Reduce size of eval to i16

src/evaluation/mod.rs

@@ -1,5 +1,5 @@
 pub mod pesto;
 
-pub const MAX_SCORE: i32 = 100000;
+pub const MAX_SCORE: i16 = 10000;
-pub const MIN_SCORE: i32 = -100000;
+pub const MIN_SCORE: i16 = -10000;
-pub const MATE_SCORE: i32 = 50000;
+pub const MATE_SCORE: i16 = 5000;

src/evaluation/pesto.rs

@@ -224,7 +224,7 @@ impl Pesto {
         Self { mg_table, eg_table }
     }
 
-    pub fn eval(&self, game: &Game) -> i32 {
+    pub fn eval(&self, game: &Game) -> i16 {
         let mut mg = [0, 0];
         let mut eg = [0, 0];
         let mut phase = 0;
@@ -243,7 +243,7 @@ impl Pesto {
         let mg_phase = std::cmp::min(phase, 24);
         let eg_phase = 24 - mg_phase;
 
-        (mg_score * mg_phase + eg_score * eg_phase) / 24
+        ((mg_score * mg_phase + eg_score * eg_phase) / 24) as i16
     }
 }
 

src/search/iterative_deepening.rs

@@ -55,7 +55,7 @@ fn log_depth_results(
     seconds: u64,
     nodes: u64,
     nps: u64,
-    best_score: i32,
+    best_score: i16,
     best_move: Option<Move>,
 ) -> Response {
     Response::Info(format!(

src/search/move_ordering.rs

@@ -5,7 +5,7 @@ pub fn score_move(
     mv: Move,
     killer_move: Option<Move>,
     tt_move: Option<Move>,
-) -> i32 {
+) -> i16 {
     if Some(mv) == tt_move {
         return -100;
     }
@@ -15,9 +15,11 @@ pub fn score_move(
     }
 
     let aggressor = mailbox.piece_at(mv.src()).expect("No aggressor found.");
-    mailbox.piece_at(mv.dst()).map_or(100, |victim| {
+    if let Some(victim) = mailbox.piece_at(mv.dst()) {
-        aggressor.0.idx() as i32 - (victim.0.idx() * 8) as i32
+        return (aggressor.0.idx() - 8 * victim.0.idx()) as i16;
-    })
+    }
+
+    100
 }
 
 #[cfg(test)]

src/search/negamax.rs

@@ -14,14 +14,14 @@ use super::{
 
 pub fn negamax(
     game: &mut Game,
-    mut alpha: i32,
+    mut alpha: i16,
-    beta: i32,
+    beta: i16,
     mut depth: u8,
     plies: u8,
     time: &TimeInfo,
     nodes: &mut u64,
     do_nmp: bool,
-) -> Result<i32> {
+) -> Result<i16> {
     if time.exceed_hard_limit() {
         bail!("Hard limit exceeded in negamax");
     }
@@ -137,7 +137,7 @@ pub fn negamax(
 
     if legal_moves == 0 {
         if in_check {
-            return Ok(-MATE_SCORE + plies as i32);
+            return Ok(-MATE_SCORE + plies as i16);
         }
         return Ok(0);
     }

src/search/quiescence.rs

@@ -6,11 +6,11 @@ use super::{move_ordering::score_move, time::TimeInfo, transposition_table::Node
 
 pub fn quiescence(
     game: &mut Game,
-    mut alpha: i32,
+    mut alpha: i16,
-    beta: i32,
+    beta: i16,
     time: &TimeInfo,
     nodes: &mut u64,
-) -> Result<i32> {
+) -> Result<i16> {
     if *nodes & 1024 == 0 && time.exceed_hard_limit() {
         bail!("Hard limit exceeded in quiescence");
     }

src/search/transposition_table.rs

@@ -31,7 +31,7 @@ pub struct TTEntry {
     pub hash: ZobristHash,
     pub mv: Option<Move>,
     pub depth: u8,
-    pub score: i32,
+    pub score: i16,
     pub node_type: NodeType,
 }
 
@@ -40,7 +40,7 @@ impl TTEntry {
         hash: ZobristHash,
         mv: Option<Move>,
         depth: u8,
-        score: i32,
+        score: i16,
         node_type: NodeType,
     ) -> Self {
         Self {