/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 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
Position RootPosition;
}
+using std::string;
using std::cout;
using std::endl;
-using std::string;
using namespace Search;
namespace {
RootMove(){}
RootMove(Move m) {
- nodes = 0;
score = prevScore = -VALUE_INFINITE;
pv.push_back(m);
pv.push_back(MOVE_NONE);
void extract_pv_from_tt(Position& pos);
void insert_pv_in_tt(Position& pos);
- int64_t nodes;
Value score;
Value prevScore;
std::vector<Move> pv;
// better than the second best move.
const Value EasyMoveMargin = Value(0x150);
+ // This is the minimum interval in msec between two check_time() calls
+ const int TimerResolution = 5;
+
/// Namespace variables
std::vector<RootMove> RootMoves;
- size_t MultiPV, UCIMultiPV, MultiPVIdx;
+ size_t MultiPV, UCIMultiPV, PVIdx;
TimeManager TimeMgr;
int BestMoveChanges;
int SkillLevel;
- bool SkillLevelEnabled;
+ bool SkillLevelEnabled, Chess960;
History H;
/// Local functions
- Move id_loop(Position& pos, Move* ponderMove);
-
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
template <NodeType NT>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
+ void id_loop(Position& pos);
bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue);
bool connected_moves(const Position& pos, Move m1, Move m2);
Value value_to_tt(Value v, int ply);
bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply);
bool connected_threat(const Position& pos, Move m, Move threat);
Value refine_eval(const TTEntry* tte, Value defaultEval, int ply);
- void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount);
- void do_skill_level(Move* best, Move* ponder);
+ Move do_skill_level();
int elapsed_time(bool reset = false);
string score_to_uci(Value v, Value alpha = -VALUE_INFINITE, Value beta = VALUE_INFINITE);
- string speed_to_uci(int64_t nodes);
- string pv_to_uci(const Move pv[], int pvNum, bool chess960);
- string pretty_pv(Position& pos, int depth, Value score, int time, Move pv[]);
- string depth_to_uci(Depth depth);
+ void pv_info_to_log(Position& pos, int depth, Value score, int time, Move pv[]);
+ void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta);
// MovePickerExt class template extends MovePicker and allows to choose at
// compile time the proper moves source according to the type of node. In the
MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, Stack* ss, Value b)
: MovePicker(p, ttm, d, h, ss, b), mp(ss->sp->mp) {}
- Move get_next_move() { return mp->get_next_move(); }
+ Move next_move() { return mp->next_move(); }
MovePicker* mp;
};
- // Overload operator<<() to make it easier to print moves in a coordinate
- // notation compatible with UCI protocol.
- std::ostream& operator<<(std::ostream& os, Move m) {
-
- bool chess960 = (os.iword(0) != 0); // See set960()
- return os << move_to_uci(m, chess960);
- }
-
- // When formatting a move for std::cout we must know if we are in Chess960 or
- // not. To keep using the handy operator<<() on the move the trick is to embed
- // this flag in the stream itself. Function-like named enum set960 is used as
- // a custom manipulator and the stream internal general-purpose array, accessed
- // through ios_base::iword(), is used to pass the flag to the move's operator<<
- // that will read it to properly format castling moves.
- enum set960 {};
-
- std::ostream& operator<<(std::ostream& os, const set960& f) {
-
- os.iword(0) = f;
- return os;
- }
-
// is_dangerous() checks whether a move belongs to some classes of known
// 'dangerous' moves so that we avoid to prune it.
FORCE_INLINE bool is_dangerous(const Position& pos, Move m, bool captureOrPromotion) {
// Test for a pawn pushed to 7th or a passed pawn move
- if (type_of(pos.piece_on(move_from(m))) == PAWN)
+ if (type_of(pos.piece_moved(m)) == PAWN)
{
Color c = pos.side_to_move();
- if ( relative_rank(c, move_to(m)) == RANK_7
- || pos.pawn_is_passed(c, move_to(m)))
+ if ( relative_rank(c, to_sq(m)) == RANK_7
+ || pos.pawn_is_passed(c, to_sq(m)))
return true;
}
// Test for a capture that triggers a pawn endgame
if ( captureOrPromotion
- && type_of(pos.piece_on(move_to(m))) != PAWN
+ && type_of(pos.piece_on(to_sq(m))) != PAWN
&& ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- - PieceValueMidgame[pos.piece_on(move_to(m))] == VALUE_ZERO)
+ - PieceValueMidgame[pos.piece_on(to_sq(m))] == VALUE_ZERO)
&& !is_special(m))
return true;
} // namespace
-/// init_search() is called during startup to initialize various lookup tables
+/// Search::init() is called during startup to initialize various lookup tables
void Search::init() {
}
-/// perft() is our utility to verify move generation. All the leaf nodes up to
-/// the given depth are generated and counted and the sum returned.
+/// Search::perft() is our utility to verify move generation. All the leaf nodes
+/// up to the given depth are generated and counted and the sum returned.
int64_t Search::perft(Position& pos, Depth depth) {
StateInfo st;
- int64_t sum = 0;
+ int64_t cnt = 0;
MoveList<MV_LEGAL> ml(pos);
// At the last ply just return the number of moves (leaf nodes)
- if (depth <= ONE_PLY)
+ if (depth == ONE_PLY)
return ml.size();
CheckInfo ci(pos);
for ( ; !ml.end(); ++ml)
{
pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci));
- sum += perft(pos, depth - ONE_PLY);
+ cnt += perft(pos, depth - ONE_PLY);
pos.undo_move(ml.move());
}
- return sum;
+ return cnt;
}
-/// think() is the external interface to Stockfish's search, and is called by the
-/// main thread when the program receives the UCI 'go' command. It searches from
-/// RootPosition and at the end prints the "bestmove" to output.
