stats: move BoardStats to their own module
This commit is contained in:
parent
d8fa2f74ec
commit
6f87c9343d
220
src/board.rs
220
src/board.rs
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@ -245,157 +245,6 @@ pub fn draw(board: &Board, f: &mut dyn std::io::Write) {
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write!(f, " abcdefgh").unwrap();
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}
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/// Storage for precomputed board pieces stats.
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#[derive(Debug, Clone, PartialEq)]
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pub struct BoardStats {
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pub num_pawns: i8,
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pub num_bishops: i8,
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pub num_knights: i8,
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pub num_rooks: i8,
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pub num_queens: i8,
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pub num_kings: i8,
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pub num_doubled_pawns: i8, // Pawns that are on the same file as a friend.
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pub num_backward_pawns: i8, // Pawns behind all other pawns on adjacent files.
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pub num_isolated_pawns: i8, // Pawns that have no friend pawns on adjacent files.
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pub mobility: i32,
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}
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impl BoardStats {
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pub const fn new() -> BoardStats {
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BoardStats {
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num_pawns: 0, num_bishops: 0, num_knights: 0, num_rooks: 0, num_queens: 0,
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num_kings: 0, num_doubled_pawns: 0, num_backward_pawns: 0, num_isolated_pawns: 0,
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mobility: 0,
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}
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}
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pub fn reset(&mut self) {
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self.num_pawns = 0;
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self.num_bishops = 0;
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self.num_knights = 0;
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self.num_rooks = 0;
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self.num_queens = 0;
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self.num_kings = 0;
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self.num_doubled_pawns = 0;
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self.num_backward_pawns = 0;
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self.num_isolated_pawns = 0;
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self.mobility = 0;
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}
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}
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impl std::fmt::Display for BoardStats {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
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write!(
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f,
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"{}P {}B {}N {}R {}Q {}K {}dp {}bp {}ip {}m",
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self.num_pawns, self.num_bishops, self.num_knights, self.num_rooks,
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self.num_queens, self.num_kings,
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self.num_doubled_pawns, self.num_backward_pawns, self.num_isolated_pawns,
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self.mobility
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)
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}
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}
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/// Create two new BoardStats objects from the board, for white and black.
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///
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/// See `compute_stats_into` for details.
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pub fn compute_stats(board: &Board) -> (BoardStats, BoardStats) {
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let mut stats = (BoardStats::new(), BoardStats::new());
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compute_stats_into(board, &mut stats);
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stats
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}
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pub fn compute_stats_into(board: &Board, stats: &mut (BoardStats, BoardStats)) {
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compute_color_stats_into(board, &mut stats.0, SQ_WH);
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compute_color_stats_into(board, &mut stats.1, SQ_BL);
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}
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/// Update `stats` for `color` from given `board`
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///
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/// Refresh all stats *except* `mobility`.
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pub fn compute_color_stats_into(board: &Board, stats: &mut BoardStats, color: u8) {
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stats.reset();
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for (piece, (pos_f, pos_r)) in get_piece_iterator(board) {
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if piece == SQ_E || !is_color(piece, color) {
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continue
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}
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match get_type(piece) {
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SQ_P => {
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stats.num_pawns += 1;
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let mut doubled = false;
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let mut isolated = true;
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let mut backward = true;
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for r in 0..8 {
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// Check for doubled pawns.
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if
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!doubled &&
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is_piece(get_square(board, &(pos_f, r)), color|SQ_P) && r != pos_r
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{
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doubled = true;
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}
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// Check for isolated pawns.
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if
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isolated &&
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(
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// Check on the left file if not on a-file...
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(
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pos_f > POS_MIN &&
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is_piece(get_square(board, &(pos_f - 1, r)), color|SQ_P)
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) ||
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// Check on the right file if not on h-file...
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(
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pos_f < POS_MAX &&
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is_piece(get_square(board, &(pos_f + 1, r)), color|SQ_P)
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)
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)
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{
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isolated = false;
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}
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// Check for backward pawns.
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if backward {
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if color == SQ_WH && r <= pos_r {
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if (
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pos_f > POS_MIN &&
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is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
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) || (
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pos_f < POS_MAX &&
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is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
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) {
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backward = false;
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}
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} else if color == SQ_BL && r >= pos_r {
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if (
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pos_f > POS_MIN &&
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is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
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) || (
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pos_f < POS_MAX &&
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is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
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) {
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backward = false;
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}
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}
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}
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}
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if doubled {
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stats.num_doubled_pawns += 1;
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}
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if isolated {
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stats.num_isolated_pawns += 1;
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}
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if backward {
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stats.num_backward_pawns += 1;
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}
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},
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SQ_R => stats.num_rooks += 1,
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SQ_N => stats.num_knights += 1,
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SQ_B => stats.num_bishops += 1,
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SQ_Q => stats.num_queens += 1,
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SQ_K => stats.num_kings += 1,
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_ => {}
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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@ -480,73 +329,4 @@ mod tests {
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assert_eq!(find_king(&b, SQ_WH), Some(pos("e1")));
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assert_eq!(find_king(&b, SQ_BL), Some(pos("e8")));
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}
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#[test]
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fn test_compute_stats() {
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// Check that initial stats are correct.
