Skip quiet moves based on moveCount pruning threshold and history stats

[stockfish] / src / movepick.cpp

diff --git a/src/movepick.cpp b/src/movepick.cpp
index afea0fa4d5d720949d591f7c4b663546aff9722c..2ea859a26fcf2b9ef4dadfe42d03c0806d082679 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.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) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
+  Copyright (C) 2015-2017 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
@@ -142,16 +142,16 @@ void MovePicker::score<QUIETS>() {
 
   const HistoryStats& history = pos.this_thread()->history;
 
-  const CounterMoveStats* cmh = (ss-1)->counterMoves;
-  const CounterMoveStats* fmh = (ss-2)->counterMoves;
-  const CounterMoveStats* fmh2 = (ss-4)->counterMoves;
+  const CounterMoveStats& cmh = *(ss-1)->counterMoves;
+  const CounterMoveStats& fmh = *(ss-2)->counterMoves;
+  const CounterMoveStats& fm2 = *(ss-4)->counterMoves;
 
   Color c = pos.side_to_move();
 
   for (auto& m : *this)
-      m.value =  (cmh  ?  (*cmh)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO)
-               + (fmh  ?  (*fmh)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO)
-               + (fmh2 ? (*fmh2)[pos.moved_piece(m)][to_sq(m)] : VALUE_ZERO)
+      m.value =  cmh[pos.moved_piece(m)][to_sq(m)]
+               + fmh[pos.moved_piece(m)][to_sq(m)]
+               + fm2[pos.moved_piece(m)][to_sq(m)]
                + history.get(c, m);
 }
 
@@ -175,7 +175,7 @@ void MovePicker::score<EVASIONS>() {
 /// left. It picks the move with the biggest value from a list of generated moves
 /// taking care not to return the ttMove if it has already been searched.
 
-Move MovePicker::next_move() {
+Move MovePicker::next_move(bool skipQuiets) {
 
   Move move;
 
@@ -248,9 +248,11 @@ Move MovePicker::next_move() {
       ++stage;
 
   case QUIET:
-      while (cur < endMoves)
+      while (    cur < endMoves
+             && (!skipQuiets || cur->value >= VALUE_ZERO))
       {
           move = *cur++;
+
           if (   move != ttMove
               && move != ss->killers[0]
               && move != ss->killers[1]