#include <fstream>
#include <iostream>
#include <sstream>
+#include <vector>
#include "book.h"
#include "evaluate.h"
#include "history.h"
#include "misc.h"
+#include "move.h"
#include "movegen.h"
#include "movepick.h"
#include "lock.h"
-#include "san.h"
#include "search.h"
#include "timeman.h"
#include "thread.h"
// Used for debugging SMP code.
const bool FakeSplit = false;
+ // Fast lookup table of sliding pieces indexed by Piece
+ 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
void init_threads();
void exit_threads();
- int active_threads() const { return ActiveThreads; }
- void set_active_threads(int newActiveThreads) { ActiveThreads = newActiveThreads; }
+ 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 thread_should_stop(int threadID) const;
+ bool cutoff_at_splitpoint(int threadID) const;
void wake_sleeping_thread(int threadID);
void idle_loop(int threadID, SplitPoint* sp);
Depth depth, Move threatMove, bool mateThreat, int moveCount, MovePicker* mp, bool pvNode);
private:
- int ActiveThreads;
- volatile bool AllThreadsShouldExit;
+ Depth minimumSplitDepth;
+ int maxThreadsPerSplitPoint;
+ bool useSleepingThreads;
+ int activeThreads;
+ volatile bool allThreadsShouldExit;
Thread threads[MAX_THREADS];
- Lock MPLock;
- WaitCondition WaitCond[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 move, we store a score, a node count, and a PV (really a refutation
- // in the case of moves which fail low).
+ // RootMove struct is used for moves at the root at 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() : mp_score(0), nodes(0) {}
+ RootMove();
+ RootMove(const RootMove& rm) { *this = rm; }
+ RootMove& operator=(const RootMove& rm);
// 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 a higher score, or if the moves
- // have equal score but m1 has the higher beta cut-off count.
+ // 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.
bool operator<(const RootMove& m) const {
-
- return score != m.score ? score < m.score : mp_score <= m.mp_score;
+ return pv_score != m.pv_score ? pv_score < m.pv_score
+ : non_pv_score < m.non_pv_score;
}
- Move move;
- Value score;
- int mp_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 = 0);
+
int64_t nodes;
+ Value pv_score;
+ Value non_pv_score;
Move pv[PLY_MAX_PLUS_2];
};
- // The RootMoveList class is essentially an array of RootMove objects, with
- // a handful of methods for accessing the data in the individual moves.
+ // RootMoveList struct is essentially a std::vector<> of RootMove objects,
+ // with an handful of methods above the standard ones.
- class RootMoveList {
+ struct RootMoveList : public std::vector<RootMove> {
- public:
- RootMoveList(Position& pos, Move searchMoves[]);
+ typedef std::vector<RootMove> Base;
- Move move(int moveNum) const { return moves[moveNum].move; }
- Move move_pv(int moveNum, int i) const { return moves[moveNum].pv[i]; }
- int move_count() const { return count; }
- Value move_score(int moveNum) const { return moves[moveNum].score; }
- int64_t move_nodes(int moveNum) const { return moves[moveNum].nodes; }
- void add_move_nodes(int moveNum, int64_t nodes) { moves[moveNum].nodes += nodes; }
- void set_move_score(int moveNum, Value score) { moves[moveNum].score = score; }
+ 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); }
- void set_move_pv(int moveNum, const Move pv[]);
- void score_moves(const Position& pos);
- void sort();
- void sort_multipv(int n);
-
- private:
- RootMove moves[MOVES_MAX];
- int count;
+ int bestMoveChanges;
};
// operator<<() that will use it to properly format castling moves.
enum set960 {};
- std::ostream& operator<< (std::ostream& os, const set960& m) {
+ std::ostream& operator<< (std::ostream& os, const set960& f) {
- os.iword(0) = int(m);
+ os.iword(0) = int(f);
return os;
}
+ // 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
// Extensions. Configurable UCI options
// Array index 0 is used at non-PV nodes, index 1 at PV nodes.
- Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2];
- Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
+ Depth CheckExtension[2], PawnPushTo7thExtension[2], PassedPawnExtension[2];
+ Depth PawnEndgameExtension[2], MateThreatExtension[2];
// Minimum depth for use of singular extension
const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */};
template <NodeType PV>
inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; }
- // Common adjustments
-
- // Search depth at iteration 1
- const Depth InitialDepth = ONE_PLY;
-
// Easy move margin. An easy move candidate must be at least this much
// better than the second best move.
const Value EasyMoveMargin = Value(0x200);
- /// Global variables
-
- // Iteration counter
- int Iteration;
+ /// Namespace variables
- // Scores and number of times the best move changed for each iteration
- Value ValueByIteration[PLY_MAX_PLUS_2];
- int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
+ // Book object
+ Book OpeningBook;
- // Search window management
- int AspirationDelta;
+ // Root move list
+ RootMoveList Rml;
// MultiPV mode
int MultiPV;
// Time managment variables
int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime;
- bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
- bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
+ bool UseTimeManagement, InfiniteSearch, Pondering, StopOnPonderhit;
+ bool FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
TimeManager TimeMgr;
// Log file
bool UseLogFile;
std::ofstream LogFile;
- // Multi-threads related variables
- Depth MinimumSplitDepth;
- int MaxThreadsPerSplitPoint;
+ // Multi-threads manager object
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.