+/// Search::think() is the external interface to Stockfish's search, and is
+/// called by the main thread when the program receives the UCI 'go' command. It
+/// searches from RootPosition and at the end prints the "bestmove" to output.
void Search::think() {
static Book book; // Defined static to initialize the PRNG only once
Position& pos = RootPosition;
+ Chess960 = pos.is_chess960();
elapsed_time(true);
TimeMgr.init(Limits, pos.startpos_ply_counter());
+ TT.new_search();
+ H.clear();
+ RootMoves.clear();
- // Set output stream mode: normal or chess960. Castling notation is different
- cout << set960(pos.is_chess960());
+ // Populate RootMoves with all the legal moves (default) or, if a SearchMoves
+ // is given, with the subset of legal moves to search.
+ for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
+ if (SearchMoves.empty() || count(SearchMoves.begin(), SearchMoves.end(), ml.move()))
+ RootMoves.push_back(RootMove(ml.move()));
- if (Options["OwnBook"].value<bool>())
+ if (Options["OwnBook"])
{
- if (Options["Book File"].value<string>() != book.name())
- book.open(Options["Book File"].value<string>());
+ Move bookMove = book.probe(pos, Options["Book File"], Options["Best Book Move"]);
- Move bookMove = book.probe(pos, Options["Best Book Move"].value<bool>());
- if (bookMove != MOVE_NONE)
+ if (bookMove && count(RootMoves.begin(), RootMoves.end(), bookMove))
{
- if (!Signals.stop && (Limits.ponder || Limits.infinite))
- Threads.wait_for_stop_or_ponderhit();
-
- cout << "bestmove " << bookMove << endl;
- return;
+ std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), bookMove));
+ goto finalize;
}
}
read_evaluation_uci_options(pos.side_to_move());
Threads.read_uci_options();
- TT.set_size(Options["Hash"].value<int>());
- if (Options["Clear Hash"].value<bool>())
+ TT.set_size(Options["Hash"]);
+ if (Options["Clear Hash"])
{
- Options["Clear Hash"].set_value("false");
+ Options["Clear Hash"] = false;
TT.clear();
}
- UCIMultiPV = Options["MultiPV"].value<size_t>();
- SkillLevel = Options["Skill Level"].value<int>();
+ UCIMultiPV = Options["MultiPV"];
+ SkillLevel = Options["Skill Level"];
// Do we have to play with skill handicap? In this case enable MultiPV that
// we will use behind the scenes to retrieve a set of possible moves.
SkillLevelEnabled = (SkillLevel < 20);
MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, (size_t)4) : UCIMultiPV);
- if (Options["Use Search Log"].value<bool>())
+ if (Options["Use Search Log"])
{
- Log log(Options["Search Log Filename"].value<string>());
+ Log log(Options["Search Log Filename"]);
log << "\nSearching: " << pos.to_fen()
<< "\ninfinite: " << Limits.infinite
<< " ponder: " << Limits.ponder
<< endl;
}
- // Wake up needed threads and reset maxPly counter
for (int i = 0; i < Threads.size(); i++)
{
Threads[i].maxPly = 0;
// Set best timer interval to avoid lagging under time pressure. Timer is
// used to check for remaining available thinking time.
- if (TimeMgr.available_time())
- Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 8, 20)));
+ if (Limits.use_time_management())
+ Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution)));
else
Threads.set_timer(100);
- // We're ready to start thinking. Call the iterative deepening loop function
- Move ponderMove = MOVE_NONE;
- Move bestMove = id_loop(pos, &ponderMove);
+ // We're ready to start searching. Call the iterative deepening loop function
+ id_loop(pos);
// Stop timer and send all the slaves to sleep, if not already sleeping
Threads.set_timer(0);
Threads.set_size(1);
- if (Options["Use Search Log"].value<bool>())
+ if (Options["Use Search Log"])
{
int e = elapsed_time();
- Log log(Options["Search Log Filename"].value<string>());
+ Log log(Options["Search Log Filename"]);
log << "Nodes: " << pos.nodes_searched()
<< "\nNodes/second: " << (e > 0 ? pos.nodes_searched() * 1000 / e : 0)
- << "\nBest move: " << move_to_san(pos, bestMove);
+ << "\nBest move: " << move_to_san(pos, RootMoves[0].pv[0]);
StateInfo st;
- pos.do_move(bestMove, st);
- log << "\nPonder move: " << move_to_san(pos, ponderMove) << endl;
- pos.undo_move(bestMove); // Return from think() with unchanged position
+ pos.do_move(RootMoves[0].pv[0], st);
+ log << "\nPonder move: " << move_to_san(pos, RootMoves[0].pv[1]) << endl;
+ pos.undo_move(RootMoves[0].pv[0]);
}
+finalize:
+
// When we reach max depth we arrive here even without a StopRequest, but if
// we are pondering or in infinite search, we shouldn't print the best move
// before we are told to do so.
if (!Signals.stop && (Limits.ponder || Limits.infinite))
Threads.wait_for_stop_or_ponderhit();
- // Could be MOVE_NONE when searching on a stalemate position
- cout << "bestmove " << bestMove;
-
- // UCI protol is not clear on allowing sending an empty ponder move, instead
- // it is clear that ponder move is optional. So skip it if empty.
