feat: add aspiration windows to iterative_deepning

1 files changed, 22 insertions, 4 deletions

diff --git a/src/board/engine.rs b/src/board/engine.rs
index b6daacf..0a99def 100644
--- a/src/board/engine.rs
+++ b/src/board/engine.rs
@@ -1,4 +1,4 @@
-use std::{cmp::Ordering, time::{Instant, Duration}, f32::INFINITY};
+use std::{time::{Instant, Duration}, f32::INFINITY};
 use crate::{bitboard::pop_count, board::*};
 
 use super::ttable::{NodeType, TranspositionTableItem};
@@ -245,20 +245,38 @@ impl Board {
         let start = Instant::now();
         let deadline = start + duration;
         let mut result = None;
-        let mut depth = 0;
+        let mut depth = 1;
+        let mut alpha = -INFINITY;
+        let mut beta = INFINITY;
+        let window_size = 0.5;
 
         loop {
-            let search_result = self.negamax_search(-INFINITY, INFINITY, depth, deadline);
+            let search_result = self.negamax_search(alpha, beta, depth, deadline);
             println!("Finished depth({}) {:?} [{:?} left]", depth, search_result, deadline - Instant::now());
 
+            if search_result.1.len() > 0 {
+                depth += 1;
+                alpha = search_result.0 - window_size;
+                beta = search_result.0 + window_size;
+            } else if search_result.0 <= alpha { // Alpha-cutoff
+                println!("Alpha cutoff {} <= {:?}", search_result.0, (alpha, beta));
+                alpha = search_result.0 - window_size;
+            } else if search_result.0 >= beta { // Beta-cutoff
+                println!("Beta cutoff {:?} <= {}", (alpha, beta), search_result.0);
+                beta = search_result.0 + window_size;
+            } else {
+                panic!("Can this ever be possible? (probably not)");
+            }
+
             if Instant::now() > deadline {
                 match result {
                     Some(r) => return r,
                     None => panic!("Could not find a move in time"),
                 }
             }
+
             result = Some(search_result);
-            depth += 1;
+
         }
     }
 }