/// ordering is at the current node.
MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const HistoryStats& h,
- Move* cm, Search::Stack* s) : pos(p), history(h), depth(d) {
+ Move* cm, Move* fm, Search::Stack* s) : pos(p), history(h), depth(d) {
assert(d > DEPTH_ZERO);
cur = end = moves;
endBadCaptures = moves + MAX_MOVES - 1;
countermoves = cm;
+ followupmoves = fm;
ss = s;
if (p.checkers())
killers[0].move = ss->killers[0];
killers[1].move = ss->killers[1];
killers[2].move = killers[3].move = MOVE_NONE;
+ killers[4].move = killers[5].move = MOVE_NONE;
// Be sure countermoves are different from killers
for (int i = 0; i < 2; ++i)
- if (countermoves[i] != cur->move && countermoves[i] != (cur+1)->move)
+ if ( countermoves[i] != (cur+0)->move
+ && countermoves[i] != (cur+1)->move)
(end++)->move = countermoves[i];
if (countermoves[1] && countermoves[1] == countermoves[0]) // Due to SMP races
killers[3].move = MOVE_NONE;
+ // Be sure followupmoves are different from killers and countermoves
+ for (int i = 0; i < 2; ++i)
+ if ( followupmoves[i] != (cur+0)->move
+ && followupmoves[i] != (cur+1)->move
+ && followupmoves[i] != (cur+2)->move
+ && followupmoves[i] != (cur+3)->move)
+ (end++)->move = followupmoves[i];
+
+ if (followupmoves[1] && followupmoves[1] == followupmoves[0]) // Due to SMP races
+ (--end)->move = MOVE_NONE;
+
return;
case QUIETS_1_S1:
&& move != killers[0].move
&& move != killers[1].move
&& move != killers[2].move
- && move != killers[3].move)
+ && move != killers[3].move
+ && move != killers[4].move
+ && move != killers[5].move)
return move;
break;
typedef Stats< true, Value> GainsStats;
typedef Stats<false, Value> HistoryStats;
-typedef Stats<false, std::pair<Move, Move> > CountermovesStats;
+typedef Stats<false, std::pair<Move, Move> > MovesStats;
/// MovePicker class is used to pick one pseudo legal move at a time from the
public:
MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
MovePicker(const Position&, Move, const HistoryStats&, PieceType);
- MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*);
+ MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Move*, Search::Stack*);
template<bool SpNode> Move next_move();
const HistoryStats& history;
Search::Stack* ss;
Move* countermoves;
+ Move* followupmoves;
Depth depth;
Move ttMove;
- ExtMove killers[4];
+ ExtMove killers[6];
Square recaptureSquare;
int captureThreshold, stage;
ExtMove *cur, *end, *endQuiets, *endBadCaptures;
Value DrawValue[COLOR_NB];
HistoryStats History;
GainsStats Gains;
- CountermovesStats Countermoves;
+ MovesStats Countermoves, Followupmoves;
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
History.clear();
Gains.clear();
Countermoves.clear();
+ Followupmoves.clear();
PVSize = Options["MultiPV"];
Skill skill(Options["Skill Level"]);
moveCount = quietCount = 0;
bestValue = -VALUE_INFINITE;
- ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
+ ss->currentMove = ss->ttMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
(ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
excludedMove = ss->excludedMove;
posKey = excludedMove ? pos.exclusion_key() : pos.key();
tte = TT.probe(posKey);
- ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
+ ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
ttValue = tte ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
// At PV nodes we check for exact scores, whilst at non-PV nodes we check for
TT.refresh(tte);
ss->currentMove = ttMove; // Can be MOVE_NONE
- // If ttMove is quiet, update killers, history, and counter move on TT hit
+ // If ttMove is quiet, update killers, history, counter move and followup move on TT hit
if (ttValue >= beta && ttMove && !pos.capture_or_promotion(ttMove) && !inCheck)
update_stats(pos, ss, ttMove, depth, NULL, 0);
Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
- MovePicker mp(pos, ttMove, depth, History, countermoves, ss);
+ Square prevOwnMoveSq = to_sq((ss-2)->currentMove);
+ Move followupmoves[] = { Followupmoves[pos.piece_on(prevOwnMoveSq)][prevOwnMoveSq].first,
+ Followupmoves[pos.piece_on(prevOwnMoveSq)][prevOwnMoveSq].second };
+
+ MovePicker mp(pos, ttMove, depth, History, countermoves, followupmoves, ss);
CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
improving = ss->staticEval >= (ss-2)->staticEval
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
depth, bestMove, ss->staticEval);
- // Quiet best move: update killers, history and countermoves
+ // Quiet best move: update killers, history, countermoves and followupmoves
if (bestValue >= beta && !pos.capture_or_promotion(bestMove) && !inCheck)
update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount - 1);
}
- // update_stats() updates killers, history and countermoves stats after a fail-high
+ // update_stats() updates killers, history, countermoves and followupmoves stats after a fail-high
// of a quiet move.
void update_stats(Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt) {
Square prevMoveSq = to_sq((ss-1)->currentMove);
Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, move);
}
+
+ if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove)
+ {
+ Square prevOwnMoveSq = to_sq((ss-2)->currentMove);
+ Followupmoves.update(pos.piece_on(prevOwnMoveSq), prevOwnMoveSq, move);
+ }
}