+ bool SendSearchedNodes;
int NodesSincePoll;
int NodesBetweenPolls = 30000;
/// Local functions
- Value id_loop(Position& pos, Move searchMoves[]);
- Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
+ Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove);
- template <NodeType PvNode, bool SpNode>
+ template <NodeType PvNode, bool SpNode, bool Root>
Value search(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) {
return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO, ply)
- : search<PvNode, false>(pos, ss, alpha, beta, depth, 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 singleEvasion, bool mateThreat, bool* dangerous);
+ Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool mateThreat, 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);
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, SearchStack* ss);
+ 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);
int current_search_time();
std::string value_to_uci(Value v);
int nps(const Position& pos);
void poll(const Position& pos);
- void ponderhit();
void wait_for_stop_or_ponderhit();
- void init_ss_array(SearchStack* ss, int size);
- void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value);
- void insert_pv_in_tt(const Position& pos, Move pv[]);
- void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
#if !defined(_MSC_VER)
void* init_thread(void* threadID);
DWORD WINAPI init_thread(LPVOID threadID);
#endif
-}
+
+ // 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;
+
+ // In Root nodes use RootMoveList Rml as source. Score and sort the root moves
+ // before to search them.
+ template<> struct MovePickerExt<false, true> : public MovePicker {
+
+ 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 the standard way used in main search, the moves
+ // are scored according to the order in which 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.
+ 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;
+ }
+
+ Rml.sort();
+ rm = Rml.begin();
+ }
+
+ Move get_next_move() {
+
+ if (!firstCall)
+ ++rm;
+ else
+ firstCall = false;
+
+ return rm != Rml.end() ? rm->pv[0] : MOVE_NONE;
+ }
+
+ RootMoveList::iterator rm;
+ bool firstCall;
+ };
+
+ // 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) {}
+
+ Move get_next_move() { return mp->get_next_move(); }
+
+ RootMoveList::iterator rm; // Dummy, needed to compile
+ MovePicker* mp;
+ };
+
+ // 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) {}
+
+ RootMoveList::iterator rm; // Dummy, needed to compile
+ };
+
+} // namespace
////
// Init reductions array
for (hd = 1; hd < 64; hd++) for (mc = 1; mc < 64; mc++)
{
- double pvRed = 0.33 + log(double(hd)) * log(double(mc)) / 4.5;
+ 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);
/// 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.
-int perft(Position& pos, Depth depth)
+int64_t perft(Position& pos, Depth depth)
{
MoveStack mlist[MOVES_MAX];
StateInfo st;
Move m;
- int sum = 0;
+ int64_t sum = 0;
// Generate all legal moves
- MoveStack* last = generate_moves(pos, mlist);
+ 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.
/// 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 root_search(). It returns false
+/// search-related 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[]) {
// Initialize global search variables
- StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false;
+ StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false;
NodesSincePoll = 0;
SearchStartTime = get_system_time();
ExactMaxTime = maxTime;
MaxDepth = maxDepth;
MaxNodes = maxNodes;
InfiniteSearch = infinite;
- PonderSearch = ponder;
+ Pondering = ponder;
UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
// Look for a book move, only during games, not tests
if (UseTimeManagement && Options["OwnBook"].value<bool>())
{
- if (Options["Book File"].value<std::string>() != OpeningBook.file_name())
+ 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 (PonderSearch)
+ if (Pondering)
wait_for_stop_or_ponderhit();
cout << "bestmove " << bookMove << endl;
- return true;
+ return !QuitRequest;
}
}
CheckExtension[1] = Options["Check Extension (PV nodes)"].value<Depth>();
CheckExtension[0] = Options["Check Extension (non-PV nodes)"].value<Depth>();
- SingleEvasionExtension[1] = Options["Single Evasion Extension (PV nodes)"].value<Depth>();
- SingleEvasionExtension[0] = Options["Single Evasion 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>();
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>();
+ UseLogFile = Options["Use Search Log"].value<bool>();
- MinimumSplitDepth = Options["Minimum Split Depth"].value<int>() * ONE_PLY;
- MaxThreadsPerSplitPoint = Options["Maximum Number of Threads per Split Point"].value<int>();
- MultiPV = Options["MultiPV"].value<int>();
- UseLogFile = Options["Use Search Log"].value<bool>();