- if (ponderMove != MOVE_NONE)
- cout << " ponder " << ponderMove;
-
- cout << endl;
+ // Best move could be MOVE_NONE when searching on a stalemate position
+ cout << "bestmove " << move_to_uci(RootMoves[0].pv[0], Chess960)
+ << " ponder " << move_to_uci(RootMoves[0].pv[1], Chess960) << endl;
}
// with increasing depth until the allocated thinking time has been consumed,
// user stops the search, or the maximum search depth is reached.
- Move id_loop(Position& pos, Move* ponderMove) {
+ void id_loop(Position& pos) {
- Stack ss[PLY_MAX_PLUS_2];
- int bestMoveChanges[PLY_MAX_PLUS_2];
- int depth;
+ Stack ss[MAX_PLY_PLUS_2];
+ int depth, prevBestMoveChanges;
Value bestValue, alpha, beta, delta;
- Move bestMove, skillBest, skillPonder;
bool bestMoveNeverChanged = true;
+ Move skillBest = MOVE_NONE;
memset(ss, 0, 4 * sizeof(Stack));
- TT.new_search();
- H.clear();
- RootMoves.clear();
- *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE;
- depth = 0;
- bestValue = alpha = -VALUE_INFINITE, beta = delta = VALUE_INFINITE;
+ depth = BestMoveChanges = 0;
+ bestValue = delta = -VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update gains
- for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
- if ( SearchMoves.empty()
- || std::count(SearchMoves.begin(), SearchMoves.end(), ml.move()))
- RootMoves.push_back(RootMove(ml.move()));
-
- // Handle special case of searching on a mate/stalemate position
+ // Handle the special case of a mated/stalemate position
if (RootMoves.empty())
{
- cout << "info" << depth_to_uci(DEPTH_ZERO)
- << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW, alpha, beta) << endl;
+ cout << "info depth 0 score "
+ << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW) << endl;
- return MOVE_NONE;
+ RootMoves.push_back(MOVE_NONE);
+ return;
}
// Iterative deepening loop until requested to stop or target depth reached
- while (!Signals.stop && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
+ while (!Signals.stop && ++depth <= MAX_PLY && (!Limits.maxDepth || depth <= Limits.maxDepth))
{
- // Save now last iteration's scores, before Rml moves are reordered
+ // Save last iteration's scores before first PV line is searched and all
+ // the move scores but the (new) PV are set to -VALUE_INFINITE.
for (size_t i = 0; i < RootMoves.size(); i++)
RootMoves[i].prevScore = RootMoves[i].score;
+ prevBestMoveChanges = BestMoveChanges;
BestMoveChanges = 0;
// MultiPV loop. We perform a full root search for each PV line
- for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, RootMoves.size()); MultiPVIdx++)
+ for (PVIdx = 0; PVIdx < std::min(MultiPV, RootMoves.size()); PVIdx++)
{
- // Calculate dynamic aspiration window based on previous iteration
- if (depth >= 5 && abs(RootMoves[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN)
+ // Set aspiration window default width
+ if (depth >= 5 && abs(RootMoves[PVIdx].prevScore) < VALUE_KNOWN_WIN)
{
delta = Value(16);
- alpha = RootMoves[MultiPVIdx].prevScore - delta;
- beta = RootMoves[MultiPVIdx].prevScore + delta;
+ alpha = RootMoves[PVIdx].prevScore - delta;
+ beta = RootMoves[PVIdx].prevScore + delta;
}
else
{
// we want to keep the same order for all the moves but the new
// PV that goes to the front. Note that in case of MultiPV search
// the already searched PV lines are preserved.
- sort<RootMove>(RootMoves.begin() + MultiPVIdx, RootMoves.end());
+ sort<RootMove>(RootMoves.begin() + PVIdx, RootMoves.end());
// In case we have found an exact score and we are going to leave
// the fail high/low loop then reorder the PV moves, otherwise
// leave the last PV move in its position so to be searched again.
// Of course this is needed only in MultiPV search.
- if (MultiPVIdx && bestValue > alpha && bestValue < beta)
- sort<RootMove>(RootMoves.begin(), RootMoves.begin() + MultiPVIdx);
+ if (PVIdx && bestValue > alpha && bestValue < beta)
+ sort<RootMove>(RootMoves.begin(), RootMoves.begin() + PVIdx);
- // Write PV back to transposition table in case the relevant entries
- // have been overwritten during the search.
- for (size_t i = 0; i <= MultiPVIdx; i++)
+ // Write PV back to transposition table in case the relevant
+ // entries have been overwritten during the search.
+ for (size_t i = 0; i <= PVIdx; i++)
RootMoves[i].insert_pv_in_tt(pos);
- // If search has been stopped exit the aspiration window loop,
- // note that sorting and writing PV back to TT is safe becuase
- // Rml is still valid, although refers to the previous iteration.
+ // If search has been stopped exit the aspiration window loop.
+ // Sorting and writing PV back to TT is safe becuase RootMoves
+ // is still valid, although refers to previous iteration.
if (Signals.stop)
break;
// Send full PV info to GUI if we are going to leave the loop or
- // if we have a fail high/low and we are deep in the search. UCI
- // protocol requires to send all the PV lines also if are still
- // to be searched and so refer to the previous search's score.
