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Rewrite the entirety of board eval or something idk

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Co-authored-by: Tymon <nomyTx@users.noreply.github.com>
minimax-pkg
Drake 1 year ago
parent cd79853be0
commit 0790e688ef
7 changed files with 330 additions and 45 deletions
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1
.gitignore vendored
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@ -1 +1,2 @@
/target
inkwell-regression-testing

4
TODO.md
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@ -1,5 +1,5 @@
# 1.666.0-rc
- [ ] Ability to evaluate game state (whether it's early/mid/end-game)
- [ ] Piece tables
- [x] Ability to evaluate game state (whether it's early/mid/end-game)
- [x] Piece tables
- [ ] Draw prevention (via `chess`'s Game struct?)
- [ ] Basic king safety (ie castling when appropriate, not always playing the double triple decker bongcloud)

2
src/config.rs
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@ -20,4 +20,4 @@ pub const INFO: Info = Info {
};
// FIXME: this needs to be configurable via UCI
pub const depth: u8 = 6;
pub const DEPTH: u8 = 6;

181
src/eval.rs
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@ -1,10 +1,114 @@
use rand::prelude::*;
use std::f64::{INFINITY, NEG_INFINITY};
use chess::{Board, BoardStatus, ChessMove, Color, MoveGen, Piece};
use chess::{Board, BoardStatus, ChessMove, Color, File, MoveGen, Piece, Rank, Square};
use crate::piece_tables;
use crate::piece_values::get_piece_value;
fn square_to_index(square: Square, playing_as: Color) -> usize {
let mut idx = 0;
if playing_as == Color::White {
match square.get_rank() {
Rank::First => idx += 0,
Rank::Second => idx += 8,
Rank::Third => idx += 16,
Rank::Fourth => idx += 24,
Rank::Fifth => idx += 32,
Rank::Sixth => idx += 40,
Rank::Seventh => idx += 48,
Rank::Eighth => idx += 56,
};
match square.get_file() {
File::A => idx += 0,
File::B => idx += 1,
File::C => idx += 2,
File::D => idx += 3,
File::E => idx += 4,
File::F => idx += 5,
File::G => idx += 6,
File::H => idx += 7,
};
} else {
match square.get_rank() {
Rank::Eighth => idx += 0,
Rank::Seventh => idx += 8,
Rank::Sixth => idx += 16,
Rank::Fifth => idx += 24,
Rank::Fourth => idx += 32,
Rank::Third => idx += 40,
Rank::Second => idx += 48,
Rank::First => idx += 56,
};
match square.get_file() {
File::H => idx += 0,
File::G => idx += 1,
File::F => idx += 2,
File::E => idx += 3,
File::D => idx += 4,
File::C => idx += 5,
File::B => idx += 6,
File::A => idx += 7,
}
}
idx
}
fn evaluate_piece_square(board: Board, square: Square, playing_as: Color) -> (f64, f64, f64) {
