From c101f2e230a2ed021ce54d6278ce120ad6d850fe Mon Sep 17 00:00:00 2001
From: eug-vs <eugene@eug-vs.xyz>
Date: Thu, 18 Jan 2024 22:12:38 +0100
Subject: fix: clamp score to keep it inside the window

---
 src/grossmeister/search.rs | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/grossmeister/search.rs b/src/grossmeister/search.rs
index 0ca5ef4..c195527 100644
--- a/src/grossmeister/search.rs
+++ b/src/grossmeister/search.rs
@@ -50,18 +50,20 @@ impl Grossmeister {
         if let Some(transposition) = self.transposition() {
             if transposition.depth >= depth_left {
                 match transposition.node_type {
-                    NodeType::PV | NodeType::Cut => {
+                    NodeType::PV => {
+                        return transposition.score.clamp(alpha, beta);
+                    }
+                    NodeType::Cut => {
                         if transposition.score >= beta {
-                            return beta
-                        }
-                        if transposition.score > alpha {
-                            alpha = transposition.score
+                            return beta;
                         }
+                        alpha = transposition.score.clamp(alpha, beta);
                     }
                     NodeType::All => {
                         if transposition.score <= alpha {
-                            return alpha
+                            return alpha;
                         }
+                        beta = transposition.score.clamp(alpha, beta);
                     }
                 }
             }
@@ -171,18 +173,20 @@ impl Grossmeister {
 
         if let Some(transposition) = self.transposition() {
             match transposition.node_type {
-                NodeType::PV | NodeType::Cut => {
+                NodeType::PV => {
+                    return transposition.score.clamp(alpha, beta);
+                }
+                NodeType::Cut => {
                     if transposition.score >= beta {
-                        return beta
-                    }
-                    if transposition.score > alpha {
-                        alpha = transposition.score
+                        return beta;
                     }
+                    alpha = transposition.score.clamp(alpha, beta);
                 }
                 NodeType::All => {
                     if transposition.score <= alpha {
-                        return alpha
+                        return alpha;
                     }
+                    beta = transposition.score.clamp(alpha, beta);
                 }
             }
         }
-- 
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