Assign negative stat bonuses for quiet moves at Pv nodes

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 3136046d2f52f6e82ec9cc70ced94eb70b73edb1..aa1a3e8c17fec2a39407c3753e95338e9cd5d443 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -72,7 +72,7 @@ namespace {
 
   Depth reduction(bool i, Depth d, int mn, Value delta, Value rootDelta) {
     int r = Reductions[d] * Reductions[mn];
-    return (r + 1449 - int(delta) * 1032 / int(rootDelta)) / 1024 + (!i && r > 941);
+    return (r + 1449 - int(delta) * 1001 / int(rootDelta)) / 1024 + (!i && r > 941);
   }
 
   constexpr int futility_move_count(bool improving, Depth depth) {
@@ -82,7 +82,7 @@ namespace {
 
   // History and stats update bonus, based on depth
   int stat_bonus(Depth d) {
-    return std::min(340 * d - 470, 1855);
+    return std::min(341 * d - 470, 1855);
   }
 
   // Add a small random component to draw evaluations to avoid 3-fold blindness
@@ -290,15 +290,13 @@ void Thread::search() {
 
   bestValue = delta = alpha = -VALUE_INFINITE;
   beta = VALUE_INFINITE;
+  optimism[WHITE] = optimism[BLACK] = VALUE_ZERO;
 
   if (mainThread)
   {
 
       int rootComplexity;
-      if (Eval::useNNUE)
-          Eval::NNUE::evaluate(rootPos, true, &rootComplexity);
-      else
-          Eval::evaluate(rootPos, &rootComplexity);
+      Eval::evaluate(rootPos, &rootComplexity);
 
       mainThread->complexity = std::min(1.03 + (rootComplexity - 241) / 1552.0, 1.45);
 
@@ -320,8 +318,6 @@ void Thread::search() {
 
   multiPV = std::min(multiPV, rootMoves.size());
 
-  optimism[us] = optimism[~us] = VALUE_ZERO;
-
   int searchAgainCounter = 0;
 
   // Iterative deepening loop until requested to stop or the target depth is reached
@@ -899,11 +895,11 @@ namespace {
         Eval::NNUE::hint_common_parent_position(pos);
     }
 
-    // Step 11. If the position is not in TT, decrease depth by 3.
+    // Step 11. If the position is not in TT, decrease depth by 2 (or by 4 if the TT entry for the current position was hit and the stored depth is greater than or equal to the current depth).
     // Use qsearch if depth is equal or below zero (~9 Elo)
     if (    PvNode
         && !ttMove)
-        depth -= 3;
+        depth -= 2 + 2 * (ss->ttHit &&  tte->depth() >= depth);
 
     if (depth <= 0)
         return qsearch<PV>(pos, ss, alpha, beta);
@@ -1061,7 +1057,7 @@ moves_loop: // When in check, search starts here
               lmrDepth = std::max(lmrDepth, 0);
 
               // Prune moves with negative SEE (~4 Elo)
-              if (!pos.see_ge(move, Value(-24 * lmrDepth * lmrDepth - 15 * lmrDepth)))
+              if (!pos.see_ge(move, Value(-24 * lmrDepth * lmrDepth - 16 * lmrDepth)))
                   continue;
           }
       }
@@ -1197,10 +1193,10 @@ moves_loop: // When in check, search starts here
                      + (*contHist[0])[movedPiece][to_sq(move)]
                      + (*contHist[1])[movedPiece][to_sq(move)]
                      + (*contHist[3])[movedPiece][to_sq(move)]
-                     - 4182;
+                     - 4082;
 
       // Decrease/increase reduction for moves with a good/bad history (~25 Elo)
-      r -= ss->statScore / (11791 + 3992 * (depth > 6 && depth < 19));
+      r -= ss->statScore / (11079 + 4626 * (depth > 6 && depth < 19));
 
       // Step 17. Late moves reduction / extension (LMR, ~117 Elo)
       // We use various heuristics for the sons of a node after the first son has
@@ -1261,6 +1257,9 @@ moves_loop: // When in check, search starts here
           (ss+1)->pv[0] = MOVE_NONE;
 
           value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, false);
+
+          if (moveCount > 1 && newDepth >= depth && !capture)
+              update_continuation_histories(ss, movedPiece, to_sq(move), -stat_bonus(newDepth));
       }
 
       // Step 19. Undo move