let mut mg_value: f64 = 0.0;
let mut eg_value: f64 = 0.0;
let mut gamephase: f64 = 0.0;
let piece = board.piece_on(square);
match piece {
Some(Piece::Pawn) => {
mg_value += get_piece_value(piece)
+ (piece_tables::MIDGAME_PAWNS[square_to_index(square, playing_as)] / 10.0);
eg_value += get_piece_value(piece)
+ (piece_tables::ENDGAME_PAWNS[square_to_index(square, playing_as)] / 10.0);
gamephase += piece_tables::GAMEPHASE[get_piece_value(piece).floor() as usize];
}
Some(Piece::Knight) => {
mg_value += get_piece_value(piece)
+ (piece_tables::MIDGAME_HORSEYS[square_to_index(square, playing_as)] / 10.0);
eg_value += get_piece_value(piece)
+ (piece_tables::ENDGAME_HORSEYS[square_to_index(square, playing_as)] / 10.0);
gamephase += piece_tables::GAMEPHASE[get_piece_value(piece).floor() as usize];
}
Some(Piece::Bishop) => {
mg_value += get_piece_value(piece)
+ (piece_tables::MIDGAME_BISHOPS[square_to_index(square, playing_as)] / 10.0);
eg_value += get_piece_value(piece)
+ (piece_tables::ENDGAME_BISHOPS[square_to_index(square, playing_as)] / 10.0);
gamephase += piece_tables::GAMEPHASE[get_piece_value(piece).floor() as usize];
}
Some(Piece::Rook) => {
mg_value += get_piece_value(piece)
+ (piece_tables::MIDGAME_ROOKS[square_to_index(square, playing_as)] / 10.0);
eg_value += get_piece_value(piece)
+ (piece_tables::ENDGAME_ROOKS[square_to_index(square, playing_as)] / 10.0);
gamephase += piece_tables::GAMEPHASE[get_piece_value(piece).floor() as usize];
}
Some(Piece::Queen) => {
mg_value += get_piece_value(piece)
+ (piece_tables::MIDGAME_QUEENS[square_to_index(square, playing_as)] / 10.0);
eg_value += get_piece_value(piece)
+ (piece_tables::ENDGAME_QUEENS[square_to_index(square, playing_as)] / 10.0);
gamephase += piece_tables::GAMEPHASE[get_piece_value(piece).floor() as usize];
}
Some(Piece::King) => {
mg_value += piece_tables::MIDGAME_KINGS[square_to_index(square, playing_as)] / 10.0;
eg_value += piece_tables::ENDGAME_KINGS[square_to_index(square, playing_as)] / 10.0;
}
None => {}
}
(mg_value, eg_value, gamephase)
}
fn static_board_eval(
mov: ChessMove,
old_board: Board,
board: Board,
playing_as: Color,
move_history: Vec<(ChessMove, Board)>,
@ -17,31 +121,33 @@ fn static_board_eval(
}
}
let mut current_eval = 0.0;
// basic material counting + midgame or endgame determination
let mut our_mg_value: f64 = 0.0;
let mut our_eg_value: f64 = 0.0;
let mut opponent_mg_value: f64 = 0.0;
let mut opponent_eg_value: f64 = 0.0;
let mut gamephase: f64 = 0.0;
// basic material counting
board.color_combined(playing_as).for_each(|square| {
match board.piece_on(square) {
Some(Piece::Pawn) => current_eval += 1.0,
Some(Piece::Knight) => current_eval += 3.0,
