Tweak capture LMR.

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index ba9265ddb38c39a5192bdb84d654e80c88b6c963..c6db82ba18026f36a5121f89e97a4a27e4ed134e 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -815,13 +815,11 @@ namespace {
         tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval);
     }
 
-    // Update static history for previous move
+    // Use static evaluation difference to improve quiet move ordering
     if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture)
     {
-        int bonus = ss->staticEval > -(ss-1)->staticEval + 2 * Tempo ? -stat_bonus(depth) :
-                    ss->staticEval < -(ss-1)->staticEval + 2 * Tempo ? stat_bonus(depth) :
-                    0;
-        thisThread->staticHistory[~us][from_to((ss-1)->currentMove)] << bonus;
+        int bonus = std::clamp(-depth * 4 * int((ss-1)->staticEval + ss->staticEval - 2 * Tempo), -1000, 1000);
+        thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus;
     }
 
     // Step 7. Razoring (~1 Elo)
@@ -985,7 +983,6 @@ moves_loop: // When in check, search starts from here
     Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
 
     MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
-                                      &thisThread->staticHistory,
                                       &thisThread->lowPlyHistory,
                                       &captureHistory,
                                       contHist,
@@ -1175,6 +1172,7 @@ 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)
               || thisThread->ttHitAverage < 432 * TtHitAverageResolution * TtHitAverageWindow / 1024))
       {
           Depth r = reduction(improving, depth, moveCount);
@@ -1192,7 +1190,7 @@ moves_loop: // When in check, search starts from here
               r -= 2;
 
           // Increase reduction at root and non-PV nodes when the best move does not change frequently
-          if ((rootNode || !PvNode) && depth > 10 && thisThread->bestMoveChanges <= 2)
+          if ((rootNode || !PvNode) && thisThread->rootDepth > 10 && thisThread->bestMoveChanges <= 2)
               r++;
 
           // More reductions for late moves if position was not in previous PV
@@ -1536,7 +1534,6 @@ moves_loop: // When in check, search starts from here
     // queen and checking knight promotions, and other checks(only if depth >= DEPTH_QS_CHECKS)
     // will be generated.
     MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
-                                      &thisThread->staticHistory,
                                       &thisThread->captureHistory,
                                       contHist,
                                       to_sq((ss-1)->currentMove));