along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
#include <cassert>
#include <cmath>
#include <cstring>
using std::cout;
using std::endl;
-////
-//// Local definitions
-////
-
namespace {
- // Types
+ // Different node types, used as template parameter
enum NodeType { NonPV, PV };
- // Set to true to force running with one thread.
- // Used for debugging SMP code.
+ // Set to true to force running with one thread. Used for debugging.
const bool FakeSplit = false;
- // Fast lookup table of sliding pieces indexed by Piece
+ // Lookup table to check if a Piece is a slider and its access function
const bool Slidings[18] = { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1 };
inline bool piece_is_slider(Piece p) { return Slidings[p]; }
- // ThreadsManager class is used to handle all the threads related stuff in search,
- // init, starting, parking and, the most important, launching a slave thread at a
- // split point are what this class does. All the access to shared thread data is
- // done through this class, so that we avoid using global variables instead.
+ // ThreadsManager class is used to handle all the threads related stuff like init,
+ // starting, parking and, the most important, launching a slave thread at a split
+ // point. All the access to shared thread data is done through this class.
class ThreadsManager {
/* As long as the single ThreadsManager object is defined as a global we don't
static storage duration are automatically set to zero before enter main()
*/
public:
+ Thread& operator[](int threadID) { return threads[threadID]; }
void init_threads();
void exit_threads();
bool available_thread_exists(int master) const;
bool thread_is_available(int slave, int master) const;
bool cutoff_at_splitpoint(int threadID) const;
- void wake_sleeping_thread(int threadID);
void idle_loop(int threadID, SplitPoint* sp);
template <bool Fake>
- void split(Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
- Depth depth, Move threatMove, bool mateThreat, int moveCount, MovePicker* mp, bool pvNode);
-
+ void split(Position& pos, SearchStack* ss, Value* alpha, const Value beta, Value* bestValue,
+ Depth depth, Move threatMove, int moveCount, MovePicker* mp, bool pvNode);
private:
+ Lock mpLock;
Depth minimumSplitDepth;
int maxThreadsPerSplitPoint;
bool useSleepingThreads;
int activeThreads;
volatile bool allThreadsShouldExit;
Thread threads[MAX_THREADS];
- Lock mpLock, sleepLock[MAX_THREADS];
- WaitCondition sleepCond[MAX_THREADS];
};
- // RootMove struct is used for moves at the root at the tree. For each root
+ // RootMove struct is used for moves at the root of the tree. For each root
// move, we store two scores, a node count, and a PV (really a refutation
// in the case of moves which fail low). Value pv_score is normally set at
// -VALUE_INFINITE for all non-pv moves, while non_pv_score is computed
// RootMove::operator<() is the comparison function used when
// sorting the moves. A move m1 is considered to be better
// than a move m2 if it has an higher pv_score, or if it has
- // equal pv_score but m1 has the higher non_pv_score. In this
- // way we are guaranteed that PV moves are always sorted as first.
+ // equal pv_score but m1 has the higher non_pv_score. In this way
+ // we are guaranteed that PV moves are always sorted as first.
bool operator<(const RootMove& m) const {
return pv_score != m.pv_score ? pv_score < m.pv_score
: non_pv_score < m.non_pv_score;
void extract_pv_from_tt(Position& pos);
void insert_pv_in_tt(Position& pos);
- std::string pv_info_to_uci(Position& pos, int depth, Value alpha, Value beta, int pvLine);
-
+ std::string pv_info_to_uci(Position& pos, int depth, int selDepth,
+ Value alpha, Value beta, int pvIdx);
int64_t nodes;
Value pv_score;
Value non_pv_score;
};
- // RootMoveList struct is essentially a std::vector<> of RootMove objects,
+ // RootMoveList struct is just a vector of RootMove objects,
// with an handful of methods above the standard ones.
struct RootMoveList : public std::vector<RootMove> {
};
+ // 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 use it to properly format castling moves.
+ // operator<<() that will read it to properly format castling moves.
enum set960 {};
std::ostream& operator<< (std::ostream& os, const set960& f) {
}
- // Overload operator << for moves to make it easier to print moves in
- // 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);
- }
-
-
/// Adjustments
// Step 6. Razoring
// Step 11. Decide the new search depth
- // Extensions. Configurable UCI options
- // Array index 0 is used at non-PV nodes, index 1 at PV nodes.
- Depth CheckExtension[2], PawnPushTo7thExtension[2], PassedPawnExtension[2];
- Depth PawnEndgameExtension[2], MateThreatExtension[2];
+ // Extensions. Configurable UCI options. Array index 0 is used at
+ // non-PV nodes, index 1 at PV nodes.
+ Depth CheckExtension[2], PawnPushTo7thExtension[2];
+ Depth PassedPawnExtension[2], PawnEndgameExtension[2];
// Minimum depth for use of singular extension
const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */};
- // If the TT move is at least SingularExtensionMargin better than the
- // remaining ones we will extend it.
- const Value SingularExtensionMargin = Value(0x20);
-
// Step 12. Futility pruning
// Futility margin for quiescence search
const Value FutilityMarginQS = Value(0x80);
- // Futility lookup tables (initialized at startup) and their getter functions
+ // Futility lookup tables (initialized at startup) and their access functions
Value FutilityMarginsMatrix[16][64]; // [depth][moveNumber]
- int FutilityMoveCountArray[32]; // [depth]
+ int FutilityMoveCountArray[32]; // [depth]
inline Value futility_margin(Depth d, int mn) { return d < 7 * ONE_PLY ? FutilityMarginsMatrix[Max(d, 1)][Min(mn, 63)] : 2 * VALUE_INFINITE; }
inline int futility_move_count(Depth d) { return d < 16 * ONE_PLY ? FutilityMoveCountArray[d] : 512; }
// Step 14. Reduced search
- // Reduction lookup tables (initialized at startup) and their getter functions
+ // Reduction lookup tables (initialized at startup) and their access function
int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber]
template <NodeType PV>
- inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / ONE_PLY, 63)][Min(mn, 63)]; }
// Easy move margin. An easy move candidate must be at least this much
// better than the second best move.
/// Namespace variables
- // Book object
+ // Book
Book OpeningBook;
// Root move list
RootMoveList Rml;
// MultiPV mode
- int MultiPV;
+ int MultiPV, UCIMultiPV;
// Time management variables
- int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime;
- bool UseTimeManagement, InfiniteSearch, Pondering, StopOnPonderhit;
- bool FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
+ bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
TimeManager TimeMgr;
+ SearchLimits Limits;
// Log file
bool UseLogFile;
std::ofstream LogFile;
- // Multi-threads manager object
+ // Skill level adjustment
+ int SkillLevel;
+ bool SkillLevelEnabled;
+ RKISS RK;
+
+ // Multi-threads manager
ThreadsManager ThreadsMgr;
// Node counters, used only by thread[0] but try to keep in different cache
// History table
History H;
+
/// Local functions
Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove);
template <NodeType PvNode, bool SpNode, bool Root>
- Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
template <NodeType PvNode>
- inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
- return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO, ply)
- : search<PvNode, false, false>(pos, ss, alpha, beta, depth, ply);
+ return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO)
+ : search<PvNode, false, false>(pos, ss, alpha, beta, depth);
}
template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool mateThreat, bool* dangerous);
+ Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool* dangerous);
bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue);
bool connected_moves(const Position& pos, Move m1, Move m2);
- bool value_is_mate(Value value);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
bool ok_to_use_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 update_killers(Move m, Move killers[]);
void update_gains(const Position& pos, Move move, Value before, Value after);
- void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last);
+ void do_skill_level(Move* best, Move* ponder);
- int current_search_time();
+ int current_search_time(int set = 0);
std::string value_to_uci(Value v);
- int nps(const Position& pos);
+ std::string speed_to_uci(int64_t nodes);
void poll(const Position& pos);
void wait_for_stop_or_ponderhit();
#endif
- // MovePickerExt is an extended MovePicker used to choose at compile time
+ // MovePickerExt is an extended MovePicker class used to choose at compile time
// the proper move source according to the type of node.
