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stats: move BoardStats to their own module

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dece 2020-06-11 20:50:32 +02:00
parent d8fa2f74ec
commit 6f87c9343d
4 changed files with 238 additions and 224 deletions
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220
src/board.rs
View file

@ -245,157 +245,6 @@ pub fn draw(board: &Board, f: &mut dyn std::io::Write) {
write!(f, " abcdefgh").unwrap();
}
/// Storage for precomputed board pieces stats.
#[derive(Debug, Clone, PartialEq)]
pub struct BoardStats {
pub num_pawns: i8,
pub num_bishops: i8,
pub num_knights: i8,
pub num_rooks: i8,
pub num_queens: i8,
pub num_kings: i8,
pub num_doubled_pawns: i8, // Pawns that are on the same file as a friend.
pub num_backward_pawns: i8, // Pawns behind all other pawns on adjacent files.
pub num_isolated_pawns: i8, // Pawns that have no friend pawns on adjacent files.
pub mobility: i32,
}
impl BoardStats {
pub const fn new() -> BoardStats {
BoardStats {
num_pawns: 0, num_bishops: 0, num_knights: 0, num_rooks: 0, num_queens: 0,
num_kings: 0, num_doubled_pawns: 0, num_backward_pawns: 0, num_isolated_pawns: 0,
mobility: 0,
}
}
pub fn reset(&mut self) {
self.num_pawns = 0;
self.num_bishops = 0;
self.num_knights = 0;
self.num_rooks = 0;
self.num_queens = 0;
self.num_kings = 0;
self.num_doubled_pawns = 0;
self.num_backward_pawns = 0;
self.num_isolated_pawns = 0;
self.mobility = 0;
}
}
impl std::fmt::Display for BoardStats {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(
f,
"{}P {}B {}N {}R {}Q {}K {}dp {}bp {}ip {}m",
self.num_pawns, self.num_bishops, self.num_knights, self.num_rooks,
self.num_queens, self.num_kings,
self.num_doubled_pawns, self.num_backward_pawns, self.num_isolated_pawns,
self.mobility
)
}
}
/// Create two new BoardStats objects from the board, for white and black.
///
/// See `compute_stats_into` for details.
pub fn compute_stats(board: &Board) -> (BoardStats, BoardStats) {
let mut stats = (BoardStats::new(), BoardStats::new());
compute_stats_into(board, &mut stats);
stats
}
pub fn compute_stats_into(board: &Board, stats: &mut (BoardStats, BoardStats)) {
compute_color_stats_into(board, &mut stats.0, SQ_WH);
compute_color_stats_into(board, &mut stats.1, SQ_BL);
}
/// Update `stats` for `color` from given `board`
///
/// Refresh all stats *except* `mobility`.
pub fn compute_color_stats_into(board: &Board, stats: &mut BoardStats, color: u8) {
stats.reset();
for (piece, (pos_f, pos_r)) in get_piece_iterator(board) {
if piece == SQ_E || !is_color(piece, color) {
continue
}
match get_type(piece) {
SQ_P => {
stats.num_pawns += 1;
let mut doubled = false;
let mut isolated = true;
let mut backward = true;
for r in 0..8 {
// Check for doubled pawns.
if
!doubled &&
is_piece(get_square(board, &(pos_f, r)), color|SQ_P) && r != pos_r
{
doubled = true;
}
// Check for isolated pawns.
if
isolated &&
(
// Check on the left file if not on a-file...
(
pos_f > POS_MIN &&
is_piece(get_square(board, &(pos_f - 1, r)), color|SQ_P)
) ||
// Check on the right file if not on h-file...
(
pos_f < POS_MAX &&
is_piece(get_square(board, &(pos_f + 1, r)), color|SQ_P)
)
)
{
isolated = false;
}
// Check for backward pawns.
if backward {
if color == SQ_WH && r <= pos_r {
if (
pos_f > POS_MIN &&
is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
) || (
pos_f < POS_MAX &&
is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
) {
backward = false;
}
} else if color == SQ_BL && r >= pos_r {
if (
pos_f > POS_MIN &&
is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
) || (
pos_f < POS_MAX &&
is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
) {
backward = false;
}
}
}
}
if doubled {
stats.num_doubled_pawns += 1;
}
if isolated {
stats.num_isolated_pawns += 1;
}
if backward {
stats.num_backward_pawns += 1;
}
},
SQ_R => stats.num_rooks += 1,
SQ_N => stats.num_knights += 1,
SQ_B => stats.num_bishops += 1,
SQ_Q => stats.num_queens += 1,
SQ_K => stats.num_kings += 1,
_ => {}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
@ -480,73 +329,4 @@ mod tests {
assert_eq!(find_king(&b, SQ_WH), Some(pos("e1")));
assert_eq!(find_king(&b, SQ_BL), Some(pos("e8")));
}
#[test]
fn test_compute_stats() {
// Check that initial stats are correct.
let b = new();
let initial_stats = BoardStats {
num_pawns: 8,
num_bishops: 2,
num_knights: 2,
num_rooks: 2,
num_queens: 1,
num_kings: 1,
num_doubled_pawns: 0,
num_backward_pawns: 0,
num_isolated_pawns: 0,
mobility: 0,
};
let mut stats = compute_stats(&b);
assert!(stats.0 == stats.1);
assert!(stats.0 == initial_stats);
// Check that doubled pawns are correctly counted.
let mut b = new_empty();
set_square(&mut b, &pos("d4"), SQ_WH_P);
set_square(&mut b, &pos("d6"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 2);
// Add a pawn on another file, no changes expected.
set_square(&mut b, &pos("e6"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 2);
// Add a pawn backward in the d-file: there are now 3 doubled pawns.
set_square(&mut b, &pos("d2"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 3);
// Check that isolated and backward pawns are correctly counted.
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 2); // A bit weird?
// Protect d4 pawn with a friend in e3: it is not isolated nor backward anymore.
set_square(&mut b, &pos("e3"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 5);
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 1);
// Add an adjacent friend to d2 pawn: no pawns are left isolated or backward.
set_square(&mut b, &pos("c2"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 5);
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 0);
// Add an isolated/backward white pawn in a far file.
set_square(&mut b, &pos("a2"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 5);
assert_eq!(stats.0.num_isolated_pawns, 1);
assert_eq!(stats.0.num_backward_pawns, 1);
// Check for pawns that are backward but not isolated.
let mut b = new_empty();
// Here, d4 pawn protects both e5 and e3, but it is backward.
set_square(&mut b, &pos("d4"), SQ_WH_P);
set_square(&mut b, &pos("e5"), SQ_WH_P);
set_square(&mut b, &pos("e3"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 2);
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 1);
}
}

