add tt and small improvements

lumiZGorlic · May 9, 2020 · b954dbd · b954dbd
1 parent 072b72f
commit b954dbd
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Showing 5 changed files with 77 additions and 29 deletions.
diff --git a/TODOs b/TODOs
@@ -7,8 +7,9 @@
 - test against TSCP in terms of strength, speed (move generation) etc.
   look at https://chess.stackexchange.com/questions/12790/how-to-measure-strength-of-my-own-chess-engine
 
-- extend search (PV, TT etc) and evaluation
+- analyse and improve search by adding some techniques and also evaluation
 
 - improve quiesce
 
+- end game, opening book
 
diff --git a/board.cpp b/board.cpp
@@ -1415,7 +1415,6 @@ void printBoard2(const U64& b)
 
 U64 Perft(chessBoard& board, int depth)
 {
-    chessBoard boardCpy;
     U64 nodes = 0;
 
     if (depth == 0)
@@ -1425,10 +1424,10 @@ U64 Perft(chessBoard& board, int depth)
     board.numOfMvs = 0;
     board.genMoves(moves);
 
+    chessBoard boardCpy = board;
+
     for (int i = 0; i < board.numOfMvs; i++)
     {
-        boardCpy = board;
-
         if (board.makeMove(moves[i]))
         {
             int tmp = Perft(board, depth - 1);
@@ -1472,7 +1471,7 @@ void debugMoveGen () {
 
 
     // same positions, not as many moves
-    debugInput.push_back(debugItem("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
+    /*debugInput.push_back(debugItem("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
                  {20, 400, 8902, 197281 }));
     debugInput.push_back(debugItem("r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -",
                  { 48, 2039, 97862 }));
@@ -1483,10 +1482,10 @@ void debugMoveGen () {
     debugInput.push_back(debugItem("rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8 ",
                  { 44, 1486, 62379, 2103487 }));
     debugInput.push_back(debugItem("r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10",
-                 { 46, 2079, 89890, 3894594 }));
+                 { 46, 2079, 89890, 3894594 }));*/
 
 
-    /*debugInput.push_back(debugItem("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
+    debugInput.push_back(debugItem("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
                  {20, 400, 8902, 197281, 4865609, 119060324 }));
     debugInput.push_back(debugItem("r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -",
                  { 48, 2039, 97862, 4085603, 193690690 }));
@@ -1497,7 +1496,7 @@ void debugMoveGen () {
     debugInput.push_back(debugItem("rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8 ",
                  { 44, 1486, 62379, 2103487, 89941194 }));
     debugInput.push_back(debugItem("r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10",
-                 { 46, 2079, 89890, 3894594, 164075551 }));*/
+                 { 46, 2079, 89890, 3894594, 164075551 }));
 
     std::vector<debugItem>::iterator it;
     for (it = debugInput.begin(); it != debugInput.end(); it++)

diff --git a/defs.h b/defs.h
@@ -4,6 +4,11 @@
 #include <set>
 #include <map>
 
+// value biger than max alpha/beta so safe to use it to
+// signal that no valid entry in tt
+#define NO_TT_ENTRY   22000000
+#define NUM_OF_TT_ENTRIES 33554432
+
 #define MAX_NUM_OF_MVS      250
 
 enum { EP=1, CASTLING, PROMOTE_R, PROMOTE_N, PROMOTE_B, PROMOTE_Q };
@@ -23,6 +28,28 @@ enum {
 typedef unsigned long long U64;
 
 
+enum ttEntryType {ALPHA, BETA, FULL};
+
+struct ttEntry {
+
+    U64 hash;
+    int depth;
+    ttEntryType eType;
+    int alpha;
+    int beta;
+
+};
+
+struct transpositionTable {
+
+    ttEntry table[NUM_OF_TT_ENTRIES];
+
+    void save(U64 hash, int depth, ttEntryType eType, int alpha, int beta);
+    int  probe(U64 hash, int depth, int alpha, int beta);
+
+};
+
+
 struct pieceValue {
 
     std::map<char,int> values;
@@ -191,9 +218,6 @@ struct magics {
 };
 
 
-extern magics mag;
-extern pieceValue pValue;
-
 
 // TODO: if use char here then need to convert char to int and vice-versa
 // is it good solution ?
@@ -223,11 +247,6 @@ struct chessBoard {
     int ep;
     int fifty;
 
-    // TODO: is it enough ? what about castling etc ?
-    unsigned long long int squaresHash[64][6][2];
-    unsigned long long int sideHash;
-    unsigned long long int epHash[64];
-
     unsigned long long int currPosHash;
     std::vector<unsigned long long int> historyHash;
 
@@ -314,3 +333,12 @@ bool savePosInFEN(chessBoard& board, std::string& pos);
 bool readInPosFromFEN(chessBoard& board, std::string pos);
 
