Link with -static in mingw

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index f374b462f8a0169be2a28399cb313975b653af56..e0ba79380c3ecbce68f2431ceeb4952e2383f970 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -90,6 +90,45 @@ namespace {
     Move best = MOVE_NONE;
   };
 
+  struct FastMove {
+    FastMove() { clear(); }
+
+    inline void clear() {
+      expectedPosKey = 0;
+      pv3[0] = pv3[1] = pv3[2] = MOVE_NONE;
+      stableCnt = 0;
+    }
+
+    void update(Position& pos) {
+      // Keep track how many times in a row the PV stays stable 3 ply deep.
+      const std::vector<Move>& RMpv = RootMoves[0].pv;
+      if (RMpv.size() >= 3)
+      {
+          if (pv3[2] == RMpv[2])
+              stableCnt++;
+          else
+              stableCnt = 0, pv3[2] = RMpv[2];
+
+          if (!expectedPosKey || pv3[0] != RMpv[0] || pv3[1] != RMpv[1])
+          {
+              pv3[0] = RMpv[0], pv3[1] = RMpv[1];
+              StateInfo st[2];
+              pos.do_move(RMpv[0], st[0], pos.gives_check(RMpv[0], CheckInfo(pos)));
+              pos.do_move(RMpv[1], st[1], pos.gives_check(RMpv[1], CheckInfo(pos)));
+              expectedPosKey = pos.key();
+              pos.undo_move(RMpv[1]);
+              pos.undo_move(RMpv[0]);
+          }
+      }
+      else
+        clear();
+    }
+
+    Key expectedPosKey;
+    Move pv3[3];
+    int stableCnt;
+  } FM;
+
   size_t PVIdx;
   TimeManager TimeMgr;
   double BestMoveChanges;
@@ -281,6 +320,10 @@ namespace {
     Depth depth;
     Value bestValue, alpha, beta, delta;
 
+    // Init fastMove if the previous search generated a candidate and we now got the predicted position.
+    const Move fastMove = (FM.expectedPosKey == pos.key()) ? FM.pv3[2] : MOVE_NONE;
+    FM.clear();
+
     std::memset(ss-2, 0, 5 * sizeof(Stack));
 
     depth = DEPTH_ZERO;
@@ -405,27 +448,43 @@ namespace {
             Signals.stop = true;
 
         // Do we have time for the next iteration? Can we stop searching now?
-        if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit)
+        if (Limits.use_time_management())
         {
-            // Take some extra time if the best move has changed
-            if (depth > 4 * ONE_PLY && multiPV == 1)
-                TimeMgr.pv_instability(BestMoveChanges);
-
-            // Stop the search if only one legal move is available or all
-            // of the available time has been used.
-            if (   RootMoves.size() == 1
-                || now() - SearchTime > TimeMgr.available_time())
+            if (!Signals.stop && !Signals.stopOnPonderhit)
             {
-                // If we are allowed to ponder do not stop the search now but
-                // keep pondering until the GUI sends "ponderhit" or "stop".
-                if (Limits.ponder)
-                    Signals.stopOnPonderhit = true;
-                else
-                    Signals.stop = true;
+                // Take some extra time if the best move has changed
+                if (depth > 4 * ONE_PLY && multiPV == 1)
+                    TimeMgr.pv_instability(BestMoveChanges);
+
+                // Stop the search if only one legal move is available or all
+                // of the available time has been used or we matched a fastMove
+                // from the previous search and just did a fast verification.
+                if (   RootMoves.size() == 1
+                    || now() - SearchTime > TimeMgr.available_time()
+                    || (   fastMove == RootMoves[0].pv[0]
+                        && BestMoveChanges < 0.03
+                        && 10 * (now() - SearchTime) > TimeMgr.available_time()))
+                {
+                    // If we are allowed to ponder do not stop the search now but
+                    // keep pondering until the GUI sends "ponderhit" or "stop".
+                    if (Limits.ponder)
+                        Signals.stopOnPonderhit = true;
+                    else
+                        Signals.stop = true;
+                }
             }
+
+            // Update fast move stats.
+            FM.update(pos);
         }
     }
 
+    // Clear any candidate fast move that wasn't completely stable for at least
+    // the 6 final search iterations. (Independent of actual depth and thus TC.)
+    // Time condition prevents consecutive fast moves.
+    if (FM.stableCnt < 6 || now() - SearchTime < TimeMgr.available_time())
+        FM.clear();
+
     // If skill level is enabled, swap best PV line with the sub-optimal one
     if (skill.enabled())
         std::swap(RootMoves[0], *std::find(RootMoves.begin(),
@@ -1012,6 +1071,10 @@ moves_loop: // When in check and at SpNode search starts from here
 
           if (value > alpha)
           {
+              // Clear fast move if unstable.
+              if (PvNode && pos.key() == FM.expectedPosKey && (move != FM.pv3[2] || moveCount > 1))
+                  FM.clear();
+
               bestMove = SpNode ? splitPoint->bestMove = move : move;
 
               if (PvNode && !RootNode) // Update pv even in fail-high case
@@ -1633,7 +1696,7 @@ void Thread::idle_loop() {
               if (   sp->allSlavesSearching
                   && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT)
               {
-                  mutex.lock();
+                  allocMutex.lock();
 
                   if (can_join(sp))
                   {
@@ -1642,7 +1705,7 @@ void Thread::idle_loop() {
                       searching = true;
                   }
 
-                  mutex.unlock();
+                  allocMutex.unlock();
               }
 
               sp->mutex.unlock();