9
src/engine.rs
View file

@ -6,6 +6,7 @@ use std::thread;
use crate::board;
use crate::notation;
use crate::rules;
use crate::stats;
use crate::uci;
const MIN_F32: f32 = std::f32::NEG_INFINITY;
@ -342,7 +343,7 @@ fn minimax(
maximizing: bool
) -> (f32, Option<rules::Move>) {
if depth == max_depth {
let stats = board::compute_stats(&node.board);
let stats = stats::compute_stats(&node.board);
return (evaluate(&stats), None);
}
let mut minmax = if maximizing { MIN_F32 } else { MAX_F32 };
@ -368,7 +369,7 @@ fn minimax(
(minmax, minmax_move)
}
fn evaluate(stats: &(board::BoardStats, board::BoardStats)) -> f32 {
fn evaluate(stats: &(stats::BoardStats, stats::BoardStats)) -> f32 {
let (ws, bs) = stats;
200.0 * (ws.num_kings - bs.num_kings) as f32
@ -416,11 +417,11 @@ mod tests {
#[test]
fn test_evaluate() {
let mut node = Node::new();
let stats = board::compute_stats(&node.board);
let stats = stats::compute_stats(&node.board);
assert_eq!(evaluate(&stats), 0.0);
rules::apply_move_to_board(&mut node.board, &notation::parse_move("d2d4"));
let stats = board::compute_stats(&node.board);
let stats = stats::compute_stats(&node.board);
assert_eq!(evaluate(&stats), 0.0);
}
}

1
src/main.rs
View file

@ -6,6 +6,7 @@ pub mod board;
pub mod engine;
pub mod notation;
pub mod rules;
pub mod stats;
pub mod uci;
fn main() {