template<bool SpNode, bool Root> struct MovePickerExt;
- // In Root nodes use RootMoveList Rml as source. Score and sort the root moves
+ // In Root nodes use RootMoveList as source. Score and sort the root moves
// before to search them.
template<> struct MovePickerExt<false, true> : public MovePicker {
Move move;
Value score = VALUE_ZERO;
- // Score root moves using the standard way used in main search, the moves
+ // Score root moves using standard ordering used in main search, the moves
// are scored according to the order in which they are returned by MovePicker.
// This is the second order score that is used to compare the moves when
- // the first order pv scores of both moves are equal.
+ // the first orders pv_score of both moves are equal.
while ((move = MovePicker::get_next_move()) != MOVE_NONE)
for (rm = Rml.begin(); rm != Rml.end(); ++rm)
if (rm->pv[0] == move)
// In SpNodes use split point's shared MovePicker object as move source
template<> struct MovePickerExt<true, false> : public MovePicker {
- MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
- SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b),
- mp(ss->sp->mp) {}
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
+ : MovePicker(p, ttm, d, h, ss, b), mp(ss->sp->mp) {}
Move get_next_move() { return mp->get_next_move(); }
// Default case, create and use a MovePicker object as source
template<> struct MovePickerExt<false, false> : public MovePicker {
- MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
- SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b) {}
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
+ : MovePicker(p, ttm, d, h, ss, b) {}
RootMoveList::iterator rm; // Dummy, needed to compile
};
} // namespace
-////
-//// Functions
-////
-
-/// init_threads(), exit_threads() and nodes_searched() are helpers to
-/// give accessibility to some TM methods from outside of current file.
-
-void init_threads() { ThreadsMgr.init_threads(); }
-void exit_threads() { ThreadsMgr.exit_threads(); }
-
+/// init_threads() is called during startup. It initializes various lookup tables
+/// and creates and launches search threads.
-/// init_search() is called during startup. It initializes various lookup tables
-
-void init_search() {
+void init_threads() {
int d; // depth (ONE_PLY == 2)
int hd; // half depth (ONE_PLY == 1)
// Init futility move count array
for (d = 0; d < 32; d++)
FutilityMoveCountArray[d] = int(3.001 + 0.25 * pow(d, 2.0));
+
+ // Create and startup threads
+ ThreadsMgr.init_threads();
}
-/// perft() is our utility to verify move generation is bug free. All the legal
-/// moves up to given depth are generated and counted and the sum returned.
+/// exit_threads() is a trampoline to access ThreadsMgr from outside of current file
+void exit_threads() { ThreadsMgr.exit_threads(); }
-int64_t perft(Position& pos, Depth depth)
-{
- MoveStack mlist[MOVES_MAX];
- StateInfo st;
- Move m;
- int64_t sum = 0;
- // Generate all legal moves
- MoveStack* last = generate<MV_LEGAL>(pos, mlist);
+/// perft() is our utility to verify move generation. All the legal moves up to
+/// given depth are generated and counted and the sum returned.
- // If we are at the last ply we don't need to do and undo
- // the moves, just to count them.
- if (depth <= ONE_PLY)
- return int(last - mlist);
+int64_t perft(Position& pos, Depth depth) {
- // Loop through all legal moves
- CheckInfo ci(pos);
- for (MoveStack* cur = mlist; cur != last; cur++)
- {
- m = cur->move;
- pos.do_move(m, st, ci, pos.move_is_check(m, ci));
- sum += perft(pos, depth - ONE_PLY);
- pos.undo_move(m);
- }
- return sum;
+ MoveStack mlist[MOVES_MAX];
+ StateInfo st;
+ Move m;
+ int64_t sum = 0;
+
+ // Generate all legal moves
+ MoveStack* last = generate<MV_LEGAL>(pos, mlist);
+
+ // If we are at the last ply we don't need to do and undo
+ // the moves, just to count them.
+ if (depth <= ONE_PLY)
+ return int(last - mlist);
+
+ // Loop through all legal moves
+ CheckInfo ci(pos);
+ for (MoveStack* cur = mlist; cur != last; cur++)
+ {
+ m = cur->move;
+ pos.do_move(m, st, ci, pos.move_is_check(m, ci));
+ sum += perft(pos, depth - ONE_PLY);
+ pos.undo_move(m);
+ }
+ return sum;
}
/// think() is the external interface to Stockfish's search, and is called when
-/// the program receives the UCI 'go' command. It initializes various
-/// search-related global variables, and calls id_loop(). It returns false
-/// when a quit command is received during the search.
+/// the program receives the UCI 'go' command. It initializes various global
+/// variables, and calls id_loop(). It returns false when a "quit" command is
+/// received during the search.
-bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[],
- int movesToGo, int maxDepth, int maxNodes, int maxTime, Move searchMoves[]) {
+bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) {
- // Initialize global search variables
+ // Initialize global search-related variables
StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false;
NodesSincePoll = 0;
- SearchStartTime = get_system_time();
- ExactMaxTime = maxTime;
- MaxDepth = maxDepth;
- MaxNodes = maxNodes;
- InfiniteSearch = infinite;
- Pondering = ponder;
- UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
+ current_search_time(get_system_time());
+ Limits = limits;
+ TimeMgr.init(Limits, pos.startpos_ply_counter());
+
+ // Set best NodesBetweenPolls interval to avoid lagging under time pressure
+ if (Limits.maxNodes)
+ NodesBetweenPolls = Min(Limits.maxNodes, 30000);
+ else if (Limits.time && Limits.time < 1000)
+ NodesBetweenPolls = 1000;
+ else if (Limits.time && Limits.time < 5000)
+ NodesBetweenPolls = 5000;
+ else
+ NodesBetweenPolls = 30000;
// Look for a book move, only during games, not tests
- if (UseTimeManagement && Options["OwnBook"].value<bool>())
+ if (Limits.useTimeManagement() && Options["OwnBook"].value<bool>())
{
if (Options["Book File"].value<std::string>() != OpeningBook.name())
OpeningBook.open(Options["Book File"].value<std::string>());
Move bookMove = OpeningBook.get_move(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE)
{
- if (Pondering)
+ if (Limits.ponder)
wait_for_stop_or_ponderhit();
cout << "bestmove " << bookMove << endl;
}
}
- // Read UCI option values
- TT.set_size(Options["Hash"].value<int>());
- if (Options["Clear Hash"].value<bool>())
- {
- Options["Clear Hash"].set_value("false");
- TT.clear();
- }
-
+ // Read UCI options
CheckExtension[1] = Options["Check Extension (PV nodes)"].value<Depth>();
CheckExtension[0] = Options["Check Extension (non-PV nodes)"].value<Depth>();
PawnPushTo7thExtension[1] = Options["Pawn Push to 7th Extension (PV nodes)"].value<Depth>();
PassedPawnExtension[0] = Options["Passed Pawn Extension (non-PV nodes)"].value<Depth>();
PawnEndgameExtension[1] = Options["Pawn Endgame Extension (PV nodes)"].value<Depth>();
PawnEndgameExtension[0] = Options["Pawn Endgame Extension (non-PV nodes)"].value<Depth>();
- MateThreatExtension[1] = Options["Mate Threat Extension (PV nodes)"].value<Depth>();
- MateThreatExtension[0] = Options["Mate Threat Extension (non-PV nodes)"].value<Depth>();
- MultiPV = Options["MultiPV"].value<int>();
+ UCIMultiPV = Options["MultiPV"].value<int>();
+ SkillLevel = Options["Skill level"].value<int>();
UseLogFile = Options["Use Search Log"].value<bool>();
read_evaluation_uci_options(pos.side_to_move());
+ if (Options["Clear Hash"].value<bool>())
+ {
+ Options["Clear Hash"].set_value("false");
+ TT.clear();
+ }
+ TT.set_size(Options["Hash"].value<int>());
+
+ // 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 ? Max(UCIMultiPV, 4) : UCIMultiPV);
+
// Set the number of active threads
ThreadsMgr.read_uci_options();
init_eval(ThreadsMgr.active_threads());
- // Wake up needed threads
- for (int i = 1; i < ThreadsMgr.active_threads(); i++)
- ThreadsMgr.wake_sleeping_thread(i);
-
- // Set thinking time
- int myTime = time[pos.side_to_move()];
- int myIncrement = increment[pos.side_to_move()];
- if (UseTimeManagement)
- TimeMgr.init(myTime, myIncrement, movesToGo, pos.startpos_ply_counter());
-
- // Set best NodesBetweenPolls interval to avoid lagging under
- // heavy time pressure.
- if (MaxNodes)
- NodesBetweenPolls = Min(MaxNodes, 30000);
- else if (myTime && myTime < 1000)
- NodesBetweenPolls = 1000;
- else if (myTime && myTime < 5000)
- NodesBetweenPolls = 5000;
- else
- NodesBetweenPolls = 30000;
+ // Wake up needed threads and reset maxPly counter
+ for (int i = 0; i < ThreadsMgr.active_threads(); i++)
+ {
+ ThreadsMgr[i].wake_up();
+ ThreadsMgr[i].maxPly = 0;
+ }
- // Write search information to log file
+ // Write to log file and keep it open to be accessed during the search
if (UseLogFile)
{
std::string name = Options["Search Log Filename"].value<std::string>();
LogFile.open(name.c_str(), std::ios::out | std::ios::app);
LogFile << "\nSearching: " << pos.to_fen()
- << "\ninfinite: " << infinite
- << " ponder: " << ponder
- << " time: " << myTime
- << " increment: " << myIncrement
- << " moves to go: " << movesToGo
+ << "\ninfinite: " << Limits.infinite
+ << " ponder: " << Limits.ponder
+ << " time: " << Limits.time
+ << " increment: " << Limits.increment
+ << " moves to go: " << Limits.movesToGo
<< endl;
}
Move ponderMove = MOVE_NONE;
Move bestMove = id_loop(pos, searchMoves, &ponderMove);
- // Print final search statistics
- cout << "info nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " time " << current_search_time() << endl;
+ cout << "info" << speed_to_uci(pos.nodes_searched()) << endl;
+ // Write final search statistics and close log file
if (UseLogFile)
{
+ int t = current_search_time();
+
LogFile << "Nodes: " << pos.nodes_searched()
- << "\nNodes/second: " << nps(pos)
+ << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0)
<< "\nBest move: " << move_to_san(pos, bestMove);
StateInfo st;
// If we are pondering or in infinite search, we shouldn't print the
// best move before we are told to do so.
- if (!StopRequest && (Pondering || InfiniteSearch))
+ if (!StopRequest && (Limits.ponder || Limits.infinite))
wait_for_stop_or_ponderhit();
- // Could be both MOVE_NONE when searching on a stalemate position
- cout << "bestmove " << bestMove << " ponder " << ponderMove << endl;
+ // 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;
return !QuitRequest;
}
SearchStack ss[PLY_MAX_PLUS_2];
Value bestValues[PLY_MAX_PLUS_2];
int bestMoveChanges[PLY_MAX_PLUS_2];
- int depth, researchCountFL, researchCountFH, aspirationDelta;
+ int depth, selDepth, aspirationDelta;
Value value, alpha, beta;
- Move bestMove, easyMove;
+ Move bestMove, easyMove, skillBest, skillPonder;
- // Moves to search are verified, scored and sorted
- Rml.init(pos, searchMoves);
-
- // Initialize FIXME move before Rml.init()
+ // Initialize stuff before a new search
+ memset(ss, 0, 4 * sizeof(SearchStack));
TT.new_search();
H.clear();
- memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack));
- *ponderMove = bestMove = easyMove = MOVE_NONE;
+ *ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
depth = aspirationDelta = 0;
- ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
+
+ // Moves to search are verified and copied
+ Rml.init(pos, searchMoves);
// Handle special case of searching on a mate/stalemate position
if (Rml.size() == 0)
return MOVE_NONE;
}
- // Is one move significantly better than others after initial scoring ?
- if ( Rml.size() == 1
- || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin)
- easyMove = Rml[0].pv[0];
-
// Iterative deepening loop
- while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest)
+ while (++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth) && !StopRequest)
{
- Rml.bestMoveChanges = researchCountFL = researchCountFH = 0;
- cout << "info depth " << depth << endl;
+ Rml.bestMoveChanges = 0;
+ cout << set960(pos.is_chess960()) << "info depth " << depth << endl;
// Calculate dynamic aspiration window based on previous iterations
if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN)
// Start with a small aspiration window and, in case of fail high/low,
// research with bigger window until not failing high/low anymore.
- while (true)
- {
+ do {
// Search starting from ss+1 to allow calling update_gains()
- value = search<PV, false, true>(pos, ss+1, alpha, beta, depth * ONE_PLY, 0);
+ value = search<PV, false, true>(pos, ss+1, alpha, beta, depth * ONE_PLY);
- // Send PV line to GUI and write to transposition table in case the
- // relevant entries have been overwritten during the search.