+ // if we have a fail high/low and we are deep in the search.
if ((bestValue > alpha && bestValue < beta) || elapsed_time() > 2000)
- for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++)
- {
- bool updated = (i <= MultiPVIdx);
-
- if (depth == 1 && !updated)
- continue;
-
- Depth d = (updated ? depth : depth - 1) * ONE_PLY;
- Value s = (updated ? RootMoves[i].score : RootMoves[i].prevScore);
-
- cout << "info"
- << depth_to_uci(d)
- << (i == MultiPVIdx ? score_to_uci(s, alpha, beta) : score_to_uci(s))
- << speed_to_uci(pos.nodes_searched())
- << pv_to_uci(&RootMoves[i].pv[0], i + 1, pos.is_chess960())
- << endl;
- }
+ pv_info_to_uci(pos, depth, alpha, beta);
// In case of failing high/low increase aspiration window and
// research, otherwise exit the fail high/low loop.
} while (abs(bestValue) < VALUE_KNOWN_WIN);
}
- bestMove = RootMoves[0].pv[0];
- *ponderMove = RootMoves[0].pv[1];
- bestMoveChanges[depth] = BestMoveChanges;
-
- // Skills: Do we need to pick now the best and the ponder moves ?
+ // Skills: Do we need to pick now the best move ?
if (SkillLevelEnabled && depth == 1 + SkillLevel)
- do_skill_level(&skillBest, &skillPonder);
+ skillBest = do_skill_level();
- if (Options["Use Search Log"].value<bool>())
- {
- Log log(Options["Search Log Filename"].value<string>());
- log << pretty_pv(pos, depth, bestValue, elapsed_time(), &RootMoves[0].pv[0]) << endl;
- }
+ if (Options["Use Search Log"])
+ pv_info_to_log(pos, depth, bestValue, elapsed_time(), &RootMoves[0].pv[0]);
// Filter out startup noise when monitoring best move stability
- if (depth > 2 && bestMoveChanges[depth])
+ if (depth > 2 && BestMoveChanges)
bestMoveNeverChanged = false;
// Do we have time for the next iteration? Can we stop searching now?
- if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement())
+ if (!Signals.stop && !Signals.stopOnPonderhit && Limits.use_time_management())
{
- bool stop = false; // Local variable instead of the volatile Signals.stop
+ bool stop = false; // Local variable, not the volatile Signals.stop
// Take in account some extra time if the best move has changed
if (depth > 4 && depth < 50)
- TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth - 1]);
+ TimeMgr.pv_instability(BestMoveChanges, prevBestMoveChanges);
- // Stop search if most of available time is already consumed. We probably don't
- // have enough time to search the first move at the next iteration anyway.
+ // Stop search if most of available time is already consumed. We
+ // probably don't have enough time to search the first move at the
+ // next iteration anyway.
if (elapsed_time() > (TimeMgr.available_time() * 62) / 100)
stop = true;
// Stop search early if one move seems to be much better than others
- if ( depth >= 10
+ if ( depth >= 12
&& !stop
- && ( bestMoveNeverChanged
+ && ( (bestMoveNeverChanged && pos.captured_piece_type())
|| elapsed_time() > (TimeMgr.available_time() * 40) / 100))
{
Value rBeta = bestValue - EasyMoveMargin;
- (ss+1)->excludedMove = bestMove;
+ (ss+1)->excludedMove = RootMoves[0].pv[0];
(ss+1)->skipNullMove = true;
- Value v = search<NonPV>(pos, ss+1, rBeta - 1, rBeta, (depth * ONE_PLY) / 2);
+ Value v = search<NonPV>(pos, ss+1, rBeta - 1, rBeta, (depth - 3) * ONE_PLY);
(ss+1)->skipNullMove = false;
(ss+1)->excludedMove = MOVE_NONE;
}
}
- // When using skills overwrite best and ponder moves with the sub-optimal ones
+ // When using skills swap best PV line with the sub-optimal one
if (SkillLevelEnabled)
{
if (skillBest == MOVE_NONE) // Still unassigned ?
- do_skill_level(&skillBest, &skillPonder);
+ skillBest = do_skill_level();
- bestMove = skillBest;
- *ponderMove = skillPonder;
+ std::swap(RootMoves[0], *find(RootMoves.begin(), RootMoves.end(), skillBest));
}
-
- return bestMove;
}
const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot);
const bool RootNode = (NT == Root || NT == SplitPointRoot);
- assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
- assert(beta > alpha && beta <= VALUE_INFINITE);
- assert(PvNode || alpha == beta - 1);
+ assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
+ assert(PvNode == (alpha != beta - 1));
+ assert(depth > DEPTH_ZERO);
assert(pos.thread() >= 0 && pos.thread() < Threads.size());
Move movesSearched[MAX_MOVES];
- int64_t nodes;
StateInfo st;
const TTEntry *tte;
Key posKey;
// Step 2. Check for aborted search and immediate draw
if (( Signals.stop
|| pos.is_draw<false>()
- || ss->ply > PLY_MAX) && !RootNode)
+ || ss->ply > MAX_PLY) && !RootNode)
return VALUE_DRAW;
- // Step 3. Mate distance pruning
+ // Step 3. Mate distance pruning. Even if we mate at the next move our score
+ // would be at best mate_in(ss->ply+1), but if alpha is already bigger because
+ // a shorter mate was found upward in the tree then there is no need to search
+ // further, we will never beat current alpha. Same logic but with reversed signs
+ // applies also in the opposite condition of being mated instead of giving mate,
+ // in this case return a fail-high score.