Some(Piece::Bishop) => current_eval += 5.0,
Some(Piece::Rook) => current_eval += 5.0,
Some(Piece::Queen) => current_eval += 8.0,
_ => { /* do nothing */ }
}
let tmp_gamephase;
(our_mg_value, our_eg_value, tmp_gamephase) =
evaluate_piece_square(board, square, playing_as);
gamephase += tmp_gamephase;
});
board.color_combined(!playing_as).for_each(|square| {
match board.piece_on(square) {
Some(Piece::Pawn) => current_eval -= 1.0,
Some(Piece::Knight) => current_eval -= 3.0,
Some(Piece::Bishop) => current_eval -= 5.0,
Some(Piece::Rook) => current_eval -= 5.0,
Some(Piece::Queen) => current_eval -= 8.0,
_ => { /* do nothing */ }
}
let tmp_gamephase;
(opponent_mg_value, opponent_eg_value, tmp_gamephase) =
evaluate_piece_square(board, square, !playing_as);
gamephase += tmp_gamephase;
});
let mg_score = our_mg_value - opponent_mg_value;
let eg_score = our_eg_value - opponent_eg_value;
let mg_phase = gamephase.min(24.0);
let eg_phase = 24.0 - mg_phase;
let mut current_eval = (mg_score * mg_phase + eg_score * eg_phase) / 24.0;
// checking heuristic
let mut are_we_in_check = false;
let mut is_opponent_in_check = false;
@ -60,12 +166,7 @@ fn static_board_eval(
.checkers()
.filter(|sq| board.color_on(*sq).unwrap() == !playing_as)
.for_each(|_| {
if !is_opponent_in_check
&& move_history.len()
> *vec![10, 11, 12, 13, 14, 15]
.choose(&mut rand::thread_rng())
.unwrap() as usize
{
if !is_opponent_in_check && move_history.len() > 10 {
current_eval += 17.5;
is_opponent_in_check = true;
} else {
@ -78,29 +179,45 @@ fn static_board_eval(
current_eval -= 12.5;
}
// incentivize capturing if material value of capturer is lower than material value of captured
// FIXME: this should take into account whether a piece is protected at all (and if so let pieces be captured by ones of equal and above importance)
if let (Some(captured_piece), Some(capturing_piece)) = (
old_board.piece_on(mov.get_dest()),
old_board.piece_on(mov.get_source()),
) {
current_eval +=
(get_piece_value(Some(captured_piece)) - get_piece_value(Some(capturing_piece)))
}
current_eval
}
pub fn eval_board(
board: Board,
last_board: Board,
is_maximizing_player: bool,
depth: u8,
move_history: Vec<(ChessMove, Board)>,
last_move: Option<ChessMove>,
original_playing_as: Color,
mut alpha: f64,
mut beta: f64,
) -> f64 {
let moves_iter = MoveGen::new_legal(&board).into_iter();
let last_move = if move_history.len() > 0 {
Some(move_history.last().unwrap().0)
} else {
None
};
if depth == 0 || board.status() == BoardStatus::Checkmate {
return static_board_eval(
last_move.unwrap_or(move_history.last().unwrap().0),
last_move.unwrap(),
last_board,
board,