+ // Write PV back to transposition table in case the relevant entries
+ // have been overwritten during the search.
for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++)
- {
Rml[i].insert_pv_in_tt(pos);
- cout << set960(pos.is_chess960())
- << Rml[i].pv_info_to_uci(pos, depth, alpha, beta, i) << endl;
- }
// Value cannot be trusted. Break out immediately!
if (StopRequest)
// otherwise exit the fail high/low loop.
if (value >= beta)
{
- beta = Min(beta + aspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
- researchCountFH++;
+ beta = Min(beta + aspirationDelta, VALUE_INFINITE);
+ aspirationDelta += aspirationDelta / 2;
}
else if (value <= alpha)
{
AspirationFailLow = true;
StopOnPonderhit = false;
- alpha = Max(alpha - aspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
- researchCountFL++;
+ alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
+ aspirationDelta += aspirationDelta / 2;
}
else
break;
- }
+
+ } while (abs(value) < VALUE_KNOWN_WIN);
// Collect info about search result
bestMove = Rml[0].pv[0];
+ *ponderMove = Rml[0].pv[1];
bestValues[depth] = value;
bestMoveChanges[depth] = Rml.bestMoveChanges;
+ // Do we need to pick now the best and the ponder moves ?
+ if (SkillLevelEnabled && depth == 1 + SkillLevel)
+ do_skill_level(&skillBest, &skillPonder);
+
+ // Retrieve max searched depth among threads
+ selDepth = 0;
+ for (int i = 0; i < ThreadsMgr.active_threads(); i++)
+ if (ThreadsMgr[i].maxPly > selDepth)
+ selDepth = ThreadsMgr[i].maxPly;
+
+ // Send PV line to GUI and to log file
+ for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
+ cout << Rml[i].pv_info_to_uci(pos, depth, selDepth, alpha, beta, i) << endl;
+
if (UseLogFile)
LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl;
- // Drop the easy move if differs from the new best move
- if (bestMove != easyMove)
+ // Init easyMove after first iteration or drop if differs from the best move
+ if (depth == 1 && (Rml.size() == 1 || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin))
+ easyMove = bestMove;
+ else if (bestMove != easyMove)
easyMove = MOVE_NONE;
- if (UseTimeManagement && !StopRequest)
+ if (Limits.useTimeManagement() && !StopRequest)
{
// Time to stop?
bool noMoreTime = false;
if (noMoreTime)
{
- if (Pondering)
+ if (Limits.ponder)
StopOnPonderhit = true;
else
break;
}
}
- *ponderMove = Rml[0].pv[1];
+ // When using skills fake best and ponder moves with the sub-optimal ones
+ if (SkillLevelEnabled)
+ {
+ if (skillBest == MOVE_NONE) // Still unassigned ?
+ do_skill_level(&skillBest, &skillPonder);
+
+ bestMove = skillBest;
+ *ponderMove = skillPonder;
+ }
+
return bestMove;
}
// here: This is taken care of after we return from the split point.
template <NodeType PvNode, bool SpNode, bool Root>
- Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta > alpha && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
- assert((Root || ply > 0) && ply < PLY_MAX);
assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
Move movesSearched[MOVES_MAX];
ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
- bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
- bool mateThreat = false;
+ bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous, isBadCap;
int moveCount = 0, playedMoveCount = 0;
int threadID = pos.thread();
SplitPoint* sp = NULL;
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
isCheck = pos.is_check();
+ ss->ply = (ss-1)->ply + 1;
+
+ // Used to send selDepth info to GUI
+ if (PvNode && ThreadsMgr[threadID].maxPly < ss->ply)
+ ThreadsMgr[threadID].maxPly = ss->ply;
if (SpNode)
{
tte = NULL;
ttMove = excludedMove = MOVE_NONE;
threatMove = sp->threatMove;
- mateThreat = sp->mateThreat;
goto split_point_start;
}
else if (Root)
bestValue = alpha;
// Step 1. Initialize node and poll. Polling can abort search
- ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
+ ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE;
+ (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
(ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
if (( StopRequest
|| ThreadsMgr.cutoff_at_splitpoint(threadID)
|| pos.is_draw()
- || ply >= PLY_MAX - 1) && !Root)
+ || ss->ply > PLY_MAX) && !Root)
return VALUE_DRAW;
// Step 3. Mate distance pruning
- alpha = Max(value_mated_in(ply), alpha);
- beta = Min(value_mate_in(ply+1), beta);
+ alpha = Max(value_mated_in(ss->ply), alpha);
+ beta = Min(value_mate_in(ss->ply+1), beta);
if (alpha >= beta)
return alpha;
ttMove = tte ? tte->move() : MOVE_NONE;
// At PV nodes we check for exact scores, while at non-PV nodes we check for
- // and return a fail high/low. Biggest advantage at probing at PV nodes is
- // to have a smooth experience in analysis mode.
+ // a fail high/low. Biggest advantage at probing at PV nodes is to have a
+ // smooth experience in analysis mode.
if ( !Root
&& tte
&& (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT
- : ok_to_use_TT(tte, depth, beta, ply)))
+ : ok_to_use_TT(tte, depth, beta, ss->ply)))
{
TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ply);
+ return value_from_tt(tte->value(), ss->ply);
}
- // Step 5. Evaluate the position statically and
- // update gain statistics of parent move.
+ // Step 5. Evaluate the position statically and update parent's gain statistics
if (isCheck)
ss->eval = ss->evalMargin = VALUE_NONE;
else if (tte)
ss->eval = tte->static_value();
ss->evalMargin = tte->static_value_margin();
- refinedValue = refine_eval(tte, ss->eval, ply);
+ refinedValue = refine_eval(tte, ss->eval, ss->ply);
}
else
{
if ( !PvNode
&& depth < RazorDepth
&& !isCheck
- && refinedValue < beta - razor_margin(depth)
+ && refinedValue + razor_margin(depth) < beta
&& ttMove == MOVE_NONE
- && !value_is_mate(beta)
+ && abs(beta) < VALUE_MATE_IN_PLY_MAX
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value rbeta = beta - razor_margin(depth);
- Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO, ply);
+ Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO);
if (v < rbeta)
// Logically we should return (v + razor_margin(depth)), but
// surprisingly this did slightly weaker in tests.