if (!RootNode)
{
- alpha = std::max(value_mated_in(ss->ply), alpha);
- beta = std::min(value_mate_in(ss->ply+1), beta);
+ alpha = std::max(mated_in(ss->ply), alpha);
+ beta = std::min(mate_in(ss->ply+1), beta);
if (alpha >= beta)
return alpha;
}
// We don't want the score of a partial search to overwrite a previous full search
// TT value, so we use a different position key in case of an excluded move.
excludedMove = ss->excludedMove;
- posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
+ posKey = excludedMove ? pos.exclusion_key() : pos.key();
tte = TT.probe(posKey);
- ttMove = RootNode ? RootMoves[MultiPVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
+ ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
// At PV nodes we check for exact scores, while at non-PV nodes we check for
// a fail high/low. Biggest advantage at probing at PV nodes is to have a
if ( (move = (ss-1)->currentMove) != MOVE_NULL
&& (ss-1)->eval != VALUE_NONE
&& ss->eval != VALUE_NONE
- && pos.captured_piece_type() == PIECE_TYPE_NONE
+ && !pos.captured_piece_type()
&& !is_special(move))
{
- Square to = move_to(move);
+ Square to = to_sq(move);
H.update_gain(pos.piece_on(to), to, -(ss-1)->eval - ss->eval);
}
&& !inCheck
&& refinedValue + razor_margin(depth) < beta
&& ttMove == MOVE_NONE
- && abs(beta) < VALUE_MATE_IN_PLY_MAX
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value rbeta = beta - razor_margin(depth);
&& depth < RazorDepth
&& !inCheck
&& refinedValue - futility_margin(depth, 0) >= beta
- && abs(beta) < VALUE_MATE_IN_PLY_MAX
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
return refinedValue - futility_margin(depth, 0);
&& depth > ONE_PLY
&& !inCheck
&& refinedValue >= beta
- && abs(beta) < VALUE_MATE_IN_PLY_MAX
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
{
ss->currentMove = MOVE_NULL;
if (nullValue >= beta)
{
// Do not return unproven mate scores
- if (nullValue >= VALUE_MATE_IN_PLY_MAX)
+ if (nullValue >= VALUE_MATE_IN_MAX_PLY)
nullValue = beta;
if (depth < 6 * ONE_PLY)
&& !inCheck
&& !ss->skipNullMove
&& excludedMove == MOVE_NONE
- && abs(beta) < VALUE_MATE_IN_PLY_MAX)
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY)
{
Value rbeta = beta + 200;
Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY;
MovePicker mp(pos, ttMove, H, pos.captured_piece_type());
CheckInfo ci(pos);
- while ((move = mp.get_next_move()) != MOVE_NONE)
+ while ((move = mp.next_move()) != MOVE_NONE)
if (pos.pl_move_is_legal(move, ci.pinned))
{
pos.do_move(move, st, ci, pos.move_gives_check(move, ci));
// Step 11. Loop through moves
// Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
- && (move = mp.get_next_move()) != MOVE_NONE
- && !thread.cutoff_occurred())
+ && (move = mp.next_move()) != MOVE_NONE
+ && !thread.cutoff_occurred()
+ && !Signals.stop)
{
assert(is_ok(move));
// At root obey the "searchmoves" option and skip moves not listed in Root
// Move List, as a consequence any illegal move is also skipped. In MultiPV
// mode we also skip PV moves which have been already searched.
- if (RootNode && !std::count(RootMoves.begin() + MultiPVIdx, RootMoves.end(), move))
+ if (RootNode && !count(RootMoves.begin() + PVIdx, RootMoves.end(), move))
continue;
// At PV and SpNode nodes we want all moves to be legal since the beginning
if (RootNode)
{
- // This is used by time management
Signals.firstRootMove = (moveCount == 1);
- nodes = pos.nodes_searched();
-
if (pos.thread() == 0 && elapsed_time() > 2000)
- cout << "info" << depth_to_uci(depth)
- << " currmove " << move
- << " currmovenumber " << moveCount + MultiPVIdx << endl;
+ cout << "info depth " << depth / ONE_PLY
+ << " currmove " << move_to_uci(move, Chess960)
+ << " currmovenumber " << moveCount + PVIdx << endl;
}
isPvMove = (PvNode && moveCount <= 1);
&& !dangerous
&& move != ttMove
&& !is_castle(move)
- && (bestValue > VALUE_MATED_IN_PLY_MAX || bestValue == -VALUE_INFINITE))
+ && (bestValue > VALUE_MATED_IN_MAX_PLY || bestValue == -VALUE_INFINITE))
{
// Move count based pruning
if ( moveCount >= futility_move_count(depth)
// but fixing this made program slightly weaker.
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
futilityValue = futilityBase + futility_margin(predictedDepth, moveCount)
- + H.gain(pos.piece_on(move_from(move)), move_to(move));
+ + H.gain(pos.piece_moved(move), to_sq(move));
if (futilityValue < beta)
{
// be trusted, and we don't update the best move and/or PV.
if (RootNode && !Signals.stop)
{
- RootMove& rm = *std::find(RootMoves.begin(), RootMoves.end(), move);
- rm.nodes += pos.nodes_searched() - nodes;
+ RootMove& rm = *find(RootMoves.begin(), RootMoves.end(), move);
// PV move or new best move ?
if (isPvMove || value > alpha)
// harmless because return value is discarded anyhow in the parent nodes.
