Add SEE bench

Cargo.toml

@@ -30,3 +30,7 @@ harness = false
 [[bench]]
 name = "eval"
 harness = false
+
+[[bench]]
+name = "see"
+harness = false

benches/see.rs

@@ -0,0 +1,33 @@
+use camel::{
+    moves::gen::MoveStage,
+    position::{fen::FromFen, Position},
+    search::see,
+};
+use criterion::{criterion_group, criterion_main, Criterion};
+
+fn see_1(c: &mut Criterion) {
+    let position =
+        Position::from_fen("rnbqkb1r/1p1p1ppp/p3pn2/8/2PNP3/8/PP3PPP/RNBQKB1R w KQkq - 1 6")
+            .unwrap();
+    let moves = position.moves(MoveStage::All);
+    let mov = moves.iter().find(|mov| mov.to_string() == "d4e6").unwrap();
+
+    c.bench_function("see_1", |b| {
+        b.iter(|| see::see::<false>(*mov, &position.board));
+    });
+}
+
+fn see_2(c: &mut Criterion) {
+    let position =
+        Position::from_fen("rnbqkb1r/1p1p1ppp/p3p3/8/2PNn3/2N5/PP3PPP/R1BQKB1R w KQkq - 0 7")
+            .unwrap();
+    let moves = position.moves(MoveStage::All);
+    let mov = moves.iter().find(|mov| mov.to_string() == "c3e4").unwrap();
+
+    c.bench_function("see_2", |b| {
+        b.iter(|| see::see::<false>(*mov, &position.board));
+    });
+}
+
+criterion_group!(see, see_1, see_2,);
+criterion_main!(see);

src/search/see.rs

@@ -25,9 +25,9 @@ pub fn see<const RETURN_EARLY: bool>(mov: Move, board: &Board) -> ValueScore {
     }
 
     // We need an auxiliary board to perform the search.
-    // We also store the max score when it is our turn.
+    // We also store a standing pat when it is our turn to move.
     let mut board = *board;
-    let mut max_score = ValueScore::MIN;
+    let mut stand_pat = ValueScore::MIN;
 
     // Make our move.
     let mut on_square = piece;
@@ -41,8 +41,8 @@ pub fn see<const RETURN_EARLY: bool>(mov: Move, board: &Board) -> ValueScore {
             if RETURN_EARLY && score >= 0 {
                 return score;
             }
-            max_score = max_score.max(score);
-        } else if RETURN_EARLY && score < 0 {
+            stand_pat = stand_pat.max(score);
+        } else if RETURN_EARLY && score <= 0 {
             return score;
         }
 
@@ -66,7 +66,7 @@ pub fn see<const RETURN_EARLY: bool>(mov: Move, board: &Board) -> ValueScore {
         }
     }
 
-    max_score.max(score)
+    stand_pat.max(score)
 }
 
 #[cfg(test)]