othello/src/logic/board_value.rs
2025-02-22 20:55:17 -05:00

48 lines
1.4 KiB
Rust

use crate::repr::{Board, Piece, PosMap};
pub struct BoardValueMap(PosMap<i64>);
impl BoardValueMap {
pub fn board_value(&self, board: &Board, color: Piece) -> i64 {
Board::all_positions()
.filter_map(|(i, j)| board.get(i, j).map(|p| (i, j, p)))
.map(|(i, j, pos_p)| (*self.0.get(i, j), pos_p))
.map(|(value, pos_p)| {
if pos_p != color {
// enemy has position
return -value;
}
// target has position
value
})
.sum()
}
/// Weights from: https://repub.eur.nl/pub/7142/ei2005-47.pdf
pub fn new() -> Self {
let mut map = PosMap::new();
assert_eq!(
Board::BOARD_SIZE,
8,
"BVM only supports Board::BOARD_SIZE of 8"
);
const POSITION_VALUES: [[i64; 8]; 8] = [
[100, -20, 10, 5, 5, 10, -20, 100],
[-20, -50, -2, -2, -2, -2, -50, -20],
[10, -2, -1, -1, -1, -1, -2, 10],
[5, -2, -1, -1, -1, -1, -2, 5],
[5, -2, -1, -1, -1, -1, -2, 5],
[10, -2, -1, -1, -1, -1, -2, 10],
[-20, -50, -2, -2, -2, -2, -50, -20],
[100, -20, 10, 5, 5, 10, -20, 100],
];
for (i, j) in Board::all_positions() {
map.set(i, j, POSITION_VALUES[i][j])
}
Self(map)
}
}