#include "move.h"
#include "movegen.h"
#include "movepick.h"
-#include "lock.h"
#include "search.h"
#include "timeman.h"
#include "thread.h"
namespace {
- // Different node types, used as template parameter
- enum NodeType { NonPV, PV };
-
- // Set to true to force running with one thread. Used for debugging.
+ // Set to true to force running with one thread. Used for debugging
const bool FakeSplit = false;
- // 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 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
- need to explicitly initialize to zero its data members because variables with
- static storage duration are automatically set to zero before enter main()
- */
- public:
- void init_threads();
- void exit_threads();
-
- int min_split_depth() const { return minimumSplitDepth; }
- int active_threads() const { return activeThreads; }
- void set_active_threads(int cnt) { activeThreads = cnt; }
-
- void read_uci_options();
- 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);
-
- private:
- Depth minimumSplitDepth;
- int maxThreadsPerSplitPoint;
- bool useSleepingThreads;
- int activeThreads;
- volatile bool allThreadsShouldExit;
- Thread threads[MAX_THREADS];
- Lock mpLock, sleepLock[MAX_THREADS];
- WaitCondition sleepCond[MAX_THREADS];
- };
-
+ // Different node types, used as template parameter
+ enum NodeType { Root, PV, NonPV, SplitPointPV, SplitPointNonPV };
// 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
// according to the order in which moves are returned by MovePicker.
-
struct RootMove {
RootMove();
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 pvIdx);
int64_t nodes;
Value pv_score;
Move pv[PLY_MAX_PLUS_2];
};
-
- // RootMoveList struct is just a std::vector<> of RootMove objects,
- // with an handful of methods above the standard ones.
-
+ // RootMoveList struct is mainly a std::vector of RootMove objects
struct RootMoveList : public std::vector<RootMove> {
-
- typedef std::vector<RootMove> Base;
-
void init(Position& pos, Move searchMoves[]);
- void sort() { insertion_sort<RootMove, Base::iterator>(begin(), end()); }
- void sort_multipv(int n) { insertion_sort<RootMove, Base::iterator>(begin(), begin() + n); }
-
int bestMoveChanges;
};
- // 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) = int(f);
- return os;
- }
-
+ /// Constants
- /// Adjustments
+ // 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]; }
// Step 6. Razoring
// Step 9. Internal iterative deepening
// Minimum depth for use of internal iterative deepening
- const Depth IIDDepth[2] = { 8 * ONE_PLY /* non-PV */, 5 * ONE_PLY /* PV */};
+ const Depth IIDDepth[] = { 8 * ONE_PLY, 5 * ONE_PLY };
// At Non-PV nodes we do an internal iterative deepening search
// when the static evaluation is bigger then beta - IIDMargin.
// 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. Array index 0 is used for non-PV nodes, index 1 for PV nodes
+ const Depth CheckExtension[] = { ONE_PLY / 2, ONE_PLY / 1 };
+ const Depth PawnEndgameExtension[] = { ONE_PLY / 1, ONE_PLY / 1 };
+ const Depth PawnPushTo7thExtension[] = { ONE_PLY / 2, ONE_PLY / 2 };
+ const Depth PassedPawnExtension[] = { DEPTH_ZERO, ONE_PLY / 2 };
// Minimum depth for use of singular extension
- const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */};
+ const Depth SingularExtensionDepth[] = { 8 * ONE_PLY, 6 * ONE_PLY };
// Step 12. Futility pruning
const Value FutilityMarginQS = Value(0x80);
// Futility lookup tables (initialized at startup) and their access functions
- Value FutilityMarginsMatrix[16][64]; // [depth][moveNumber]
- int FutilityMoveCountArray[32]; // [depth]
+ Value FutilityMargins[16][64]; // [depth][moveNumber]
+ int FutilityMoveCounts[32]; // [depth]
+
+ inline Value futility_margin(Depth d, int mn) {
+
+ return d < 7 * ONE_PLY ? FutilityMargins[Max(d, 1)][Min(mn, 63)]
+ : 2 * VALUE_INFINITE;
+ }
- 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; }
+ inline int futility_move_count(Depth d) {
+
+ return d < 16 * ONE_PLY ? FutilityMoveCounts[d] : MAX_MOVES;
+ }
// Step 14. Reduced search
- // Reduction lookup tables (initialized at startup) and their getter functions
- int8_t ReductionMatrix[2][64][64]; // [pv][depth][moveNumber]
+ // Reduction lookup tables (initialized at startup) and their access function
+ int8_t Reductions[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)]; }
+ template <bool PvNode> inline Depth reduction(Depth d, int mn) {
+
+ return (Depth) Reductions[PvNode][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
- Book OpeningBook;
-
// Root move list
RootMoveList Rml;
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;
// 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
// lines (64 bytes each) from the heavy multi-thread read accessed variables.
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);
-
- template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
-
- template <NodeType PvNode>
- inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ template <NodeType NT>
+ 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);
- }
-
- template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool mateThreat, bool* dangerous);
+ template <NodeType NT>
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue);
bool connected_moves(const Position& pos, Move m1, Move m2);
void update_gains(const Position& pos, Move move, Value before, Value after);
void do_skill_level(Move* best, Move* ponder);
- int current_search_time();
- std::string value_to_uci(Value v);
+ int current_search_time(int set = 0);
+ std::string score_to_uci(Value v, Value alpha, Value beta);
std::string speed_to_uci(int64_t nodes);
+ std::string pv_to_uci(Move pv[], int pvNum);
+ std::string depth_to_uci(Depth depth);
void poll(const Position& pos);
void wait_for_stop_or_ponderhit();
-#if !defined(_MSC_VER)
- void* init_thread(void* threadID);
-#else
- DWORD WINAPI init_thread(LPVOID threadID);
-#endif
+ // MovePickerExt template class extends MovePicker and allows to choose at compile
+ // time the proper moves source according to the type of node. In the default case
+ // we simply create and use a standard MovePicker object.
+ template<NodeType> struct MovePickerExt : 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 is an extended MovePicker used to choose at compile time
- // the proper move source according to the type of node.
- template<bool SpNode, bool Root> struct MovePickerExt;
+ RootMove& current() { assert(false); return Rml[0]; } // Dummy, needed to compile
+ };
- // In Root nodes use RootMoveList as source. Score and sort the root moves
- // before to search them.
- template<> struct MovePickerExt<false, true> : public MovePicker {
+ // In case of a SpNode we use split point's shared MovePicker object as moves source
+ template<> struct MovePickerExt<SplitPointNonPV> : public MovePickerExt<NonPV> {
MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
- : MovePicker(p, ttm, d, h, ss, b), firstCall(true) {
- Move move;
- Value score = VALUE_ZERO;
-
- // 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 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)
- {
- rm->non_pv_score = score--;
- break;
- }
+ : MovePickerExt<NonPV>(p, ttm, d, h, ss, b), mp(ss->sp->mp) {}
- Rml.sort();
- rm = Rml.begin();
- }
+ Move get_next_move() { return mp->get_next_move(); }
+ MovePicker* mp;
+ };
- Move get_next_move() {
+ template<> struct MovePickerExt<SplitPointPV> : public MovePickerExt<SplitPointNonPV> {
- if (!firstCall)
- ++rm;
- else
- firstCall = false;
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
+ : MovePickerExt<SplitPointNonPV>(p, ttm, d, h, ss, b) {}
+ };
- return rm != Rml.end() ? rm->pv[0] : MOVE_NONE;
- }
+ // In case of a Root node we use RootMoveList as moves source
+ template<> struct MovePickerExt<Root> : public MovePicker {
+
+ MovePickerExt(const Position&, Move, Depth, const History&, SearchStack*, Value);
+ RootMove& current() { return Rml[cur]; }
+ Move get_next_move() { return ++cur < (int)Rml.size() ? Rml[cur].pv[0] : MOVE_NONE; }
- RootMoveList::iterator rm;
- bool firstCall;
+ int cur;
};
- // In SpNodes use split point's shared MovePicker object as move source
- template<> struct MovePickerExt<true, false> : public MovePicker {
+ // 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) {
- 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) {}
+ bool chess960 = (os.iword(0) != 0); // See set960()
+ return os << move_to_uci(m, chess960);
+ }
- Move get_next_move() { return mp->get_next_move(); }
+ // 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 {};
- RootMoveList::iterator rm; // Dummy, needed to compile
- MovePicker* mp;
- };
+ std::ostream& operator<< (std::ostream& os, const set960& f) {
- // Default case, create and use a MovePicker object as source
- template<> struct MovePickerExt<false, false> : public MovePicker {
+ os.iword(0) = int(f);
+ return os;
+ }
- MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
- : MovePicker(p, ttm, d, h, ss, b) {}
+ // extension() decides whether a move should be searched with normal depth,
+ // or with extended depth. Certain classes of moves (checking moves, in
+ // particular) are searched with bigger depth than ordinary moves and in
+ // any case are marked as 'dangerous'. Note that also if a move is not
+ // extended, as example because the corresponding UCI option is set to zero,
+ // the move is marked as 'dangerous' so, at least, we avoid to prune it.