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let b = new();
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let initial_stats = BoardStats {
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num_pawns: 8,
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num_bishops: 2,
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num_knights: 2,
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num_rooks: 2,
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num_queens: 1,
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num_kings: 1,
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num_doubled_pawns: 0,
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num_backward_pawns: 0,
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num_isolated_pawns: 0,
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mobility: 0,
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};
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let mut stats = compute_stats(&b);
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assert!(stats.0 == stats.1);
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assert!(stats.0 == initial_stats);
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// Check that doubled pawns are correctly counted.
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let mut b = new_empty();
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set_square(&mut b, &pos("d4"), SQ_WH_P);
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set_square(&mut b, &pos("d6"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 2);
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// Add a pawn on another file, no changes expected.
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set_square(&mut b, &pos("e6"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 2);
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// Add a pawn backward in the d-file: there are now 3 doubled pawns.
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set_square(&mut b, &pos("d2"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 3);
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// Check that isolated and backward pawns are correctly counted.
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assert_eq!(stats.0.num_isolated_pawns, 0);
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assert_eq!(stats.0.num_backward_pawns, 2); // A bit weird?
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// Protect d4 pawn with a friend in e3: it is not isolated nor backward anymore.
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set_square(&mut b, &pos("e3"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 5);
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assert_eq!(stats.0.num_isolated_pawns, 0);
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assert_eq!(stats.0.num_backward_pawns, 1);
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// Add an adjacent friend to d2 pawn: no pawns are left isolated or backward.
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set_square(&mut b, &pos("c2"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 5);
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assert_eq!(stats.0.num_isolated_pawns, 0);
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assert_eq!(stats.0.num_backward_pawns, 0);
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// Add an isolated/backward white pawn in a far file.
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set_square(&mut b, &pos("a2"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 5);
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assert_eq!(stats.0.num_isolated_pawns, 1);
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assert_eq!(stats.0.num_backward_pawns, 1);
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// Check for pawns that are backward but not isolated.
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let mut b = new_empty();
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// Here, d4 pawn protects both e5 and e3, but it is backward.
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set_square(&mut b, &pos("d4"), SQ_WH_P);
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set_square(&mut b, &pos("e5"), SQ_WH_P);
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set_square(&mut b, &pos("e3"), SQ_WH_P);
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compute_color_stats_into(&b, &mut stats.0, SQ_WH);
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assert_eq!(stats.0.num_doubled_pawns, 2);
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assert_eq!(stats.0.num_isolated_pawns, 0);
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assert_eq!(stats.0.num_backward_pawns, 1);
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}
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}
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@ -6,6 +6,7 @@ use std::thread;
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use crate::board;
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use crate::notation;
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use crate::rules;
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use crate::stats;
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use crate::uci;
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const MIN_F32: f32 = std::f32::NEG_INFINITY;
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@ -342,7 +343,7 @@ fn minimax(
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maximizing: bool
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) -> (f32, Option<rules::Move>) {
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if depth == max_depth {
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let stats = board::compute_stats(&node.board);
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let stats = stats::compute_stats(&node.board);
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return (evaluate(&stats), None);
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}
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let mut minmax = if maximizing { MIN_F32 } else { MAX_F32 };
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@ -368,7 +369,7 @@ fn minimax(
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(minmax, minmax_move)
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}
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fn evaluate(stats: &(board::BoardStats, board::BoardStats)) -> f32 {
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fn evaluate(stats: &(stats::BoardStats, stats::BoardStats)) -> f32 {
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let (ws, bs) = stats;
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200.0 * (ws.num_kings - bs.num_kings) as f32
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@ -416,11 +417,11 @@ mod tests {
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#[test]
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fn test_evaluate() {
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let mut node = Node::new();
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let stats = board::compute_stats(&node.board);
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let stats = stats::compute_stats(&node.board);
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assert_eq!(evaluate(&stats), 0.0);
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rules::apply_move_to_board(&mut node.board, ¬ation::parse_move("d2d4"));
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let stats = board::compute_stats(&node.board);
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let stats = stats::compute_stats(&node.board);
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assert_eq!(evaluate(&stats), 0.0);
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}
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}
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@ -6,6 +6,7 @@ pub mod board;
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pub mod engine;
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pub mod notation;
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pub mod rules;
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pub mod stats;
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pub mod uci;
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fn main() {
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232
src/stats.rs
Normal file
232
src/stats.rs
Normal file
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@ -0,0 +1,232 @@
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//! Board statistics used for heuristics.