// If we are in a singular extension search then return a fail low score.
if (!moveCount)
- return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
+ return excludedMove ? oldAlpha : inCheck ? mated_in(ss->ply) : VALUE_DRAW;
// If we have pruned all the moves without searching return a fail-low score
if (bestValue == -VALUE_INFINITE)
}
// Step 21. Update tables
- // Update transposition table entry, history and killers
+ // Update transposition table entry, killers and history
if (!SpNode && !Signals.stop && !thread.cutoff_occurred())
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
TT.store(posKey, value_to_tt(bestValue, ss->ply), vt, depth, move, ss->eval, ss->evalMargin);
- // Update killers and history only for non capture moves that fails high
+ // Update killers and history for non capture cut-off moves
if ( bestValue >= beta
- && !pos.is_capture_or_promotion(move))
+ && !pos.is_capture_or_promotion(move)
+ && !inCheck)
{
if (move != ss->killers[0])
{
ss->killers[1] = ss->killers[0];
ss->killers[0] = move;
}
- update_history(pos, move, depth, movesSearched, playedMoveCount);
+
+ // Increase history value of the cut-off move
+ Value bonus = Value(int(depth) * int(depth));
+ H.add(pos.piece_moved(move), to_sq(move), bonus);
+
+ // Decrease history of all the other played non-capture moves
+ for (int i = 0; i < playedMoveCount - 1; i++)
+ {
+ Move m = movesSearched[i];
+ H.add(pos.piece_moved(m), to_sq(m), -bonus);
+ }
}
}
const bool PvNode = (NT == PV);
assert(NT == PV || NT == NonPV);
- assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
- assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
- assert(PvNode || alpha == beta - 1);
- assert(depth <= 0);
+ assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
+ assert(PvNode == (alpha != beta - 1));
+ assert(depth <= DEPTH_ZERO);
assert(pos.thread() >= 0 && pos.thread() < Threads.size());
StateInfo st;
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (pos.is_draw<true>() || ss->ply > PLY_MAX)
+ if (pos.is_draw<true>() || ss->ply > MAX_PLY)
return VALUE_DRAW;
// Decide whether or not to include checks, this fixes also the type of
// Transposition table lookup. At PV nodes, we don't use the TT for
// pruning, but only for move ordering.
- tte = TT.probe(pos.get_key());
+ tte = TT.probe(pos.key());
ttMove = (tte ? tte->move() : MOVE_NONE);
if (!PvNode && tte && can_return_tt(tte, ttDepth, beta, ss->ply))
if (bestValue >= beta)
{
if (!tte)
- TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
+ TT.store(pos.key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
return bestValue;
}
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
- MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove));
+ MovePicker mp(pos, ttMove, depth, H, to_sq((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
- && (move = mp.get_next_move()) != MOVE_NONE)
+ && (move = mp.next_move()) != MOVE_NONE)
{
assert(is_ok(move));
&& !pos.is_passed_pawn_push(move))
{
futilityValue = futilityBase
- + PieceValueEndgame[pos.piece_on(move_to(move))]
+ + PieceValueEndgame[pos.piece_on(to_sq(move))]
+ (is_enpassant(move) ? PawnValueEndgame : VALUE_ZERO);
if (futilityValue < beta)
// Detect non-capture evasions that are candidate to be pruned
evasionPrunable = !PvNode
&& inCheck
- && bestValue > VALUE_MATED_IN_PLY_MAX
+ && bestValue > VALUE_MATED_IN_MAX_PLY
&& !pos.is_capture(move)
&& !pos.can_castle(pos.side_to_move());
// All legal moves have been searched. A special case: If we're in check
// and no legal moves were found, it is checkmate.
if (inCheck && bestValue == -VALUE_INFINITE)
- return value_mated_in(ss->ply);
+ return mated_in(ss->ply); // Plies to mate from the root
// Update transposition table
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
: bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
- TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin);
+ TT.store(pos.key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
Color them;
Value futilityValue, bv = *bestValue;
- from = move_from(move);
- to = move_to(move);
- them = flip(pos.side_to_move());
+ from = from_sq(move);
+ to = to_sq(move);
+ them = ~pos.side_to_move();
ksq = pos.king_square(them);
kingAtt = pos.attacks_from<KING>(ksq);
pc = pos.piece_on(from);
assert(is_ok(m2));
// Case 1: The moving piece is the same in both moves
- f2 = move_from(m2);
- t1 = move_to(m1);
+ f2 = from_sq(m2);
+ t1 = to_sq(m1);
if (f2 == t1)
return true;
// Case 2: The destination square for m2 was vacated by m1
- t2 = move_to(m2);
- f1 = move_from(m1);
+ t2 = to_sq(m2);
+ f1 = from_sq(m1);
if (t2 == f1)
return true;
// value_to_tt() adjusts a mate score from "plies to mate from the root" to
- // "plies to mate from the current ply". Non-mate scores are unchanged.
+ // "plies to mate from the current position". Non-mate scores are unchanged.
// The function is called before storing a value to the transposition table.
Value value_to_tt(Value v, int ply) {
- if (v >= VALUE_MATE_IN_PLY_MAX)
+ if (v >= VALUE_MATE_IN_MAX_PLY)
return v + ply;
- if (v <= VALUE_MATED_IN_PLY_MAX)
+ if (v <= VALUE_MATED_IN_MAX_PLY)
return v - ply;
return v;
}
- // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score from
- // the transposition table to a mate score corrected for the current ply.
+ // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score
+ // from the transposition table (where refers to the plies to mate/be mated
+ // from current position) to "plies to mate/be mated from the root".
