endgame.c File Reference

#include "search.h"
#include "bit.h"
#include "settings.h"
#include "stats.h"
#include "ybwc.h"
#include <assert.h>

Functions
static int	board_solve (const Board *board, const int n_empties)
	Get the final score. More...
int	search_solve (const Search *search)
	Get the final score. More...
static int	board_solve_0 (const Board *board)
	Get the final score. More...
int	search_solve_0 (const Search *search)
	Get the final score. More...
int	board_score_1 (const Board *board, const int beta, const int x)
	Get the final score. More...
static int	board_solve_2 (Board *board, int alpha, const int x1, const int x2, Search *search)
	Get the final score. More...
static int	search_solve_3 (Search *search, const int alpha)
	Get the final score. More...
static int	search_solve_4 (Search *search, const int alpha)
	Get the final score. More...
static int	search_shallow (Search *search, const int alpha)
	Evaluate a position using a shallow NWS. More...
int	NWS_endgame (Search *search, const int alpha)
	Evaluate an endgame position with a Null Window Search algorithm. More...

Detailed Description

Search near the end of the game.

Date

1998 - 2017

Author

Richard Delorme

Version

4.4

Function Documentation

board_score_1()

int board_score_1 ( const Board *  board, const int  beta, const int  x  )

inline

Get the final score.

Get the final score, when 1 empty squares remain. The following code has been adapted from Zebra by Gunnar Anderson.

Parameters

board	Board to evaluate.
beta	Beta bound.
x	Last empty square to play.

Returns

The final opponent score, as a disc difference.

board_solve()

static int board_solve ( const Board *  board, const int  n_empties  )

inlinestatic

Get the final score.

Get the final score, when no move can be made.

Parameters

board	Board.
n_empties	Number of empty squares remaining on the board.

Returns

The final score, as a disc difference.

board_solve_0()

static int board_solve_0 ( const Board *  board )

inlinestatic

Get the final score.

Get the final score, when the board is full.

Parameters

board

Board.

Returns

The final score, as a disc difference.

board_solve_2()

static int board_solve_2 ( Board *  board, int  alpha, const int  x1, const int  x2, Search *  search  )

static

Get the final score.

Get the final score, when 2 empty squares remain.

Parameters

board	The board to evaluate.
alpha	Alpha bound.
x1	First empty square coordinate.
x2	Second empty square coordinate.
search	Search.

Returns

The final score, as a disc difference.

NWS_endgame()

int NWS_endgame	(	Search *	search,
		const int	alpha
	)

Evaluate an endgame position with a Null Window Search algorithm.

This function is used when there are still many empty squares on the board. Move ordering, hash table cutoff, enhanced transposition cutoff, etc. are used in order to diminish the size of the tree to analyse, but at the expense of a slower speed.

Parameters

search	Search.
alpha	Alpha bound.

Returns

The final score, as a disc difference.

search_shallow()

static int search_shallow ( Search *  search, const int  alpha  )

static

Evaluate a position using a shallow NWS.

This function is used when there are few empty squares on the board. Here, optimizations are in favour of speed instead of efficiency. Move ordering is constricted to the hole parity and the type of squares. No hashtable are used and anticipated cut-off is limited to stability cut-off.

Parameters

search	Search.
alpha	Alpha bound.

Returns

The final score, as a disc difference.

search_solve()

int search_solve

(

const Search *

search

)

Get the final score.

Get the final score, when no move can be made.

Parameters

search

Search.

Returns

The final score, as a disc difference.

search_solve_0()

int search_solve_0

(

const Search *

search

)

Get the final score.

Get the final score, when the board is full.

Parameters

search

Search.

Returns

The final score, as a disc difference.

search_solve_3()

static int search_solve_3 ( Search *  search, const int  alpha  )

static

Get the final score.

Get the final score, when 3 empty squares remain.

Parameters

search	Search.
alpha	Alpha bound.

Returns

The final score, as a disc difference.

search_solve_4()

static int search_solve_4 ( Search *  search, const int  alpha  )

static

Get the final score.

Get the final score, when 4 empty squares remain.

Parameters

search	Search position.
alpha	Upper score value.

Returns

The final score, as a disc difference.