&& !ss->skipNullMove
&& depth < RazorDepth
&& !isCheck
- && refinedValue >= beta + futility_margin(depth, 0)
- && !value_is_mate(beta)
+ && refinedValue - futility_margin(depth, 0) >= beta
+ && abs(beta) < VALUE_MATE_IN_PLY_MAX
&& pos.non_pawn_material(pos.side_to_move()))
return refinedValue - futility_margin(depth, 0);
&& depth > ONE_PLY
&& !isCheck
&& refinedValue >= beta
- && !value_is_mate(beta)
+ && abs(beta) < VALUE_MATE_IN_PLY_MAX
&& pos.non_pawn_material(pos.side_to_move()))
{
ss->currentMove = MOVE_NULL;
int R = 3 + (depth >= 5 * ONE_PLY ? depth / 8 : 0);
// Null move dynamic reduction based on value
- if (refinedValue - beta > PawnValueMidgame)
+ if (refinedValue - PawnValueMidgame > beta)
R++;
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
- nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
+ nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
if (nullValue >= beta)
{
// Do not return unproven mate scores
- if (nullValue >= value_mate_in(PLY_MAX))
+ if (nullValue >= VALUE_MATE_IN_PLY_MAX)
nullValue = beta;
if (depth < 6 * ONE_PLY)
// Do verification search at high depths
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*ONE_PLY, ply);
+ Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*ONE_PLY);
ss->skipNullMove = false;
if (v >= beta)
// move which was reduced. If a connection is found, return a fail
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
- if (nullValue == value_mated_in(ply + 2))
- mateThreat = true;
-
threatMove = (ss+1)->bestMove;
+
if ( depth < ThreatDepth
&& (ss-1)->reduction
&& threatMove != MOVE_NONE
// Step 9. Internal iterative deepening
if ( depth >= IIDDepth[PvNode]
&& ttMove == MOVE_NONE
- && (PvNode || (!isCheck && ss->eval >= beta - IIDMargin)))
+ && (PvNode || (!isCheck && ss->eval + IIDMargin >= beta)))
{
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
ss->skipNullMove = true;
- search<PvNode>(pos, ss, alpha, beta, d, ply);
+ search<PvNode>(pos, ss, alpha, beta, d);
ss->skipNullMove = false;
ttMove = ss->bestMove;
tte = TT.retrieve(posKey);
}
- // Expensive mate threat detection (only for PV nodes)
- if (PvNode)
- mateThreat = pos.has_mate_threat();
-
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
if (SendSearchedNodes)
{
SendSearchedNodes = false;
- cout << "info nodes " << nodes
- << " nps " << nps(pos)
- << " time " << current_search_time() << endl;
+ cout << "info" << speed_to_uci(pos.nodes_searched()) << endl;
}
- if (current_search_time() >= 1000)
+ if (current_search_time() > 2000)
cout << "info currmove " << move
<< " currmovenumber " << moveCount << endl;
}
- isPvMove = (PvNode && moveCount <= (Root ? MultiPV : 1));
+ // At Root and at first iteration do a PV search on all the moves to score root moves
+ isPvMove = (PvNode && moveCount <= (Root ? depth <= ONE_PLY ? 1000 : MultiPV : 1));
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Step 11. Decide the new search depth
- ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, mateThreat, &dangerous);
+ ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, &dangerous);
- // Singular extension search. If all moves but one fail low on a search of (alpha-s, beta-s),
- // and just one fails high on (alpha, beta), then that move is singular and should be extended.
- // To verify this we do a reduced search on all the other moves but the ttMove, if result is
- // lower than ttValue minus a margin then we extend ttMove.
+ // Singular extension search. If all moves but one fail low on a search of
+ // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move
+ // is singular and should be extended. To verify this we do a reduced search
+ // on all the other moves but the ttMove, if result is lower than ttValue minus
+ // a margin then we extend ttMove.
if ( singularExtensionNode
&& move == tte->move()
&& ext < ONE_PLY)
{
- Value ttValue = value_from_tt(tte->value(), ply);
+ Value ttValue = value_from_tt(tte->value(), ss->ply);
if (abs(ttValue) < VALUE_KNOWN_WIN)
{
- Value b = ttValue - SingularExtensionMargin;
+ Value rBeta = ttValue - int(depth);
ss->excludedMove = move;
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, b - 1, b, depth / 2, ply);
+ Value v = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
ss->skipNullMove = false;
ss->excludedMove = MOVE_NONE;
ss->bestMove = MOVE_NONE;
- if (v < b)
+ if (v < rBeta)
ext = ONE_PLY;
}
}
// Update current move (this must be done after singular extension search)
ss->currentMove = move;
- newDepth = depth - (!Root ? ONE_PLY : DEPTH_ZERO) + ext;
+ newDepth = depth - ONE_PLY + ext;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
{
// Move count based pruning
if ( moveCount >= futility_move_count(depth)
- && !(threatMove && connected_threat(pos, move, threatMove))
- && bestValue > value_mated_in(PLY_MAX)) // FIXME bestValue is racy
+ && (!threatMove || !connected_threat(pos, move, threatMove))
+ && bestValue > VALUE_MATED_IN_PLY_MAX) // FIXME bestValue is racy
{
if (SpNode)
lock_grab(&(sp->lock));
// Prune moves with negative SEE at low depths
if ( predictedDepth < 2 * ONE_PLY
- && bestValue > value_mated_in(PLY_MAX)
+ && bestValue > VALUE_MATED_IN_PLY_MAX
&& pos.see_sign(move) < 0)
{
if (SpNode)
}
}
+ // Bad capture detection. Will be used by prob-cut search
+ isBadCap = depth >= 3 * ONE_PLY
+ && depth < 8 * ONE_PLY
+ && captureOrPromotion
+ && move != ttMove
+ && !dangerous
+ && !move_is_promotion(move)
+ && abs(alpha) < VALUE_MATE_IN_PLY_MAX
+ && pos.see_sign(move) < 0;
+
// Step 13. Make the move
pos.do_move(move, st, ci, moveIsCheck);
if (Root && MultiPV > 1)
alpha = -VALUE_INFINITE;
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth);
}
else
{
// Step 14. Reduced depth search
// If the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true;
+ alpha = SpNode ? sp->alpha : alpha;
if ( depth >= 3 * ONE_PLY
&& !captureOrPromotion
{
alpha = SpNode ? sp->alpha : alpha;
Depth d = newDepth - ss->reduction;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
doFullDepthSearch = (value > alpha);
}
ss->reduction = DEPTH_ZERO; // Restore original reduction
}
+ // Probcut search for bad captures. If a reduced search returns a value
+ // very below beta then we can (almost) safely prune the bad capture.
+ if (isBadCap)
+ {
+ ss->reduction = 3 * ONE_PLY;
+ Value rAlpha = alpha - 300;
+ Depth d = newDepth - ss->reduction;
+ value = -search<NonPV>(pos, ss+1, -(rAlpha+1), -rAlpha, d);
+ doFullDepthSearch = (value > rAlpha);
+ ss->reduction = DEPTH_ZERO; // Restore original reduction
+ }
+
// Step 15. Full depth search
if (doFullDepthSearch)
{
alpha = SpNode ? sp->alpha : alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth);
// Step extra. pv search (only in PV nodes)
// Search only for possible new PV nodes, if instead value >= beta then
// parent node fails low with value <= alpha and tries another move.
if (PvNode && value > alpha && (Root || value < beta))
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth);
}
}
else if (SpNode)
sp->betaCutoff = true;
- if (value == value_mate_in(ply + 1))
+ if (value == value_mate_in(ss->ply + 1))
ss->mateKiller = move;
ss->bestMove = move;
if (SpNode)
- sp->parentSstack->bestMove = move;
+ sp->ss->bestMove = move;
}
}
&& ThreadsMgr.available_thread_exists(threadID)
&& !StopRequest
&& !ThreadsMgr.cutoff_at_splitpoint(threadID))
- ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
- threatMove, mateThreat, moveCount, &mp, PvNode);
+ ThreadsMgr.split<FakeSplit>(pos, ss, &alpha, beta, &bestValue, depth,
+ threatMove, moveCount, &mp, PvNode);
}
// Step 19. Check for mate and stalemate
// no legal moves, it must be mate or stalemate.
// If one move was excluded return fail low score.
if (!SpNode && !moveCount)
- return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW;
+ return excludedMove ? oldAlpha : isCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
: bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
- TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
+ 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
if ( bestValue >= beta
&& !pos.move_is_capture_or_promotion(move))
{
+ if (move != ss->killers[0])
+ {
+ ss->killers[1] = ss->killers[0];
+ ss->killers[0] = move;
+ }
update_history(pos, move, depth, movesSearched, playedMoveCount);
- update_killers(move, ss->killers);
}
}
// less than ONE_PLY).
