X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=7f29f771c0a9eb3e05f8881502182c822e0f1e0f;hp=dae1e23c0339b6daa0b1fff438d4079b25ee21ff;hb=353e20674b2019094059caaa3567e9a44abe9cd1;hpb=0e51ff1074d5a66495a21990bd1826a8d06447e8

diff --git a/src/search.cpp b/src/search.cpp
index dae1e23c..7f29f771 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -61,8 +61,8 @@ namespace {
   // Different node types, used as a template parameter
   enum NodeType { NonPV, PV };
 
-  constexpr uint64_t ttHitAverageWindow     = 4096;
-  constexpr uint64_t ttHitAverageResolution = 1024;
+  constexpr uint64_t TtHitAverageWindow     = 4096;
+  constexpr uint64_t TtHitAverageResolution = 1024;
 
   // Razor and futility margins
   constexpr int RazorMargin = 531;
@@ -378,7 +378,7 @@ void Thread::search() {
       multiPV = std::max(multiPV, (size_t)4);
 
   multiPV = std::min(multiPV, rootMoves.size());
-  ttHitAverage = ttHitAverageWindow * ttHitAverageResolution / 2;
+  ttHitAverage = TtHitAverageWindow * TtHitAverageResolution / 2;
 
   int ct = int(Options["Contempt"]) * PawnValueEg / 100; // From centipawns
 
@@ -626,14 +626,14 @@ namespace {
     Move ttMove, move, excludedMove, bestMove;
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue;
-    bool ttHit, ttPv, formerPv, inCheck, givesCheck, improving, didLMR, priorCapture;
+    bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularLMR;
     Piece movedPiece;
     int moveCount, captureCount, quietCount;
 
     // Step 1. Initialize node
     Thread* thisThread = pos.this_thread();
-    inCheck = pos.checkers();
+    ss->inCheck = pos.checkers();
     priorCapture = pos.captured_piece();
     Color us = pos.side_to_move();
     moveCount = captureCount = quietCount = ss->moveCount = 0;
@@ -654,7 +654,7 @@ namespace {
         if (   Threads.stop.load(std::memory_order_relaxed)
             || pos.is_draw(ss->ply)
             || ss->ply >= MAX_PLY)
-            return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos)
+            return (ss->ply >= MAX_PLY && !ss->inCheck) ? evaluate(pos)
                                                     : value_draw(pos.this_thread());
 
         // Step 3. Mate distance pruning. Even if we mate at the next move our score
@@ -702,8 +702,8 @@ namespace {
         thisThread->lowPlyHistory[ss->ply - 1][from_to((ss-1)->currentMove)] << stat_bonus(depth - 5);
 
     // thisThread->ttHitAverage can be used to approximate the running average of ttHit
-    thisThread->ttHitAverage =   (ttHitAverageWindow - 1) * thisThread->ttHitAverage / ttHitAverageWindow
-                                + ttHitAverageResolution * ttHit;
+    thisThread->ttHitAverage =   (TtHitAverageWindow - 1) * thisThread->ttHitAverage / TtHitAverageWindow
+                                + TtHitAverageResolution * ttHit;
 
     // At non-PV nodes we check for an early TT cutoff
     if (  !PvNode
@@ -793,7 +793,7 @@ namespace {
     CapturePieceToHistory& captureHistory = thisThread->captureHistory;
 
     // Step 6. Static evaluation of the position
-    if (inCheck)
+    if (ss->inCheck)
     {
         ss->staticEval = eval = VALUE_NONE;
         improving = false;
@@ -909,7 +909,6 @@ namespace {
         while (   (move = mp.next_move()) != MOVE_NONE
                && probCutCount < 2 + 2 * cutNode
                && !(   move == ttMove
-                    && (tte->bound() & BOUND_LOWER)
                     && tte->depth() >= depth - 4
                     && ttValue < raisedBeta))
             if (move != excludedMove && pos.legal(move))
@@ -921,7 +920,7 @@ namespace {
                 probCutCount++;
 
                 ss->currentMove = move;
-                ss->continuationHistory = &thisThread->continuationHistory[inCheck]
+                ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
                                                                           [captureOrPromotion]
                                                                           [pos.moved_piece(move)]
                                                                           [to_sq(move)];
@@ -1031,7 +1030,7 @@ moves_loop: // When in check, search starts from here
 
               // Futility pruning: parent node (~5 Elo)
               if (   lmrDepth < 6
-                  && !inCheck
+                  && !ss->inCheck
                   && ss->staticEval + 235 + 172 * lmrDepth <= alpha
                   &&  (*contHist[0])[movedPiece][to_sq(move)]
                     + (*contHist[1])[movedPiece][to_sq(move)]
@@ -1050,6 +1049,13 @@ moves_loop: // When in check, search starts from here
                   && captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] < 0)
                   continue;
 
+              // Futility pruning for captures
+              if (   !givesCheck
+                  && lmrDepth < 6
+                  && !ss->inCheck
+                  && ss->staticEval + 270 + 384 * lmrDepth + PieceValue[MG][type_of(pos.piece_on(to_sq(move)))] <= alpha)
+                  continue;
+
               // See based pruning
               if (!pos.see_ge(move, Value(-194) * depth)) // (~25 Elo)
                   continue;
@@ -1092,6 +1098,18 @@ moves_loop: // When in check, search starts from here
           // a soft bound.
           else if (singularBeta >= beta)
               return singularBeta;
+
+          // If the eval of ttMove is greater than beta we try also if there is an other move that
+          // pushes it over beta, if so also produce a cutoff
+          else if (ttValue >= beta)
+          {
+              ss->excludedMove = move;
+              value = search<NonPV>(pos, ss, beta - 1, beta, (depth + 3) / 2, cutNode);
+              ss->excludedMove = MOVE_NONE;
+
+              if (value >= beta)
+                  return beta;
+          }
       }
 
