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Make mvv_lva to map pieces to their material score instead of abritrary matrix

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stefiosif
2024-11-13 21:13:05 +02:00
parent 429485ae73
commit 30d90cb3a0
1 changed files with 8 additions and 20 deletions
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28
src/search/move_ordering.rs
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@@ -1,20 +1,10 @@
use crate::{board::mailbox::Mailbox, movegen::r#move::Move}; use crate::{
board::mailbox::Mailbox, evaluation::evaluation::material_score, movegen::r#move::Move,
};
// Rows: Aggressors (P, N, B, R, Q, K) pub const fn mvv_lva(mailbox: &Mailbox, mv: Move) -> i32 {
// Columns: Victims (K, Q, R, B, N, P)
#[rustfmt::skip]
const MVV_LVA: [[usize; 6]; 6] = [
[30, 29, 28, 27, 26, 0],
[25, 24, 23, 22, 21, 0],
[20, 19, 18, 17, 16, 0],
[15, 14, 13, 12, 11, 0],
[10, 9, 8, 7, 6, 0],
[5, 4, 3, 2, 1, 0],
];
pub const fn score_by_mvv_lva(mailbox: &Mailbox, mv: Move) -> usize {
match (mailbox.piece_at(mv.src), mailbox.piece_at(mv.dst)) { match (mailbox.piece_at(mv.src), mailbox.piece_at(mv.dst)) {
(Some(aggressor), Some(victim)) => MVV_LVA[aggressor.idx()][victim.idx()], (Some(aggressor), Some(victim)) => material_score(victim) - material_score(aggressor),
_ => 0, _ => 0,
} }
} }
@@ -22,9 +12,9 @@ pub const fn score_by_mvv_lva(mailbox: &Mailbox, mv: Move) -> usize {
#[cfg(test)] #[cfg(test)]
mod tests { mod tests {
use crate::{ use crate::{
board::{board::PieceType, fen::from_fen, square::Square}, board::{fen::from_fen, square::Square},
movegen::r#move::{Move, MoveType}, movegen::r#move::{Move, MoveType},
search::move_ordering::{score_by_mvv_lva, MVV_LVA}, search::move_ordering::mvv_lva,
}; };
const FEN: &'static str = "1r2k2r/2P1pq1p/2npb3/1p3ppP/p3P3/P2B1Q2/1P1PNPP1/R3K2R w KQk g6 0 1"; const FEN: &'static str = "1r2k2r/2P1pq1p/2npb3/1p3ppP/p3P3/P2B1Q2/1P1PNPP1/R3K2R w KQk g6 0 1";
@@ -33,10 +23,8 @@ mod tests {
fn test_score_by_mvv_lva() -> Result<(), String> { fn test_score_by_mvv_lva() -> Result<(), String> {
let game = from_fen(FEN)?; let game = from_fen(FEN)?;
let f3f5 = Move::with_type(Square::F3, Square::F5, MoveType::Capture); let f3f5 = Move::with_type(Square::F3, Square::F5, MoveType::Capture);
let actual = score_by_mvv_lva(&game.mailbox, f3f5);
let expected = MVV_LVA[PieceType::Queen.idx()][PieceType::Pawn.idx()];
assert_eq!(expected, actual); assert_eq!(mvv_lva(&game.mailbox, f3f5), -800);
Ok(()) Ok(())
} }