Add Razoring and removed History component from LMP

Added the same form of razoring used by SF Removed history component from Late Move Pruning No longer doing Late Move Pruning on checking moves Extended the depth at which Late Move Pruning is done Reduced move counts before enabling Late Move Pruning ------------------------------------------------------------------------------- RazoringHistory @ 30.0+0.3 with 128MB Hash Base Alpha Beta Games Test Elo Base Elo Status LateMovePruning10 0.01 0.01 24900 2742.34 2729.09 PASSED MATCHUPS FOR CANDIDATE Opponent Wins Draws Losses Games Score ELO + - Floyd0.9 974 256 320 1550 71.10% 2746.36 19.55 18.66 Laser1.0 546 412 592 1550 48.52% 2716.69 17.29 17.34 Sloppy0.2.2 992 287 271 1550 73.26% 2792.07 20.09 19.06 WyldChess1.4 934 360 256 1550 71.87% 2772.96 19.73 18.80 DiscoCheck4.03 494 414 642 1550 45.23% 2678.72 17.31 17.47 RedQueen1.1.98 574 396 580 1550 49.81% 2670.66 17.31 17.31 Ethereal8.15 753 575 222 1550 67.13% 2738.04 18.77 18.10 Tucano3.0 981 407 162 1550 76.42% 2823.26 21.05 19.78 MATCHUPS FOR BASE Opponent Wins Draws Losses Games Score ELO + - Floyd0.9 944 247 359 1550 68.87% 2727.95 19.08 18.32 Laser1.0 561 420 619 1600 48.19% 2714.40 17.02 17.08 Sloppy0.2.2 938 312 300 1550 70.58% 2769.02 19.44 18.58 WyldChess1.4 893 360 297 1550 69.23% 2750.83 19.15 18.37 DiscoCheck4.03 471 451 678 1600 43.53% 2666.80 17.07 17.29 RedQueen1.1.98 547 378 625 1550 47.48% 2654.50 17.29 17.38 Ethereal8.15 766 575 209 1550 67.97% 2744.69 18.92 18.20 Tucano3.0 957 393 200 1550 74.42% 2804.51 20.41 19.30 ------------------------------------------------------------------------------- RazoringHistory @ 5.0+0.05 with 128MB Hash Base Alpha Beta Games Test Elo Base Elo Status LateMovePruning10 0.01 0.01 17800 2771.24 2738.09 PASSED MATCHUPS FOR CANDIDATE Opponent Wins Draws Losses Games Score ELO + - Floyd0.9 185 29 36 250 79.80% 2828.66 59.65 49.45 Laser1.0 104 60 86 250 53.60% 2752.06 43.80 43.02 Sloppy0.2.2 163 41 46 250 73.40% 2793.33 52.56 46.00 WyldChess1.4 166 45 39 250 75.40% 2804.57 54.38 46.88 DiscoCheck4.03 79 51 120 250 41.80% 2654.50 43.00 44.83 RedQueen1.1.98 116 58 76 250 58.00% 2728.07 44.77 42.99 Ethereal8.15 139 71 40 250 69.80% 2759.54 49.89 44.77 Tucano3.0 180 35 35 250 79.00% 2849.16 58.54 48.90 MATCHUPS FOR BASE Opponent Wins Draws Losses Games Score ELO + - Floyd0.9 1441 211 348 2000 77.33% 2803.11 18.74 17.69 Laser1.0 753 452 745 1950 50.21% 2728.43 15.43 15.43 Sloppy0.2.2 1212 344 444 2000 69.20% 2757.62 16.81 16.21 WyldChess1.4 1226 349 375 1950 71.82% 2772.53 17.53 16.79 DiscoCheck4.03 546 434 970 1950 39.13% 2635.23 15.65 15.97 RedQueen1.1.98 861 398 741 2000 53.00% 2692.87 15.30 15.22 Ethereal8.15 937 675 388 2000 63.73% 2711.88 16.05 15.65 Tucano3.0 1248 400 302 1950 74.26% 2803.03 18.10 17.23
AndyGrant · Jul 31, 2017 · 1c18eac · 1c18eac
1 parent 8cd0115
commit 1c18eac
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Showing 5 changed files with 48 additions and 13 deletions.
diff --git a/dist/Ethereal8.22.zip b/dist/Ethereal8.22.zip
diff --git a/dist/Ethereal8.23.zip b/dist/Ethereal8.23.zip
diff --git a/src/search.c b/src/search.c
@@ -346,6 +346,26 @@ int alphaBetaSearch(PVariation * pv, Board * board, int alpha, int beta,
         optimal = eval + depth * 1.25 * PawnValue;
     }
 
