Introduce separate counter-move tables for captures

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index c05e72e0bcdc6ea7bc9d3180c7ac6ea5abd345e9..156f6d1c626c216dab9f133ae981069d93591b31 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -334,7 +334,8 @@ void Thread::search() {
 
   std::memset(ss-7, 0, 10 * sizeof(Stack));
   for (int i = 7; i > 0; i--)
-     (ss-i)->continuationHistory = &this->continuationHistory[NO_PIECE][0]; // Use as sentinel
+      (ss-i)->continuationHistory = &this->continuationHistory[0][NO_PIECE][0]; // Use as a sentinel
+
   ss->pv = pv;
 
   bestValue = delta = alpha = -VALUE_INFINITE;
@@ -595,12 +596,13 @@ namespace {
     Value bestValue, value, ttValue, eval, maxValue;
     bool ttHit, ttPv, inCheck, givesCheck, improving, doLMR;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture;
-    Piece movedPiece;
+    Piece movedPiece, priorCapture;
     int moveCount, captureCount, quietCount, singularLMR;
 
     // Step 1. Initialize node
     Thread* thisThread = pos.this_thread();
     inCheck = pos.checkers();
+    priorCapture = pos.captured_piece();
     Color us = pos.side_to_move();
     moveCount = captureCount = quietCount = singularLMR = ss->moveCount = 0;
     bestValue = -VALUE_INFINITE;
@@ -680,7 +682,7 @@ namespace {
                     update_quiet_stats(pos, ss, ttMove, nullptr, 0, stat_bonus(depth));
 
                 // Extra penalty for early quiet moves of the previous ply
-                if ((ss-1)->moveCount <= 2 && !pos.captured_piece())
+                if ((ss-1)->moveCount <= 2 && !priorCapture)
                     update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1));
             }
             // Penalty for a quiet ttMove that fails low
@@ -814,7 +816,7 @@ namespace {
         Depth R = (835 + 70 * depth) / 256 + std::min(int(eval - beta) / 185, 3);
 
         ss->currentMove = MOVE_NULL;
-        ss->continuationHistory = &thisThread->continuationHistory[NO_PIECE][0];
+        ss->continuationHistory = &thisThread->continuationHistory[0][NO_PIECE][0];
 
         pos.do_null_move(st);
 
@@ -865,7 +867,7 @@ namespace {
                 probCutCount++;
 
                 ss->currentMove = move;
-                ss->continuationHistory = &thisThread->continuationHistory[pos.moved_piece(move)][to_sq(move)];
+                ss->continuationHistory = &thisThread->continuationHistory[!!priorCapture][pos.moved_piece(move)][to_sq(move)];
 
                 assert(depth >= 5);
 
@@ -1066,7 +1068,7 @@ moves_loop: // When in check, search starts from here
 
       // Update the current move (this must be done after singular extension search)
       ss->currentMove = move;
-      ss->continuationHistory = &thisThread->continuationHistory[movedPiece][to_sq(move)];
+      ss->continuationHistory = &thisThread->continuationHistory[!!priorCapture][movedPiece][to_sq(move)];
 
       // Step 15. Make the move
       pos.do_move(move, st, givesCheck);
@@ -1279,13 +1281,13 @@ moves_loop: // When in check, search starts from here
 
         // Extra penalty for a quiet TT or main killer move in previous ply when it gets refuted
         if (   ((ss-1)->moveCount == 1 || ((ss-1)->currentMove == (ss-1)->killers[0]))
-            && !pos.captured_piece())
+            && !priorCapture)
                 update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1));
 
     }
     // Bonus for prior countermove that caused the fail low
     else if (   (depth >= 3 || PvNode)
-             && !pos.captured_piece())
+             && !priorCapture)
         update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
 
     if (PvNode)
@@ -1321,6 +1323,7 @@ moves_loop: // When in check, search starts from here
     Move ttMove, move, bestMove;
     Depth ttDepth;
     Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
+    Piece priorCapture;
     bool ttHit, pvHit, inCheck, givesCheck, evasionPrunable;
     int moveCount;
 
@@ -1335,6 +1338,7 @@ moves_loop: // When in check, search starts from here
     (ss+1)->ply = ss->ply + 1;
     bestMove = MOVE_NONE;
     inCheck = pos.checkers();
+    priorCapture = pos.captured_piece();
     moveCount = 0;
 
     // Check for an immediate draw or maximum ply reached
@@ -1472,7 +1476,7 @@ moves_loop: // When in check, search starts from here
       }
 
       ss->currentMove = move;
-      ss->continuationHistory = &thisThread->continuationHistory[pos.moved_piece(move)][to_sq(move)];
+      ss->continuationHistory = &thisThread->continuationHistory[!!priorCapture][pos.moved_piece(move)][to_sq(move)];
 
       // Make and search the move
       pos.do_move(move, st, givesCheck);