX_DEPTH, METRICS_NODES_EXPANDED, utilMax, utilMin

Constructor Summary

Constructors

Constructor and Description
ConnectFourAIPlayer(Game<ConnectFourState,java.lang.Integer,java.lang.String> game, int time)

Method Summary

Modifier and Type	Method and Description
protected double	eval(ConnectFourState state, java.lang.String player) Modifies the super implementation by making safe winner values even more attractive if depth is small.
protected boolean	hasSafeWinner(double resultUtility) Primitive operation which is used to stop iterative deepening search in situations where a safe winner has been identified.
protected boolean	isSignificantlyBetter(double newUtility, double utility) Primitive operation which is used to stop iterative deepening search in situations where a clear best action exists.
java.util.List<java.lang.Integer>	orderActions(ConnectFourState state, java.util.List<java.lang.Integer> actions, java.lang.String player, int depth) Orders actions with respect to the number of potential win positions which profit from the action.

Methods inherited from class aima.core.search.adversarial.IterativeDeepeningAlphaBetaSearch

createFor, getMetrics, incrementDepthLimit, makeDecision, maxValue, minValue, setLogEnabled

Methods inherited from class java.lang.Object

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

Constructor Detail

ConnectFourAIPlayer

public ConnectFourAIPlayer(Game<ConnectFourState,java.lang.Integer,java.lang.String> game,
                           int time)

Method Detail

isSignificantlyBetter

protected boolean isSignificantlyBetter(double newUtility,
                                        double utility)

Description copied from class: IterativeDeepeningAlphaBetaSearch

Primitive operation which is used to stop iterative deepening search in situations where a clear best action exists. This implementation returns always false.

Overrides:

isSignificantlyBetter in class IterativeDeepeningAlphaBetaSearch<ConnectFourState,java.lang.Integer,java.lang.String>

hasSafeWinner

protected boolean hasSafeWinner(double resultUtility)

Description copied from class: IterativeDeepeningAlphaBetaSearch

Primitive operation which is used to stop iterative deepening search in situations where a safe winner has been identified. This implementation returns true if the given value (for the currently preferred action result) is the highest or lowest utility value possible.

Overrides:

hasSafeWinner in class IterativeDeepeningAlphaBetaSearch<ConnectFourState,java.lang.Integer,java.lang.String>

eval

protected double eval(ConnectFourState state,
                      java.lang.String player)

Modifies the super implementation by making safe winner values even more attractive if depth is small.

Overrides:

eval in class IterativeDeepeningAlphaBetaSearch<ConnectFourState,java.lang.Integer,java.lang.String>

orderActions

public java.util.List<java.lang.Integer> orderActions(ConnectFourState state,
                                                      java.util.List<java.lang.Integer> actions,
                                                      java.lang.String player,
                                                      int depth)

Orders actions with respect to the number of potential win positions which profit from the action.

Overrides:

orderActions in class IterativeDeepeningAlphaBetaSearch<ConnectFourState,java.lang.Integer,java.lang.String>