 
+extern magics mag;
+extern pieceValue pValue;
+extern transpositionTable tt;
+
+// TODO: is it enough ? what about castling etc ?
+extern unsigned long long int squaresHash[64][6][2];
+extern unsigned long long int sideHash;
+extern unsigned long long int epHash[64];
+
diff --git a/main.cpp b/main.cpp
@@ -427,13 +427,15 @@ void testSearch(){
     readInPosFromFEN (board, pos);
     board.populateOccup();
     board.populateCharBoard();
+    board.calcHash();
 
-    for (int i = 0; i < 3; i++)
+    for (int i = 0; i < 5; i++)
     {
         clock_t begin = clock();
 
         searchEngine se;
-        move m = se.doSearch(board, 3);
+        move m = se.doSearch(board, i+1);
+        //move m = se.doSearch(board, 2);
 
         clock_t end = clock();
         double elapsed_secs = double(end - begin) / CLOCKS_PER_SEC;
@@ -461,14 +463,18 @@ void handler(int sig) {
 
 magics mag;
 pieceValue pValue;
+transpositionTable tt;
+unsigned long long int squaresHash[64][6][2];
+unsigned long long int sideHash;
+unsigned long long int epHash[64];
 
 int main ()
 {
     signal(SIGSEGV, handler);
 
-    testSearch();
+    //testSearch();
 
-    //debugMoveGen();
+    debugMoveGen();
     //testMoveGenSpeed();
     //playDummyGame();
     //engineVsEngine();

diff --git a/search.cpp b/search.cpp
@@ -59,19 +59,18 @@ move searchEngine::searchMain(chessBoard& board, int depth)
     nodes++;
 
     move m(0, 0, 0);
-    chessBoard boardCpy;
     int score = -20000000, tmp;
 
     move moves[MAX_NUM_OF_MVS];
     board.numOfMvs = 0;
     board.genMoves(moves);
 
+    chessBoard boardCpy = board;
+
     for (int i = 0; i < board.numOfMvs; i++)
     {
         sortMoves(moves, board.numOfMvs, i);
 
-        boardCpy = board;
-
         if (board.makeMove(moves[i]))
         {
             tmp = -search(board, depth - 1, -20000000, -score);
@@ -85,11 +84,20 @@ move searchEngine::searchMain(chessBoard& board, int depth)
         board = boardCpy;
     }
 
+    tt.save(board.currPosHash, depth, FULL, score, 20000000);
+
     return m;
 }
 
 int searchEngine::search(chessBoard& board, int depth, int alpha, int beta)
 {
+    //assert(alpha < beta);
+    int origAlpha = alpha;
+
+    int ttScore = tt.probe(board.currPosHash, depth, alpha, beta);
+    if (ttScore != NO_TT_ENTRY)
+        return ttScore;
+
     if (depth == 0)
     {
         return quiesce(board, alpha, beta);
@@ -120,22 +128,24 @@ int searchEngine::search(chessBoard& board, int depth, int alpha, int beta)
     board.numOfMvs = 0;
     board.genMoves(moves);
 
-    chessBoard boardCpy;
+    chessBoard boardCpy = board;
     int tmp = 0;
 
     for (int i = 0; i < board.numOfMvs; i++)
     {
         sortMoves(moves, board.numOfMvs, i);
 
-        boardCpy = board;
-
         if (board.makeMove(moves[i]))
         {
             playedMoves = true;
 
             tmp = -search(board, depth - 1, -beta, -alpha);
             if (tmp >= beta)
+            {
+                // needs to be boardCpy as board has been modified at this point
+                tt.save(boardCpy.currPosHash, depth, BETA, alpha, beta);
                 return beta;
+            }
             if (tmp > alpha)
                 alpha = tmp;
         }
@@ -158,6 +168,11 @@ int searchEngine::search(chessBoard& board, int depth, int alpha, int beta)
     if (board.fifty >= 100)
         return 0;
 
+    if (alpha == origAlpha)
+        tt.save(board.currPosHash, depth, ALPHA, alpha, beta);
+    else
+        tt.save(board.currPosHash, depth, FULL,  alpha, beta);
+
     return alpha;
 }
 
@@ -183,6 +198,7 @@ int searchEngine::quiesce(chessBoard& board, int alpha, int beta ) {
     // TODO have to modify it to handle mate etc
     // TODO might be worth adding some margin
     int standPat = eval(board);
+
     if( standPat >= beta )
         return beta;
     if( alpha < standPat )
@@ -192,7 +208,7 @@ int searchEngine::quiesce(chessBoard& board, int alpha, int beta ) {
     board.numOfMvs = 0;
     board.genMoves(moves);
 
-    chessBoard boardCpy;
+    chessBoard boardCpy = board;
     int tmp = 0;
 
     // TODO add checks, promotions etc
@@ -205,8 +221,6 @@ int searchEngine::quiesce(chessBoard& board, int alpha, int beta ) {
 
         if (board.charBoard[(int)(moves[i].to)] != ' ' || moves[i].flag == EP)
         {
-            boardCpy = board;
-
             if (board.makeMove(moves[i]))
             {
                  tmp = -quiesce(board, -beta, -alpha);