+ template <bool PvNode>
+ FORCE_INLINE Depth extension(const Position& pos, Move m, bool captureOrPromotion,
+ bool moveIsCheck, bool* dangerous) {
+ assert(m != MOVE_NONE);
- RootMoveList::iterator rm; // Dummy, needed to compile
- };
+ Depth result = DEPTH_ZERO;
+ *dangerous = moveIsCheck;
+
+ if (moveIsCheck && pos.see_sign(m) >= 0)
+ result += CheckExtension[PvNode];
+
+ if (piece_type(pos.piece_on(move_from(m))) == PAWN)
+ {
+ Color c = pos.side_to_move();
+ if (relative_rank(c, move_to(m)) == RANK_7)
+ {
+ result += PawnPushTo7thExtension[PvNode];
+ *dangerous = true;
+ }
+ if (pos.pawn_is_passed(c, move_to(m)))
+ {
+ result += PassedPawnExtension[PvNode];
+ *dangerous = true;
+ }
+ }
+
+ if ( captureOrPromotion
+ && piece_type(pos.piece_on(move_to(m))) != PAWN
+ && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
+ - piece_value_midgame(pos.piece_on(move_to(m))) == VALUE_ZERO)
+ && !move_is_special(m))
+ {
+ result += PawnEndgameExtension[PvNode];
+ *dangerous = true;
+ }
+
+ return Min(result, ONE_PLY);
+ }
} // namespace
-/// init_threads() is called during startup. It initializes various lookup tables
-/// and creates and launches search threads.
+/// init_search() is called during startup to initialize various lookup tables
-void init_threads() {
+void init_search() {
int d; // depth (ONE_PLY == 2)
int hd; // half depth (ONE_PLY == 1)
{
double pvRed = log(double(hd)) * log(double(mc)) / 3.0;
double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
- ReductionMatrix[PV][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
- ReductionMatrix[NonPV][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
+ Reductions[1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
+ Reductions[0][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
}
// Init futility margins array
for (d = 1; d < 16; d++) for (mc = 0; mc < 64; mc++)
- FutilityMarginsMatrix[d][mc] = Value(112 * int(log(double(d * d) / 2) / log(2.0) + 1.001) - 8 * mc + 45);
+ FutilityMargins[d][mc] = Value(112 * int(log(double(d * d) / 2) / log(2.0) + 1.001) - 8 * mc + 45);
// 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();
+ FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(d, 2.0));
}
-/// exit_threads() is a trampoline to access ThreadsMgr from outside of current file
-void exit_threads() { ThreadsMgr.exit_threads(); }
-
-
-/// perft() is our utility to verify move generation. All the legal moves up to
-/// given depth are generated and counted and the sum returned.
+/// 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 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);
+ MoveList<MV_LEGAL> ml(pos);
// 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);
+ return ml.size();
// Loop through all legal moves
CheckInfo ci(pos);
- for (MoveStack* cur = mlist; cur != last; cur++)
+ for ( ; !ml.end(); ++ml)
{
- m = cur->move;
- pos.do_move(m, st, ci, pos.move_is_check(m, ci));
+ pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci));
sum += perft(pos, depth - ONE_PLY);
- pos.undo_move(m);
+ pos.undo_move(ml.move());
}
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 global
-/// variables, and calls id_loop(). It returns false when a quit command is
+/// 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[]) {
+
+ static Book book;
// 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;
-
- // Look for a book move, only during games, not tests
- if (UseTimeManagement && Options["OwnBook"].value<bool>())
+ current_search_time(get_system_time());
+ Limits = limits;
+ TimeMgr.init(Limits, pos.startpos_ply_counter());
+
+ // Set output steram in normal or chess960 mode
+ cout << set960(pos.is_chess960());
+
+ // 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
+ if (Options["OwnBook"].value<bool>())
{
- if (Options["Book File"].value<std::string>() != OpeningBook.name())
- OpeningBook.open(Options["Book File"].value<std::string>());
+ if (Options["Book File"].value<std::string>() != book.name())
+ book.open(Options["Book File"].value<std::string>());
- Move bookMove = OpeningBook.get_move(pos, Options["Best Book Move"].value<bool>());
+ Move bookMove = book.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 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>();
- PawnPushTo7thExtension[0] = Options["Pawn Push to 7th Extension (non-PV nodes)"].value<Depth>();
- PassedPawnExtension[1] = Options["Passed Pawn 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>();
- UCIMultiPV = Options["MultiPV"].value<int>();
- SkillLevel = Options["Skill level"].value<int>();
- UseLogFile = Options["Use Search Log"].value<bool>();
+ UCIMultiPV = Options["MultiPV"].value<int>();
+ SkillLevel = Options["Skill Level"].value<int>();
read_evaluation_uci_options(pos.side_to_move());
+ Threads.read_uci_options();
+
+ // If needed allocate pawn and material hash tables and adjust TT size
+ Threads.init_hash_tables();
+ TT.set_size(Options["Hash"].value<int>());
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. Main thread, with threadID == 0, is always active
- 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 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 < Threads.size(); i++)
+ {
+ Threads[i].wake_up();
+ Threads[i].maxPly = 0;
+ }
- // Write search information to log file
- if (UseLogFile)
+ // Write to log file and keep it open to be accessed during the search
+ if (Options["Use Search Log"].value<bool>())
{
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
- << endl;
+ if (LogFile.is_open())
+ LogFile << "\nSearching: " << pos.to_fen()
+ << "\ninfinite: " << Limits.infinite
+ << " ponder: " << Limits.ponder
+ << " time: " << Limits.time
+ << " increment: " << Limits.increment
+ << " moves to go: " << Limits.movesToGo
+ << endl;
}
// We're ready to start thinking. Call the iterative deepening loop function
Move ponderMove = MOVE_NONE;
Move bestMove = id_loop(pos, searchMoves, &ponderMove);
- // Print final search statistics
- cout << "info" << speed_to_uci(pos.nodes_searched()) << endl;
-
- if (UseLogFile)
+ // Write final search statistics and close log file
+ if (LogFile.is_open())
{
int t = current_search_time();
LogFile << "Nodes: " << pos.nodes_searched()
- << "\nNodes/second: " << (t > 0 ? int(pos.nodes_searched() * 1000 / t) : 0)
+ << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0)
<< "\nBest move: " << move_to_san(pos, bestMove);
StateInfo st;
}
// This makes all the threads to go to sleep
- ThreadsMgr.set_active_threads(1);
+ Threads.set_size(1);
// 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 MOVE_NONE when searching on a stalemate position
SearchStack ss[PLY_MAX_PLUS_2];
Value bestValues[PLY_MAX_PLUS_2];
int bestMoveChanges[PLY_MAX_PLUS_2];
- int depth, aspirationDelta, skillSamplingDepth;
+ int depth, aspirationDelta;
Value value, alpha, beta;
Move bestMove, easyMove, skillBest, skillPonder;
TT.new_search();
H.clear();
*ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
- depth = aspirationDelta = skillSamplingDepth = 0;
+ depth = aspirationDelta = 0;
alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
Rml.init(pos, searchMoves);
// Handle special case of searching on a mate/stalemate position
- if (Rml.size() == 0)
+ if (!Rml.size())
{
- cout << "info depth 0 score "
- << value_to_uci(pos.is_check() ? -VALUE_MATE : VALUE_DRAW)
- << endl;
+ cout << "info" << depth_to_uci(DEPTH_ZERO)
+ << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW, alpha, beta) << endl;
return MOVE_NONE;
}
- // Choose a random sampling depth according to SkillLevel so that at low
- // skills there is an higher risk to pick up a blunder.
