Migrate to Map for TT (#24)

nguyenphuminh · Oct 12, 2024 · 0339a85 · 0339a85
1 parent 01890fa
commit 0339a85
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Showing 3 changed files with 19 additions and 18 deletions.
diff --git a/catto.config.js b/catto.config.js
@@ -1,6 +1,6 @@
 module.exports = {
     // Current version to show in UCI
-    version: "v0.12.3",
+    version: "v0.12.4",
     // Late move reduction config
     lmrFullDepth: 4, // Number of moves to be searched in full depth
     lmrMaxReduction: 3, // Only apply LMR above this depth

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "catto",
-  "version": "0.12.3",
+  "version": "0.12.4",
   "description": "The Catto chess engine",
   "main": "index.js",
   "scripts": {

diff --git a/src/core.ts b/src/core.ts
@@ -100,28 +100,28 @@ export class Engine {
     }
 
     // Tranposition table
-    public hashTable: Record<string, HashEntry> = {};
+    public hashTable: Map<bigint, HashEntry> = new Map();
 
-    recordHash(score: number, depth: number, hashFlag: HashFlag, move: Move, customHash?: string) {
-        const hash = customHash || genZobristKey(this.chess).toString();
+    recordHash(score: number, depth: number, hashFlag: HashFlag, move: Move, customHash?: bigint) {
+        const hash = customHash || genZobristKey(this.chess);
         // const hash = this.chess.fen();
 
         if (score < -MATE_SCORE) score -= this.ply;
         if (score > MATE_SCORE) score += this.ply;
 
-        this.hashTable[hash] = {
+        this.hashTable.set(hash, {
             score,
             depth,
             hashFlag,
             move
-        }
+        }); 
     }
 
-    probeHash(alpha: number, beta: number, depth: number, customHash?: string): number {
-        const hash = customHash || genZobristKey(this.chess).toString();
+    probeHash(alpha: number, beta: number, depth: number, customHash?: bigint): number {
+        const hash = customHash || genZobristKey(this.chess);
         // const hash = this.chess.fen();
 
-        const hashEntry = this.hashTable[hash];
+        const hashEntry = this.hashTable.get(hash);
 
         if (!hashEntry)
             // If position does not exist the transposition table
@@ -145,15 +145,16 @@ export class Engine {
     }
 
     // Move ordering
-    getMovePrio(move: Move, currentBoardHash: string): number {
+    getMovePrio(move: Move, currentBoardHash: bigint): number {
         let priority = 0;
 
         // Hash Move
-        // const currentBoardHash = this.chess.fen();
+        const hashEntry = this.hashTable.get(currentBoardHash);
+
         if (
-            this.hashTable[currentBoardHash] && 
-            this.hashTable[currentBoardHash].move &&
-            move.san === this.hashTable[currentBoardHash].move.san
+            hashEntry && 
+            hashEntry.move &&
+            move.san === hashEntry.move.san
         ) {
             priority += 100000;
         }
@@ -202,8 +203,8 @@ export class Engine {
         return priority;
     }
 
-    sortMoves(moves: Move[], customHash?: string) {
-        const currentBoardHash = customHash || genZobristKey(this.chess).toString();
+    sortMoves(moves: Move[], customHash?: bigint) {
+        const currentBoardHash = customHash || genZobristKey(this.chess);
 
         return moves
             .map(move => ({ move, priority: this.getMovePrio(move, currentBoardHash) }))
@@ -285,7 +286,7 @@ export class Engine {
         const inCheck = this.chess.inCheck();
         this.pvLength[this.ply] = this.ply;
         // Hash onced to prevent duplications
-        const currentHash = genZobristKey(this.chess).toString();
+        const currentHash = genZobristKey(this.chess);
 
         this.nodes++;