scale evaluation down by 3.2

lib/nnue/evaluator.rs

@@ -51,7 +51,8 @@ impl<T: Accumulator> Evaluator<T> {
     /// The [`Position`]'s evaluation.
     pub fn evaluate(&self) -> Value {
         let phase = (self.occupied().len() - 1) / 4;
-        self.acc.evaluate(self.turn(), phase).saturate()
+        let value = self.acc.evaluate(self.turn(), phase) >> 8;
+        value.saturate()
     }
 
     /// The Static Exchange Evaluation ([SEE]) algorithm.

lib/nnue/material.rs

@@ -44,9 +44,7 @@ impl Accumulator for Material {
 
     #[inline(always)]
     fn evaluate(&self, turn: Color, phase: usize) -> i32 {
-        let us = self.0[turn as usize];
-        let them = self.0[turn.flip() as usize];
-        (us.get(phase).assume() - them.get(phase).assume()) / 80
+        self.0[turn as usize].get(phase).assume() - self.0[turn.flip() as usize].get(phase).assume()
     }
 }
 

lib/nnue/positional.rs

@@ -44,7 +44,7 @@ impl Accumulator for Positional {
 
     #[inline(always)]
     fn evaluate(&self, turn: Color, phase: usize) -> i32 {
-        Nnue::hidden(phase).forward(&self.0[turn as usize], &self.0[turn.flip() as usize]) / 40
+        Nnue::hidden(phase).forward(&self.0[turn as usize], &self.0[turn.flip() as usize]) << 1
     }
 }
 

lib/search/engine.rs

@@ -103,11 +103,10 @@ impl Engine {
         depth: Depth,
         ply: Ply,
     ) -> Option<Depth> {
-        let bounds = -(alpha - 24)..-(alpha - 161);
-        let r = match (alpha + next.clone().see(m.whither(), bounds)).get() {
-            ..=24 => return None,
-            25..=80 => 1,
-            81..=160 => 2,
+        let r = match (alpha + next.clone().see(m.whither(), -(alpha - 8)..-(alpha - 49))).get() {
+            ..=8 => return None,
+            9..=24 => 1,
+            25..=48 => 2,
             _ => 3,
         };
 
@@ -223,7 +222,7 @@ impl Engine {
                 if Some(m) == transposition.map(|t| t.best()) {
                     (m, Value::upper())
                 } else if Self::KILLERS.with_borrow(|ks| ks.contains(ply, pos.turn(), m)) {
-                    (m, Value::new(40))
+                    (m, Value::new(16))
                 } else if m.is_quiet() {
                     (m, Value::new(0))
                 } else {
@@ -309,7 +308,7 @@ impl Engine {
         'id: for d in depth.get()..=limit.get() {
             let mut overtime = time.end - time.start;
             let mut depth = Depth::new(d);
-            let mut delta: i16 = 10;
+            let mut delta: i16 = 4;
 
             let (mut lower, mut upper) = match d {
                 ..=4 => (Score::lower(), Score::upper()),