- if (SkillLevelEnabled)
- skillSamplingDepth = 4 + SkillLevel + (RK.rand<unsigned>() % 4);
-
- // Iterative deepening loop
- while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest)
+ // Iterative deepening loop until requested to stop or target depth reached
+ while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
{
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)
// research with bigger window until not failing high/low anymore.
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<Root>(pos, ss+1, alpha, beta, depth * ONE_PLY);
// Write PV back to transposition table in case the relevant entries
// have been overwritten during the search.
if (StopRequest)
break;
- assert(value >= alpha);
+ // 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.
+ if ((value > alpha && value < beta) || current_search_time() > 2000)
+ for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
+ cout << "info"
+ << depth_to_uci(depth * ONE_PLY)
+ << score_to_uci(Rml[i].pv_score, alpha, beta)
+ << speed_to_uci(pos.nodes_searched())
+ << pv_to_uci(Rml[i].pv, i + 1) << endl;
// In case of failing high/low increase aspiration window and research,
// otherwise exit the fail high/low loop.
bestMoveChanges[depth] = Rml.bestMoveChanges;
// Do we need to pick now the best and the ponder moves ?
- if (SkillLevelEnabled && depth == skillSamplingDepth)
+ if (SkillLevelEnabled && depth == 1 + SkillLevel)
do_skill_level(&skillBest, &skillPonder);
- // 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, alpha, beta, i) << endl;
-
- if (UseLogFile)
+ if (LogFile.is_open())
LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl;
// Init easyMove after first iteration or drop if differs from the best move
else if (bestMove != easyMove)
easyMove = MOVE_NONE;
- if (UseTimeManagement && !StopRequest)
+ // Check for some early stop condition
+ if (!StopRequest && Limits.useTimeManagement())
{
- // Time to stop?
- bool noMoreTime = false;
-
// Stop search early when the last two iterations returned a mate score
if ( depth >= 5
- && abs(bestValues[depth]) >= abs(VALUE_MATE) - 100
- && abs(bestValues[depth - 1]) >= abs(VALUE_MATE) - 100)
- noMoreTime = true;
+ && abs(bestValues[depth]) >= VALUE_MATE_IN_PLY_MAX
+ && abs(bestValues[depth - 1]) >= VALUE_MATE_IN_PLY_MAX)
+ StopRequest = true;
// Stop search early if one move seems to be much better than the
- // others or if there is only a single legal move. In this latter
- // case we search up to Iteration 8 anyway to get a proper score.
+ // others or if there is only a single legal move. Also in the latter
+ // case we search up to some depth anyway to get a proper score.
if ( depth >= 7
&& easyMove == bestMove
&& ( Rml.size() == 1
&& current_search_time() > TimeMgr.available_time() / 16)
||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100
&& current_search_time() > TimeMgr.available_time() / 32)))
- noMoreTime = true;
+ StopRequest = true;
- // Add some extra time if the best move has changed during the last two iterations
+ // 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[depth], bestMoveChanges[depth - 1]);
- // Stop search if most of MaxSearchTime is consumed at the end of the
- // iteration. We probably don't have enough time to search the first
- // move at the next iteration anyway.
- if (current_search_time() > (TimeMgr.available_time() * 80) / 128)
- noMoreTime = true;
+ // 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 (current_search_time() > (TimeMgr.available_time() * 62) / 100)
+ StopRequest = true;
- if (noMoreTime)
+ // If we are allowed to ponder do not stop the search now but keep pondering
+ if (StopRequest && Limits.ponder)
{
- if (Pondering)
- StopOnPonderhit = true;
- else
- break;
+ StopRequest = false;
+ StopOnPonderhit = true;
}
}
}
- // When using skills fake best and ponder moves with the sub-optimal ones
+ // When using skills overwrite best and ponder moves with the sub-optimal ones
if (SkillLevelEnabled)
{
if (skillBest == MOVE_NONE) // Still unassigned ?
// all this work again. We also don't need to store anything to the hash table
// 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) {
+ template <NodeType NT>
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
+
+ const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV);
+ const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV);
+ const bool RootNode = (NT == Root);
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());
+ assert(pos.thread() >= 0 && pos.thread() < Threads.size());
- Move movesSearched[MOVES_MAX];
+ Move movesSearched[MAX_MOVES];
int64_t nodes;
StateInfo st;
const TTEntry *tte;
ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
- bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous, isBadCap;
- bool mateThreat = false;
+ bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous;
int moveCount = 0, playedMoveCount = 0;
- int threadID = pos.thread();
+ Thread& thread = Threads[pos.thread()];
SplitPoint* sp = NULL;
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
- isCheck = pos.is_check();
+ inCheck = pos.in_check();
+ ss->ply = (ss-1)->ply + 1;
- if (SpNode)
+ // Used to send selDepth info to GUI
+ if (PvNode && thread.maxPly < ss->ply)
+ thread.maxPly = ss->ply;
+
+ // Step 1. Initialize node.
+ if (!SpNode)
+ {
+ 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] = MOVE_NONE;
+ }
+ else
{
sp = ss->sp;
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 = (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)
+ // Step 3. Mate distance pruning
+ if (!RootNode)
{
- NodesSincePoll = 0;
- poll(pos);
+ alpha = Max(value_mated_in(ss->ply), alpha);
+ beta = Min(value_mate_in(ss->ply+1), beta);
+ if (alpha >= beta)
+ return alpha;
}
- // Step 2. Check for aborted search and immediate draw
- if (( StopRequest
- || ThreadsMgr.cutoff_at_splitpoint(threadID)
- || pos.is_draw()
- || ply >= PLY_MAX - 1) && !Root)
- return VALUE_DRAW;
-
- // Step 3. Mate distance pruning
- alpha = Max(value_mated_in(ply), alpha);
- beta = Min(value_mate_in(ply+1), beta);
- if (alpha >= beta)
- return alpha;
-
// Step 4. Transposition table lookup
// 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();
-
- tte = TT.retrieve(posKey);
+ tte = TT.probe(posKey);
ttMove = 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
// 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)))
+ if (tte && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT
+ : 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 parent's gain statistics
- if (isCheck)
+ if (inCheck)
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
{
// Step 6. Razoring (is omitted in PV nodes)
if ( !PvNode
&& depth < RazorDepth
- && !isCheck
+ && !inCheck
&& refinedValue + razor_margin(depth) < beta
&& ttMove == MOVE_NONE
&& 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.
if ( !PvNode
&& !ss->skipNullMove
&& depth < RazorDepth
- && !isCheck
+ && !inCheck
&& refinedValue - futility_margin(depth, 0) >= beta
&& abs(beta) < VALUE_MATE_IN_PLY_MAX
&& pos.non_pawn_material(pos.side_to_move()))
if ( !PvNode
&& !ss->skipNullMove
&& depth > ONE_PLY
- && !isCheck
+ && !inCheck
&& refinedValue >= beta
&& abs(beta) < VALUE_MATE_IN_PLY_MAX
&& pos.non_pawn_material(pos.side_to_move()))
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
- nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
+ nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
// 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
}
}
- // Step 9. Internal iterative deepening
+ // Step 9. ProbCut (is omitted in PV nodes)
+ // If we have a very good capture (i.e. SEE > seeValues[captured_piece_type])
+ // and a reduced search returns a value much above beta, we can (almost) safely
+ // prune the previous move.