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
assert(depth <= 0);
- assert(ply > 0 && ply < PLY_MAX);
assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
StateInfo st;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
+ ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (pos.is_draw() || ply >= PLY_MAX - 1)
+ if (ss->ply > PLY_MAX || pos.is_draw())
return VALUE_DRAW;
// Decide whether or not to include checks, this fixes also the type of
tte = TT.retrieve(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ply))
+ if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ss->ply))
{
ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ply);
+ return value_from_tt(tte->value(), ss->ply);
}
// Evaluate the position statically
if (bestValue >= beta)
{
if (!tte)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
return bestValue;
}
bestValue = futilityValue;
continue;
}
+
+ // Prune moves with negative or equal SEE
+ if ( futilityBase < beta
+ && depth < DEPTH_ZERO
+ && pos.see(move) <= 0)
+ continue;
}
// Detect non-capture evasions that are candidate to be pruned
evasionPrunable = isCheck
- && bestValue > value_mated_in(PLY_MAX)
+ && bestValue > VALUE_MATED_IN_PLY_MAX
&& !pos.move_is_capture(move)
&& !pos.can_castle(pos.side_to_move());
// Make and search the move
pos.do_move(move, st, ci, moveIsCheck);
- value = -qsearch<PvNode>(pos, ss+1, -beta, -alpha, depth-ONE_PLY, ply+1);
+ value = -qsearch<PvNode>(pos, ss+1, -beta, -alpha, depth-ONE_PLY);
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
// All legal moves have been searched. A special case: If we're in check
// and no legal moves were found, it is checkmate.
if (isCheck && bestValue == -VALUE_INFINITE)
- return value_mated_in(ply);
+ return value_mated_in(ss->ply);
// Update transposition table
ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
}
- // qsearch_scoring() scores each move of a list using a qsearch() evaluation,
- // it is used in RootMoveList to get an initial scoring.
- void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last) {
-
- SearchStack ss[PLY_MAX_PLUS_2];
- StateInfo st;
-
- memset(ss, 0, 4 * sizeof(SearchStack));
- ss[0].eval = ss[0].evalMargin = VALUE_NONE;
-
- for (MoveStack* cur = mlist; cur != last; cur++)
- {
- ss[0].currentMove = cur->move;
- pos.do_move(cur->move, st);
- cur->score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
- pos.undo_move(cur->move);
- }
- }
-
-
// check_is_dangerous() tests if a checking move can be pruned in qsearch().
// bestValue is updated only when returning false because in that case move
// will be pruned.
}
- // value_is_mate() checks if the given value is a mate one eventually
- // compensated for the ply.
-
- bool value_is_mate(Value value) {
-
- assert(abs(value) <= VALUE_INFINITE);
-
- return value <= value_mated_in(PLY_MAX)
- || value >= value_mate_in(PLY_MAX);
- }
-
-
// 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.
// 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_PLY_MAX)
return v + ply;
- if (v <= value_mated_in(PLY_MAX))
+ if (v <= VALUE_MATED_IN_PLY_MAX)
return v - ply;
return v;
Value value_from_tt(Value v, int ply) {
- if (v >= value_mate_in(PLY_MAX))
+ if (v >= VALUE_MATE_IN_PLY_MAX)
return v - ply;
- if (v <= value_mated_in(PLY_MAX))
+ if (v <= VALUE_MATED_IN_PLY_MAX)
return v + ply;
return v;
// the move is marked as 'dangerous' so, at least, we avoid to prune it.
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion,
- bool moveIsCheck, bool mateThreat, bool* dangerous) {
+ bool moveIsCheck, bool* dangerous) {
assert(m != MOVE_NONE);
Depth result = DEPTH_ZERO;
- *dangerous = moveIsCheck | mateThreat;
+ *dangerous = moveIsCheck;
- if (*dangerous)
- {
- if (moveIsCheck && pos.see_sign(m) >= 0)
- result += CheckExtension[PvNode];
-
- if (mateThreat)
- result += MateThreatExtension[PvNode];
- }
+ if (moveIsCheck && pos.see_sign(m) >= 0)
+ result += CheckExtension[PvNode];
if (pos.type_of_piece_on(move_from(m)) == PAWN)
{
&& pos.type_of_piece_on(move_to(m)) != PAWN
&& ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- pos.midgame_value_of_piece_on(move_to(m)) == VALUE_ZERO)
- && !move_is_promotion(m)
- && !move_is_ep(m))
+ && !move_is_special(m))
{
result += PawnEndgameExtension[PvNode];
*dangerous = true;
}
- if ( PvNode
- && captureOrPromotion
- && pos.type_of_piece_on(move_to(m)) != PAWN
- && pos.see_sign(m) >= 0)
- {
- result += ONE_PLY / 2;
- *dangerous = true;
- }
-
return Min(result, ONE_PLY);
}
Value v = value_from_tt(tte->value(), ply);
return ( tte->depth() >= depth
- || v >= Max(value_mate_in(PLY_MAX), beta)
- || v < Min(value_mated_in(PLY_MAX), beta))
+ || v >= Max(VALUE_MATE_IN_PLY_MAX, beta)
+ || v < Min(VALUE_MATED_IN_PLY_MAX, beta))
&& ( ((tte->type() & VALUE_TYPE_LOWER) && v >= beta)
|| ((tte->type() & VALUE_TYPE_UPPER) && v < beta));
}
- // update_killers() add a good move that produced a beta-cutoff
- // among the killer moves of that ply.
-
- void update_killers(Move m, Move killers[]) {
-
- if (m != killers[0])
- {
- killers[1] = killers[0];
- killers[0] = m;
- }
- }
-
-
// update_gains() updates the gains table of a non-capture move given
// the static position evaluation before and after the move.
}
+ // current_search_time() returns the number of milliseconds which have passed
+ // since the beginning of the current search.
+
+ int current_search_time(int set) {
+
+ static int searchStartTime;
+
+ if (set)
+ searchStartTime = set;
+
+ return get_system_time() - searchStartTime;
+ }
+
+
// value_to_uci() converts a value to a string suitable for use with the UCI
// protocol specifications:
//
std::stringstream s;
if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
+ s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
else
- s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2);
+ s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
return s.str();
}
- // current_search_time() returns the number of milliseconds which have passed
- // since the beginning of the current search.
-
- int current_search_time() {
-
- return get_system_time() - SearchStartTime;
- }
+ // speed_to_uci() returns a string with time stats of current search suitable
+ // to be sent to UCI gui.
+ std::string speed_to_uci(int64_t nodes) {
- // nps() computes the current nodes/second count
+ std::stringstream s;
+ int t = current_search_time();
- int nps(const Position& pos) {
+ s << " nodes " << nodes
+ << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0)
+ << " time " << t;
- int t = current_search_time();
- return (t > 0 ? int((pos.nodes_searched() * 1000) / t) : 0);
+ return s.str();
}
// We are line oriented, don't read single chars
std::string command;
- if (!std::getline(std::cin, command))
- command = "quit";
-
- if (command == "quit")
+ if (!std::getline(std::cin, command) || command == "quit")
{
// Quit the program as soon as possible
- Pondering = false;
+ Limits.ponder = false;
QuitRequest = StopRequest = true;
return;
}
{
// Stop calculating as soon as possible, but still send the "bestmove"
// and possibly the "ponder" token when finishing the search.
