Stockfish 10-beta

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index c78a71a96e3c258d6e749b973d878d0a890e0546..ec443bef92d090b9b92176a4b15fccdd0ababd7d 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -2,7 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
-  Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -187,6 +187,7 @@ void Search::clear() {
   Time.availableNodes = 0;
   TT.clear();
   Threads.clear();
+  Tablebases::init(Options["SyzygyPath"]); // Free up mapped files
 }
 
 
@@ -387,7 +388,7 @@ void Thread::search() {
           if (rootDepth >= 5 * ONE_PLY)
           {
               Value previousScore = rootMoves[pvIdx].previousScore;
-              delta = Value(18);
+              delta = Value(20);
               alpha = std::max(previousScore - delta,-VALUE_INFINITE);
               beta  = std::min(previousScore + delta, VALUE_INFINITE);
 
@@ -401,9 +402,11 @@ void Thread::search() {
           // Start with a small aspiration window and, in the case of a fail
           // high/low, re-search with a bigger window until we don't fail
           // high/low anymore.
+          int failedHighCnt = 0;
           while (true)
           {
-              bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false);
+              Depth adjustedDepth = std::max(ONE_PLY, rootDepth - failedHighCnt * ONE_PLY);
+              bestValue = ::search<PV>(rootPos, ss, alpha, beta, adjustedDepth, false);
 
               // Bring the best move to the front. It is critical that sorting
               // is done with a stable algorithm because all the values but the
@@ -436,12 +439,17 @@ void Thread::search() {
 
                   if (mainThread)
                   {
+                      failedHighCnt = 0;
                       failedLow = true;
                       Threads.stopOnPonderhit = false;
                   }
               }
               else if (bestValue >= beta)
+              {
                   beta = std::min(bestValue + delta, VALUE_INFINITE);
+                  if (mainThread)
+                         ++failedHighCnt;
+              }
               else
                   break;
 
@@ -936,6 +944,10 @@ moves_loop: // When in check, search starts from here
                &&  pos.see_ge(move))
           extension = ONE_PLY;
 
+      else if (   pos.can_castle(us) // Extension for king moves that change castling rights
+               && type_of(movedPiece) == KING)
+          extension = ONE_PLY;
+
       // Calculate new depth for this move
       newDepth = depth - ONE_PLY + extension;
 
@@ -1132,8 +1144,6 @@ moves_loop: // When in check, search starts from here
                   break;
               }
           }
-          else if (PvNode && !rootNode && value == alpha)
-              update_pv(ss->pv, move, (ss+1)->pv);
       }
 
       if (move != bestMove)