Use less reduction for escaping moves

[stockfish] / src / thread.cpp

diff --git a/src/thread.cpp b/src/thread.cpp
index c03079d18e3da13522531962e3b87969fd4ddb83..288588b0ee84cd805f0bc4e52868c91e21a81731 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -1,6 +1,6 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
+  Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -59,15 +59,15 @@ void Thread::clear() {
 
   counterMoves.fill(MOVE_NONE);
   mainHistory.fill(0);
-  lowPlyHistory.fill(0);
   captureHistory.fill(0);
+  previousDepth = 0;
 
   for (bool inCheck : { false, true })
       for (StatsType c : { NoCaptures, Captures })
       {
           for (auto& to : continuationHistory[inCheck][c])
                 for (auto& h : to)
-                      h->fill(0);
+                      h->fill(-71);
           continuationHistory[inCheck][c][NO_PIECE][0]->fill(Search::CounterMovePruneThreshold - 1);
       }
 }
@@ -237,7 +237,9 @@ Thread* ThreadPool::get_best_thread() const {
         }
         else if (   th->rootMoves[0].score >= VALUE_TB_WIN_IN_MAX_PLY
                  || (   th->rootMoves[0].score > VALUE_TB_LOSS_IN_MAX_PLY
-                     && votes[th->rootMoves[0].pv[0]] > votes[bestThread->rootMoves[0].pv[0]]))
+                     && (   votes[th->rootMoves[0].pv[0]] > votes[bestThread->rootMoves[0].pv[0]]
+                         || (   votes[th->rootMoves[0].pv[0]] == votes[bestThread->rootMoves[0].pv[0]]
+                             && th->rootMoves[0].pv.size() > bestThread->rootMoves[0].pv.size()))))
             bestThread = th;
     }