Value value_from_tt(Value v, int ply) {
- if (v >= VALUE_MATE_IN_PLY_MAX)
+ if (v >= VALUE_MATE_IN_MAX_PLY)
return v - ply;
- if (v <= VALUE_MATED_IN_PLY_MAX)
+ if (v <= VALUE_MATED_IN_MAX_PLY)
return v + ply;
return v;
Square mfrom, mto, tfrom, tto;
- mfrom = move_from(m);
- mto = move_to(m);
- tfrom = move_from(threat);
- tto = move_to(threat);
+ mfrom = from_sq(m);
+ mto = to_sq(m);
+ tfrom = from_sq(threat);
+ tto = to_sq(threat);
// Case 1: Don't prune moves which move the threatened piece
if (mfrom == tto)
Value v = value_from_tt(tte->value(), ply);
return ( tte->depth() >= depth
- || v >= std::max(VALUE_MATE_IN_PLY_MAX, beta)
- || v < std::min(VALUE_MATED_IN_PLY_MAX, beta))
+ || v >= std::max(VALUE_MATE_IN_MAX_PLY, beta)
+ || v < std::min(VALUE_MATED_IN_MAX_PLY, beta))
&& ( ((tte->type() & VALUE_TYPE_LOWER) && v >= beta)
|| ((tte->type() & VALUE_TYPE_UPPER) && v < beta));
}
- // update_history() registers a good move that produced a beta-cutoff in
- // history and marks as failures all the other moves of that ply.
-
- void update_history(const Position& pos, Move move, Depth depth,
- Move movesSearched[], int moveCount) {
- Move m;
- Value bonus = Value(int(depth) * int(depth));
-
- H.update(pos.piece_on(move_from(move)), move_to(move), bonus);
-
- for (int i = 0; i < moveCount - 1; i++)
- {
- m = movesSearched[i];
-
- assert(m != move);
-
- H.update(pos.piece_on(move_from(m)), move_to(m), -bonus);
- }
- }
-
-
// current_search_time() returns the number of milliseconds which have passed
// since the beginning of the current search.
static int searchStartTime;
if (reset)
- searchStartTime = get_system_time();
+ searchStartTime = system_time();
- return get_system_time() - searchStartTime;
+ return system_time() - searchStartTime;
}
std::stringstream s;
- if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << " score cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
+ if (abs(v) < VALUE_MATE_IN_MAX_PLY)
+ s << "cp " << v * 100 / int(PawnValueMidgame);
else
- s << " score mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
+ s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
s << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
}
- // speed_to_uci() returns a string with time stats of current search suitable
- // to be sent to UCI gui.
+ // pv_info_to_uci() sends search info to GUI. UCI protocol requires to send all
+ // the PV lines also if are still to be searched and so refer to the previous
+ // search score.
- string speed_to_uci(int64_t nodes) {
+ void pv_info_to_uci(const Position& pos, int depth, Value alpha, Value beta) {
- std::stringstream s;
int t = elapsed_time();
-
- s << " nodes " << nodes
- << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0)
- << " time " << t;
-
- return s.str();
- }
-
-
- // pv_to_uci() returns a string with information on the current PV line
- // formatted according to UCI specification.
-
- string pv_to_uci(const Move pv[], int pvNum, bool chess960) {
-
- std::stringstream s;
-
- s << " multipv " << pvNum << " pv " << set960(chess960);
-
- for ( ; *pv != MOVE_NONE; pv++)
- s << *pv << " ";
-
- return s.str();
- }
-
-
- // depth_to_uci() returns a string with information on the current depth and
- // seldepth formatted according to UCI specification.
-
- string depth_to_uci(Depth depth) {
-
- std::stringstream s;
int selDepth = 0;
- // Retrieve max searched depth among threads
for (int i = 0; i < Threads.size(); i++)
if (Threads[i].maxPly > selDepth)
selDepth = Threads[i].maxPly;
- s << " depth " << depth / ONE_PLY << " seldepth " << selDepth;
-
- return s.str();
+ for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++)
+ {
+ bool updated = (i <= PVIdx);
+
+ if (depth == 1 && !updated)
+ continue;
+
+ int d = (updated ? depth : depth - 1);
+ Value v = (updated ? RootMoves[i].score : RootMoves[i].prevScore);
+ std::stringstream s;
+
+ for (int j = 0; RootMoves[i].pv[j] != MOVE_NONE; j++)
+ s << " " << move_to_uci(RootMoves[i].pv[j], Chess960);
+
+ cout << "info depth " << d
+ << " seldepth " << selDepth
+ << " score " << (i == PVIdx ? score_to_uci(v, alpha, beta) : score_to_uci(v))
+ << " nodes " << pos.nodes_searched()
+ << " nps " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0)
+ << " time " << t
+ << " multipv " << i + 1
+ << " pv" << s.str() << endl;
+ }
}
- // pretty_pv() creates a human-readable string from a position and a PV. It is
- // used to write search information to the log file (which is created when the
- // UCI parameter "Use Search Log" is "true"). It uses the two below helper to
- // pretty format time and score respectively.