+ if ( !PvNode
+ && depth >= RazorDepth + ONE_PLY
+ && !inCheck
+ && !ss->skipNullMove
+ && excludedMove == MOVE_NONE
+ && abs(beta) < VALUE_MATE_IN_PLY_MAX)
+ {
+ Value rbeta = beta + 200;
+ Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY;
+
+ assert(rdepth >= ONE_PLY);
+
+ MovePicker mp(pos, ttMove, H, pos.captured_piece_type());
+ CheckInfo ci(pos);
+
+ while ((move = mp.get_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));
+
+ if (pos.is_draw<false>() || ss->ply + 1 > PLY_MAX)
+ value = VALUE_DRAW;
+ else
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth);
+
+ pos.undo_move(move);
+ if (value >= rbeta)
+ return value;
+ }
+ }
+
+ // Step 10. Internal iterative deepening
if ( depth >= IIDDepth[PvNode]
&& ttMove == MOVE_NONE
- && (PvNode || (!isCheck && ss->eval + IIDMargin >= beta)))
+ && (PvNode || (!inCheck && 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 ? PV : NonPV>(pos, ss, alpha, beta, d);
ss->skipNullMove = false;
- ttMove = ss->bestMove;
- tte = TT.retrieve(posKey);
+ tte = TT.probe(posKey);
+ ttMove = tte ? tte->move() : MOVE_NONE;
}
- // Mate threat detection for PV nodes, otherwise we use null move search
- 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
- MovePickerExt<SpNode, Root> mp(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
+ MovePickerExt<NT> mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
futilityBase = ss->eval + ss->evalMargin;
- singularExtensionNode = !Root
+ singularExtensionNode = !RootNode
&& !SpNode
&& depth >= SingularExtensionDepth[PvNode]
- && tte
- && tte->move()
+ && ttMove != MOVE_NONE
&& !excludedMove // Do not allow recursive singular extension search
&& (tte->type() & VALUE_TYPE_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;
bestValue = sp->bestValue;
}
- // Step 10. Loop through moves
- // Loop through all legal moves until no moves remain or a beta cutoff occurs
+ // 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
- && !ThreadsMgr.cutoff_at_splitpoint(threadID))
+ && !thread.cutoff_occurred())
{
assert(move_is_ok(move));
+ if (move == excludedMove)
+ continue;
+
+ // At PV and SpNode nodes we want all moves to be legal since the beginning
+ if ((PvNode || SpNode) && !pos.pl_move_is_legal(move, ci.pinned))
+ continue;
+
if (SpNode)
{
moveCount = ++sp->moveCount;
lock_release(&(sp->lock));
}
- else if (move == excludedMove)
- continue;
else
moveCount++;
- if (Root)
+ if (RootNode)
{
// This is used by time management
FirstRootMove = (moveCount == 1);
cout << "info" << speed_to_uci(pos.nodes_searched()) << endl;
}
+ // For long searches send current move info to GUI
if (current_search_time() > 2000)
- cout << "info currmove " << move
- << " currmovenumber " << moveCount << endl;
+ cout << "info" << depth_to_uci(depth)
+ << " currmove " << move << " currmovenumber " << moveCount << endl;
}
// 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);
+ isPvMove = (PvNode && moveCount <= (!RootNode ? 1 : depth <= ONE_PLY ? MAX_MOVES : MultiPV));
+ givesCheck = pos.move_gives_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);
+ // Step 12. Decide the new search depth
+ ext = extension<PvNode>(pos, move, captureOrPromotion, givesCheck, &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
// 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()
+ && move == ttMove
+ && pos.pl_move_is_legal(move, ci.pinned)
&& 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 rBeta = ttValue - int(depth);
ss->excludedMove = move;
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, rBeta - 1, rBeta, 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;
}
// Update current move (this must be done after singular extension search)
- ss->currentMove = move;
newDepth = depth - ONE_PLY + ext;
- // Step 12. Futility pruning (is omitted in PV nodes)
+ // Step 13. Futility pruning (is omitted in PV nodes)
if ( !PvNode
&& !captureOrPromotion
- && !isCheck
+ && !inCheck
&& !dangerous
&& move != ttMove
&& !move_is_castle(move))
// Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
- Depth predictedDepth = newDepth - reduction<NonPV>(depth, moveCount);
+ Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
futilityValueScaled = futilityBase + futility_margin(predictedDepth, moveCount)
+ H.gain(pos.piece_on(move_from(move)), move_to(move));
}
}
- // 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);
+ // Check for legality only before to do the move
+ if (!pos.pl_move_is_legal(move, ci.pinned))
+ {
+ moveCount--;
+ continue;
+ }
+ ss->currentMove = move;
if (!SpNode && !captureOrPromotion)
movesSearched[playedMoveCount++] = move;
- // Step extra. pv search (only in PV nodes)
- // The first move in list is the expected PV
- if (isPvMove)
+ // Step 14. Make the move
+ pos.do_move(move, st, ci, givesCheck);
+
+ // Step XX. Poll. Check if search should be aborted.
+ if (pos.thread() == 0 && ++NodesSincePoll > NodesBetweenPolls)
{
- // Aspiration window is disabled in multi-pv case
- if (Root && MultiPV > 1)
- alpha = -VALUE_INFINITE;
+ NodesSincePoll = 0;
+ poll(pos);
+ }
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ // Step XX. Check for aborted search and immediate draw
+ if ( StopRequest
+ || pos.is_draw<false>()
+ || ss->ply + 1 > PLY_MAX)
+ {
+ value = VALUE_DRAW;
+ goto undo;
}
+
+ // Step extra. pv search (only in PV nodes)
+ // The first move in list is the expected PV
+ if (isPvMove)
+ value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
else
{
- // Step 14. Reduced depth search
+ // Step 15. 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
+ if ( depth > 3 * ONE_PLY
&& !captureOrPromotion
&& !dangerous
&& !move_is_castle(move)
&& ss->killers[0] != move
- && ss->killers[1] != move)
+ && ss->killers[1] != move
+ && (ss->reduction = reduction<PvNode>(depth, moveCount)) != DEPTH_ZERO)
{
- ss->reduction = reduction<PvNode>(depth, moveCount);
- if (ss->reduction)
- {
- alpha = SpNode ? sp->alpha : alpha;
- Depth d = newDepth - ss->reduction;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+ Depth d = newDepth - ss->reduction;
+ alpha = SpNode ? sp->alpha : alpha;
- doFullDepthSearch = (value > alpha);
- }
- ss->reduction = DEPTH_ZERO; // Restore original reduction
- }
+ value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
- // 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, ply+1);
- doFullDepthSearch = (value > rAlpha);
- ss->reduction = DEPTH_ZERO; // Restore original reduction
+ ss->reduction = DEPTH_ZERO;
+ doFullDepthSearch = (value > alpha);
}
- // Step 15. Full depth search
+ // Step 16. Full depth search
if (doFullDepthSearch)
{
alpha = SpNode ? sp->alpha : alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
+ value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
+ : - 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);
+ if (PvNode && value > alpha && (RootNode || value < beta))
+ value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
}
}
- // Step 16. Undo move
+ // Step 17. Undo move
+undo:
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
- // Step 17. Check for new best move
+ // Step 18. Check for new best move
if (SpNode)
{
lock_grab(&(sp->lock));
alpha = sp->alpha;
}
- if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID)))
+ if (value > bestValue)
{
bestValue = value;
+ ss->bestMove = move;
- if (SpNode)
- sp->bestValue = value;
+ if ( !RootNode
+ && PvNode
+ && value > alpha
+ && value < beta) // We want always alpha < beta
+ alpha = value;
- if (!Root && value > alpha)
+ if (SpNode && !thread.cutoff_occurred())
{
- if (PvNode && value < beta) // We want always alpha < beta
- {
- alpha = value;
-
- if (SpNode)
- sp->alpha = value;
- }
- else if (SpNode)
- sp->betaCutoff = true;
-
- if (value == value_mate_in(ply + 1))
- ss->mateKiller = move;
-
- ss->bestMove = move;
-
- if (SpNode)
- sp->ss->bestMove = move;
+ sp->bestValue = value;
+ sp->ss->bestMove = move;
+ sp->alpha = alpha;
+ sp->is_betaCutoff = (value >= beta);
}
}
- if (Root)
+ if (RootNode)
{
// Finished searching the move. If StopRequest is true, the search
// was aborted because the user interrupted the search or because we
break;
// Remember searched nodes counts for this move
- mp.rm->nodes += pos.nodes_searched() - nodes;
+ mp.current().nodes += pos.nodes_searched() - nodes;
// PV move or new best move ?
if (isPvMove || value > alpha)
{
// Update PV
- ss->bestMove = move;
- mp.rm->pv_score = value;
- mp.rm->extract_pv_from_tt(pos);
+ mp.current().pv_score = value;
+ mp.current().extract_pv_from_tt(pos);
// We record how often the best move has been changed in each
// iteration. This information is used for time management: When
if (!isPvMove && MultiPV == 1)
Rml.bestMoveChanges++;
- Rml.sort_multipv(moveCount);
+ // It is critical that sorting is done with a stable algorithm
+ // because all the values but the first are usually set to
+ // -VALUE_INFINITE and we want to keep the same order for all
+ // the moves but the new PV that goes to head.
