More bonus for bestMoves on past PV nodes

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 035dd40a5c7c17d4b92dd11a2ff35f8d1b709cbb..84f9bb23f0e01925be290646e80f1e1390c15275 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -158,7 +158,7 @@ namespace {
   void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus);
   void update_quiet_stats(const Position& pos, Stack* ss, Move move, int bonus);
   void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq,
-                        Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth);
+                        Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth, bool pastPV);
 
   // perft() is our utility to verify move generation. All the leaf nodes up
   // to the given depth are generated and counted, and the sum is returned.
@@ -713,7 +713,7 @@ namespace {
             if (ttValue >= beta)
             {
                 if (!pos.capture_or_promotion(ttMove))
-                    update_quiet_stats(pos, ss, ttMove, stat_bonus(depth));
+                    update_quiet_stats(pos, ss, ttMove, stat_bonus(depth + (!PvNode && ttPv)));
 
                 // Extra penalty for early quiet moves of the previous ply
                 if ((ss-1)->moveCount <= 2 && !priorCapture)
@@ -722,7 +722,7 @@ namespace {
             // Penalty for a quiet ttMove that fails low
             else if (!pos.capture_or_promotion(ttMove))
             {
-                int penalty = -stat_bonus(depth);
+                int penalty = -stat_bonus(depth + (!PvNode && ttPv));
                 thisThread->mainHistory[us][from_to(ttMove)] << penalty;
                 update_continuation_histories(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
             }
@@ -825,8 +825,8 @@ namespace {
         &&  eval <= alpha - RazorMargin)
         return qsearch<NT>(pos, ss, alpha, beta);
 
-    improving =  (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval >= (ss-4)->staticEval
-              || (ss-4)->staticEval == VALUE_NONE) : ss->staticEval >= (ss-2)->staticEval;
+    improving =  (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval > (ss-4)->staticEval
+              || (ss-4)->staticEval == VALUE_NONE) : ss->staticEval > (ss-2)->staticEval;
 
     // Step 8. Futility pruning: child node (~50 Elo)
     if (   !PvNode
@@ -841,7 +841,7 @@ namespace {
         && (ss-1)->statScore < 23397
         &&  eval >= beta
         &&  eval >= ss->staticEval
-        &&  ss->staticEval >= beta - 32 * depth + 292 - improving * 30
+        &&  ss->staticEval >= beta - 32 * depth - 30 * improving + 120 * ttPv + 292
         && !excludedMove
         &&  pos.non_pawn_material(us)
         && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
@@ -1028,7 +1028,11 @@ moves_loop: // When in check, search starts from here
                   continue;
           }
           else if (!pos.see_ge(move, Value(-194) * depth)) // (~25 Elo)
-                  continue;
+          {
+              if (captureOrPromotion && captureCount < 32)
+                  capturesSearched[captureCount++] = move;
+              continue;
+          }
       }
 
       // Step 14. Extensions (~75 Elo)
@@ -1115,7 +1119,7 @@ moves_loop: // When in check, search starts from here
       // Step 16. Reduced depth search (LMR, ~200 Elo). If the move fails high it will be
       // re-searched at full depth.
       if (    depth >= 3
-          &&  moveCount > 1 + 2 * rootNode
+          &&  moveCount > 1 + rootNode + (rootNode && bestValue < alpha)
           && (!rootNode || thisThread->best_move_count(move) == 0)
           && (  !captureOrPromotion
               || moveCountPruning
@@ -1160,7 +1164,7 @@ moves_loop: // When in check, search starts from here
               // hence break make_move(). (~2 Elo)
               else if (    type_of(move) == NORMAL
                        && !pos.see_ge(reverse_move(move)))
-                  r -= 2;
+                  r -= 2 + ttPv;
 
               ss->statScore =  thisThread->mainHistory[us][from_to(move)]
                              + (*contHist[0])[movedPiece][to_sq(move)]
@@ -1186,6 +1190,10 @@ moves_loop: // When in check, search starts from here
               r -= ss->statScore / 16384;
           }
 
+          // Increase reduction for captures/promotions if late move and at low depth
+          else if (depth < 8 && moveCount > 2)
+              r++;
+
           Depth d = clamp(newDepth - r, 1, newDepth);
 
           value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
@@ -1318,7 +1326,7 @@ moves_loop: // When in check, search starts from here
 
     else if (bestMove)
         update_all_stats(pos, ss, bestMove, bestValue, beta, prevSq,
-                         quietsSearched, quietCount, capturesSearched, captureCount, depth);
+                         quietsSearched, quietCount, capturesSearched, captureCount, depth, (!PvNode && ttPv));
 
     // Bonus for prior countermove that caused the fail low
     else if (   (depth >= 3 || PvNode)
@@ -1594,7 +1602,7 @@ moves_loop: // When in check, search starts from here
   // update_all_stats() updates stats at the end of search() when a bestMove is found
 
   void update_all_stats(const Position& pos, Stack* ss, Move bestMove, Value bestValue, Value beta, Square prevSq,
-                        Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth) {
+                        Move* quietsSearched, int quietCount, Move* capturesSearched, int captureCount, Depth depth, bool pastPV) {
 
     int bonus1, bonus2;
     Color us = pos.side_to_move();
@@ -1604,8 +1612,8 @@ 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 = pastPV || bestValue > beta + PawnValueMg ? bonus1               // larger bonus
+                                                      : stat_bonus(depth);   // smaller bonus
 
     if (!pos.capture_or_promotion(bestMove))
     {