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Hyperbola Quintessence #81

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Hyperbola Quintessence #81

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20592a1
draft hyperbola quintessence
niklasf Aug 7, 2024
a12295b
eliminate ray table
niklasf Aug 7, 2024
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92 changes: 42 additions & 50 deletions src/attacks.rs
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ use crate::{
bitboard::Bitboard,
bootstrap::{
ATTACKS, BLACK_PAWN_ATTACKS, KING_ATTACKS, KNIGHT_ATTACKS, RAYS, WHITE_PAWN_ATTACKS,
DIAG_RANGE, ANTI_DIAG_RANGE, FILE_RANGE, RANK_RANGE,
},
color::Color,
magics,
Expand Down Expand Up @@ -54,10 +55,35 @@ pub fn king_attacks(sq: Square) -> Bitboard {
Bitboard(KING_ATTACKS[usize::from(sq)])
}

fn hyperbola(sq: Square, range: u64, occupied: Bitboard) -> Bitboard {
let forward = occupied & Bitboard(range);
let reverse = forward.flip_vertical();
let forward = Bitboard(forward.0.wrapping_sub(1 << usize::from(sq)));
let reverse = Bitboard(reverse.0.wrapping_sub(1 << usize::from(sq.flip_vertical())));
(forward ^ reverse.flip_vertical()) & range
}
fn file_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
hyperbola(sq, FILE_RANGE[usize::from(sq)], occupied)
}
fn rank_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
let range = RANK_RANGE[usize::from(sq)];
let forward = occupied & range;
let reverse = forward.rotate_180();
let forward = Bitboard(forward.0.wrapping_sub(1 << usize::from(sq)));
let reverse = Bitboard(reverse.0.wrapping_sub(1 << usize::from(sq.rotate_180())));
(forward ^ reverse.rotate_180()) & range
}
pub fn bishop_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
hyperbola(sq, DIAG_RANGE[usize::from(sq)], occupied) ^ hyperbola(sq, ANTI_DIAG_RANGE[usize::from(sq)], occupied)
}
pub fn rook_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
file_attacks(sq, occupied) ^ rank_attacks(sq, occupied)
}

static ROOK_MAGICS: [Magic; 64] = magics::ROOK_MAGICS;

/// Looks up attacks for a rook on `sq` with `occupied` squares.
#[inline]
/* #[inline]
pub fn rook_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
let m = ROOK_MAGICS[usize::from(sq)];

Expand All @@ -69,29 +95,6 @@ pub fn rook_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
Bitboard(unsafe { *ATTACKS.get_unchecked(idx) })
}

/// Gets the set of potential blocking squares for a rook on `sq`.
///
/// # Example
///
/// ```
/// use shakmaty::{attacks, Square};
///
/// let mask = attacks::rook_mask(Square::E8);
/// // 0 1 1 1 0 1 1 0
/// // . . . . 1 . . .
/// // . . . . 1 . . .
/// // . . . . 1 . . .
/// // . . . . 1 . . .
/// // . . . . 1 . . .
/// // . . . . 1 . . .
/// // . . . . 0 . . .
///
/// assert_eq!(mask.count(), 11);
#[inline]
pub fn rook_mask(sq: Square) -> Bitboard {
Bitboard(ROOK_MAGICS[usize::from(sq)].mask)
}

static BISHOP_MAGICS: [Magic; 64] = magics::BISHOP_MAGICS;

/// Looks up attacks for a bishop on `sq` with `occupied` squares.
Expand All @@ -105,31 +108,7 @@ pub fn bishop_attacks(sq: Square, occupied: Bitboard) -> Bitboard {
let idx = (m.factor.wrapping_mul(occupied.0 & m.mask) >> (64 - 9)) as usize + m.offset;
debug_assert!(idx < ATTACKS.len());
Bitboard(unsafe { *ATTACKS.get_unchecked(idx) })
}

/// Gets the set of potential blocking squares for a bishop on `sq`.
///
/// # Example
///
/// ```
/// use shakmaty::{attacks, Square};
///
/// let mask = attacks::bishop_mask(Square::D5);
/// // 0 . . . . . 0 .
/// // . 1 . . . 1 . .
/// // . . 1 . 1 . . .
/// // . . . 0 . . . .
/// // . . 1 . 1 . . .
/// // . 1 . . . 1 . .
/// // 0 . . . . . 1 .
/// // . . . . . . . 0
///
/// assert_eq!(mask.count(), 9);
/// ```
#[inline]
pub fn bishop_mask(sq: Square) -> Bitboard {
Bitboard(BISHOP_MAGICS[usize::from(sq)].mask)
}
} */