       // Check extension (~2 Elo)
@@ -1135,7 +1153,7 @@ moves_loop: // When in check, search starts from here
 
       // Update the current move (this must be done after singular extension search)
       ss->currentMove = move;
-      ss->continuationHistory = &thisThread->continuationHistory[inCheck]
+      ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
                                                                 [captureOrPromotion]
                                                                 [movedPiece]
                                                                 [to_sq(move)];
@@ -1152,12 +1170,12 @@ moves_loop: // When in check, search starts from here
               || moveCountPruning
               || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha
               || cutNode
-              || thisThread->ttHitAverage < 375 * ttHitAverageResolution * ttHitAverageWindow / 1024))
+              || thisThread->ttHitAverage < 375 * TtHitAverageResolution * TtHitAverageWindow / 1024))
       {
           Depth r = reduction(improving, depth, moveCount);
 
           // Decrease reduction if the ttHit running average is large
-          if (thisThread->ttHitAverage > 500 * ttHitAverageResolution * ttHitAverageWindow / 1024)
+          if (thisThread->ttHitAverage > 500 * TtHitAverageResolution * TtHitAverageWindow / 1024)
               r--;
 
           // Reduction if other threads are searching this position.
@@ -1354,11 +1372,11 @@ moves_loop: // When in check, search starts from here
     // must be a mate or a stalemate. If we are in a singular extension search then
     // return a fail low score.
 
-    assert(moveCount || !inCheck || excludedMove || !MoveList<LEGAL>(pos).size());
+    assert(moveCount || !ss->inCheck || excludedMove || !MoveList<LEGAL>(pos).size());
 
     if (!moveCount)
         bestValue = excludedMove ? alpha
-                   :     inCheck ? mated_in(ss->ply) : VALUE_DRAW;
+                   :     ss->inCheck ? mated_in(ss->ply) : VALUE_DRAW;
 
     else if (bestMove)
         update_all_stats(pos, ss, bestMove, bestValue, beta, prevSq,
@@ -1402,7 +1420,7 @@ moves_loop: // When in check, search starts from here
     Move ttMove, move, bestMove;
     Depth ttDepth;
     Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
-    bool ttHit, pvHit, inCheck, givesCheck, captureOrPromotion;
+    bool ttHit, pvHit, givesCheck, captureOrPromotion;
     int moveCount;
 
     if (PvNode)
@@ -1415,20 +1433,20 @@ moves_loop: // When in check, search starts from here
     Thread* thisThread = pos.this_thread();
     (ss+1)->ply = ss->ply + 1;
     bestMove = MOVE_NONE;
-    inCheck = pos.checkers();
+    ss->inCheck = pos.checkers();
     moveCount = 0;
 
     // Check for an immediate draw or maximum ply reached
     if (   pos.is_draw(ss->ply)
         || ss->ply >= MAX_PLY)
-        return (ss->ply >= MAX_PLY && !inCheck) ? evaluate(pos) : VALUE_DRAW;
+        return (ss->ply >= MAX_PLY && !ss->inCheck) ? evaluate(pos) : VALUE_DRAW;
 
     assert(0 <= ss->ply && ss->ply < MAX_PLY);
 
     // Decide whether or not to include checks: this fixes also the type of
     // TT entry depth that we are going to use. Note that in qsearch we use
     // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
-    ttDepth = inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
+    ttDepth = ss->inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
                                                   : DEPTH_QS_NO_CHECKS;
     // Transposition table lookup
     posKey = pos.key();
@@ -1446,7 +1464,7 @@ moves_loop: // When in check, search starts from here
         return ttValue;
 
     // Evaluate the position statically
-    if (inCheck)
+    if (ss->inCheck)
     {
         ss->staticEval = VALUE_NONE;
         bestValue = futilityBase = -VALUE_INFINITE;
@@ -1509,7 +1527,7 @@ moves_loop: // When in check, search starts from here
       moveCount++;
 
       // Futility pruning
-      if (   !inCheck
+      if (   !ss->inCheck
           && !givesCheck
           &&  futilityBase > -VALUE_KNOWN_WIN
           && !pos.advanced_pawn_push(move))
@@ -1532,7 +1550,7 @@ moves_loop: // When in check, search starts from here
       }
 
       // Don't search moves with negative SEE values
-      if (  !inCheck && !pos.see_ge(move))
+      if (  !ss->inCheck && !pos.see_ge(move))
           continue;
 
       // Speculative prefetch as early as possible
@@ -1546,7 +1564,7 @@ moves_loop: // When in check, search starts from here
       }
 
       ss->currentMove = move;
-      ss->continuationHistory = &thisThread->continuationHistory[inCheck]
+      ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
                                                                 [captureOrPromotion]
                                                                 [pos.moved_piece(move)]
                                                                 [to_sq(move)];
@@ -1580,7 +1598,7 @@ moves_loop: // When in check, search starts from here
 
     // All legal moves have been searched. A special case: If we're in check
     // and no legal moves were found, it is checkmate.
-    if (inCheck && bestValue == -VALUE_INFINITE)
+    if (ss->inCheck && bestValue == -VALUE_INFINITE)
         return mated_in(ss->ply); // Plies to mate from the root
 
     tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit,
@@ -1699,8 +1717,12 @@ moves_loop: // When in check, search starts from here
   void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) {
 
     for (int i : {1, 2, 4, 6})
+    {
+        if (ss->inCheck && i > 2)
+            break;
         if (is_ok((ss-i)->currentMove))
             (*(ss-i)->continuationHistory)[pc][to] << bonus;
+    }
   }