X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=2c9240146b32b46791efcb755a46f3236a83f18c;hp=cb16798dc427fcc30162a9f346c0402aac680a95;hb=8b15961349e18a9ba113973c53f53913d0cd0fad;hpb=a6d6a2c2fad093a47b575ee4cfb8d346ba037fb3

diff --git a/src/search.cpp b/src/search.cpp
index cb16798d..2c924014 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -68,21 +68,25 @@ namespace {
   const int skipPhase[] = { 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7 };
 
   // Razoring and futility margin based on depth
-  const int razor_margin[4] = { 483, 570, 603, 554 };
+  // razor_margin[0] is unused as long as depth >= ONE_PLY in search
+  const int razor_margin[] = { 0, 570, 603, 554 };
   Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); }
 
   // Futility and reductions lookup tables, initialized at startup
   int FutilityMoveCounts[2][16]; // [improving][depth]
   int Reductions[2][2][64][64];  // [pv][improving][depth][moveNumber]
 
+  // Threshold used for countermoves based pruning
+  const int CounterMovePruneThreshold = 0;
+
   template <bool PvNode> Depth reduction(bool i, Depth d, int mn) {
     return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY;
   }
 
   // History and stats update bonus, based on depth
-  Value stat_bonus(Depth depth) {
+  int stat_bonus(Depth depth) {
     int d = depth / ONE_PLY ;
-    return Value(d * d + 2 * d - 2);
+    return d > 17 ? 0 : d * d + 2 * d - 2;
   }
 
   // Skill structure is used to implement strength limit
@@ -97,8 +101,8 @@ namespace {
     Move best = MOVE_NONE;
   };
 
-  // EasyMoveManager structure is used to detect an 'easy move'. When the PV is
-  // stable across multiple search iterations, we can quickly return the best move.
+  // EasyMoveManager structure is used to detect an 'easy move'. When the PV is stable
+  // across multiple search iterations, we can quickly return the best move.
   struct EasyMoveManager {
 
     void clear() {
@@ -148,8 +152,8 @@ namespace {
   Value value_to_tt(Value v, int ply);
   Value value_from_tt(Value v, int ply);
   void update_pv(Move* pv, Move move, Move* childPv);
-  void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus);
-  void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, Value bonus);
+  void update_cm_stats(Stack* ss, Piece pc, Square s, int bonus);
+  void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, int bonus);
   void check_time();
 
 } // namespace
@@ -163,7 +167,7 @@ void Search::init() {
       for (int d = 1; d < 64; ++d)
           for (int mc = 1; mc < 64; ++mc)
           {
-              double r = log(d) * log(mc) / 2;
+              double r = log(d) * log(mc) / 1.95;
 
               Reductions[NonPV][imp][d][mc] = int(std::round(r));
               Reductions[PV][imp][d][mc] = std::max(Reductions[NonPV][imp][d][mc] - 1, 0);
@@ -175,8 +179,8 @@ void Search::init() {
 
   for (int d = 0; d < 16; ++d)
   {
-      FutilityMoveCounts[0][d] = int(2.4 + 0.773 * pow(d + 0.00, 1.8));
-      FutilityMoveCounts[1][d] = int(2.9 + 1.045 * pow(d + 0.49, 1.8));
+      FutilityMoveCounts[0][d] = int(2.4 + 0.74 * pow(d, 1.78));
+      FutilityMoveCounts[1][d] = int(5.0 + 1.00 * pow(d, 2.00));
   }
 }
 
@@ -193,6 +197,9 @@ void Search::clear() {
       th->history.clear();
       th->counterMoveHistory.clear();
       th->resetCalls = true;
+      CounterMoveStats& cm = th->counterMoveHistory[NO_PIECE][0];
+      int* t = &cm[NO_PIECE][0];
+      std::fill(t, t + sizeof(cm), CounterMovePruneThreshold - 1);
   }
 
   Threads.main()->previousScore = VALUE_INFINITE;
@@ -542,7 +549,7 @@ namespace {
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval;
     bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
-    bool captureOrPromotion, doFullDepthSearch, moveCountPruning;
+    bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets;
     Piece moved_piece;
     int moveCount, quietCount;
 
