Adjust penalty on refuted early quiet moves

Vizvezdenec · vondele · commit 9a063fc3cbc8 · 2020-09-04T18:52:46.000+02:00
This patch changes how previous early moves are penalized in case search finds a best move. Here, the first quiet move that was not a transposition table move is penalized. passed STC https://tests.stockfishchess.org/tests/view/5f51d839ba100690c5cc5f69 LLR: 2.94 (-2.94,2.94) {-0.25,1.25} Total: 10088 W: 1150 L: 997 D: 7941 Ptnml(0-2): 41, 772, 3278, 899, 54 passed LTC https://tests.stockfishchess.org/tests/view/5f51e435ba100690c5cc5f76 LLR: 2.93 (-2.94,2.94) {0.25,1.25} Total: 30808 W: 1564 L: 1405 D: 27839 Ptnml(0-2): 19, 1245, 12717, 1404, 19 closes #3106 bench 3983758
diff --git a/src/search.cpp b/src/search.cpp
@@ -597,7 +597,7 @@ namespace {
     Move ttMove, move, excludedMove, bestMove;
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue, probCutBeta;
-    bool ttHit, formerPv, givesCheck, improving, didLMR, priorCapture;
+    bool formerPv, givesCheck, improving, didLMR, priorCapture;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning,
          ttCapture, singularQuietLMR;
     Piece movedPiece;
@@ -664,12 +664,12 @@ namespace {
     // position key in case of an excluded move.
     excludedMove = ss->excludedMove;
     posKey = excludedMove == MOVE_NONE ? pos.key() : pos.key() ^ make_key(excludedMove);
-    tte = TT.probe(posKey, ttHit);
-    ttValue = ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
+    tte = TT.probe(posKey, ss->ttHit);
+    ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
     ttMove =  rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0]
-            : ttHit    ? tte->move() : MOVE_NONE;
+            : ss->ttHit    ? tte->move() : MOVE_NONE;
     if (!excludedMove)
-        ss->ttPv = PvNode || (ttHit && tte->is_pv());
+        ss->ttPv = PvNode || (ss->ttHit && tte->is_pv());
     formerPv = ss->ttPv && !PvNode;
 
     if (   ss->ttPv
@@ -681,11 +681,11 @@ namespace {
 
     // thisThread->ttHitAverage can be used to approximate the running average of ttHit
     thisThread->ttHitAverage =   (TtHitAverageWindow - 1) * thisThread->ttHitAverage / TtHitAverageWindow
-                                + TtHitAverageResolution * ttHit;
+                                + TtHitAverageResolution * ss->ttHit;
 
     // At non-PV nodes we check for an early TT cutoff
     if (  !PvNode
-        && ttHit
+        && ss->ttHit
         && tte->depth() >= depth
         && ttValue != VALUE_NONE // Possible in case of TT access race
         && (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
@@ -778,7 +778,7 @@ namespace {
         improving = false;
         goto moves_loop;
     }
-    else if (ttHit)
+    else if (ss->ttHit)
     {
         // Never assume anything about values stored in TT
         ss->staticEval = eval = tte->eval();
@@ -882,14 +882,14 @@ namespace {
         // there and in further interactions with transposition table cutoff depth is set to depth - 3
         // because probCut search has depth set to depth - 4 but we also do a move before it
         // so effective depth is equal to depth - 3
-        && !(   ttHit
+        && !(   ss->ttHit
              && tte->depth() >= depth - 3
              && ttValue != VALUE_NONE
              && ttValue < probCutBeta))
     {
         // if ttMove is a capture and value from transposition table is good enough produce probCut
         // cutoff without digging into actual probCut search
-        if (   ttHit
+        if (   ss->ttHit
             && tte->depth() >= depth - 3
             && ttValue != VALUE_NONE
             && ttValue >= probCutBeta
@@ -933,7 +933,7 @@ namespace {
                 if (value >= probCutBeta)
                 {
                     // if transposition table doesn't have equal or more deep info write probCut data into it
-                    if ( !(ttHit
+                    if ( !(ss->ttHit
                        && tte->depth() >= depth - 3
                        && ttValue != VALUE_NONE))
                         tte->save(posKey, value_to_tt(value, ss->ply), ttPv,
@@ -1423,7 +1423,7 @@ namespace {
     Move ttMove, move, bestMove;
     Depth ttDepth;
     Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
-    bool ttHit, pvHit, givesCheck, captureOrPromotion;
+    bool pvHit, givesCheck, captureOrPromotion;
     int moveCount;
 
     if (PvNode)
@@ -1453,13 +1453,13 @@ namespace {
                                                   : DEPTH_QS_NO_CHECKS;
     // Transposition table lookup
     posKey = pos.key();
-    tte = TT.probe(posKey, ttHit);
-    ttValue = ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
-    ttMove = ttHit ? tte->move() : MOVE_NONE;
-    pvHit = ttHit && tte->is_pv();
+    tte = TT.probe(posKey, ss->ttHit);
+    ttValue = ss->ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
+    ttMove = ss->ttHit ? tte->move() : MOVE_NONE;
+    pvHit = ss->ttHit && tte->is_pv();
 
     if (  !PvNode
-        && ttHit
+        && ss->ttHit
         && tte->depth() >= ttDepth
         && ttValue != VALUE_NONE // Only in case of TT access race
         && (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
@@ -1474,7 +1474,7 @@ namespace {
     }
     else
     {
-        if (ttHit)
+        if (ss->ttHit)
         {
             // Never assume anything about values stored in TT
             if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE)
@@ -1493,7 +1493,7 @@ namespace {
         // Stand pat. Return immediately if static value is at least beta
         if (bestValue >= beta)
         {
-            if (!ttHit)
+            if (!ss->ttHit)
                 tte->save(posKey, value_to_tt(bestValue, ss->ply), false, BOUND_LOWER,
                           DEPTH_NONE, MOVE_NONE, ss->staticEval);
 
@@ -1711,8 +1711,8 @@ namespace {
     else
         captureHistory[moved_piece][to_sq(bestMove)][captured] << bonus1;
 
-    // Extra penalty for a quiet TT or main killer move in previous ply when it gets refuted
-    if (   ((ss-1)->moveCount == 1 || ((ss-1)->currentMove == (ss-1)->killers[0]))
+    // Extra penalty for a quiet early move that was not a TT move or main killer move in previous ply when it gets refuted
+    if (   ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0]))
         && !pos.captured_piece())
             update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -bonus1);
 
diff --git a/src/search.h b/src/search.h
@@ -49,6 +49,7 @@ struct Stack {
   int moveCount;
   bool inCheck;
   bool ttPv;
+  bool ttHit;
 };
 
 
