Combo

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index b34d4ae7c108abfb2040a1dac2eb2da8bff632e1..b5ce0c1899d843d84502c85b9cab32d164761d6d 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -556,7 +556,7 @@ namespace {
     Key posKey;
     Move ttMove, move, excludedMove, bestMove;
     Depth extension, newDepth;
-    Value bestValue, value, ttValue, eval, maxValue;
+    Value bestValue, value, ttValue, eval, maxValue, pureStaticEval;
     bool ttHit, inCheck, givesCheck, improving;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact;
     Piece movedPiece;
@@ -704,15 +704,16 @@ namespace {
     // Step 6. Static evaluation of the position
     if (inCheck)
     {
-        ss->staticEval = eval = VALUE_NONE;
+        ss->staticEval = eval = pureStaticEval = VALUE_NONE;
         improving = false;
         goto moves_loop;  // Skip early pruning when in check
     }
     else if (ttHit)
     {
         // Never assume anything on values stored in TT
-        if ((ss->staticEval = eval = tte->eval()) == VALUE_NONE)
-            eval = ss->staticEval = evaluate(pos);
+        ss->staticEval = eval = pureStaticEval = tte->eval();
+        if (eval == VALUE_NONE)
+            ss->staticEval = eval = pureStaticEval = evaluate(pos);
 
         // Can ttValue be used as a better position evaluation?
         if (    ttValue != VALUE_NONE
@@ -721,12 +722,19 @@ namespace {
     }
     else
     {
-        ss->staticEval = eval =
-        (ss-1)->currentMove != MOVE_NULL ? evaluate(pos)
-                                         : -(ss-1)->staticEval + 2 * Eval::Tempo;
+        if ((ss-1)->currentMove != MOVE_NULL)
+        {
+            int p = (ss-1)->statScore;
+            int bonus = p > 0 ? (-p - 2500) / 512 :
+                        p < 0 ? (-p + 2500) / 512 : 0;
+
+            pureStaticEval = evaluate(pos);
+            ss->staticEval = eval = pureStaticEval + bonus;
+        }
+        else
+            ss->staticEval = eval = pureStaticEval = -(ss-1)->staticEval + 2 * Eval::Tempo;
 
-        tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE,
-                  ss->staticEval);
+        tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, pureStaticEval);
     }
 
     // Step 7. Razoring (~2 Elo)
@@ -749,7 +757,7 @@ namespace {
         && (ss-1)->currentMove != MOVE_NULL
         && (ss-1)->statScore < 23200
         &&  eval >= beta
-        &&  ss->staticEval >= beta - 36 * depth / ONE_PLY + 225
+        &&  pureStaticEval >= beta - 36 * depth / ONE_PLY + 225
         && !excludedMove
         &&  pos.non_pawn_material(us)
         && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
@@ -757,7 +765,7 @@ namespace {
         assert(eval - beta >= 0);
 
         // Null move dynamic reduction based on depth and value
-        Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
+        Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min(int(eval - beta) / 200, 3)) * ONE_PLY;
 
         ss->currentMove = MOVE_NULL;
         ss->continuationHistory = &thisThread->continuationHistory[NO_PIECE][0];
@@ -806,7 +814,7 @@ namespace {
 
         while (  (move = mp.next_move()) != MOVE_NONE
                && probCutCount < 3)
-            if (pos.legal(move))
+            if (move != excludedMove && pos.legal(move))
             {
                 probCutCount++;
 
@@ -897,7 +905,7 @@ moves_loop: // When in check, search starts from here
       // Singular extension search (~60 Elo). If all moves but one fail low on a
       // search of (alpha-s, beta-s), and just one fails high on (alpha, beta),
       // then that move is singular and should be extended. To verify this we do
-      // a reduced search on on all the other moves but the ttMove and if the
+      // a reduced search on all the other moves but the ttMove and if the
       // result is lower than ttValue minus a margin then we will extend the ttMove.
       if (    depth >= 8 * ONE_PLY
           &&  move == ttMove
@@ -1176,7 +1184,7 @@ moves_loop: // When in check, search starts from here
         tte->save(posKey, value_to_tt(bestValue, ss->ply),
                   bestValue >= beta ? BOUND_LOWER :
                   PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
-                  depth, bestMove, ss->staticEval);
+                  depth, bestMove, pureStaticEval);
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);