board

package
v1.0.2-beta Latest Latest
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 Go to latest Published: Feb 16, 2021 License: GPL-3.0 Imports: 7 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	// HFNONE NONE flag for hash table
	HFNONE = iota
	// HFALPHA Alpha flag for hash table
	HFALPHA
	// HFBETA Beta flag for hash table
	HFBETA
	// HFEXACT Exact flag for hash table
	HFEXACT
)
View Source 
const Infinite = 30000

Infinite Largest score value

View Source 
const IsMate = Infinite - MaxDepth
View Source 
const MaxDepth = 64

MaxDepth The max depth the engine will try to search to

View Source 
const NoMove = 0

NoMove constant for no move found

View Source 
const SquareNumber = 120

SquareNumber Number of squares in the board representastion

View Source 
const StartPosFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 0"

StartPosFEN The fen string for a starting position

Variables

View Source 
var DEBUG bool = false //Default set to true while debugging, should be false normally

DEBUG tells us if we should output debug messages

View Source 
var MoveFlagCA = 0x1000000

MoveFlagCA Castel flag

View Source 
var MoveFlagCAP = 0x7C000

MoveFlagCAP Capture flag

View Source 
var MoveFlagEP = 0x40000

MoveFlagEP EnPas flag

View Source 
var MoveFlagPROM = 0xF00000

MoveFlagPROM Promotion flag

View Source 
var MoveFlagPS = 0x80000

MoveFlagPS Pawn Start flag

Functions

func GetCapture 

func GetCapture(move int) int

GetCapture get capture value from move int

func GetFrom 

func GetFrom(move int) int

GetFrom value from move int

func GetPieceValue 

func GetPieceValue(piece int) int

GetPieceValue returns the value of a piece

func GetPromoted 

func GetPromoted(move int) int

GetPromoted Get promote value from move int

func GetTo 

func GetTo(move int) int

GetTo get TO value from move int

func InitMvvLva 

func InitMvvLva()

InitMvvLva MvvLva (Most valuable victim least valuable attacker)

func Initialize 

func Initialize()

Initialize conversion arrays for engine operation

func MoveToString 

func MoveToString(move int) string

MoveToString move int to algebraic notation

func SquareToString 

func SquareToString(sq int) string

SquareToString square to algebraic notation

func ToMove 

func ToMove(from, to, capture, promotion, flag int) int

ToMove Puts all move info into a single move int

Types

type HashEnteryStruct 

type HashEnteryStruct struct {
	PosKey uint64
	Move   int
	Score  int
	Depth  int
	Flags  int
}

PVEnteryStruct The struct for each entry in the PV table

type HashTableStruct 

type HashTableStruct struct {
	Entries     []HashEnteryStruct
	EntrieCount uint64
	NewWrite    int
	OverWrite   int
	Hit         int
	Cut         int
}

PVTableStruct Struct to hole the PVTable

func (*HashTableStruct) Clear 

func (table *HashTableStruct) Clear()

Clear Clear the PV table

func (*HashTableStruct) Init 

func (table *HashTableStruct) Init(hashSizeMB uint64)

initPVTables Initilize our PV Table slice with a exact amount of memory based on hashSizeMB

type MoveListStruct 

type MoveListStruct struct {
	Moves [maxPositionMoves]MoveStruct
	Count int
}

MoveListStruct List of moves

func (*MoveListStruct) Print 

func (list *MoveListStruct) Print()

Print prints the move list struct to console

type MoveStruct 

type MoveStruct struct {
	Move  int
	Score int
}

MoveStruct used to store a move

type PositionStruct 

type PositionStruct struct {
	Pieces      [SquareNumber]int
	Pawns       [3]uint64
	KingSquare  [2]int
	PieceNum    [13]int
	BigPieces   [2]int
	MajorPieces [2]int
	MinorPieces [2]int
	Material    [2]int

	CastelPerm int
	Side       int
	EnPassant  int
	FiftyMove  int
	Ply        int
	HisPly     int
	PosKey     uint64