+ sort<RootMove>(Rml.begin(), Rml.begin() + moveCount);
- // Update alpha. In multi-pv we don't use aspiration window, so
- // set alpha equal to minimum score among the PV lines.
+ // Update alpha. In multi-pv we don't use aspiration window, so set
+ // alpha equal to minimum score among the PV lines searched so far.
if (MultiPV > 1)
- alpha = Rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount?
+ alpha = Rml[Min(moveCount, MultiPV) - 1].pv_score;
else if (value > alpha)
alpha = value;
}
else
- mp.rm->pv_score = -VALUE_INFINITE;
+ // All other moves but the PV are set to the lowest value, this
+ // is not a problem when sorting becuase sort is stable and move
+ // position in the list is preserved, just the PV is pushed up.
+ mp.current().pv_score = -VALUE_INFINITE;
- } // Root
+ } // RootNode
- // Step 18. Check for split
- if ( !Root
+ // Step 19. Check for split
+ if ( !RootNode
&& !SpNode
- && depth >= ThreadsMgr.min_split_depth()
- && ThreadsMgr.active_threads() > 1
+ && depth >= Threads.min_split_depth()
&& bestValue < beta
- && ThreadsMgr.available_thread_exists(threadID)
+ && Threads.available_slave_exists(pos.thread())
&& !StopRequest
- && !ThreadsMgr.cutoff_at_splitpoint(threadID))
- ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
- threatMove, mateThreat, moveCount, &mp, PvNode);
+ && !thread.cutoff_occurred())
+ Threads.split<FakeSplit>(pos, ss, &alpha, beta, &bestValue, depth,
+ threatMove, moveCount, &mp, PvNode);
}
- // Step 19. Check for mate and stalemate
+ // Step 20. Check for mate and stalemate
// All legal moves have been searched and if there are
// 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 : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
- // Step 20. Update tables
+ // Step 21. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (!SpNode && !StopRequest && !ThreadsMgr.cutoff_at_splitpoint(threadID))
+ if (!SpNode && !StopRequest && !thread.cutoff_occurred())
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
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
if (SpNode)
{
// Here we have the lock still grabbed
- sp->slaves[threadID] = 0;
+ sp->is_slave[pos.thread()] = false;
sp->nodes += pos.nodes_searched();
lock_release(&(sp->lock));
}
// search function when the remaining depth is zero (or, to be more precise,
// less than ONE_PLY).
- template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
+ template <NodeType NT>
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
+
+ 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(ply > 0 && ply < PLY_MAX);
- assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
+ assert(pos.thread() >= 0 && pos.thread() < Threads.size());
StateInfo st;
Move ttMove, move;
Value bestValue, value, evalMargin, futilityValue, futilityBase;
- bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
+ bool inCheck, enoughMaterial, givesCheck, evasionPrunable;
const TTEntry* tte;
Depth ttDepth;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
-
- // Check for an instant draw or maximum ply reached
- if (pos.is_draw() || ply >= PLY_MAX - 1)
- return VALUE_DRAW;
+ ss->ply = (ss-1)->ply + 1;
// Decide whether or not to include checks, this fixes also the type of
// TT entry depth that we are going to use. Note that in qsearch we use
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
- isCheck = pos.is_check();
- ttDepth = (isCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS);
+ inCheck = pos.in_check();
+ ttDepth = (inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS);
// Transposition table lookup. At PV nodes, we don't use the TT for
// pruning, but only for move ordering.
- tte = TT.retrieve(pos.get_key());
+ tte = TT.probe(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 (isCheck)
+ if (inCheck)
{
bestValue = futilityBase = -VALUE_INFINITE;
ss->eval = evalMargin = VALUE_NONE;
else
ss->eval = bestValue = evaluate(pos, evalMargin);
- update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
-
// Stand pat. Return immediately if static value is at least beta
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;
}
// 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);
+ MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
{
assert(move_is_ok(move));
- moveIsCheck = pos.move_is_check(move, ci);
+ givesCheck = pos.move_gives_check(move, ci);
// Futility pruning
if ( !PvNode
- && !isCheck
- && !moveIsCheck
+ && !inCheck
+ && !givesCheck
&& move != ttMove
&& enoughMaterial
&& !move_is_promotion(move)
&& !pos.move_is_passed_pawn_push(move))
{
futilityValue = futilityBase
- + pos.endgame_value_of_piece_on(move_to(move))
+ + piece_value_endgame(pos.piece_on(move_to(move)))
+ (move_is_ep(move) ? PawnValueEndgame : VALUE_ZERO);
if (futilityValue < alpha)
}
// Detect non-capture evasions that are candidate to be pruned
- evasionPrunable = isCheck
+ evasionPrunable = !PvNode
+ && inCheck
&& bestValue > VALUE_MATED_IN_PLY_MAX
&& !pos.move_is_capture(move)
&& !pos.can_castle(pos.side_to_move());
// Don't search moves with negative SEE values
if ( !PvNode
- && (!isCheck || evasionPrunable)
+ && (!inCheck || evasionPrunable)
&& move != ttMove
&& !move_is_promotion(move)
&& pos.see_sign(move) < 0)
// Don't search useless checks
if ( !PvNode
- && !isCheck
- && moveIsCheck
+ && !inCheck
+ && givesCheck
&& move != ttMove
&& !pos.move_is_capture_or_promotion(move)
&& ss->eval + PawnValueMidgame / 4 < beta
continue;
}
+ // Check for legality only before to do the move
+ if (!pos.pl_move_is_legal(move, ci.pinned))
+ continue;
+
// Update current move
ss->currentMove = 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);
+ pos.do_move(move, st, ci, givesCheck);
+
+ if (pos.is_draw<true>() || ss->ply+1 > PLY_MAX)
+ value = VALUE_DRAW;
+ else
+ value = -qsearch<NT>(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);
+ if (inCheck && bestValue == -VALUE_INFINITE)
+ 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);
newAtt = pos.attacks_from(pc, to, occ);
// Rule 1. Checks which give opponent's king at most one escape square are dangerous
- b = kingAtt & ~pos.pieces_of_color(them) & ~newAtt & ~(1ULL << to);
+ b = kingAtt & ~pos.pieces(them) & ~newAtt & ~(1ULL << to);
if (!(b && (b & (b - 1))))
return true;
// Rule 2. Queen contact check is very dangerous
- if ( type_of_piece(pc) == QUEEN
+ if ( piece_type(pc) == QUEEN
&& bit_is_set(kingAtt, to))
return true;
// Rule 3. Creating new double threats with checks
- b = pos.pieces_of_color(them) & newAtt & ~oldAtt & ~(1ULL << ksq);
+ b = pos.pieces(them) & newAtt & ~oldAtt & ~(1ULL << ksq);
while (b)
{
victimSq = pop_1st_bit(&b);
- futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq);
+ futilityValue = futilityBase + piece_value_endgame(pos.piece_on(victimSq));
// Note that here we generate illegal "double move"!
if ( futilityValue >= beta
bool connected_moves(const Position& pos, Move m1, Move m2) {
Square f1, t1, f2, t2;
- Piece p;
+ Piece p1, p2;
+ Square ksq;
assert(m1 && move_is_ok(m1));
assert(m2 && move_is_ok(m2));
return true;
// Case 3: Moving through the vacated square
- if ( piece_is_slider(pos.piece_on(f2))
+ p2 = pos.piece_on(f2);
+ if ( piece_is_slider(p2)
&& bit_is_set(squares_between(f2, t2), f1))
return true;
// Case 4: The destination square for m2 is defended by the moving piece in m1
- p = pos.piece_on(t1);
- if (bit_is_set(pos.attacks_from(p, t1), t2))
+ p1 = pos.piece_on(t1);
+ if (bit_is_set(pos.attacks_from(p1, t1), t2))
return true;
// Case 5: Discovered check, checking piece is the piece moved in m1
- if ( piece_is_slider(p)
- && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
- && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2))
+ ksq = pos.king_square(pos.side_to_move());
+ if ( piece_is_slider(p1)
+ && bit_is_set(squares_between(t1, ksq), f2))
{
- // discovered_check_candidates() works also if the Position's side to
- // move is the opposite of the checking piece.