@@ -550,7 +557,7 @@ namespace {
     Thread* thisThread = pos.this_thread();
     inCheck = pos.checkers();
     moveCount = quietCount =  ss->moveCount = 0;
-    ss->history = VALUE_ZERO;
+    ss->history = 0;
     bestValue = -VALUE_INFINITE;
     ss->ply = (ss-1)->ply + 1;
 
@@ -558,9 +565,10 @@ namespace {
     if (thisThread->resetCalls.load(std::memory_order_relaxed))
     {
         thisThread->resetCalls = false;
+
         // At low node count increase the checking rate to about 0.1% of nodes
         // otherwise use a default value.
-        thisThread->callsCnt = Limits.nodes ? std::min((int64_t)4096, Limits.nodes / 1024)
+        thisThread->callsCnt = Limits.nodes ? std::min(4096, int(Limits.nodes / 1024))
                                             : 4096;
     }
 
@@ -635,7 +643,7 @@ namespace {
             // Penalty for a quiet ttMove that fails low
             else if (!pos.capture_or_promotion(ttMove))
             {
-                Value penalty = -stat_bonus(depth + ONE_PLY);
+                int penalty = -stat_bonus(depth);
                 thisThread->history.update(pos.side_to_move(), ttMove, penalty);
                 update_cm_stats(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
             }
@@ -812,9 +820,6 @@ moves_loop: // When in check search starts from here
     const CounterMoveStats& cmh = *(ss-1)->counterMoves;
     const CounterMoveStats& fmh = *(ss-2)->counterMoves;
     const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
-    const bool cm_ok = is_ok((ss-1)->currentMove);
-    const bool fm_ok = is_ok((ss-2)->currentMove);
-    const bool f2_ok = is_ok((ss-4)->currentMove);
 
     MovePicker mp(pos, ttMove, depth, ss);
     value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
@@ -829,10 +834,11 @@ moves_loop: // When in check search starts from here
                            && !excludedMove // Recursive singular search is not allowed
                            && (tte->bound() & BOUND_LOWER)
                            &&  tte->depth() >= depth - 3 * ONE_PLY;
+    skipQuiets = false;
 
     // Step 11. Loop through moves
     // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
-    while ((move = mp.next_move()) != MOVE_NONE)
+    while ((move = mp.next_move(skipQuiets)) != MOVE_NONE)
     {
       assert(is_ok(move));
 
@@ -867,21 +873,15 @@ moves_loop: // When in check search starts from here
       moveCountPruning =   depth < 16 * ONE_PLY
                         && moveCount >= FutilityMoveCounts[improving][depth / ONE_PLY];
 
-      // Step 12. Extensions
-      // Extend checks
-      if (    givesCheck
-          && !moveCountPruning
-          &&  pos.see_ge(move, VALUE_ZERO))
-          extension = ONE_PLY;
+      // Step 12. Singular and Gives Check Extensions
 
       // Singular extension search. 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 all the other moves but the ttMove and if the result is lower than
-      // ttValue minus a margin then we extend the ttMove.
+      // ttValue minus a margin then we will extend the ttMove.
       if (    singularExtensionNode
           &&  move == ttMove
-          && !extension
           &&  pos.legal(move))
       {
           Value rBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE);
@@ -893,30 +893,37 @@ moves_loop: // When in check search starts from here
           if (value < rBeta)
               extension = ONE_PLY;
       }
+      else if (    givesCheck
+               && !moveCountPruning
+               &&  pos.see_ge(move, VALUE_ZERO))
+          extension = ONE_PLY;
 
       // Calculate new depth for this move
       newDepth = depth - ONE_PLY + extension;
 
