X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=95f1332ed1ddb6e1ca743e006cdf1039bcd034d8;hp=a08256d740953b00caeb0eca075ade01e33679bb;hb=d48a304262eb6b96864df11734976b4a57fcc72a;hpb=6a6fd0b5f51046d09ee1f2377ef14c6aad611b18

diff --git a/src/search.cpp b/src/search.cpp
index a08256d7..95f1332e 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -51,6 +51,12 @@ using std::string;
 using Eval::evaluate;
 using namespace Search;
 
+// Fast wrapper for common case of pos.gives_check()
+#define FAST_GIVES_CHECK(pos, m, ci) \
+    ((type_of(m) == NORMAL && ci.dcCandidates == 0) \
+       ? (ci.checkSq[type_of(pos.piece_on(from_sq(m)))] & to_sq(m)) \
+	   : pos.gives_check(m, ci))
+
 namespace {
 
   // Set to true to force running with one thread. Used for debugging
@@ -83,7 +89,7 @@ namespace {
   Value DrawValue[COLOR_NB];
   HistoryStats History;
   GainsStats Gains;
-  CountermovesStats Countermoves;
+  MovesStats Countermoves, Followupmoves;
 
   template <NodeType NT>
   Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
@@ -304,6 +310,7 @@ namespace {
     History.clear();
     Gains.clear();
     Countermoves.clear();
+    Followupmoves.clear();
 
     PVSize = Options["MultiPV"];
     Skill skill(Options["Skill Level"]);
@@ -499,7 +506,7 @@ namespace {
 
     moveCount = quietCount = 0;
     bestValue = -VALUE_INFINITE;
-    ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
+    ss->currentMove = ss->ttMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
     ss->ply = (ss-1)->ply + 1;
     (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
     (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
@@ -532,7 +539,7 @@ namespace {
     excludedMove = ss->excludedMove;
     posKey = excludedMove ? pos.exclusion_key() : pos.key();
     tte = TT.probe(posKey);
-    ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
+    ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
     ttValue = tte ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
 
     // At PV nodes we check for exact scores, whilst at non-PV nodes we check for
@@ -550,7 +557,7 @@ namespace {
         TT.refresh(tte);
         ss->currentMove = ttMove; // Can be MOVE_NONE
 
-        // If ttMove is quiet, update killers, history, and counter move on TT hit
+        // If ttMove is quiet, update killers, history, counter move and followup move on TT hit
         if (ttValue >= beta && ttMove && !pos.capture_or_promotion(ttMove) && !inCheck)
             update_stats(pos, ss, ttMove, depth, NULL, 0);
 
@@ -594,16 +601,14 @@ namespace {
     // Step 6. Razoring (skipped when in check)
     if (   !PvNode
         &&  depth < 4 * ONE_PLY
-        &&  eval + razor_margin(depth) < beta
+        &&  eval + razor_margin(depth) <= alpha
         &&  ttMove == MOVE_NONE
         &&  abs(beta) < VALUE_MATE_IN_MAX_PLY
         && !pos.pawn_on_7th(pos.side_to_move()))
     {
-        Value rbeta = beta - razor_margin(depth);
-        Value v = qsearch<NonPV, false>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO);
-        if (v < rbeta)
-            // Logically we should return (v + razor_margin(depth)), but
-            // surprisingly this performed slightly weaker in tests.
+        Value ralpha = alpha - razor_margin(depth);
+        Value v = qsearch<NonPV, false>(pos, ss, ralpha, ralpha+1, DEPTH_ZERO);
+        if (v <= ralpha)
             return v;
     }
 
@@ -627,37 +632,22 @@ namespace {
     {
         ss->currentMove = MOVE_NULL;
 
-        // Null move dynamic reduction based on depth
-        Depth R = 3 * ONE_PLY + depth / 4;
+        assert(eval - beta >= 0);
 