original_playing_as,
!board.side_to_move(),
move_history,
);
} else {
let moves_iter = MoveGen::new_legal(&board).into_iter();
if is_maximizing_player {
let mut max_eval = NEG_INFINITY;
for mov in moves_iter {
@ -111,10 +228,10 @@ pub fn eval_board(
let eval = eval_board(
new_board,
board,
false,
depth - 1,
new_move_history,
Some(mov),
original_playing_as,
alpha,
beta,
@ -136,10 +253,10 @@ pub fn eval_board(
let eval = eval_board(
new_board,
board,
true,
depth - 1,
new_move_history,
Some(mov),
original_playing_as,
alpha,
beta,

18
src/main.rs
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@ -1,5 +1,7 @@
mod config;
mod eval;
mod piece_tables;
mod piece_values;
use chess::{Board, ChessMove, MoveGen};
use config::INFO;
@ -14,12 +16,12 @@ use std::str::FromStr;
use vampirc_uci::parse_one;
use vampirc_uci::{UciMessage, UciOptionConfig, UciTimeControl};
use crate::config::depth;
use crate::config::DEPTH;
fn main() {
let _rng = rand::thread_rng();
let mut board: Option<Board> = None;
let mut move_history: Vec<(ChessMove, Board)> = vec![];
for line in io::stdin().lock().lines() {
let msg: UciMessage = parse_one(&line.unwrap());
match msg {
@ -106,14 +108,10 @@ fn main() {
*a,
eval_board(
a.1,
board,
true,
depth,
DEPTH,
move_history.clone(),
if move_history.len() > 0 {
Some(move_history.last().unwrap().0)
} else {
None
},
color,
NEG_INFINITY,
INFINITY,
@ -126,10 +124,10 @@ fn main() {
*b,
eval_board(
b.1,
board,
true,
depth,
DEPTH,
move_history.clone(),
None,
color,
NEG_INFINITY,
INFINITY,

147
src/piece_tables.rs
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@ -0,0 +1,147 @@
// piece tables originally sourced from https://www.talkchess.com/forum3/viewtopic.php?f=2&t=68311&start=19 via https://www.chessprogramming.org/PeSTO%27s_Evaluation_Function
pub const GAMEPHASE: [f64; 12] = [0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 2.0, 2.0, 4.0, 4.0, 0.0, 0.0];
#[rustfmt::skip]
pub const MIDGAME_PAWNS: [f64; 64] = [
0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
98.0, 134.0, 61.0, 95.0, 68.0, 126.0, 34.0, -11.0,
-6.0, 7.0, 26.0, 31.0, 65.0, 56.0, 25.0, -20.0,
-14.0, 13.0, 6.0, 21.0, 23.0, 12.0, 17.0, -23.0,
-27.0, -2.0, -5.0, 12.0, 17.0, 6.0, 10.0, -25.0,
-26.0, -4.0, -4.0, -10.0, 3.0, 3.0, 33.0, -12.0,
-35.0, -1.0, -20.0, -23.0, -15.0, 24.0, 38.0, -22.0,
0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
];
#[rustfmt::skip]
pub const ENDGAME_PAWNS: [f64; 64] = [
0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
178.0, 173.0, 158.0, 134.0, 147.0, 132.0, 165.0, 187.0,
94.0, 100.0, 85.0, 67.0, 56.0, 53.0, 82.0, 84.0,
32.0, 24.0, 13.0, 5.0, -2.0, 4.0, 17.0, 17.0,
