From 19c2df8907ebc0d13c4d745796ce63a34083186a Mon Sep 17 00:00:00 2001
From: eug-vs <eugene@eug-vs.xyz>
Date: Fri, 19 Jan 2024 17:21:35 +0100
Subject: feat!: try again with ttable in quiescence

But now with exact scores in table
---
 src/grossmeister/search.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

(limited to 'src/grossmeister')

diff --git a/src/grossmeister/search.rs b/src/grossmeister/search.rs
index 0df0628..bf080eb 100644
--- a/src/grossmeister/search.rs
+++ b/src/grossmeister/search.rs
@@ -172,10 +172,38 @@ impl Grossmeister {
             return 0.0
         }
 
+        if let Some(transposition) = self.transposition() {
+            match transposition.node_type {
+                NodeType::PV => {
+                    return transposition.score.clamp(alpha, beta);
+                }
+                NodeType::Cut => {
+                    if transposition.score >= beta {
+                        return beta;
+                    }
+                    alpha = transposition.score.clamp(alpha, beta);
+                }
+                NodeType::All => {
+                    if transposition.score <= alpha {
+                        return alpha;
+                    }
+                    beta = transposition.score.clamp(alpha, beta);
+                }
+            }
+        }
+
+        let mut transposition = TranspositionTableItem {
+            hash: self.board.hash,
+            depth: 0,
+            mov: None,
+            score: alpha,
+            node_type: NodeType::All,
+        };
 
         // Mate distance pruning
         let mating_score = Grossmeister::MDP(&mut alpha, &mut beta, root_distance);
         if mating_score != 0.0 {
+            transposition.score = mating_score;
             return mating_score
         }
 
@@ -210,10 +238,22 @@ impl Grossmeister {
                 self.board.unmake_move(mov, captured_piece, ep_target_before, castling_rights_before, hash_before);
 
                 if evaluation >= beta {
+                    transposition.mov = Some(mov);
+                    transposition.score = evaluation;
+                    transposition.node_type = NodeType::Cut;
+                    self.store_transposition(transposition);
+
                     return beta; // Fail-hard beta-cutoff
                 }
                 if evaluation > alpha {
+                    transposition.mov = Some(mov);
+                    transposition.score = evaluation;
+                    transposition.node_type = NodeType::Cut;
                     alpha = evaluation;
+                } else if transposition.node_type == NodeType::All {
+                    transposition.mov = None;
+                    transposition.score = evaluation;
+                    transposition.node_type = NodeType::All;
                 }
             } else {
                 self.board.unmake_move(mov, captured_piece, ep_target_before, castling_rights_before, hash_before);
@@ -224,6 +264,7 @@ impl Grossmeister {
             return -SCORE_MATE + root_distance as Score
         }
 
+        self.store_transposition(transposition);
         alpha
     }
 
-- 
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