- Pondering = false;
+ Limits.ponder = false;
StopRequest = true;
}
else if (command == "ponderhit")
// The opponent has played the expected move. GUI sends "ponderhit" if
// we were told to ponder on the same move the opponent has played. We
// should continue searching but switching from pondering to normal search.
- Pondering = false;
+ Limits.ponder = false;
if (StopOnPonderhit)
StopRequest = true;
{
lastInfoTime = t;
- if (dbg_show_mean)
- dbg_print_mean();
-
- if (dbg_show_hit_rate)
- dbg_print_hit_rate();
+ dbg_print_mean();
+ dbg_print_hit_rate();
// Send info on searched nodes as soon as we return to root
SendSearchedNodes = true;
}
// Should we stop the search?
- if (Pondering)
+ if (Limits.ponder)
return;
bool stillAtFirstMove = FirstRootMove
bool noMoreTime = t > TimeMgr.maximum_time()
|| stillAtFirstMove;
- if ( (UseTimeManagement && noMoreTime)
- || (ExactMaxTime && t >= ExactMaxTime)
- || (MaxNodes && pos.nodes_searched() >= MaxNodes)) // FIXME
+ if ( (Limits.useTimeManagement() && noMoreTime)
+ || (Limits.maxTime && t >= Limits.maxTime)
+ || (Limits.maxNodes && pos.nodes_searched() >= Limits.maxNodes)) // FIXME
StopRequest = true;
}
std::string command;
- while (true)
- {
- // Wait for a command from stdin
- if (!std::getline(std::cin, command))
- command = "quit";
+ // Wait for a command from stdin
+ while ( std::getline(std::cin, command)
+ && command != "ponderhit" && command != "stop" && command != "quit") {};
- if (command == "quit")
- {
- QuitRequest = true;
- break;
- }
- else if (command == "ponderhit" || command == "stop")
- break;
- }
+ if (command != "ponderhit" && command != "stop")
+ QuitRequest = true; // Must be "quit" or getline() returned false
}
assert(threadID >= 0 && threadID < MAX_THREADS);
int i;
- bool allFinished = false;
+ bool allFinished;
while (true)
{
// If we are not thinking, wait for a condition to be signaled
// instead of wasting CPU time polling for work.
- while ( threadID >= activeThreads || threads[threadID].state == THREAD_INITIALIZING
+ while ( threadID >= activeThreads
+ || threads[threadID].state == THREAD_INITIALIZING
|| (useSleepingThreads && threads[threadID].state == THREAD_AVAILABLE))
{
assert(!sp || useSleepingThreads);
if (threads[threadID].state == THREAD_INITIALIZING)
threads[threadID].state = THREAD_AVAILABLE;
- // Grab the lock to avoid races with wake_sleeping_thread()
- lock_grab(&sleepLock[threadID]);
+ // Grab the lock to avoid races with Thread::wake_up()
+ lock_grab(&threads[threadID].sleepLock);
// If we are master and all slaves have finished do not go to sleep
for (i = 0; sp && i < activeThreads && !sp->slaves[i]; i++) {}
if (allFinished || allThreadsShouldExit)
{
- lock_release(&sleepLock[threadID]);
+ lock_release(&threads[threadID].sleepLock);
break;
}
// Do sleep here after retesting sleep conditions
if (threadID >= activeThreads || threads[threadID].state == THREAD_AVAILABLE)
- cond_wait(&sleepCond[threadID], &sleepLock[threadID]);
+ cond_wait(&threads[threadID].sleepCond, &threads[threadID].sleepLock);
- lock_release(&sleepLock[threadID]);
+ lock_release(&threads[threadID].sleepLock);
}
// If this thread has been assigned work, launch a search
threads[threadID].state = THREAD_SEARCHING;
- // Here we call search() with SplitPoint template parameter set to true
+ // Copy split point position and search stack and call search()
+ // with SplitPoint template parameter set to true.
+ SearchStack ss[PLY_MAX_PLUS_2];
SplitPoint* tsp = threads[threadID].splitPoint;
Position pos(*tsp->pos, threadID);
- SearchStack* ss = tsp->sstack[threadID] + 1;
- ss->sp = tsp;
+
+ memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack));
+ (ss+1)->sp = tsp;
if (tsp->pvNode)
- search<PV, true, false>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ search<PV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
else
- search<NonPV, true, false>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ search<NonPV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
assert(threads[threadID].state == THREAD_SEARCHING);
// Wake up master thread so to allow it to return from the idle loop in
// case we are the last slave of the split point.
- if (useSleepingThreads && threadID != tsp->master && threads[tsp->master].state == THREAD_AVAILABLE)
- wake_sleeping_thread(tsp->master);
+ if ( useSleepingThreads
+ && threadID != tsp->master
+ && threads[tsp->master].state == THREAD_AVAILABLE)
+ threads[tsp->master].wake_up();
}
// If this thread is the master of a split point and all slaves have
}
- // init_threads() is called during startup. It launches all helper threads,
- // and initializes the split point stack and the global locks and condition
- // objects.
+ // init_threads() is called during startup. Initializes locks and condition
+ // variables and launches all threads sending them immediately to sleep.
void ThreadsManager::init_threads() {
int i, arg[MAX_THREADS];
bool ok;
- // Initialize global locks
+ // This flag is needed to properly end the threads when program exits
+ allThreadsShouldExit = false;
+
+ // Threads will sent to sleep as soon as created, only main thread is kept alive
+ activeThreads = 1;
+
lock_init(&mpLock);
for (i = 0; i < MAX_THREADS; i++)
{
- lock_init(&sleepLock[i]);
- cond_init(&sleepCond[i]);
- }
+ // Initialize thread and split point locks
+ lock_init(&threads[i].sleepLock);
+ cond_init(&threads[i].sleepCond);
- // Initialize splitPoints[] locks
- for (i = 0; i < MAX_THREADS; i++)
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
lock_init(&(threads[i].splitPoints[j].lock));
- // Will be set just before program exits to properly end the threads
- allThreadsShouldExit = false;
-
- // Threads will be put all threads to sleep as soon as created
- activeThreads = 1;
-
- // All threads except the main thread should be initialized to THREAD_INITIALIZING
- threads[0].state = THREAD_SEARCHING;
- for (i = 1; i < MAX_THREADS; i++)
- threads[i].state = THREAD_INITIALIZING;
+ // All threads but first should be set to THREAD_INITIALIZING
+ threads[i].state = (i == 0 ? THREAD_SEARCHING : THREAD_INITIALIZING);
+ }
- // Launch the helper threads
+ // Create and startup the threads
for (i = 1; i < MAX_THREADS; i++)
{
arg[i] = i;
void ThreadsManager::exit_threads() {
- allThreadsShouldExit = true; // Let the woken up threads to exit idle_loop()
+ // Force the woken up threads to exit idle_loop() and hence terminate
+ allThreadsShouldExit = true;
- // Wake up all the threads and waits for termination
- for (int i = 1; i < MAX_THREADS; i++)
+ for (int i = 0; i < MAX_THREADS; i++)
{
- wake_sleeping_thread(i);
- while (threads[i].state != THREAD_TERMINATED) {}
- }
+ // Wake up all the threads and waits for termination
+ if (i != 0)
+ {
+ threads[i].wake_up();
+ while (threads[i].state != THREAD_TERMINATED) {}
+ }
+
+ // Now we can safely destroy the locks and wait conditions
+ lock_destroy(&threads[i].sleepLock);
+ cond_destroy(&threads[i].sleepCond);
- // Now we can safely destroy the locks
- for (int i = 0; i < MAX_THREADS; i++)
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
lock_destroy(&(threads[i].splitPoints[j].lock));
+ }
lock_destroy(&mpLock);
-
- // Now we can safely destroy the wait conditions
- for (int i = 0; i < MAX_THREADS; i++)
- {
- lock_destroy(&sleepLock[i]);
- cond_destroy(&sleepCond[i]);
- }
}
// call search().When all threads have returned from search() then split() returns.
