X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=756b2d5769fb6f44b854cad829f9e1b1242746ef;hp=5b6a048500b0842c1b59a97f7913532139ae54e0;hb=656aad8b0c10f43eae7744edc1b7171720ac7426;hpb=4e2bb8fa44fe03a2fdb2d3448ac93986354bf9ae

diff --git a/src/search.cpp b/src/search.cpp
index 5b6a0485..756b2d57 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -254,7 +254,7 @@ void MainThread::search() {
       && !Skill(Options["Skill Level"]).enabled()
       &&  rootMoves[0].pv[0] != MOVE_NONE)
   {
-      std::map<Move, int> votes;
+      std::map<Move, int64_t> votes;
       Value minScore = this->rootMoves[0].score;
 
       // Find out minimum score and reset votes for moves which can be voted
@@ -265,12 +265,13 @@ void MainThread::search() {
       }
 
       // Vote according to score and depth
+      auto square = [](int64_t x) { return x * x; };
       for (Thread* th : Threads)
-          votes[th->rootMoves[0].pv[0]] +=  int(th->rootMoves[0].score - minScore)
-                                          + int(th->completedDepth);
+          votes[th->rootMoves[0].pv[0]] += 200 + (square(th->rootMoves[0].score - minScore + 1)
+                                                  * int64_t(th->completedDepth));
 
       // Select best thread
-      int bestVote = votes[this->rootMoves[0].pv[0]];
+      int64_t bestVote = votes[this->rootMoves[0].pv[0]];
       for (Thread* th : Threads)
       {
           if (votes[th->rootMoves[0].pv[0]] > bestVote)
@@ -655,9 +656,11 @@ namespace {
                 if (!pos.capture_or_promotion(ttMove))
                     update_quiet_stats(pos, ss, ttMove, nullptr, 0, stat_bonus(depth));
 
-                // Extra penalty for a quiet TT move in previous ply when it gets refuted
-                if ((ss-1)->moveCount == 1 && !pos.captured_piece())
-                    update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY));
+                // 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] && (ss-1)->killers[0]))
+                    if (!pos.captured_piece())
+                        update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY));
             }
             // Penalty for a quiet ttMove that fails low
             else if (!pos.capture_or_promotion(ttMove))