232
src/stats.rs Normal file
View file

@ -0,0 +1,232 @@
//! Board statistics used for heuristics.
use crate::board::*;
use crate::rules;
/// Storage for board pieces stats.
#[derive(Debug, Clone, PartialEq)]
pub struct BoardStats {
pub num_pawns: i8,
pub num_bishops: i8,
pub num_knights: i8,
pub num_rooks: i8,
pub num_queens: i8,
pub num_kings: i8,
pub num_doubled_pawns: i8, // Pawns that are on the same file as a friend.
pub num_backward_pawns: i8, // Pawns behind all other pawns on adjacent files.
pub num_isolated_pawns: i8, // Pawns that have no friend pawns on adjacent files.
pub mobility: i32,
}
impl BoardStats {
pub const fn new() -> BoardStats {
BoardStats {
num_pawns: 0, num_bishops: 0, num_knights: 0, num_rooks: 0, num_queens: 0,
num_kings: 0, num_doubled_pawns: 0, num_backward_pawns: 0, num_isolated_pawns: 0,
mobility: 0,
}
}
pub fn reset(&mut self) {
self.num_pawns = 0;
self.num_bishops = 0;
self.num_knights = 0;
self.num_rooks = 0;
self.num_queens = 0;
self.num_kings = 0;
self.num_doubled_pawns = 0;
self.num_backward_pawns = 0;
self.num_isolated_pawns = 0;
self.mobility = 0;
}
}
impl std::fmt::Display for BoardStats {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(
f,
"{}P {}B {}N {}R {}Q {}K {}dp {}bp {}ip {}m",
self.num_pawns, self.num_bishops, self.num_knights, self.num_rooks,
self.num_queens, self.num_kings,
self.num_doubled_pawns, self.num_backward_pawns, self.num_isolated_pawns,
self.mobility
)
}
}
/// Create two new BoardStats objects from the board, for white and black.
///
/// See `compute_stats_into` for details.
pub fn compute_stats(board: &Board) -> (BoardStats, BoardStats) {
let mut stats = (BoardStats::new(), BoardStats::new());
compute_stats_into(board, &mut stats);
stats
}
pub fn compute_stats_into(board: &Board, stats: &mut (BoardStats, BoardStats)) {
compute_color_stats_into(board, &mut stats.0, SQ_WH);
compute_color_stats_into(board, &mut stats.1, SQ_BL);
}
/// Update `stats` for `color` from given `board`
///
/// Refresh all stats *except* `mobility`.
pub fn compute_color_stats_into(board: &Board, stats: &mut BoardStats, color: u8) {
stats.reset();
for (piece, (pos_f, pos_r)) in get_piece_iterator(board) {
if piece == SQ_E || !is_color(piece, color) {
continue
}
// For all piece types, increment its number. Pawns have a few additional stats.
match get_type(piece) {
SQ_R => stats.num_rooks += 1,
SQ_N => stats.num_knights += 1,
SQ_B => stats.num_bishops += 1,
SQ_Q => stats.num_queens += 1,
SQ_K => stats.num_kings += 1,
SQ_P => {
stats.num_pawns += 1;
let mut doubled = false;
let mut isolated = true;
let mut backward = true;
for r in 0..8 {
// Check for doubled pawns.
if
!doubled &&
is_piece(get_square(board, &(pos_f, r)), color|SQ_P) && r != pos_r
{
doubled = true;
}
// Check for isolated pawns.
if
isolated &&
(
// Check on the left file if not on a-file...
(
pos_f > POS_MIN &&
is_piece(get_square(board, &(pos_f - 1, r)), color|SQ_P)
) ||
// Check on the right file if not on h-file...
(
pos_f < POS_MAX &&
is_piece(get_square(board, &(pos_f + 1, r)), color|SQ_P)
)
)
{
isolated = false;
}
// Check for backward pawns.
if backward {
if color == SQ_WH && r <= pos_r {
if (
pos_f > POS_MIN &&
is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
) || (
pos_f < POS_MAX &&
is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
) {
backward = false;
}
} else if color == SQ_BL && r >= pos_r {
if (
pos_f > POS_MIN &&
is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
) || (
pos_f < POS_MAX &&
is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
) {
backward = false;
}
}
}
}
if doubled {
stats.num_doubled_pawns += 1;
}
if isolated {
stats.num_isolated_pawns += 1;
}
if backward {
stats.num_backward_pawns += 1;
}
},
_ => {}
}
// Compute mobility for all pieces.
// stats.mobility +=
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_compute_stats() {
// Check that initial stats are correct.
let b = new();
let initial_stats = BoardStats {
num_pawns: 8,
num_bishops: 2,
num_knights: 2,
num_rooks: 2,
num_queens: 1,
num_kings: 1,
num_doubled_pawns: 0,
num_backward_pawns: 0,
num_isolated_pawns: 0,
mobility: 0,
};
let mut stats = compute_stats(&b);
assert!(stats.0 == stats.1);
assert!(stats.0 == initial_stats);
// Check that doubled pawns are correctly counted.
let mut b = new_empty();
set_square(&mut b, &pos("d4"), SQ_WH_P);
set_square(&mut b, &pos("d6"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 2);
// Add a pawn on another file, no changes expected.
set_square(&mut b, &pos("e6"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 2);
// Add a pawn backward in the d-file: there are now 3 doubled pawns.
set_square(&mut b, &pos("d2"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 3);
// Check that isolated and backward pawns are correctly counted.
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 2); // A bit weird?
// Protect d4 pawn with a friend in e3: it is not isolated nor backward anymore.
set_square(&mut b, &pos("e3"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 5);
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 1);
// Add an adjacent friend to d2 pawn: no pawns are left isolated or backward.
set_square(&mut b, &pos("c2"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 5);
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 0);
// Add an isolated/backward white pawn in a far file.
set_square(&mut b, &pos("a2"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 5);
assert_eq!(stats.0.num_isolated_pawns, 1);
assert_eq!(stats.0.num_backward_pawns, 1);
// Check for pawns that are backward but not isolated.
let mut b = new_empty();
// Here, d4 pawn protects both e5 and e3, but it is backward.
set_square(&mut b, &pos("d4"), SQ_WH_P);
set_square(&mut b, &pos("e5"), SQ_WH_P);
set_square(&mut b, &pos("e3"), SQ_WH_P);
compute_color_stats_into(&b, &mut stats.0, SQ_WH);
assert_eq!(stats.0.num_doubled_pawns, 2);
assert_eq!(stats.0.num_isolated_pawns, 0);
assert_eq!(stats.0.num_backward_pawns, 1);
}
}