       // Step 13. Pruning at shallow depth
       if (  !rootNode
+          && pos.non_pawn_material(pos.side_to_move())
           && bestValue > VALUE_MATED_IN_MAX_PLY)
       {
           if (   !captureOrPromotion
               && !givesCheck
-              && (!pos.advanced_pawn_push(move) || pos.non_pawn_material() >= 5000))
+              && (!pos.advanced_pawn_push(move) || pos.non_pawn_material() >= Value(5000)))
           {
               // Move count based pruning
               if (moveCountPruning)
+              {
+                  skipQuiets = true;
                   continue;
+              }
 
               // Reduced depth of the next LMR search
               int lmrDepth = std::max(newDepth - reduction<PvNode>(improving, depth, moveCount), DEPTH_ZERO) / ONE_PLY;
 
               // Countermoves based pruning
               if (   lmrDepth < 3
-                  && ((cmh[moved_piece][to_sq(move)] < VALUE_ZERO) || !cm_ok)
-                  && ((fmh[moved_piece][to_sq(move)] < VALUE_ZERO) || !fm_ok)
-                  && ((fm2[moved_piece][to_sq(move)] < VALUE_ZERO) || !f2_ok || (cm_ok && fm_ok)))
+                  && (cmh[moved_piece][to_sq(move)] < CounterMovePruneThreshold)
+                  && (fmh[moved_piece][to_sq(move)] < CounterMovePruneThreshold))
                   continue;
 
               // Futility pruning: parent node
@@ -983,10 +990,10 @@ moves_loop: // When in check search starts from here
                            - 4000; // Correction factor
 
               // Decrease/increase reduction by comparing opponent's stat score
-              if (ss->history > VALUE_ZERO && (ss-1)->history < VALUE_ZERO)
+              if (ss->history > 0 && (ss-1)->history < 0)
                   r -= ONE_PLY;
 
-              else if (ss->history < VALUE_ZERO && (ss-1)->history > VALUE_ZERO)
+              else if (ss->history < 0 && (ss-1)->history > 0)
                   r += ONE_PLY;
 
               // Decrease/increase reduction for moves with a good/bad history
@@ -1121,13 +1128,14 @@ moves_loop: // When in check search starts from here
     // Bonus for prior countermove that caused the fail low
     else if (    depth >= 3 * ONE_PLY
              && !pos.captured_piece()
-             && cm_ok)
+             && is_ok((ss-1)->currentMove))
         update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
 
-    tte->save(posKey, value_to_tt(bestValue, ss->ply),
-              bestValue >= beta ? BOUND_LOWER :
-              PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
-              depth, bestMove, ss->staticEval, TT.generation());
+    if (!excludedMove)
+        tte->save(posKey, value_to_tt(bestValue, ss->ply),
+                  bestValue >= beta ? BOUND_LOWER :
+                  PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
+                  depth, bestMove, ss->staticEval, TT.generation());
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
@@ -1275,6 +1283,7 @@ moves_loop: // When in check search starts from here
 
       // Detect non-capture evasions that are candidates to be pruned
       evasionPrunable =    InCheck
+                       &&  depth != DEPTH_ZERO
                        &&  bestValue > VALUE_MATED_IN_MAX_PLY
                        && !pos.capture(move);
 
@@ -1379,7 +1388,7 @@ moves_loop: // When in check search starts from here
 
   // update_cm_stats() updates countermove and follow-up move history
 
-  void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus) {
+  void update_cm_stats(Stack* ss, Piece pc, Square s, int bonus) {
 
     for (int i : {1, 2, 4})
         if (is_ok((ss-i)->currentMove))
@@ -1390,7 +1399,7 @@ moves_loop: // When in check search starts from here
   // update_stats() updates move sorting heuristics when a new quiet best move is found
 
   void update_stats(const Position& pos, Stack* ss, Move move,
-                    Move* quiets, int quietsCnt, Value bonus) {
+                    Move* quiets, int quietsCnt, int bonus) {
 
     if (ss->killers[0] != move)
     {
@@ -1496,7 +1505,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) {
 
   for (size_t i = 0; i < multiPV; ++i)
   {
-      bool updated = (i <= PVIdx);
+      bool updated = (i <= PVIdx && rootMoves[i].score != -VALUE_INFINITE);
 
       if (depth == ONE_PLY && !updated)
           continue;