Package search.ab

Class Minimax_AB

java.lang.Object

search.AI

search.ab.Minimax_AB

public class Minimax_AB
extends AI

An implementation of a Minimax Search for the game Jump Sturdy with Alpha-Beta Pruning, Aspiration Windows, Transposition Tables and a Quiescence Search.

Field Summary

Fields

Modifier and Type	Field	Description
static SearchConfig	bestConfig
int	maxDepth
HashMap<String,Integer>	positionsHM
HashMap<String,TranspositionTableObject>	transpositionTable

Constructor Summary

Constructors

Constructor	Description
Minimax_AB()

Method Summary

Modifier and Type	Method	Description
int	getBestMove(String fen)	Determines the best move for a given board state represented by a FEN string.
double	iterativeDeepening(MoveGenerator gameState, double moveTimeLimit, Color ourColor)	Performs an iterative deepening search to find the best move score within the given time limit.
String	orchestrator(String fen, SearchConfig config)	Orchestrates the AI on the given FEN position and search configuration.
double	quiescenceSearch(MoveGenerator gameState, double alpha, double beta, Color currentColor, Color ourColor)	Performs a quiescence search to evaluate positions more accurately by only exploring capture moves.
String	showConfig()	Returns the configuration of the AI.
double	treeSearch(MoveGenerator gameState, double alpha, double beta, double endTime, int depth, Color currentColor, Color ourColor)	Executes a recursive tree search with alpha-beta pruning to evaluate game positions and find the best possible move for the current player.

Methods inherited from class search.AI

toString

Methods inherited from class java.lang.Object

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

Field Details

maxDepth

public int maxDepth

positionsHM

public HashMap<String,Integer> positionsHM

transpositionTable

public HashMap<String,TranspositionTableObject> transpositionTable

bestConfig

public static SearchConfig bestConfig

Constructor Details

Minimax_AB

public Minimax_AB()

Method Details

orchestrator

public String orchestrator(String fen,
 SearchConfig config)

Description copied from class: AI

Orchestrates the AI on the given FEN position and search configuration.

Specified by:

orchestrator in class AI

Parameters:

fen - The current position in FEN notation

config - The configuration object specifying the AI search parameters

Returns:

The best move determined by the search algorithm

showConfig

public String showConfig()

Description copied from class: AI

Returns the configuration of the AI.

Specified by:

showConfig in class AI

Returns:

The configuration object

getBestMove

public int getBestMove(String fen)

Determines the best move for a given board state represented by a FEN string. This method utilizes iterative deepening search with time management to evaluate possible moves and select the one with the highest score.

Parameters:

fen - The current position in FEN notation.

Returns:

The best move determined based on the evaluation, represented as an integer.

quiescenceSearch

public double quiescenceSearch(MoveGenerator gameState,
 double alpha,
 double beta,
 Color currentColor,
 Color ourColor)

Performs a quiescence search to evaluate positions more accurately by only exploring capture moves.

Parameters:

gameState - The current game state.

alpha - The alpha value for alpha-beta pruning.

beta - The beta value for alpha-beta pruning.

currentColor - The color of the player whose turn it is.

ourColor - The color of our player.

Returns:

The best score for the current game state after exploring capture moves.

iterativeDeepening

public double iterativeDeepening(MoveGenerator gameState,
 double moveTimeLimit,
 Color ourColor)

Performs an iterative deepening search to find the best move score within the given time limit. This method incrementally deepens the search depth until the time runs out or the maximum allowed depth is reached. Alpha-Beta pruning is used to optimize the search.

Parameters:

gameState - The current state of the game represented by a MoveGenerator object.

moveTimeLimit - The maximum time allowed for evaluating a move, in milliseconds.

ourColor - The color of the player whose best move gets evaluated.

Returns:

The best score obtained for the evaluated moves within the given time limit.

treeSearch

public double treeSearch(MoveGenerator gameState,
 double alpha,
 double beta,
 double endTime,
 int depth,
 Color currentColor,
 Color ourColor)

Executes a recursive tree search with alpha-beta pruning to evaluate game positions and find the best possible move for the current player. This method can use, based on the configuration, transposition tables to store and get previously evaluated positions to optimize the search.

Parameters:

gameState - The current state of the game represented by a MoveGenerator object.

alpha - The alpha value used in alpha-beta pruning.

beta - The beta value used in alpha-beta pruning.

endTime - The time when the search should stop, used for time management.

depth - The depth left for the search tree.

currentColor - The color of the player currently making a move.

ourColor - The color of the player whose best move gets evaluated.

Returns:

The best score obtained for the evaluated game position.