+ // pv_info_to_log() writes human-readable search information to the log file
+ // (which is created when the UCI parameter "Use Search Log" is "true"). It
+ // uses the two below helpers to pretty format time and score respectively.
string time_to_string(int millisecs) {
std::stringstream s;
- if (v >= VALUE_MATE_IN_PLY_MAX)
+ if (v >= VALUE_MATE_IN_MAX_PLY)
s << "#" << (VALUE_MATE - v + 1) / 2;
- else if (v <= VALUE_MATED_IN_PLY_MAX)
+ else if (v <= VALUE_MATED_IN_MAX_PLY)
s << "-#" << (VALUE_MATE + v) / 2;
else
s << std::setprecision(2) << std::fixed << std::showpos
return s.str();
}
- string pretty_pv(Position& pos, int depth, Value value, int time, Move pv[]) {
+ void pv_info_to_log(Position& pos, int depth, Value value, int time, Move pv[]) {
const int64_t K = 1000;
const int64_t M = 1000000;
- StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ StateInfo state[MAX_PLY_PLUS_2], *st = state;
Move* m = pv;
string san, padding;
size_t length;
std::stringstream s;
- s << set960(pos.is_chess960())
- << std::setw(2) << depth
+ s << std::setw(2) << depth
<< std::setw(8) << score_to_string(value)
<< std::setw(8) << time_to_string(time);
if (pos.nodes_searched() < M)
s << std::setw(8) << pos.nodes_searched() / 1 << " ";
+
else if (pos.nodes_searched() < K * M)
s << std::setw(7) << pos.nodes_searched() / K << "K ";
+
else
s << std::setw(7) << pos.nodes_searched() / M << "M ";
pos.do_move(*m++, *st++);
}
- // Restore original position before to leave
while (m != pv)
pos.undo_move(*--m);
- return s.str();
+ Log l(Options["Search Log Filename"]);
+ l << s.str() << endl;
}
// When playing with strength handicap choose best move among the MultiPV set
// using a statistical rule dependent on SkillLevel. Idea by Heinz van Saanen.
- void do_skill_level(Move* best, Move* ponder) {
+ Move do_skill_level() {
assert(MultiPV > 1);
static RKISS rk;
// PRNG sequence should be not deterministic
- for (int i = abs(get_system_time() % 50); i > 0; i--)
+ for (int i = abs(system_time() % 50); i > 0; i--)
rk.rand<unsigned>();
- // Rml list is already sorted by score in descending order
+ // RootMoves are already sorted by score in descending order
size_t size = std::min(MultiPV, RootMoves.size());
int variance = std::min(RootMoves[0].score - RootMoves[size - 1].score, PawnValueMidgame);
int weakness = 120 - 2 * SkillLevel;
int max_s = -VALUE_INFINITE;
+ Move best = MOVE_NONE;
// Choose best move. For each move score we add two terms both dependent on
// weakness, one deterministic and bigger for weaker moves, and one random,
if (s > max_s)
{
max_s = s;
- *best = RootMoves[i].pv[0];
- *ponder = RootMoves[i].pv[1];
+ best = RootMoves[i].pv[0];
}
}
+ return best;
}
void RootMove::extract_pv_from_tt(Position& pos) {
- StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ StateInfo state[MAX_PLY_PLUS_2], *st = state;
TTEntry* tte;
int ply = 1;
Move m = pv[0];
pv.push_back(m);
pos.do_move(m, *st++);
- while ( (tte = TT.probe(pos.get_key())) != NULL
+ while ( (tte = TT.probe(pos.key())) != NULL
&& tte->move() != MOVE_NONE
&& pos.is_pseudo_legal(tte->move())
&& pos.pl_move_is_legal(tte->move(), pos.pinned_pieces())
- && ply < PLY_MAX
+ && ply < MAX_PLY
&& (!pos.is_draw<false>() || ply < 2))
{
pv.push_back(tte->move());
void RootMove::insert_pv_in_tt(Position& pos) {
- StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ StateInfo state[MAX_PLY_PLUS_2], *st = state;
TTEntry* tte;
Key k;
Value v, m = VALUE_NONE;
int ply = 0;
- assert(pv[0] != MOVE_NONE && pos.is_pseudo_legal(pv[0]));
+ assert(pv[ply] != MOVE_NONE && pos.is_pseudo_legal(pv[ply]));
do {
- k = pos.get_key();
+ k = pos.key();
tte = TT.probe(k);
// Don't overwrite existing correct entries
assert(!do_terminate);
// Copy split point position and search stack and call search()
- Stack ss[PLY_MAX_PLUS_2];
+ Stack ss[MAX_PLY_PLUS_2];
SplitPoint* tsp = splitPoint;
Position pos(*tsp->pos, threadID);
}
-/// do_timer_event() is called by the timer thread when the timer triggers. It
-/// is used to print debug info and, more important, to detect when we are out of
+/// check_time() is called by the timer thread when the timer triggers. It is
+/// used to print debug info and, more important, to detect when we are out of
/// available time and so stop the search.
-void do_timer_event() {
+void check_time() {
static int lastInfoTime;
int e = elapsed_time();
- if (get_system_time() - lastInfoTime >= 1000 || !lastInfoTime)
+ if (system_time() - lastInfoTime >= 1000 || !lastInfoTime)
{
- lastInfoTime = get_system_time();
-
- dbg_print_mean();
- dbg_print_hit_rate();
+ lastInfoTime = system_time();
+ dbg_print();
}
if (Limits.ponder)
&& !Signals.failedLowAtRoot
&& e > TimeMgr.available_time();
- bool noMoreTime = e > TimeMgr.maximum_time()
+ bool noMoreTime = e > TimeMgr.maximum_time() - 2 * TimerResolution
|| stillAtFirstMove;
- if ( (Limits.useTimeManagement() && noMoreTime)
+ if ( (Limits.use_time_management() && noMoreTime)
|| (Limits.maxTime && e >= Limits.maxTime)
/* missing nodes limit */ ) // FIXME
Signals.stop = true;