Do not visit hash move twice

bdmendes · Jan 11, 2024 · 24aeab8 · 24aeab8
1 parent 8ebddd1
commit 24aeab8
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/src/search/movepick.rs b/src/search/movepick.rs
@@ -94,9 +94,17 @@ impl std::iter::Iterator for MovePicker<false> {
     fn next(&mut self) -> Option<Self::Item> {
         if let Some((mov, score, index)) = find_next_max_and_swap(&mut self.moves, &mut self.index)
         {
+            if self.stage != MoveStage::HashMove {
+                let hash_move =
+                    self.table.as_ref().unwrap().lock().unwrap().get_hash_move(&self.position);
+                if hash_move == Some(mov) {
+                    return self.next();
+                }
+            }
             return Some((mov, score, index));
         }
 
+        // Advance to the next stage
         match self.stage {
             MoveStage::HashMove => {
                 self.stage = MoveStage::CapturesAndPromotions;