template <bool Fake>
- void ThreadsManager::split(Position& pos, SearchStack* ss, int ply, Value* alpha,
- const Value beta, Value* bestValue, Depth depth, Move threatMove,
- bool mateThreat, int moveCount, MovePicker* mp, bool pvNode) {
+ void ThreadsManager::split(Position& pos, SearchStack* ss, Value* alpha, const Value beta,
+ Value* bestValue, Depth depth, Move threatMove,
+ int moveCount, MovePicker* mp, bool pvNode) {
assert(pos.is_ok());
- assert(ply > 0 && ply < PLY_MAX);
assert(*bestValue >= -VALUE_INFINITE);
assert(*bestValue <= *alpha);
assert(*alpha < beta);
splitPoint.parent = masterThread.splitPoint;
splitPoint.master = master;
splitPoint.betaCutoff = false;
- splitPoint.ply = ply;
splitPoint.depth = depth;
splitPoint.threatMove = threatMove;
- splitPoint.mateThreat = mateThreat;
splitPoint.alpha = *alpha;
splitPoint.beta = beta;
splitPoint.pvNode = pvNode;
splitPoint.moveCount = moveCount;
splitPoint.pos = &pos;
splitPoint.nodes = 0;
- splitPoint.parentSstack = ss;
+ splitPoint.ss = ss;
for (i = 0; i < activeThreads; i++)
splitPoint.slaves[i] = 0;
lock_release(&mpLock);
// Tell the threads that they have work to do. This will make them leave
- // their idle loop. But before copy search stack tail for each thread.
+ // their idle loop.
for (i = 0; i < activeThreads; i++)
if (i == master || splitPoint.slaves[i])
{
- memcpy(splitPoint.sstack[i], ss - 1, 4 * sizeof(SearchStack));
-
assert(i == master || threads[i].state == THREAD_BOOKED);
threads[i].state = THREAD_WORKISWAITING; // This makes the slave to exit from idle_loop()
if (useSleepingThreads && i != master)
- wake_sleeping_thread(i);
+ threads[i].wake_up();
}
// Everything is set up. The master thread enters the idle loop, from
}
- // wake_sleeping_thread() wakes up the thread with the given threadID
- // when it is time to start a new search.
-
- void ThreadsManager::wake_sleeping_thread(int threadID) {
-
- lock_grab(&sleepLock[threadID]);
- cond_signal(&sleepCond[threadID]);
- lock_release(&sleepLock[threadID]);
- }
-
-
/// RootMove and RootMoveList method's definitions
RootMove::RootMove() {
TTEntry* tte;
int ply = 1;
- assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+ assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0]));
pos.do_move(pv[0], *st++);
while ( (tte = TT.retrieve(pos.get_key())) != NULL
&& tte->move() != MOVE_NONE
- && move_is_legal(pos, tte->move())
+ && pos.move_is_legal(tte->move())
&& ply < PLY_MAX
&& (!pos.is_draw() || ply < 2))
{
Value v, m = VALUE_NONE;
int ply = 0;
- assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+ assert(pv[0] != MOVE_NONE && pos.move_is_legal(pv[0]));
do {
k = pos.get_key();
}
// pv_info_to_uci() returns a string with information on the current PV line
- // formatted according to UCI specification. It is called at each iteration
- // or after a new pv is found.
+ // formatted according to UCI specification.
- std::string RootMove::pv_info_to_uci(Position& pos, int depth, Value alpha, Value beta, int pvLine) {
-
- std::stringstream s, l;
- Move* m = pv;
-
- while (*m != MOVE_NONE)
- l << *m++ << " ";
+ std::string RootMove::pv_info_to_uci(Position& pos, int depth, int selDepth, Value alpha,
+ Value beta, int pvIdx) {
+ std::stringstream s;
s << "info depth " << depth
- << " seldepth " << int(m - pv)
- << " multipv " << pvLine + 1
+ << " seldepth " << selDepth
+ << " multipv " << pvIdx + 1
<< " score " << value_to_uci(pv_score)
<< (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "")
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv " << l.str();
+ << speed_to_uci(pos.nodes_searched())
+ << " pv ";
+
+ for (Move* m = pv; *m != MOVE_NONE; m++)
+ s << *m << " ";
return s.str();
}
clear();
bestMoveChanges = 0;
- // Generate all legal moves and score them
+ // Generate all legal moves and add them to RootMoveList
MoveStack* last = generate<MV_LEGAL>(pos, mlist);
- qsearch_scoring(pos, mlist, last);
-
- // Add each move to the RootMoveList's vector
for (MoveStack* cur = mlist; cur != last; cur++)
{
// If we have a searchMoves[] list then verify cur->move
RootMove rm;
rm.pv[0] = cur->move;
rm.pv[1] = MOVE_NONE;
- rm.pv_score = Value(cur->score);
+ rm.pv_score = -VALUE_INFINITE;
push_back(rm);
}
- sort();
+ }
+
+
+ // 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) {
+
+ assert(MultiPV > 1);
+
+ // Rml list is already sorted by pv_score in descending order
+ int s;
+ int max_s = -VALUE_INFINITE;
+ int size = Min(MultiPV, (int)Rml.size());
+ int max = Rml[0].pv_score;
+ int var = Min(max - Rml[size - 1].pv_score, PawnValueMidgame);
+ int wk = 120 - 2 * SkillLevel;
+
+ // PRNG sequence should be non deterministic
+ for (int i = abs(get_system_time() % 50); i > 0; i--)
+ RK.rand<unsigned>();
+
+ // Choose best move. For each move's score we add two terms both dependent
+ // on wk, one deterministic and bigger for weaker moves, and one random,
+ // then we choose the move with the resulting highest score.
+ for (int i = 0; i < size; i++)
+ {
+ s = Rml[i].pv_score;
+
+ // Don't allow crazy blunders even at very low skills
+ if (i > 0 && Rml[i-1].pv_score > s + EasyMoveMargin)
+ break;
+
+ // This is our magical formula
+ s += ((max - s) * wk + var * (RK.rand<unsigned>() % wk)) / 128;
+
+ if (s > max_s)
+ {
+ max_s = s;
+ *best = Rml[i].pv[0];
+ *ponder = Rml[i].pv[1];
+ }
+ }
}
} // namespace
projects / stockfish / blobdiff