/// Looks up attacks for a queen on `sq` with `occupied` squares.
#[inline]
Expand Down Expand Up @@ -169,7 +148,20 @@ pub fn attacks(sq: Square, piece: Piece, occupied: Bitboard) -> Bitboard {
/// ```
#[inline]
pub fn ray(a: Square, b: Square) -> Bitboard {
Bitboard(RAYS[usize::from(a)][usize::from(b)])
if a == b {
Bitboard::EMPTY
} else if a.rank() == b.rank() {
Bitboard::from_rank(a.rank())
} else if a.file() == b.file() {
Bitboard::from_file(a.file())
} else if Bitboard(DIAG_RANGE[usize::from(a)]).contains(b) {
Bitboard(DIAG_RANGE[usize::from(a)]).with(a)
} else if Bitboard(ANTI_DIAG_RANGE[usize::from(a)]).contains(b) {
Bitboard(ANTI_DIAG_RANGE[usize::from(a)]).with(a)
} else {
Bitboard::EMPTY
}
//Bitboard(RAYS[usize::from(a)][usize::from(b)])
}

/// The squares between the two squares (bounds not included), or an empty
Expand Down
30 changes: 20 additions & 10 deletions src/bootstrap.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,11 @@ const KNIGHT_DELTAS: [i32; 8] = [17, 15, 10, 6, -17, -15, -10, -6];
const WHITE_PAWN_DELTAS: [i32; 2] = [7, 9];
const BLACK_PAWN_DELTAS: [i32; 2] = [-7, -9];

const FILE_DELTAS: [i32; 2] = [8, -8];
const RANK_DELTAS: [i32; 2] = [1, -1];
const DIAG_DELTAS: [i32; 2] = [9, -9];
const ANTI_DIAG_DELTAS: [i32; 2] = [7, -7];

const fn sliding_attacks(square: i32, occupied: u64, deltas: &[i32]) -> u64 {
let mut attack = 0;

Expand All @@ -35,22 +40,31 @@ const fn sliding_attacks(square: i32, occupied: u64, deltas: &[i32]) -> u64 {
attack
}

const fn init_stepping_attacks(deltas: &[i32]) -> [u64; 64] {
const fn init_sliding_attacks(occupied: u64, deltas: &[i32]) -> [u64; 64] {
let mut table = [0; 64];
let mut sq = 0;
while sq < 64 {
table[sq] = sliding_attacks(sq as i32, !0, deltas);
table[sq] = sliding_attacks(sq as i32, occupied, deltas);
sq += 1;
}
table
}

const fn init_stepping_attacks(deltas: &[i32]) -> [u64; 64] {
init_sliding_attacks(!0, deltas)
}

pub static KNIGHT_ATTACKS: [u64; 64] = init_stepping_attacks(&KNIGHT_DELTAS);
pub static KING_ATTACKS: [u64; 64] = init_stepping_attacks(&KING_DELTAS);
pub static WHITE_PAWN_ATTACKS: [u64; 64] = init_stepping_attacks(&WHITE_PAWN_DELTAS);
pub static BLACK_PAWN_ATTACKS: [u64; 64] = init_stepping_attacks(&BLACK_PAWN_DELTAS);

const fn init_rays() -> [[u64; 64]; 64] {
pub static FILE_RANGE: [u64; 64] = init_sliding_attacks(0, &FILE_DELTAS);
pub static RANK_RANGE: [u64; 64] = init_sliding_attacks(0, &RANK_DELTAS);
pub static DIAG_RANGE: [u64; 64] = init_sliding_attacks(0, &DIAG_DELTAS);
pub static ANTI_DIAG_RANGE: [u64; 64] = init_sliding_attacks(0, &ANTI_DIAG_DELTAS);

pub static RAYS: [[u64; 64]; 64] = {
let mut table = [[0; 64]; 64];
let mut a = 0;
while a < 64 {
Expand Down Expand Up @@ -86,11 +100,9 @@ const fn init_rays() -> [[u64; 64]; 64] {
a += 1;
}
table
}

pub static RAYS: [[u64; 64]; 64] = init_rays();
};

const fn init_magics() -> [u64; 88772] {
pub static ATTACKS: [u64; 88772] = {
let mut table = [0; 88772];
let mut square = 0;
while square < 64 {
Expand Down Expand Up @@ -125,6 +137,4 @@ const fn init_magics() -> [u64; 88772] {
square += 1;
}
table
}

pub static ATTACKS: [u64; 88772] = init_magics();
};