+    // Node Razoring at expected ALLNODEs
+    if (USE_RAZORING
+        && nodeType != PVNODE
+        && !inCheck
+        && depth <= 4
+        && !tableIsTactical
+        && hasNonPawnMaterial(board, board->turn)
+        && eval + RazorMargins[depth] < alpha){
+
+
+        if (depth <= 1)
+            return quiescenceSearch(board, alpha, beta, height);
+
+        value = quiescenceSearch(board, alpha - RazorMargins[depth],
+                                beta - RazorMargins[depth], height);
+
+        if (value + RazorMargins[depth] < alpha)
+            return value;
+    }
+
     // Static null move pruning
     if (USE_STATIC_NULL_PRUNING
         && depth <= 3
@@ -413,17 +433,6 @@ int alphaBetaSearch(PVariation * pv, Board * board, int alpha, int beta,
             hist = getHistoryScore(History, currentMove, board->turn, 128);
         }
 
-        // Late Move Pruning
-        if (USE_LATE_MOVE_PRUNING
-            && nodeType != PVNODE
-            && played >= 1
-            && !inCheck
-            && isQuiet
-            && depth < 6
-            && quiets > LateMovePruningCounts[depth]
-            && hist < 32)
-            continue;
-
         // Use futility pruning
         if (USE_FUTILITY_PRUNING
             && nodeType != PVNODE
@@ -441,6 +450,20 @@ int alphaBetaSearch(PVariation * pv, Board * board, int alpha, int beta,
             continue;
         }
 
+        // Late Move Pruning
+        if (USE_LATE_MOVE_PRUNING
+            && nodeType != PVNODE
+            && played >= 1
+            && !inCheck
+            && isQuiet
+            && depth <= 8
+            && quiets > LateMovePruningCounts[depth]
+            && isNotInCheck(board, board->turn)){
+
+            revertMove(board, currentMove, undo);
+            continue;
+        }
+
         // Update counter of moves actually played
         played += 1;
 
@@ -658,4 +681,11 @@ int moveWasTactical(Undo * undo, uint16_t move){
     return undo->capturePiece != EMPTY
         || MoveType(move) == PROMOTION_MOVE
         || MoveType(move) == ENPASS_MOVE;
+}
+
+int hasNonPawnMaterial(Board * board, int turn){
+    uint64_t friendly = board->colours[turn];
+    uint64_t kings = board->pieces[5];
+    uint64_t pawns = board->pieces[0];
+    return (friendly & (kings | pawns)) != friendly;
 }
diff --git a/src/search.h b/src/search.h
@@ -44,7 +44,11 @@ int moveIsTactical(Board * board, uint16_t move);
 
 int moveWasTactical(Undo * undo, uint16_t move);
 
-static const int LateMovePruningCounts[6] = {0, 6, 11, 15, 20, 25}; 
+int hasNonPawnMaterial(Board * board, int turn);
+
+static const int LateMovePruningCounts[] = {0, 6, 9, 14, 21, 30, 41, 54, 69};
+
+static const int RazorMargins[] = {0, 450, 480, 520, 580};
 
 #define USE_STATIC_NULL_PRUNING             (1)
 #define USE_FUTILITY_PRUNING                (1)
@@ -53,5 +57,6 @@ static const int LateMovePruningCounts[6] = {0, 6, 11, 15, 20, 25};
 #define USE_INTERNAL_ITERATIVE_DEEPENING    (1)
 #define USE_TRANSPOSITION_TABLE             (1)
 #define USE_LATE_MOVE_PRUNING               (1)
+#define USE_RAZORING                        (1)
 
 #endif
diff --git a/src/uci.c b/src/uci.c
@@ -82,7 +82,7 @@ int main(){
            http://wbec-ridderkerk.nl/html/UCIProtocol.html */
 
         if (stringEquals(str, "uci")){
-            printf("id name Ethereal 8.22\n");
+            printf("id name Ethereal 8.23\n");
             printf("id author Andrew Grant\n");
             printf("option name Hash type spin default 16 min 1 max 2048\n");
             printf("uciok\n");