Document asymmetric SEE pruning trick

[stockfish] / src / position.h

diff --git a/src/position.h b/src/position.h
index 235cc8259ff05f83f3d035777453dacd9c04b325..0951b4669cd28ee61d32771a602d68a484d95de4 100644 (file)
--- a/src/position.h
+++ b/src/position.h
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, 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
@@ -160,6 +160,7 @@ public:
   // Static exchange evaluation
   int see(Move m) const;
   int see_sign(Move m) const;
+  int see_asymm(Move m, int asymmThreshold) const;
 
   // Accessing hash keys
   Key key() const;
@@ -174,12 +175,12 @@ public:
 
   // Other properties of the position
   Color side_to_move() const;
-  int startpos_ply_counter() const;
+  int game_ply() const;
   bool is_chess960() const;
   Thread* this_thread() const;
   int64_t nodes_searched() const;
   void set_nodes_searched(int64_t n);
-  template<bool CheckRepetition, bool CheckThreeFold> bool is_draw() const;
+  template<bool SkipRepetition> bool is_draw() const;
 
   // Position consistency check, for debugging
   bool pos_is_ok(int* failedStep = NULL) const;
@@ -191,8 +192,9 @@ private:
   void put_piece(Piece p, Square s);
   void set_castle_right(Color c, Square rfrom);
 
-  // Helper template functions
-  template<bool Do> void do_castle_move(Move m);
+  // Helper functions
+  void do_castle(Square kfrom, Square kto, Square rfrom, Square rto);
+  template<bool Asymmetric> int do_see(Move m, int asymmThreshold) const;
   template<bool FindPinned> Bitboard hidden_checkers() const;
 
   // Computing hash keys from scratch (for initialization and debugging)
@@ -218,7 +220,7 @@ private:
   Bitboard castlePath[COLOR_NB][CASTLING_SIDE_NB];
   StateInfo startState;
   int64_t nodes;
-  int startPosPly;
+  int gamePly;
   Color sideToMove;
   Thread* thisThread;
   StateInfo* st;
@@ -376,8 +378,8 @@ inline bool Position::is_passed_pawn_push(Move m) const {
         && pawn_is_passed(sideToMove, to_sq(m));
 }
 
-inline int Position::startpos_ply_counter() const {
-  return startPosPly + st->pliesFromNull; // HACK
+inline int Position::game_ply() const {
+  return gamePly;
 }
 
 inline bool Position::opposite_bishops() const {