Remove history counters

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index b86693289c8b2688070e74382a1b64c286528af2..c1f90e119a24d82379eac5521bb950ca2732f4de 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -173,14 +173,14 @@ namespace {
 
   // If the TT move is at least SingleReplyMargin better then the
   // remaining ones we will extend it.
-  const Value SingleReplyMargin = Value(0x64);
+  const Value SingleReplyMargin = Value(0x20);
 
   // Margins for futility pruning in the quiescence search, and at frontier
   // and near frontier nodes.
   const Value FutilityMarginQS = Value(0x80);
 
   // Each move futility margin is decreased
-  const Value IncrementalFutilityMargin = Value(0x4);
+  const Value IncrementalFutilityMargin = Value(0x8);
 
   // Razoring
   const Depth RazorDepth = 4*OnePly;
@@ -288,7 +288,7 @@ namespace {
   bool move_is_killer(Move m, const SearchStack& ss);
   Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
   bool ok_to_do_nullmove(const Position& pos);
-  bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d);
+  bool ok_to_prune(const Position& pos, Move m, Move threat);
   bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
   void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
   void update_killers(Move m, SearchStack& ss);
@@ -402,13 +402,13 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
   Problem = false;
   ExactMaxTime = maxTime;
 
+  if (button_was_pressed("New Game"))
+      loseOnTime = false; // reset at the beginning of a new game
+
   // Read UCI option values
   TT.set_size(get_option_value_int("Hash"));
   if (button_was_pressed("Clear Hash"))
-  {
       TT.clear();
-      loseOnTime = false; // reset at the beginning of a new game
-  }
 
   bool PonderingEnabled = get_option_value_bool("Ponder");
   MultiPV = get_option_value_int("MultiPV");
@@ -677,6 +677,14 @@ namespace {
     // searchMoves are verified, copied, scored and sorted
     RootMoveList rml(p, searchMoves);
 
+    if (rml.move_count() == 0)
+    {
+        if (PonderSearch)
+            wait_for_stop_or_ponderhit();
+
+        return pos.is_check()? -VALUE_MATE : VALUE_DRAW;
+    }
+
     // Print RootMoveList c'tor startup scoring to the standard output,
     // so that we print information also for iteration 1.
     std::cout << "info depth " << 1 << "\ninfo depth " << 1
@@ -1502,26 +1510,23 @@ namespace {
           && !captureOrPromotion
           &&  move != ttMove)
       {
-          // History pruning. See ok_to_prune() definition
+          // Move count based pruning
           if (   moveCount >= FutilityMoveCountMargin
-              && ok_to_prune(pos, move, ss[ply].threatMove, depth)
+              && ok_to_prune(pos, move, ss[ply].threatMove)
               && bestValue > value_mated_in(PLY_MAX))
               continue;
 
           // Value based pruning
-          if (approximateEval < beta)
-          {
-              if (futilityValue == VALUE_NONE)
-                  futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
+          if (futilityValue == VALUE_NONE)
+              futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
 
-              futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
+          futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
 
-              if (futilityValueScaled < beta)
-              {
-                  if (futilityValueScaled > bestValue)
-                      bestValue = futilityValueScaled;
-                  continue;
-              }
+          if (futilityValueScaled < beta)
+          {
+              if (futilityValueScaled > bestValue)
+                  bestValue = futilityValueScaled;
+              continue;
           }
       }
 
@@ -1836,9 +1841,9 @@ namespace {
           && !dangerous
           && !captureOrPromotion)
       {
-          // History pruning. See ok_to_prune() definition
+          // Move count based pruning
           if (   moveCount >= 2 + int(sp->depth)
-              && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth)
+              && ok_to_prune(pos, move, ss[sp->ply].threatMove)
               && sp->bestValue > value_mated_in(PLY_MAX))
               continue;
 
@@ -2459,7 +2464,7 @@ namespace {
   // non-tactical moves late in the move list close to the leaves are
   // candidates for pruning.
 
-  bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d) {
+  bool ok_to_prune(const Position& pos, Move m, Move threat) {
 
     assert(move_is_ok(m));
     assert(threat == MOVE_NONE || move_is_ok(threat));
@@ -2493,11 +2498,7 @@ namespace {
         && pos.move_attacks_square(m, tto))
         return false;
 
-    // Case 4: Don't prune moves with good history
-    if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d))
-        return false;
-
-    // Case 5: If the moving piece in the threatened move is a slider, don't
+    // Case 4: If the moving piece in the threatened move is a slider, don't
     // prune safe moves which block its ray.
     if (  !PruneBlockingMoves
         && threat != MOVE_NONE
@@ -2518,8 +2519,8 @@ namespace {
     Value v = value_from_tt(tte->value(), ply);
 
     return   (   tte->depth() >= depth
-              || v >= Max(value_mate_in(100), beta)
-              || v < Min(value_mated_in(100), beta))
+              || v >= Max(value_mate_in(PLY_MAX), beta)
+              || v < Min(value_mated_in(PLY_MAX), beta))
 
           && (   (is_lower_bound(tte->type()) && v >= beta)
               || (is_upper_bound(tte->type()) && v < beta));
@@ -2538,7 +2539,7 @@ namespace {
     {
         assert(m != movesSearched[i]);
         if (!pos.move_is_capture_or_promotion(movesSearched[i]))
-            H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
+            H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]), depth);
     }
   }