13.0, 9.0, -3.0, -7.0, -7.0, -8.0, 3.0, -1.0,
4.0, 7.0, -6.0, 1.0, 0.0, -5.0, -1.0, -8.0,
13.0, 8.0, 8.0, 10.0, 13.0, 0.0, 2.0, -7.0,
0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
];
#[rustfmt::skip]
pub const MIDGAME_HORSEYS: [f64; 64] = [
-167.0, -89.0, -34.0, -49.0, 61.0, -97.0, -15.0, -107.0,
-73.0, -41.0, 72.0, 36.0, 23.0, 62.0, 7.0, -17.0,
-47.0, 60.0, 37.0, 65.0, 84.0, 129.0, 73.0, 44.0,
-9.0, 17.0, 19.0, 53.0, 37.0, 69.0, 18.0, 22.0,
-13.0, 4.0, 16.0, 13.0, 28.0, 19.0, 21.0, -8.0,
-23.0, -9.0, 12.0, 10.0, 19.0, 17.0, 25.0, -16.0,
-29.0, -53.0, -12.0, -3.0, -1.0, 18.0, -14.0, -19.0,
-105.0, -21.0, -58.0, -33.0, -17.0, -28.0, -19.0, -23.0,
];
#[rustfmt::skip]
pub const ENDGAME_HORSEYS: [f64; 64] = [
-58.0, -38.0, -13.0, -28.0, -31.0, -27.0, -63.0, -99.0,
-25.0, -8.0, -25.0, -2.0, -9.0, -25.0, -24.0, -52.0,
-24.0, -20.0, 10.0, 9.0, -1.0, -9.0, -19.0, -41.0,
-17.0, 3.0, 22.0, 22.0, 22.0, 11.0, 8.0, -18.0,
-18.0, -6.0, 16.0, 25.0, 16.0, 17.0, 4.0, -18.0,
-23.0, -3.0, -1.0, 15.0, 10.0, -3.0, -20.0, -22.0,
-42.0, -20.0, -10.0, -5.0, -2.0, -20.0, -23.0, -44.0,
-29.0, -51.0, -23.0, -15.0, -22.0, -18.0, -50.0, -64.0,
];
#[rustfmt::skip]
pub const MIDGAME_BISHOPS: [f64; 64] = [
-29.0, 4.0, -82.0, -37.0, -25.0, -42.0, 7.0, -8.0,
-26.0, 16.0, -18.0, -13.0, 30.0, 59.0, 18.0, -47.0,
-16.0, 37.0, 43.0, 40.0, 35.0, 50.0, 37.0, -2.0,
-4.0, 5.0, 19.0, 50.0, 37.0, 37.0, 7.0, -2.0,
-6.0, 13.0, 13.0, 26.0, 34.0, 12.0, 10.0, 4.0,
0.0, 15.0, 15.0, 15.0, 14.0, 27.0, 18.0, 10.0,
4.0, 15.0, 16.0, 0.0, 7.0, 21.0, 33.0, 1.0,
-33.0, -3.0, -14.0, -21.0, -13.0, -12.0, -39.0, -21.0,
];
#[rustfmt::skip]
pub const ENDGAME_BISHOPS: [f64; 64] = [
-14.0, -21.0, -11.0, -8.0, -7.0, -9.0, -17.0, -24.0,
-8.0, -4.0, 7.0, -12.0, -3.0, -13.0, -4.0, -14.0,
2.0, -8.0, 0.0, -1.0, -2.0, 6.0, 0.0, 4.0,
-3.0, 9.0, 12.0, 9.0, 14.0, 10.0, 3.0, 2.0,
-6.0, 3.0, 13.0, 19.0, 7.0, 10.0, -3.0, -9.0,
-12.0, -3.0, 8.0, 10.0, 13.0, 3.0, -7.0, -15.0,
-14.0, -18.0, -7.0, -1.0, 4.0, -9.0, -15.0, -27.0,
-23.0, -9.0, -23.0, -5.0, -9.0, -16.0, -5.0, -17.0,
];
#[rustfmt::skip]
pub const MIDGAME_ROOKS: [f64; 64] = [
32.0, 42.0, 32.0, 51.0, 63.0, 9.0, 31.0, 43.0,
27.0, 32.0, 58.0, 62.0, 80.0, 67.0, 26.0, 44.0,
-5.0, 19.0, 26.0, 36.0, 17.0, 45.0, 61.0, 16.0,
-24.0, -11.0, 7.0, 26.0, 24.0, 35.0, -8.0, -20.0,
-36.0, -26.0, -12.0, -1.0, 9.0, -7.0, 6.0, -23.0,
-45.0, -25.0, -16.0, -17.0, 3.0, 0.0, -5.0, -33.0,
-44.0, -16.0, -20.0, -9.0, -1.0, 11.0, -6.0, -71.0,
-19.0, -13.0, 1.0, 17.0, 16.0, 7.0, -37.0, -26.0,
];
#[rustfmt::skip]
pub const ENDGAME_ROOKS: [f64; 64] = [
13.0, 10.0, 18.0, 15.0, 12.0, 12.0, 8.0, 5.0,
11.0, 13.0, 13.0, 11.0, -3.0, 3.0, 8.0, 3.0,
