- // EasyMoveManager struct is used to detect a so called 'easy move'; when PV is
- // stable across multiple search iterations we can fast return the best move.
- struct EasyMoveManager {
-
- void clear() {
- stableCnt = 0;
- expectedPosKey = 0;
- pv[0] = pv[1] = pv[2] = MOVE_NONE;
- }
-
- Move get(Key key) const {
- return expectedPosKey == key ? pv[2] : MOVE_NONE;
- }
-
- void update(Position& pos, const std::vector<Move>& newPv) {
-
- assert(newPv.size() >= 3);
-
- // Keep track of how many times in a row 3rd ply remains stable
- stableCnt = (newPv[2] == pv[2]) ? stableCnt + 1 : 0;
-
- if (!std::equal(newPv.begin(), newPv.begin() + 3, pv))
- {
- std::copy(newPv.begin(), newPv.begin() + 3, pv);
-
- StateInfo st[2];
- pos.do_move(newPv[0], st[0], pos.gives_check(newPv[0], CheckInfo(pos)));
- pos.do_move(newPv[1], st[1], pos.gives_check(newPv[1], CheckInfo(pos)));
- expectedPosKey = pos.key();
- pos.undo_move(newPv[1]);
- pos.undo_move(newPv[0]);
- }
- }
-
- int stableCnt;
- Key expectedPosKey;
- Move pv[3];
- };
-
- EasyMoveManager EasyMove;
- double BestMoveChanges;
- Value DrawValue[COLOR_NB];
- CounterMovesHistoryStats CounterMovesHistory;
-