- Color them = opposite_color(pos.side_to_move());
- Bitboard dcCandidates = pos.discovered_check_candidates(them);
-
- if (bit_is_set(dcCandidates, f2))
+ Bitboard occ = pos.occupied_squares();
+ clear_bit(&occ, f2);
+ if (bit_is_set(pos.attacks_from(p1, t1, occ), ksq))
return true;
}
return false;
}
- // extension() decides whether a move should be searched with normal depth,
- // or with extended depth. Certain classes of moves (checking moves, in
- // particular) are searched with bigger depth than ordinary moves and in
- // any case are marked as 'dangerous'. Note that also if a move is not
- // extended, as example because the corresponding UCI option is set to zero,
- // 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) {
+ // connected_threat() tests whether it is safe to forward prune a move or if
+ // is somehow connected to the threat move returned by null search.
- assert(m != MOVE_NONE);
+ bool connected_threat(const Position& pos, Move m, Move threat) {
- Depth result = DEPTH_ZERO;
- *dangerous = moveIsCheck | mateThreat;
+ assert(move_is_ok(m));
+ assert(threat && move_is_ok(threat));
+ assert(!pos.move_is_capture_or_promotion(m));
+ assert(!pos.move_is_passed_pawn_push(m));
- if (*dangerous)
- {
- if (moveIsCheck && pos.see_sign(m) >= 0)
- result += CheckExtension[PvNode];
-
- if (mateThreat)
- result += MateThreatExtension[PvNode];
- }
-
- if (pos.type_of_piece_on(move_from(m)) == PAWN)
- {
- Color c = pos.side_to_move();
- if (relative_rank(c, move_to(m)) == RANK_7)
- {
- result += PawnPushTo7thExtension[PvNode];
- *dangerous = true;
- }
- if (pos.pawn_is_passed(c, move_to(m)))
- {
- result += PassedPawnExtension[PvNode];
- *dangerous = true;
- }
- }
-
- if ( captureOrPromotion
- && 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))
- {
- result += PawnEndgameExtension[PvNode];
- *dangerous = true;
- }
-
- return Min(result, ONE_PLY);
- }
-
-
- // connected_threat() tests whether it is safe to forward prune a move or if
- // is somehow connected to the threat move returned by null search.
-
- bool connected_threat(const Position& pos, Move m, Move threat) {
-
- assert(move_is_ok(m));
- assert(threat && move_is_ok(threat));
- assert(!pos.move_is_check(m));
- assert(!pos.move_is_capture_or_promotion(m));
- assert(!pos.move_is_passed_pawn_push(m));
-
- Square mfrom, mto, tfrom, tto;
+ Square mfrom, mto, tfrom, tto;
mfrom = move_from(m);
mto = move_to(m);
// Case 2: If the threatened piece has value less than or equal to the
// value of the threatening piece, don't prune moves which defend it.
if ( pos.move_is_capture(threat)
- && ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto)
- || pos.type_of_piece_on(tfrom) == KING)
+ && ( piece_value_midgame(pos.piece_on(tfrom)) >= piece_value_midgame(pos.piece_on(tto))
+ || piece_type(pos.piece_on(tfrom)) == KING)
&& pos.move_attacks_square(m, tto))
return true;
// current_search_time() returns the number of milliseconds which have passed
// since the beginning of the current search.
- int current_search_time() {
+ int current_search_time(int set) {
+
+ static int searchStartTime;
+
+ if (set)
+ searchStartTime = set;
- return get_system_time() - SearchStartTime;
+ return get_system_time() - searchStartTime;
}
- // value_to_uci() converts a value to a string suitable for use with the UCI
+ // score_to_uci() converts a value to a string suitable for use with the UCI
// protocol specifications:
//
// cp <x> The score from the engine's point of view in centipawns.
// mate <y> Mate in y moves, not plies. If the engine is getting mated
// use negative values for y.
- std::string value_to_uci(Value v) {
+ std::string score_to_uci(Value v, Value alpha, Value beta) {
std::stringstream s;
if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
+ s << " score cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
else
- s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
+ s << " score mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
+
+ s << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
return s.str();
}
int t = current_search_time();
s << " nodes " << nodes
- << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0)
+ << " 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.
+
+ std::string pv_to_uci(Move pv[], int pvNum) {
+
+ std::stringstream s;
+
+ s << " multipv " << pvNum << " pv ";
+
+ 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.
+
+ std::string depth_to_uci(Depth depth) {
+
+ std::stringstream s;
+
+ // Retrieve max searched depth among threads
+ int selDepth = 0;
+ 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();
+ }
+
// poll() performs two different functions: It polls for user input, and it
// looks at the time consumed so far and decides if it's time to abort the
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;
}
}
- // init_thread() is the function which is called when a new thread is
- // launched. It simply calls the idle_loop() function with the supplied
- // threadID. There are two versions of this function; one for POSIX
- // threads and one for Windows threads.
-
-#if !defined(_MSC_VER)
-
- void* init_thread(void* threadID) {
-
- ThreadsMgr.idle_loop(*(int*)threadID, NULL);
- return NULL;
- }
-
-#else
-
- DWORD WINAPI init_thread(LPVOID threadID) {
-
- ThreadsMgr.idle_loop(*(int*)threadID, NULL);
- return 0;
- }
-
-#endif
-
-
- /// The ThreadsManager class
-
-
- // read_uci_options() updates number of active threads and other internal
- // parameters according to the UCI options values. It is called before
- // to start a new search.
-
- void ThreadsManager::read_uci_options() {
-
- maxThreadsPerSplitPoint = Options["Maximum Number of Threads per Split Point"].value<int>();
- minimumSplitDepth = Options["Minimum Split Depth"].value<int>() * ONE_PLY;
- useSleepingThreads = Options["Use Sleeping Threads"].value<bool>();
- activeThreads = Options["Threads"].value<int>();
- }
-
-
- // idle_loop() is where the threads are parked when they have no work to do.
- // The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint
- // object for which the current thread is the master.
-
- void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) {
-
- assert(threadID >= 0 && threadID < MAX_THREADS);
-
- int i;
- bool allFinished = false;
-
- while (true)
- {
- // Slave threads can exit as soon as AllThreadsShouldExit raises,
- // master should exit as last one.
- if (allThreadsShouldExit)
- {
- assert(!sp);
- threads[threadID].state = THREAD_TERMINATED;
- return;
- }
-
- // 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
- || (useSleepingThreads && threads[threadID].state == THREAD_AVAILABLE))
- {
- assert(!sp || useSleepingThreads);
- assert(threadID != 0 || 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]);
-
- // If we are master and all slaves have finished do not go to sleep
- for (i = 0; sp && i < activeThreads && !sp->slaves[i]; i++) {}
- allFinished = (i == activeThreads);
-
- if (allFinished || allThreadsShouldExit)
- {
- lock_release(&sleepLock[threadID]);
- break;
- }
-
- // Do sleep here after retesting sleep conditions
- if (threadID >= activeThreads || threads[threadID].state == THREAD_AVAILABLE)
- cond_wait(&sleepCond[threadID], &sleepLock[threadID]);
-
- lock_release(&sleepLock[threadID]);
- }
-
- // If this thread has been assigned work, launch a search
- if (threads[threadID].state == THREAD_WORKISWAITING)
- {
- assert(!allThreadsShouldExit);
-
- threads[threadID].state = THREAD_SEARCHING;
-
- // Copy SplitPoint 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);
-
- memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack));
- (ss+1)->sp = tsp;
-
- if (tsp->pvNode)
- search<PV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
- else
- search<NonPV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
-
- assert(threads[threadID].state == THREAD_SEARCHING);
-
- threads[threadID].state = THREAD_AVAILABLE;
-
- // 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 this thread is the master of a split point and all slaves have
- // finished their work at this split point, return from the idle loop.
