Combination of two ideas:

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index cbc5038ab901889e3e875c901f07309481501349..4988dc8e67695fa9251cf23a55211e023d07032d 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -531,7 +531,7 @@ namespace {
     Depth extension, newDepth, predictedDepth;
     Value bestValue, value, ttValue, eval, nullValue, futilityValue;
     bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
-    bool captureOrPromotion, dangerous, doFullDepthSearch;
+    bool captureOrPromotion, doFullDepthSearch;
     int moveCount, quietCount;
 
     // Step 1. Initialize node
@@ -553,7 +553,7 @@ namespace {
         goto moves_loop;
     }
 
-    moveCount = quietCount = 0;
+    moveCount = quietCount =  ss->moveCount = 0;
     bestValue = -VALUE_INFINITE;
     ss->ply = (ss-1)->ply + 1;
 
@@ -674,8 +674,7 @@ namespace {
     if (   !PvNode
         &&  depth < 4 * ONE_PLY
         &&  eval + razor_margin(depth) <= alpha
-        &&  ttMove == MOVE_NONE
-        && !pos.pawn_on_7th(pos.side_to_move()))
+        &&  ttMove == MOVE_NONE)
     {
         if (   depth <= ONE_PLY
             && eval + razor_margin(3 * ONE_PLY) <= alpha)
@@ -750,7 +749,7 @@ namespace {
         assert((ss-1)->currentMove != MOVE_NONE);
         assert((ss-1)->currentMove != MOVE_NULL);
 
-        MovePicker mp(pos, ttMove, History, CounterMovesHistory, pos.captured_piece_type());
+        MovePicker mp(pos, ttMove, History, CounterMovesHistory, PieceValue[MG][pos.captured_piece_type()]);
         CheckInfo ci(pos);
 
         while ((move = mp.next_move<false>()) != MOVE_NONE)
@@ -770,9 +769,9 @@ namespace {
         && !ttMove
         && (PvNode || ss->staticEval + 256 >= beta))
     {
-        Depth d = 2 * (depth - 2 * ONE_PLY) - (PvNode ? DEPTH_ZERO : depth / 2);
+        Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
         ss->skipEarlyPruning = true;
-        search<PvNode ? PV : NonPV, false>(pos, ss, alpha, beta, d / 2, true);
+        search<PvNode ? PV : NonPV, false>(pos, ss, alpha, beta, d, true);
         ss->skipEarlyPruning = false;
 
         tte = TT.probe(posKey, ttHit);
@@ -822,11 +821,11 @@ moves_loop: // When in check and at SpNode search starts from here
           if (!pos.legal(move, ci.pinned))
               continue;
 
-          moveCount = ++splitPoint->moveCount;
+          ss->moveCount = moveCount = ++splitPoint->moveCount;
           splitPoint->spinlock.release();
       }
       else
-          ++moveCount;
+          ss->moveCount = ++moveCount;
 
       if (RootNode)
       {
@@ -848,10 +847,6 @@ moves_loop: // When in check and at SpNode search starts from here
                   ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
                   : pos.gives_check(move, ci);
 
-      dangerous =   givesCheck
-                 || type_of(move) != NORMAL
-                 || pos.advanced_pawn_push(move);
-
       // Step 12. Extend checks
       if (givesCheck && pos.see_sign(move) >= VALUE_ZERO)
           extension = ONE_PLY;
@@ -884,7 +879,8 @@ moves_loop: // When in check and at SpNode search starts from here
       if (   !RootNode
           && !captureOrPromotion
           && !inCheck
-          && !dangerous
+          && !givesCheck
+          && !pos.advanced_pawn_push(move)
           &&  bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           // Move count based pruning
@@ -934,7 +930,7 @@ moves_loop: // When in check and at SpNode search starts from here
       // Check for legality just before making the move
       if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
       {
-          moveCount--;
+          ss->moveCount = --moveCount;
           continue;
       }
 
@@ -959,7 +955,9 @@ moves_loop: // When in check and at SpNode search starts from here
                                         [pos.piece_on(to_sq(move))][to_sq(move)] <= VALUE_ZERO))
               ss->reduction += ONE_PLY;
 
-          if (move == countermove)
+          if (   History[pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO
+              && CounterMovesHistory[pos.piece_on(prevMoveSq)][prevMoveSq]
+                                    [pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO)
               ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY);
 
           // Decrease reduction for moves that escape a capture
@@ -1134,6 +1132,19 @@ moves_loop: // When in check and at SpNode search starts from here
     else if (bestMove && !pos.capture_or_promotion(bestMove))
         update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount);
 
+    // Bonus for prior countermove that caused the fail low
+    else if (!bestMove)
+    {
+        if (is_ok((ss - 2)->currentMove) && is_ok((ss - 1)->currentMove) && !pos.captured_piece_type() && !inCheck && depth>=3*ONE_PLY)
+        {
+            Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY));
+            Square prevSq = to_sq((ss - 1)->currentMove);
+            Square prevPrevSq = to_sq((ss - 2)->currentMove);
+            HistoryStats& flMoveCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
+            flMoveCmh.updateCMH(pos.piece_on(prevSq), prevSq, bonus);
+        }
+    }
+
     tte->save(posKey, value_to_tt(bestValue, ss->ply),
               bestValue >= beta ? BOUND_LOWER :
               PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
@@ -1407,29 +1418,29 @@ moves_loop: // When in check and at SpNode search starts from here
     Square prevSq = to_sq((ss-1)->currentMove);
     HistoryStats& cmh = CounterMovesHistory[pos.piece_on(prevSq)][prevSq];
 
-    History.update(pos.moved_piece(move), to_sq(move), bonus);
+    History.updateH(pos.moved_piece(move), to_sq(move), bonus);
 
     if (is_ok((ss-1)->currentMove))
     {
         Countermoves.update(pos.piece_on(prevSq), prevSq, move);
-        cmh.update(pos.moved_piece(move), to_sq(move), bonus);
+        cmh.updateCMH(pos.moved_piece(move), to_sq(move), bonus);
     }
 
     // Decrease all the other played quiet moves
     for (int i = 0; i < quietsCnt; ++i)
     {
-        History.update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
+        History.updateH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
 
         if (is_ok((ss-1)->currentMove))
-            cmh.update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
+            cmh.updateCMH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
     }
 
-    // Extra penalty for TT move in previous ply when it gets refuted
-    if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove)
+    // Extra penalty for PV move in previous ply when it gets refuted
+    if (is_ok((ss-2)->currentMove) && (ss-1)->moveCount == 1 && !pos.captured_piece_type())
     {
         Square prevPrevSq = to_sq((ss-2)->currentMove);
         HistoryStats& ttMoveCmh = CounterMovesHistory[pos.piece_on(prevPrevSq)][prevPrevSq];
-        ttMoveCmh.update(pos.piece_on(prevSq), prevSq, -bonus - 2 * depth / ONE_PLY - 1);
+        ttMoveCmh.updateCMH(pos.piece_on(prevSq), prevSq, -bonus - 2 * depth / ONE_PLY - 1);
     }
   }
 
@@ -1626,8 +1637,13 @@ void Thread::idle_loop() {
 
           assert(searching);
 
+          spinlock.acquire();
+
           searching = false;
           activePosition = nullptr;
+
+          spinlock.release();
+
           sp->slavesMask.reset(idx);
           sp->allSlavesSearching = false;
           sp->nodes += pos.nodes_searched();