X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=01d2a387e3aefa2592ff476d824063d41e1f81f4;hp=097faf90f7c2fc4d15f5845335c306fa792ae99f;hb=17ffc22279b33ef2015a76461e1e644909d43a10;hpb=41641e3b1eea0038ab6984766d2b3bca869be7fa

diff --git a/src/search.cpp b/src/search.cpp
index 097faf90..01d2a387 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -77,7 +77,7 @@ namespace {
     return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
   }
 
-  size_t PVSize, PVIdx;
+  size_t MultiPV, PVIdx;
   TimeManager TimeMgr;
   double BestMoveChanges;
   Value DrawValue[COLOR_NB];
@@ -127,7 +127,7 @@ void Search::init() {
   // Init reductions array
   for (hd = 1; hd < 64; ++hd) for (mc = 1; mc < 64; ++mc)
   {
-      double    pvRed = log(double(hd)) * log(double(mc)) / 3.0;
+      double    pvRed = 0.00 + log(double(hd)) * log(double(mc)) / 3.00;
       double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
       Reductions[1][1][hd][mc] = (int8_t) (   pvRed >= 1.0 ? floor(   pvRed * int(ONE_PLY)) : 0);
       Reductions[0][1][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
@@ -145,8 +145,8 @@ void Search::init() {
   // Init futility move count array
   for (d = 0; d < 32; ++d)
   {
-      FutilityMoveCounts[0][d] = int(2.4 + 0.222 * pow(d +  0.0, 1.8));
-      FutilityMoveCounts[1][d] = int(3.0 +   0.3 * pow(d + 0.98, 1.8));
+      FutilityMoveCounts[0][d] = int(2.4 + 0.222 * pow(d + 0.00, 1.8));
+      FutilityMoveCounts[1][d] = int(3.0 + 0.300 * pow(d + 0.98, 1.8));
   }
 }
 
@@ -306,21 +306,21 @@ namespace {
     Countermoves.clear();
     Followupmoves.clear();
 
-    PVSize = Options["MultiPV"];
+    MultiPV = Options["MultiPV"];
     Skill skill(Options["Skill Level"]);
 
     // Do we have to play with skill handicap? In this case enable MultiPV search
     // that we will use behind the scenes to retrieve a set of possible moves.
-    if (skill.enabled() && PVSize < 4)
-        PVSize = 4;
+    if (skill.enabled() && MultiPV < 4)
+        MultiPV = 4;
 
-    PVSize = std::min(PVSize, RootMoves.size());
+    MultiPV = std::min(MultiPV, RootMoves.size());
 
     // Iterative deepening loop until requested to stop or target depth reached
     while (++depth <= MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
     {
         // Age out PV variability metric
-        BestMoveChanges *= 0.8;
+        BestMoveChanges *= 0.5;
 
         // Save the last iteration's scores before first PV line is searched and
         // all the move scores except the (new) PV are set to -VALUE_INFINITE.
@@ -328,7 +328,7 @@ namespace {
             RootMoves[i].prevScore = RootMoves[i].score;
 
         // MultiPV loop. We perform a full root search for each PV line
-        for (PVIdx = 0; PVIdx < PVSize && !Signals.stop; ++PVIdx)
+        for (PVIdx = 0; PVIdx < MultiPV && !Signals.stop; ++PVIdx)
         {
             // Reset aspiration window starting size
             if (depth >= 5)
@@ -393,7 +393,7 @@ namespace {
             // Sort the PV lines searched so far and update the GUI
             std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
 
-            if (PVIdx + 1 == PVSize || Time::now() - SearchTime > 3000)
+            if (PVIdx + 1 == MultiPV || Time::now() - SearchTime > 3000)
                 sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
         }
 
@@ -426,14 +426,13 @@ namespace {
             bool stop = false; // Local variable, not the volatile Signals.stop
 
             // Take some extra time if the best move has changed
-            if (depth > 4 && depth < 50 &&  PVSize == 1)
+            if (depth > 4 && depth < 50 &&  MultiPV == 1)
                 TimeMgr.pv_instability(BestMoveChanges);
 