- for (i = 0; sp && i < activeThreads && !sp->slaves[i]; i++) {}
- allFinished = (i == activeThreads);
-
- if (allFinished)
- {
- // Because sp->slaves[] is reset under lock protection,
- // be sure sp->lock has been released before to return.
- lock_grab(&(sp->lock));
- lock_release(&(sp->lock));
-
- // In helpful master concept a master can help only a sub-tree, and
- // because here is all finished is not possible master is booked.
- assert(threads[threadID].state == THREAD_AVAILABLE);
-
- threads[threadID].state = THREAD_SEARCHING;
- return;
- }
- }
- }
-
+ // 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) {
- // init_threads() is called during startup. It launches all helper threads,
- // and initializes the split point stack and the global locks and condition
- // objects.
+ assert(MultiPV > 1);
- void ThreadsManager::init_threads() {
+ static RKISS rk;
- int i, arg[MAX_THREADS];
- bool ok;
+ // 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;
- // Initialize global locks
- lock_init(&mpLock);
+ // PRNG sequence should be non deterministic
+ for (int i = abs(get_system_time() % 50); i > 0; i--)
+ rk.rand<unsigned>();
- for (i = 0; i < MAX_THREADS; i++)
+ // 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++)
{
- lock_init(&sleepLock[i]);
- cond_init(&sleepCond[i]);
- }
-
- // 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;
+ s = Rml[i].pv_score;
- // Threads will be put all threads to sleep as soon as created
- activeThreads = 1;
+ // Don't allow crazy blunders even at very low skills
+ if (i > 0 && Rml[i-1].pv_score > s + EasyMoveMargin)
+ break;
- // 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;
+ // This is our magical formula
+ s += ((max - s) * wk + var * (rk.rand<unsigned>() % wk)) / 128;
- // Launch the helper threads
- for (i = 1; i < MAX_THREADS; i++)
- {
- arg[i] = i;
-
-#if !defined(_MSC_VER)
- pthread_t pthread[1];
- ok = (pthread_create(pthread, NULL, init_thread, (void*)(&arg[i])) == 0);
- pthread_detach(pthread[0]);
-#else
- ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&arg[i]), 0, NULL) != NULL);
-#endif
- if (!ok)
+ if (s > max_s)
{
- cout << "Failed to create thread number " << i << endl;
- exit(EXIT_FAILURE);
+ max_s = s;
+ *best = Rml[i].pv[0];
+ *ponder = Rml[i].pv[1];
}
-
- // Wait until the thread has finished launching and is gone to sleep
- while (threads[i].state == THREAD_INITIALIZING) {}
- }
- }
-
-
- // exit_threads() is called when the program exits. It makes all the
- // helper threads exit cleanly.
-
- void ThreadsManager::exit_threads() {
-
- allThreadsShouldExit = true; // Let the woken up threads to exit idle_loop()
-
- // Wake up all the threads and waits for termination
- for (int i = 1; i < MAX_THREADS; i++)
- {
- wake_sleeping_thread(i);
- while (threads[i].state != THREAD_TERMINATED) {}
- }
-
- // 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]);
}
}
- // cutoff_at_splitpoint() checks whether a beta cutoff has occurred in
- // the thread's currently active split point, or in some ancestor of
- // the current split point.
-
- bool ThreadsManager::cutoff_at_splitpoint(int threadID) const {
-
- assert(threadID >= 0 && threadID < activeThreads);
-
- SplitPoint* sp = threads[threadID].splitPoint;
-
- for ( ; sp && !sp->betaCutoff; sp = sp->parent) {}
- return sp != NULL;
- }
-
-
- // thread_is_available() checks whether the thread with threadID "slave" is
- // available to help the thread with threadID "master" at a split point. An
- // obvious requirement is that "slave" must be idle. With more than two
- // threads, this is not by itself sufficient: If "slave" is the master of
- // some active split point, it is only available as a slave to the other
- // threads which are busy searching the split point at the top of "slave"'s
- // split point stack (the "helpful master concept" in YBWC terminology).
-
- bool ThreadsManager::thread_is_available(int slave, int master) const {
-
- assert(slave >= 0 && slave < activeThreads);
- assert(master >= 0 && master < activeThreads);
- assert(activeThreads > 1);
-
- if (threads[slave].state != THREAD_AVAILABLE || slave == master)
- return false;
-
- // Make a local copy to be sure doesn't change under our feet
- int localActiveSplitPoints = threads[slave].activeSplitPoints;
-
- // No active split points means that the thread is available as
- // a slave for any other thread.
- if (localActiveSplitPoints == 0 || activeThreads == 2)
- return true;
-
- // Apply the "helpful master" concept if possible. Use localActiveSplitPoints
- // that is known to be > 0, instead of threads[slave].activeSplitPoints that
- // could have been set to 0 by another thread leading to an out of bound access.
- if (threads[slave].splitPoints[localActiveSplitPoints - 1].slaves[master])
- return true;
-
- return false;
- }
-
-
- // available_thread_exists() tries to find an idle thread which is available as
- // a slave for the thread with threadID "master".
-
- bool ThreadsManager::available_thread_exists(int master) const {
-
- assert(master >= 0 && master < activeThreads);
- assert(activeThreads > 1);
-
- for (int i = 0; i < activeThreads; i++)
- if (thread_is_available(i, master))
- return true;
-
- return false;
- }
-
-
- // split() does the actual work of distributing the work at a node between
- // several available threads. If it does not succeed in splitting the
- // node (because no idle threads are available, or because we have no unused
- // split point objects), the function immediately returns. If splitting is
- // possible, a SplitPoint object is initialized with all the data that must be
- // copied to the helper threads and we tell our helper threads that they have
- // been assigned work. This will cause them to instantly leave their idle loops and
- // 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) {
- assert(pos.is_ok());
- assert(ply > 0 && ply < PLY_MAX);
- assert(*bestValue >= -VALUE_INFINITE);
- assert(*bestValue <= *alpha);
- assert(*alpha < beta);
- assert(beta <= VALUE_INFINITE);
- assert(depth > DEPTH_ZERO);
- assert(pos.thread() >= 0 && pos.thread() < activeThreads);
- assert(activeThreads > 1);
-
- int i, master = pos.thread();
- Thread& masterThread = threads[master];
-
- lock_grab(&mpLock);
-
- // If no other thread is available to help us, or if we have too many
- // active split points, don't split.
- if ( !available_thread_exists(master)
- || masterThread.activeSplitPoints >= MAX_ACTIVE_SPLIT_POINTS)
- {
- lock_release(&mpLock);
- return;
- }
-
- // Pick the next available split point object from the split point stack
- SplitPoint& splitPoint = masterThread.splitPoints[masterThread.activeSplitPoints++];
-
- // Initialize the split point object
- 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.bestValue = *bestValue;
- splitPoint.mp = mp;
- splitPoint.moveCount = moveCount;
- splitPoint.pos = &pos;
- splitPoint.nodes = 0;
- splitPoint.ss = ss;
- for (i = 0; i < activeThreads; i++)
- splitPoint.slaves[i] = 0;
-
- masterThread.splitPoint = &splitPoint;
-
- // If we are here it means we are not available
- assert(masterThread.state != THREAD_AVAILABLE);
-
- int workersCnt = 1; // At least the master is included
-
- // Allocate available threads setting state to THREAD_BOOKED
- for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
- if (thread_is_available(i, master))
- {
- threads[i].state = THREAD_BOOKED;
- threads[i].splitPoint = &splitPoint;
- splitPoint.slaves[i] = 1;
- workersCnt++;
- }
-
- assert(Fake || workersCnt > 1);
-
- // We can release the lock because slave threads are already booked and master is not available
- lock_release(&mpLock);
-
- // Tell the threads that they have work to do. This will make them leave
- // their idle loop.
- for (i = 0; i < activeThreads; i++)
- if (i == master || splitPoint.slaves[i])
- {
- 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);
- }
-
- // Everything is set up. The master thread enters the idle loop, from
- // which it will instantly launch a search, because its state is
- // THREAD_WORKISWAITING. We send the split point as a second parameter to the
- // idle loop, which means that the main thread will return from the idle
- // loop when all threads have finished their work at this split point.
- idle_loop(master, &splitPoint);
-
- // We have returned from the idle loop, which means that all threads are
- // finished. Update alpha and bestValue, and return.
