Search Parameters Tuning

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index d2a641768fe906c76d73442157598f7841656918..80c3e4c245fe5e5be672fb5587d6275e0ddbdcba 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -81,10 +81,10 @@ namespace {
 
   // History and stats update bonus, based on depth
   int stat_bonus(Depth d) {
-    return d > 14 ? 29 : 8 * d * d + 224 * d - 215;
+    return d > 14 ? 66 : 6 * d * d + 231 * d - 206;
   }
 
-  // Add a small random component to draw evaluations to avoid 3fold-blindness
+  // Add a small random component to draw evaluations to avoid 3-fold blindness
   Value value_draw(Thread* thisThread) {
     return VALUE_DRAW + Value(2 * (thisThread->nodes & 1) - 1);
   }
@@ -839,10 +839,10 @@ namespace {
     // Step 8. Null move search with verification search (~40 Elo)
     if (   !PvNode
         && (ss-1)->currentMove != MOVE_NULL
-        && (ss-1)->statScore < 22977
+        && (ss-1)->statScore < 22661
         &&  eval >= beta
         &&  eval >= ss->staticEval
-        &&  ss->staticEval >= beta - 30 * depth - 28 * improving + 84 * ss->ttPv + 168
+        &&  ss->staticEval >= beta - 24 * depth - 34 * improving + 162 * ss->ttPv + 159
         && !excludedMove
         &&  pos.non_pawn_material(us)
         && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
@@ -850,7 +850,7 @@ namespace {
         assert(eval - beta >= 0);
 
         // Null move dynamic reduction based on depth and value
-        Depth R = (1015 + 85 * depth) / 256 + std::min(int(eval - beta) / 191, 3);
+        Depth R = (1062 + 68 * depth) / 256 + std::min(int(eval - beta) / 190, 3);
 
         ss->currentMove = MOVE_NULL;
         ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
@@ -886,7 +886,7 @@ namespace {
         }
     }
 
-    probCutBeta = beta + 194 - 49 * improving;
+    probCutBeta = beta + 209 - 44 * improving;
 
     // Step 9. ProbCut (~10 Elo)
     // If we have a good enough capture and a reduced search returns a value
@@ -1063,11 +1063,11 @@ moves_loop: // When in check, search starts from here
               // Futility pruning: parent node (~5 Elo)
               if (   lmrDepth < 7
                   && !ss->inCheck
-                  && ss->staticEval + 254 + 159 * lmrDepth <= alpha
+                  && ss->staticEval + 174 + 157 * lmrDepth <= alpha
                   &&  (*contHist[0])[movedPiece][to_sq(move)]
                     + (*contHist[1])[movedPiece][to_sq(move)]
                     + (*contHist[3])[movedPiece][to_sq(move)]
-                    + (*contHist[5])[movedPiece][to_sq(move)] / 2 < 26394)
+                    + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 26237)
                   continue;
 
               // Prune moves with negative SEE (~20 Elo)
@@ -1127,7 +1127,7 @@ moves_loop: // When in check, search starts from here
 
       // Check extension (~2 Elo)
       else if (    givesCheck
-               && (pos.is_discovery_check_on_king(~us, move) || pos.see_ge(move)))
+               && (pos.is_discovered_check_on_king(~us, move) || pos.see_ge(move)))
           extension = 1;
 
       // Last captures extension
@@ -1159,7 +1159,7 @@ moves_loop: // When in check, search starts from here
               || moveCountPruning
               || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha
               || cutNode
-              || (!PvNode && !formerPv && thisThread->captureHistory[movedPiece][to_sq(move)][type_of(pos.captured_piece())] < 4506)
+              || (!PvNode && !formerPv && captureHistory[movedPiece][to_sq(move)][type_of(pos.captured_piece())] < 4506)
               || thisThread->ttHitAverage < 432 * TtHitAverageResolution * TtHitAverageWindow / 1024))
       {
           Depth r = reduction(improving, depth, moveCount);
@@ -1223,17 +1223,23 @@ moves_loop: // When in check, search starts from here
                              + (*contHist[0])[movedPiece][to_sq(move)]
                              + (*contHist[1])[movedPiece][to_sq(move)]
                              + (*contHist[3])[movedPiece][to_sq(move)]
-                             - 5287;
+                             - 5337;
 
               // Decrease/increase reduction by comparing opponent's stat score (~10 Elo)
-              if (ss->statScore >= -105 && (ss-1)->statScore < -103)
+              if (ss->statScore >= -89 && (ss-1)->statScore < -116)
                   r--;
 
-              else if ((ss-1)->statScore >= -122 && ss->statScore < -129)
+              else if ((ss-1)->statScore >= -112 && ss->statScore < -100)
                   r++;
 
               // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
-              r -= ss->statScore / 14884;
+              // If we are not in check use statScore, if we are in check
+              // use sum of main history and first continuation history with an offset
+              if (ss->inCheck)
+                  r -= (thisThread->mainHistory[us][from_to(move)]
+                     + (*contHist[0])[movedPiece][to_sq(move)] - 4341) / 16384;
+              else
+                  r -= ss->statScore / 14382;
           }
 
           Depth d = std::clamp(newDepth - r, 1, newDepth);
@@ -1541,7 +1547,7 @@ moves_loop: // When in check, search starts from here
           &&  futilityBase > -VALUE_KNOWN_WIN
           && !pos.advanced_pawn_push(move))
       {
-          assert(type_of(move) != ENPASSANT); // Due to !pos.advanced_pawn_push
+          assert(type_of(move) != EN_PASSANT); // Due to !pos.advanced_pawn_push
 
           // moveCount pruning
           if (moveCount > 2)
@@ -1705,8 +1711,8 @@ moves_loop: // When in check, search starts from here
     PieceType captured = type_of(pos.piece_on(to_sq(bestMove)));
 
     bonus1 = stat_bonus(depth + 1);
-    bonus2 = bestValue > beta + PawnValueMg ? bonus1               // larger bonus
-                                            : stat_bonus(depth);   // smaller bonus
+    bonus2 = bestValue > beta + PawnValueMg ? bonus1                                 // larger bonus
+                                            : std::min(bonus1, stat_bonus(depth));   // smaller bonus
 
     if (!pos.capture_or_promotion(bestMove))
     {