More bonus for bestMoves on past PV nodes

pb00068 · vondele · commit 71e0b5385e27 · 2020-01-28T16:28:56.000+01:00
It looks like it is important to keep past PV (ttPv) nodes as close as possible to current PV nodes. Credits to Mark Tenzer (31m059) & Stefan Geschwentner who first tried ideas on ttPv nodes. STC: https://tests.stockfishchess.org/tests/view/5e2ff5efab2d69d58394fd52 LLR: 2.95 (-2.94,2.94) {-1.00,3.00} Total: 13302 W: 2647 L: 2507 D: 8148 Ptnml(0-2): 237, 1540, 2956, 1632, 260 LTC: https://tests.stockfishchess.org/tests/view/5e2fff38ab2d69d58394fd55 LLR: 2.95 (-2.94,2.94) {0.00,2.00} Total: 15797 W: 2137 L: 1960 D: 11700 Ptnml(0-2): 96, 1443, 4628, 1547, 130 closes #2529 bench: 5545845
diff --git 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);
             }
@@ -1326,7 +1326,7 @@ namespace {
 
     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)
@@ -1602,7 +1602,7 @@ namespace {
   // 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();
@@ -1612,8 +1612,8 @@ namespace {
     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))
     {