- lock_grab(&mpLock);
-
- *alpha = splitPoint.alpha;
- *bestValue = splitPoint.bestValue;
- masterThread.activeSplitPoints--;
- masterThread.splitPoint = splitPoint.parent;
- pos.set_nodes_searched(pos.nodes_searched() + splitPoint.nodes);
-
- lock_release(&mpLock);
- }
-
-
- // 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() {
return *this;
}
+ void RootMoveList::init(Position& pos, Move searchMoves[]) {
+
+ Move* sm;
+ bestMoveChanges = 0;
+ clear();
+
+ // Generate all legal moves and add them to RootMoveList
+ for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
+ {
+ // If we have a searchMoves[] list then verify the move
+ // is in the list before to add it.
+ for (sm = searchMoves; *sm && *sm != ml.move(); sm++) {}
+
+ if (sm != searchMoves && *sm != ml.move())
+ continue;
+
+ RootMove rm;
+ rm.pv[0] = ml.move();
+ rm.pv[1] = MOVE_NONE;
+ rm.pv_score = -VALUE_INFINITE;
+ push_back(rm);
+ }
+ }
+
// extract_pv_from_tt() builds a PV by adding moves from the transposition table.
// We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
// allow to always have a ponder move even when we fail high at root and also a
TTEntry* tte;
int ply = 1;
- assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+ assert(pv[0] != MOVE_NONE && pos.move_is_pl(pv[0]));
pos.do_move(pv[0], *st++);
- while ( (tte = TT.retrieve(pos.get_key())) != NULL
+ while ( (tte = TT.probe(pos.get_key())) != NULL
&& tte->move() != MOVE_NONE
- && move_is_legal(pos, tte->move())
+ && pos.move_is_pl(tte->move())
+ && pos.pl_move_is_legal(tte->move(), pos.pinned_pieces())
&& ply < PLY_MAX
- && (!pos.is_draw() || ply < 2))
+ && (!pos.is_draw<false>() || ply < 2))
{
pv[ply] = tte->move();
pos.do_move(pv[ply++], *st++);
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_pl(pv[0]));
do {
k = pos.get_key();
- tte = TT.retrieve(k);
+ tte = TT.probe(k);
// Don't overwrite existing correct entries
if (!tte || tte->move() != pv[ply])
{
- v = (pos.is_check() ? VALUE_NONE : evaluate(pos, m));
+ v = (pos.in_check() ? VALUE_NONE : evaluate(pos, m));
TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m);
}
pos.do_move(pv[ply], *st++);
do pos.undo_move(pv[--ply]); while (ply);
}
- // pv_info_to_uci() returns a string with information on the current PV line
- // formatted according to UCI specification.
+ // Specializations for MovePickerExt in case of Root node
+ MovePickerExt<Root>::MovePickerExt(const Position& p, Move ttm, Depth d,
+ const History& h, SearchStack* ss, Value b)
+ : MovePicker(p, ttm, d, h, ss, b), cur(-1) {
+ Move move;
+ Value score = VALUE_ZERO;
+
+ // 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 orders pv_score of both moves are equal.
+ while ((move = MovePicker::get_next_move()) != MOVE_NONE)
+ for (RootMoveList::iterator rm = Rml.begin(); rm != Rml.end(); ++rm)
+ if (rm->pv[0] == move)
+ {
+ rm->non_pv_score = score--;
+ break;
+ }
- std::string RootMove::pv_info_to_uci(Position& pos, int depth, Value alpha,
- Value beta, int pvIdx) {
- std::stringstream s, l;
- Move* m = pv;
+ sort<RootMove>(Rml.begin(), Rml.end());
+ }
- while (*m != MOVE_NONE)
- l << *m++ << " ";
+} // namespace
- s << "info depth " << depth
- << " seldepth " << int(m - pv)
- << " multipv " << pvIdx + 1
- << " score " << value_to_uci(pv_score)
- << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "")
- << speed_to_uci(pos.nodes_searched())
- << " pv " << l.str();
- return s.str();
- }
+// ThreadsManager::idle_loop() is where the threads are parked when they have no work
+// to do. The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint
+// object for which the current thread is the master.
+void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) {
- void RootMoveList::init(Position& pos, Move searchMoves[]) {
+ assert(threadID >= 0 && threadID < MAX_THREADS);
- MoveStack mlist[MOVES_MAX];
- Move* sm;
+ int i;
+ bool allFinished;
- clear();
- bestMoveChanges = 0;
+ while (true)
+ {
+ // Slave threads can exit as soon as AllThreadsShouldExit raises,
+ // master should exit as last one.
+ if (allThreadsShouldExit)
+ {
+ assert(!sp);
+ threads[threadID].state = Thread::TERMINATED;
+ return;
+ }
- // Generate all legal moves and add them to RootMoveList
- MoveStack* last = generate<MV_LEGAL>(pos, mlist);
- for (MoveStack* cur = mlist; cur != last; cur++)
- {
- // If we have a searchMoves[] list then verify cur->move
- // is in the list before to add it.
- for (sm = searchMoves; *sm && *sm != cur->move; sm++) {}
+ // 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
+ || (useSleepingThreads && threads[threadID].state == Thread::AVAILABLE))
+ {
+ assert(!sp || useSleepingThreads);
+ assert(threadID != 0 || useSleepingThreads);
- if (searchMoves[0] && *sm != cur->move)
- continue;
+ if (threads[threadID].state == Thread::INITIALIZING)
+ threads[threadID].state = Thread::AVAILABLE;
- RootMove rm;
- rm.pv[0] = cur->move;
- rm.pv[1] = MOVE_NONE;
- rm.pv_score = -VALUE_INFINITE;
- push_back(rm);
- }
- }
+ // 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->is_slave[i]; i++) {}
+ allFinished = (i == activeThreads);
- // 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) {
+ if (allFinished || allThreadsShouldExit)
+ {
+ lock_release(&threads[threadID].sleepLock);
+ break;
+ }
- assert(MultiPV > 1);
+ // Do sleep here after retesting sleep conditions
+ if (threadID >= activeThreads || threads[threadID].state == Thread::AVAILABLE)
+ cond_wait(&threads[threadID].sleepCond, &threads[threadID].sleepLock);
- // 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;
+ lock_release(&threads[threadID].sleepLock);
+ }
- // PRNG sequence should be non deterministic
- for (int i = abs(get_system_time() % 50); i > 0; i--)
- RK.rand<unsigned>();
+ // If this thread has been assigned work, launch a search
+ if (threads[threadID].state == Thread::WORKISWAITING)
+ {
+ assert(!allThreadsShouldExit);
- // 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;
+ threads[threadID].state = Thread::SEARCHING;
- // Don't allow crazy blunders even at very low skills
- if (i > 0 && Rml[i-1].pv_score > s + EasyMoveMargin)
- break;
+ // 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);
- // This is our magical formula
- s += ((max - s) * wk + var * (RK.rand<unsigned>() % wk)) / 128;
+ memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack));
+ (ss+1)->sp = tsp;
- if (s > max_s)
- {
- max_s = s;
- *best = Rml[i].pv[0];
- *ponder = Rml[i].pv[1];
- }
- }
- }
+ if (tsp->pvNode)
+ search<SplitPointPV>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
+ else
+ search<SplitPointNonPV>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
-} // namespace
+ assert(threads[threadID].state == Thread::SEARCHING);
+
+ threads[threadID].state = Thread::AVAILABLE;
+
+ // 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)
+ threads[tsp->master].wake_up();
+ }
+
+ // If this thread is the master of a split point and all slaves have
+ // finished their work at this split point, return from the idle loop.
+ for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {}
+ allFinished = (i == activeThreads);
+
+ if (allFinished)
+ {
+ // Because sp->slaves[] is reset under lock protection,
+ // be sure sp->lock has been released before to return.
+ lock_grab(&(sp->lock));
+ lock_release(&(sp->lock));
+
+ // In helpful master concept a master can help only a sub-tree, and
+ // because here is all finished is not possible master is booked.
+ assert(threads[threadID].state == Thread::AVAILABLE);
+
+ threads[threadID].state = Thread::SEARCHING;
+ return;
+ }
+ }
+}
projects / stockfish / blobdiff