	History [2048]UndoStruct

	PieceList [13][10]int

	HashTable HashTableStruct
	PvArray   [MaxDepth]int

	SearchHistory [13][SquareNumber]int
	SearchKillers [2][MaxDepth]int
}

PositionStruct the boards struct

func (*PositionStruct) CheckBoard 

func (pos *PositionStruct) CheckBoard() error

CheckBoard VERY expensive only use for debugging

func (*PositionStruct) ClearMoveFromHash 

func (pos *PositionStruct) ClearMoveFromHash() error

ClearMoveFromHash Clear the move made at the current position from the hash table

func (*PositionStruct) Evaluate 

func (pos *PositionStruct) Evaluate() int

Evaluate the currect position and return a score

func (*PositionStruct) GenerateAllCaptureMoves 

func (pos *PositionStruct) GenerateAllCaptureMoves(list *MoveListStruct) error

GenerateAllMoves Generate all moves

func (*PositionStruct) GenerateAllMoves 

func (pos *PositionStruct) GenerateAllMoves(list *MoveListStruct) error

GenerateAllMoves Generate all moves

func (*PositionStruct) GetPvLine 

func (pos *PositionStruct) GetPvLine(depth int) (int, error)

GetPvLine return the PVLine if found for the curren position

func (*PositionStruct) IsAttacked 

func (pos *PositionStruct) IsAttacked(sq, side int) (bool, error)

IsAttacked Returns if square is attacked

func (*PositionStruct) IsRepition 

func (pos *PositionStruct) IsRepition() bool

IsRepition tests for 3 fold repitition

func (*PositionStruct) LoadFEN 

func (pos *PositionStruct) LoadFEN(fen string) error

LoadFEN loads the engine with a new board position from a FEN string

func (*PositionStruct) MakeMove 

func (pos *PositionStruct) MakeMove(move int) (bool, error)

MakeMove Make a move if legal and return legality

func (*PositionStruct) MakeNullMove 

func (pos *PositionStruct) MakeNullMove() error

MakeNullMove Make a null move

For more info go to https://www.chessprogramming.org/Null_Move_Pruning

func (*PositionStruct) MirrorBoard 

func (pos *PositionStruct) MirrorBoard() error

mirrorBoard Mirror the position

func (*PositionStruct) MoveExists 

func (pos *PositionStruct) MoveExists(move int) (bool, error)

func (*PositionStruct) ParseMove 

func (pos *PositionStruct) ParseMove(move string) (int, error)

ParseMove algebraic notation to move int

func (*PositionStruct) Perft 

func (pos *PositionStruct) Perft(depth int) (int, error)

Perft is a performance test used to test move generation

returns leaf node count

For more information of Perft: https://www.chessprogramming.org/Perft

func (*PositionStruct) PerftDivide 

func (pos *PositionStruct) PerftDivide(depth int) error

PerftDivide divides the result of Perft() to each root node

returns leaf node count for a given root node

For more information of Perft: https://www.chessprogramming.org/Perft

func (*PositionStruct) Print 

func (pos *PositionStruct) Print()

Print a representation of the current board state to the console

func (*PositionStruct) ProbeHashEntry 

func (pos *PositionStruct) ProbeHashEntry(move *int, score *int, alpha, beta, depth int) (bool, error)

func (*PositionStruct) ProbePVMove 

func (pos *PositionStruct) ProbePVMove() (int, error)

ProbePVTable probe the table for a move on the current position

func (*PositionStruct) StoreHashEntry 

func (pos *PositionStruct) StoreHashEntry(move, score, flags, depth int) error

StorePVMove a move in the PV table

func (*PositionStruct) TakeMove 

func (pos *PositionStruct) TakeMove() error

TakeMove Take back the last move

func (*PositionStruct) TakeNullMove 

func (pos *PositionStruct) TakeNullMove() error

TakeNullMove Take back the last null move

type UndoStruct 

type UndoStruct struct {
	Move       int
	CastelPerm int
	EnPassant  int
	FiftyMove  int
	PosKey     uint64
}

UndoStruct the undo move struct

Source Files

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