eval.h File Reference

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Classes
struct	Eval
	evaluation function More...

Typedefs
typedef struct Eval	Eval
	evaluation function

Functions
void	eval_open (const char *)
	Load the evaluation function features' weights.
void	eval_close (void)
	Free global resources allocated to the evaluation function.
void	eval_init (Eval *)
	Initialize a new evaluation function.
void	eval_free (Eval *)
	Free resources used by the evaluation function.
void	eval_set (Eval *, const struct Board *)
void	eval_update (Eval *, const struct Move *)
void	eval_restore (Eval *, const struct Move *)
void	eval_pass (Eval *)
	Update/Restore the features after a passing move.
double	eval_sigma (const int, const int, const int)
	Compute the error-type of the evaluation function according to the depths.

Variables
short ***	EVAL_WEIGHT

Detailed Description

Evaluation function's header.

Date

1998 - 2017

Author

Richard Delorme

Version

4.4

Typedef Documentation

Eval

typedef struct Eval Eval

evaluation function

struct Eval

Function Documentation

eval_close()

void eval_close

(

void

)

Free global resources allocated to the evaluation function.

eval_free()

void eval_free

(

Eval *

eval

)

Free resources used by the evaluation function.

Parameters

eval	Evaluation function.

eval_init()

void eval_init

(

Eval *

eval

)

Initialize a new evaluation function.

Allocate space to store the state of the evaluation function.

Parameters

eval	Evaluation function.

eval_open()

void eval_open

(

const char *

file

)

Load the evaluation function features' weights.

The weights are stored in a global variable, because, once loaded from the file, they stay constant during the lifetime of the program. As loading the weights is time & resource consuming, a counter variable check that the weights are effectively loaded only once.

Parameters

file	File name of the evaluation function data.

eval_pass()

void eval_pass

(

Eval *

eval

)

Update/Restore the features after a passing move.

Parameters

eval	Evaluation function.

eval_restore()

void eval_restore	(	Eval *	,
		const struct Move *	)

eval_set()

void eval_set	(	Eval *	,
		const struct Board *	)

eval_sigma()

double eval_sigma	(	const int	n_empty,
		const int	depth,
		const int	probcut_depth )

Compute the error-type of the evaluation function according to the depths.

A statistical study showed that the accuracy of the alphabeta mostly depends on the depth & the ply of the game. This function is useful to the probcut algorithm. Using a function instead of a table of data makes easier to inter- or extrapolate new values.

Parameters

n_empty	Number of empty squares on the board.
depth	Depth used in alphabeta.
probcut_depth	A shallow depth used in probcut algorithm.

eval_update()

void eval_update	(	Eval *	,
		const struct Move *	)

Variable Documentation

EVAL_WEIGHT

short*** EVAL_WEIGHT

extern

eval weights