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use crate::board::*;
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use crate::rules;
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/// Storage for board pieces stats.
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#[derive(Debug, Clone, PartialEq)]
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pub struct BoardStats {
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pub num_pawns: i8,
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pub num_bishops: i8,
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pub num_knights: i8,
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pub num_rooks: i8,
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pub num_queens: i8,
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pub num_kings: i8,
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pub num_doubled_pawns: i8, // Pawns that are on the same file as a friend.
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pub num_backward_pawns: i8, // Pawns behind all other pawns on adjacent files.
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pub num_isolated_pawns: i8, // Pawns that have no friend pawns on adjacent files.
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pub mobility: i32,
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}
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impl BoardStats {
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pub const fn new() -> BoardStats {
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BoardStats {
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num_pawns: 0, num_bishops: 0, num_knights: 0, num_rooks: 0, num_queens: 0,
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num_kings: 0, num_doubled_pawns: 0, num_backward_pawns: 0, num_isolated_pawns: 0,
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mobility: 0,
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}
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}
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pub fn reset(&mut self) {
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self.num_pawns = 0;
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self.num_bishops = 0;
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self.num_knights = 0;
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self.num_rooks = 0;
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self.num_queens = 0;
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self.num_kings = 0;
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self.num_doubled_pawns = 0;
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self.num_backward_pawns = 0;
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self.num_isolated_pawns = 0;
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self.mobility = 0;
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}
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}
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impl std::fmt::Display for BoardStats {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
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write!(
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f,
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"{}P {}B {}N {}R {}Q {}K {}dp {}bp {}ip {}m",
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self.num_pawns, self.num_bishops, self.num_knights, self.num_rooks,
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self.num_queens, self.num_kings,
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self.num_doubled_pawns, self.num_backward_pawns, self.num_isolated_pawns,
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self.mobility
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)
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}
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}
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/// Create two new BoardStats objects from the board, for white and black.
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///
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/// See `compute_stats_into` for details.
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pub fn compute_stats(board: &Board) -> (BoardStats, BoardStats) {
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let mut stats = (BoardStats::new(), BoardStats::new());
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compute_stats_into(board, &mut stats);
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stats
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}
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pub fn compute_stats_into(board: &Board, stats: &mut (BoardStats, BoardStats)) {
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compute_color_stats_into(board, &mut stats.0, SQ_WH);
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compute_color_stats_into(board, &mut stats.1, SQ_BL);
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}
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/// Update `stats` for `color` from given `board`
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///
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/// Refresh all stats *except* `mobility`.
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pub fn compute_color_stats_into(board: &Board, stats: &mut BoardStats, color: u8) {
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stats.reset();
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for (piece, (pos_f, pos_r)) in get_piece_iterator(board) {
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if piece == SQ_E || !is_color(piece, color) {
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continue
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}
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// For all piece types, increment its number. Pawns have a few additional stats.
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match get_type(piece) {
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SQ_R => stats.num_rooks += 1,
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SQ_N => stats.num_knights += 1,
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SQ_B => stats.num_bishops += 1,
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SQ_Q => stats.num_queens += 1,
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SQ_K => stats.num_kings += 1,
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SQ_P => {
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stats.num_pawns += 1;
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let mut doubled = false;
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let mut isolated = true;
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let mut backward = true;
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for r in 0..8 {
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// Check for doubled pawns.
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if
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!doubled &&
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is_piece(get_square(board, &(pos_f, r)), color|SQ_P) && r != pos_r
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{
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doubled = true;
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}
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// Check for isolated pawns.
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if
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isolated &&
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(
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// Check on the left file if not on a-file...
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(
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pos_f > POS_MIN &&
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is_piece(get_square(board, &(pos_f - 1, r)), color|SQ_P)
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) ||
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// Check on the right file if not on h-file...
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(
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pos_f < POS_MAX &&
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is_piece(get_square(board, &(pos_f + 1, r)), color|SQ_P)
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)
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)
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{
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isolated = false;
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}
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// Check for backward pawns.
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if backward {
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if color == SQ_WH && r <= pos_r {
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if (
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pos_f > POS_MIN &&
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is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
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) || (
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pos_f < POS_MAX &&
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is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
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) {
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backward = false;
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}
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} else if color == SQ_BL && r >= pos_r {
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if (
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pos_f > POS_MIN &&
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is_type(get_square(board, &(pos_f - 1, r)), SQ_P)
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) || (
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pos_f < POS_MAX &&
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is_type(get_square(board, &(pos_f + 1, r)), SQ_P)
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) {
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backward = false;
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}
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}
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}
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}
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if doubled {
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stats.num_doubled_pawns += 1;
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}
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if isolated {
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stats.num_isolated_pawns += 1;
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}
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if backward {
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stats.num_backward_pawns += 1;
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}
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},
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_ => {}
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}
|
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// 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);
|
||||
}
|
||||
}
|
Reference in a new issue