-            // Stop the search if only one legal move is available or most
-            // of the available time has been used. We probably don't have
-            // enough time to search the first move at the next iteration anyway.
+            // Stop the search if only one legal move is available or all
+            // of the available time has been used.
             if (   RootMoves.size() == 1
-                || IterationTime > (TimeMgr.available_time() * 62) / 100)
+                || IterationTime > TimeMgr.available_time() )
                 stop = true;
 
             if (stop)
@@ -464,7 +463,7 @@ namespace {
     const bool SpNode   = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot);
     const bool RootNode = (NT == Root || NT == SplitPointRoot);
 
-    assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
+    assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE);
     assert(PvNode || (alpha == beta - 1));
     assert(depth > DEPTH_ZERO);
 
@@ -513,7 +512,7 @@ namespace {
     {
         // Step 2. Check for aborted search and immediate draw
         if (Signals.stop || pos.is_draw() || ss->ply > MAX_PLY)
-            return DrawValue[pos.side_to_move()];
+            return ss->ply > MAX_PLY && !inCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
 
         // Step 3. Mate distance pruning. Even if we mate at the next move our score
         // would be at best mate_in(ss->ply+1), but if alpha is already bigger because
@@ -640,8 +639,24 @@ namespace {
         (ss+1)->skipNullMove = false;
         pos.undo_null_move();
 
-        if (nullValue >= beta) // Do not return unproven mate scores
-            return nullValue >= VALUE_MATE_IN_MAX_PLY ? beta : nullValue;
+        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 = depth-R < ONE_PLY ? qsearch<NonPV, false>(pos, ss, beta-1, beta, DEPTH_ZERO)
+                                        :  search<NonPV>(pos, ss, beta-1, beta, depth-R, false);
+            ss->skipNullMove = false;
+
+            if (v >= beta)
+                return nullValue;
+        }
     }
 
     // Step 9. ProbCut (skipped when in check)
@@ -676,8 +691,8 @@ namespace {
     }
 
     // Step 10. Internal iterative deepening (skipped when in check)
-    if (   depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
-        && ttMove == MOVE_NONE
+    if (    depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
+        && !ttMove
         && (PvNode || ss->staticEval + Value(256) >= beta))
     {
         Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
@@ -1063,7 +1078,7 @@ moves_loop: // When in check and at SpNode search starts from here
 
     // Check for an instant draw or if the maximum ply has been reached
     if (pos.is_draw() || ss->ply > MAX_PLY)
-        return DrawValue[pos.side_to_move()];
+        return ss->ply > MAX_PLY && !InCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
 
     // 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
@@ -1305,7 +1320,7 @@ moves_loop: // When in check and at SpNode search starts from here
         rk.rand<unsigned>();
 
     // RootMoves are already sorted by score in descending order
-    int variance = std::min(RootMoves[0].score - RootMoves[PVSize - 1].score, PawnValueMg);
+    int variance = std::min(RootMoves[0].score - RootMoves[MultiPV - 1].score, PawnValueMg);
     int weakness = 120 - 2 * level;
     int max_s = -VALUE_INFINITE;
     best = MOVE_NONE;
@@ -1313,7 +1328,7 @@ moves_loop: // When in check and at SpNode search starts from here
     // Choose best move. For each move score we add two terms both dependent on
     // weakness. One deterministic and bigger for weaker moves, and one random,
     // then we choose the move with the resulting highest score.
-    for (size_t i = 0; i < PVSize; ++i)
+    for (size_t i = 0; i < MultiPV; ++i)
     {
         int s = RootMoves[i].score;
 
@@ -1612,9 +1627,8 @@ void check_time() {
   Time::point elapsed = Time::now() - SearchTime;
   bool stillAtFirstMove =    Signals.firstRootMove
                          && !Signals.failedLowAtRoot
-                         && (   elapsed > TimeMgr.available_time()
-                             || (   elapsed > (TimeMgr.available_time() * 62) / 100
-                                 && elapsed > IterationTime * 1.4));
+                         &&  elapsed > TimeMgr.available_time()
+                         &&  elapsed > IterationTime * 1.4;
 
   bool noMoreTime =   elapsed > TimeMgr.maximum_time() - 2 * TimerThread::Resolution
                    || stillAtFirstMove;