-        // Null move dynamic reduction based on value
-        if (eval - PawnValueMg > beta)
-            R += ONE_PLY;
+        // Null move dynamic reduction based on depth and value
+        Depth R =  3 * ONE_PLY
+                 + depth / 4
+                 + int(eval - beta) / PawnValueMg * ONE_PLY;
 
         pos.do_null_move(st);
         (ss+1)->skipNullMove = true;
-        nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
-                                      : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R, !cutNode);
+        nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -beta+1, DEPTH_ZERO)
+                                      : - search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
         (ss+1)->skipNullMove = false;
         pos.undo_null_move();
 
-        if (nullValue >= beta)
-        {
-            // Do not return unproven mate scores
-            if (nullValue >= VALUE_MATE_IN_MAX_PLY)
-                nullValue = beta;
-
-            if (depth < 12 * ONE_PLY)
-                return nullValue;
-
-            // Do verification search at high depths
-            ss->skipNullMove = true;
-            Value v = search<NonPV>(pos, ss, alpha, beta, depth-R, false);
-            ss->skipNullMove = false;
-
-            if (v >= beta)
-                return nullValue;
-        }
+        if (nullValue >= beta) // Do not return unproven mate scores
+            return nullValue >= VALUE_MATE_IN_MAX_PLY ? beta : nullValue;
     }
 
     // Step 9. ProbCut (skipped when in check)
@@ -712,7 +702,11 @@ moves_loop: // When in check and at SpNode search starts from here
     Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
                             Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
 
-    MovePicker mp(pos, ttMove, depth, History, countermoves, ss);
+    Square prevOwnMoveSq = to_sq((ss-2)->currentMove);
+    Move followupmoves[] = { Followupmoves[pos.piece_on(prevOwnMoveSq)][prevOwnMoveSq].first,
+                             Followupmoves[pos.piece_on(prevOwnMoveSq)][prevOwnMoveSq].second };
+
+    MovePicker mp(pos, ttMove, depth, History, countermoves, followupmoves, ss);
     CheckInfo ci(pos);
     value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
     improving =   ss->staticEval >= (ss-2)->staticEval
@@ -766,7 +760,7 @@ moves_loop: // When in check and at SpNode search starts from here
 
       ext = DEPTH_ZERO;
       captureOrPromotion = pos.capture_or_promotion(move);
-      givesCheck = pos.gives_check(move, ci);
+      givesCheck = FAST_GIVES_CHECK(pos, move, ci);
       dangerous =   givesCheck
                  || type_of(move) != NORMAL
                  || pos.advanced_pawn_push(move);
@@ -1029,7 +1023,7 @@ moves_loop: // When in check and at SpNode search starts from here
              PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
              depth, bestMove, ss->staticEval);
 
-    // Quiet best move: update killers, history and countermoves
+    // Quiet best move: update killers, history, countermoves and followupmoves
     if (bestValue >= beta && !pos.capture_or_promotion(bestMove) && !inCheck)
         update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount - 1);
 
@@ -1146,7 +1140,7 @@ moves_loop: // When in check and at SpNode search starts from here
     {
       assert(is_ok(move));
 
-      givesCheck = pos.gives_check(move, ci);
+      givesCheck = FAST_GIVES_CHECK(pos, move, ci);
 
       // Futility pruning
       if (   !PvNode
@@ -1264,7 +1258,7 @@ moves_loop: // When in check and at SpNode search starts from here
   }
 
 
-  // update_stats() updates killers, history and countermoves stats after a fail-high
+  // update_stats() updates killers, history, countermoves and followupmoves stats after a fail-high
   // of a quiet move.
 
   void update_stats(Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt) {
@@ -1290,6 +1284,12 @@ moves_loop: // When in check and at SpNode search starts from here
         Square prevMoveSq = to_sq((ss-1)->currentMove);
         Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, move);
     }
+
+    if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove)
+    {
+        Square prevOwnMoveSq = to_sq((ss-2)->currentMove);
+        Followupmoves.update(pos.piece_on(prevOwnMoveSq), prevOwnMoveSq, move);
+    }
   }