7.0, 7.0, 7.0, 5.0, 4.0, -3.0, -5.0, -3.0,
4.0, 3.0, 13.0, 1.0, 2.0, 1.0, -1.0, 2.0,
3.0, 5.0, 8.0, 4.0, -5.0, -6.0, -8.0, -11.0,
-4.0, 0.0, -5.0, -1.0, -7.0, -12.0, -8.0, -16.0,
-6.0, -6.0, 0.0, 2.0, -9.0, -9.0, -11.0, -3.0,
-9.0, 2.0, 3.0, -1.0, -5.0, -13.0, 4.0, -20.0,
];
#[rustfmt::skip]
pub const MIDGAME_QUEENS: [f64; 64] = [
-28.0, 0.0, 29.0, 12.0, 59.0, 44.0, 43.0, 45.0,
-24.0, -39.0, -5.0, 1.0, -16.0, 57.0, 28.0, 54.0,
-13.0, -17.0, 7.0, 8.0, 29.0, 56.0, 47.0, 57.0,
-27.0, -27.0, -16.0, -16.0, -1.0, 17.0, -2.0, 1.0,
-9.0, -26.0, -9.0, -10.0, -2.0, -4.0, 3.0, -3.0,
-14.0, 2.0, -11.0, -2.0, -5.0, 2.0, 14.0, 5.0,
-35.0, -8.0, 11.0, 2.0, 8.0, 15.0, -3.0, 1.0,
-1.0, -18.0, -9.0, 10.0, -15.0, -25.0, -31.0, -50.0,
];
#[rustfmt::skip]
pub const ENDGAME_QUEENS: [f64; 64] = [
-9.0, 22.0, 22.0, 27.0, 27.0, 19.0, 10.0, 20.0,
-17.0, 20.0, 32.0, 41.0, 58.0, 25.0, 30.0, 0.0,
-20.0, 6.0, 9.0, 49.0, 47.0, 35.0, 19.0, 9.0,
3.0, 22.0, 24.0, 45.0, 57.0, 40.0, 57.0, 36.0,
-18.0, 28.0, 19.0, 47.0, 31.0, 34.0, 39.0, 23.0,
-16.0, -27.0, 15.0, 6.0, 9.0, 17.0, 10.0, 5.0,
-22.0, -23.0, -30.0, -16.0, -16.0, -23.0, -36.0, -32.0,
-33.0, -28.0, -22.0, -43.0, -5.0, -32.0, -20.0, -41.0,
];
#[rustfmt::skip]
pub const MIDGAME_KINGS: [f64; 64] = [
-65.0, 23.0, 16.0, -15.0, -56.0, -34.0, 2.0, 13.0,
29.0, -1.0, -20.0, -7.0, -8.0, -4.0, -38.0, -29.0,
-9.0, 24.0, 2.0, -16.0, -20.0, 6.0, 22.0, -22.0,
-17.0, -20.0, -12.0, -27.0, -30.0, -25.0, -14.0, -36.0,
-49.0, -1.0, -27.0, -39.0, -46.0, -44.0, -33.0, -51.0,
-14.0, -14.0, -22.0, -46.0, -44.0, -30.0, -15.0, -27.0,
1.0, 7.0, -8.0, -64.0, -43.0, -16.0, 9.0, 8.0,
-15.0, 36.0, 12.0, -54.0, 8.0, -28.0, 24.0, 14.0,
];
#[rustfmt::skip]
pub const ENDGAME_KINGS: [f64; 64] = [
-74.0, -35.0, -18.0, -18.0, -11.0, 15.0, 4.0, -17.0,
-12.0, 17.0, 14.0, 17.0, 17.0, 38.0, 23.0, 11.0,
10.0, 17.0, 23.0, 15.0, 20.0, 45.0, 44.0, 13.0,
-8.0, 22.0, 24.0, 27.0, 26.0, 33.0, 26.0, 3.0,
-18.0, -4.0, 21.0, 24.0, 27.0, 23.0, 9.0, -11.0,
-19.0, -3.0, 11.0, 21.0, 23.0, 16.0, 7.0, -9.0,
-27.0, -11.0, 4.0, 13.0, 14.0, 4.0, -5.0, -17.0,
-53.0, -34.0, -21.0, -11.0, -28.0, -14.0, -24.0, -43.0,
];

22
src/piece_values.rs
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@ -0,0 +1,22 @@
use chess::Piece;
pub const PAWN: f64 = 1.0;
pub const HORSEY: f64 = 3.0;
pub const BISHOP: f64 = 5.0;
pub const ROOK: f64 = 5.5;
pub const QUEEN: f64 = 10.0;
pub fn get_piece_value(piece: Option<Piece>) -> f64 {
match piece {
Some(Piece::Pawn) => PAWN,
Some(Piece::Knight) => HORSEY,
Some(Piece::Bishop) => BISHOP,
Some(Piece::Rook) => ROOK,
Some(Piece::Queen) => QUEEN,
_ => 0.0,
}
}
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