-
- if (UseLogFile)
- LogFile.open(Options["Search Log Filename"].value<std::string>().c_str(), std::ios::out | std::ios::app);
-
- read_weights(pos.side_to_move());
+ read_evaluation_uci_options(pos.side_to_move());
// Set the number of active threads
- int newActiveThreads = Options["Threads"].value<int>();
- if (newActiveThreads != ThreadsMgr.active_threads())
- {
- ThreadsMgr.set_active_threads(newActiveThreads);
- init_eval(ThreadsMgr.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()];
// Write search information to log file
if (UseLogFile)
- LogFile << "Searching: " << pos.to_fen() << endl
- << "infinite: " << infinite
- << " ponder: " << ponder
- << " time: " << myTime
+ {
+ std::string name = Options["Search Log Filename"].value<std::string>();
+ LogFile.open(name.c_str(), std::ios::out | std::ios::app);
+
+ LogFile << "Searching: " << pos.to_fen()
+ << "\ninfinite: " << infinite
+ << " ponder: " << ponder
+ << " time: " << myTime
<< " increment: " << myIncrement
<< " moves to go: " << movesToGo << endl;
+ }
// We're ready to start thinking. Call the iterative deepening loop function
- id_loop(pos, searchMoves);
+ 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;
if (UseLogFile)
+ {
+ LogFile << "\nNodes: " << pos.nodes_searched()
+ << "\nNodes/second: " << nps(pos)
+ << "\nBest move: " << move_to_san(pos, bestMove);
+
+ StateInfo st;
+ pos.do_move(bestMove, st);
+ LogFile << "\nPonder move: "
+ << move_to_san(pos, ponderMove) // Works also with MOVE_NONE
+ << endl;
+
+ // Return from think() with unchanged position
+ pos.undo_move(bestMove);
+
LogFile.close();
+ }
+
+ // This makes all the threads to go to sleep
+ ThreadsMgr.set_active_threads(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))
+ wait_for_stop_or_ponderhit();
+
+ // Could be both MOVE_NONE when searching on a stalemate position
+ cout << "bestmove " << bestMove << " ponder " << ponderMove << endl;
- return !Quit;
+ return !QuitRequest;
}
namespace {
- // id_loop() is the main iterative deepening loop. It calls root_search
- // repeatedly with increasing depth until the allocated thinking time has
- // been consumed, the user stops the search, or the maximum search depth is
- // reached.
+ // id_loop() is the main iterative deepening loop. It calls search() repeatedly
+ // with increasing depth until the allocated thinking time has been consumed,
+ // user stops the search, or the maximum search depth is reached.
- Value id_loop(Position& pos, Move searchMoves[]) {
+ Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) {
SearchStack ss[PLY_MAX_PLUS_2];
- Move pv[PLY_MAX_PLUS_2];
- Move EasyMove = MOVE_NONE;
- Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ Value bestValues[PLY_MAX_PLUS_2];
+ int bestMoveChanges[PLY_MAX_PLUS_2];
+ int depth, researchCountFL, researchCountFH, aspirationDelta;
+ Value value, alpha, beta;
+ Move bestMove, easyMove;
+
+ // Moves to search are verified, scored and sorted
+ Rml.init(pos, searchMoves);
- // Moves to search are verified, copied, scored and sorted
- RootMoveList rml(pos, searchMoves);
+ // Initialize FIXME move before Rml.init()
+ TT.new_search();
+ H.clear();
+ memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack));
+ *ponderMove = bestMove = easyMove = MOVE_NONE;
+ depth = aspirationDelta = 0;
+ ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
+ alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
// Handle special case of searching on a mate/stale position
- if (rml.move_count() == 0)
+ if (Rml.size() == 0)
{
- if (PonderSearch)
- wait_for_stop_or_ponderhit();
+ cout << "info depth 0 score "
+ << value_to_uci(pos.is_check() ? -VALUE_MATE : VALUE_DRAW)
+ << endl;
- return pos.is_check() ? -VALUE_MATE : VALUE_DRAW;
+ return MOVE_NONE;
}
- // Print RootMoveList startup scoring to the standard output,
- // so to output information also for iteration 1.
- cout << set960(pos.is_chess960()) // Is enough to set once at the beginning
- << "info depth " << 1
- << "\ninfo depth " << 1
- << " score " << value_to_uci(rml.move_score(0))
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv " << rml.move(0) << "\n";
-
- // Initialize
- TT.new_search();
- H.clear();
- init_ss_array(ss, PLY_MAX_PLUS_2);
- pv[0] = pv[1] = MOVE_NONE;
- ValueByIteration[1] = rml.move_score(0);
- Iteration = 1;
-
// Is one move significantly better than others after initial scoring ?
- if ( rml.move_count() == 1
- || rml.move_score(0) > rml.move_score(1) + EasyMoveMargin)
- EasyMove = rml.move(0);
+ if ( Rml.size() == 1
+ || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin)
+ easyMove = Rml[0].pv[0];
// Iterative deepening loop
- while (Iteration < PLY_MAX)
+ while (++depth <= PLY_MAX && (!MaxDepth || depth <= MaxDepth) && !StopRequest)
{
- // Initialize iteration
- Iteration++;
- BestMoveChangesByIteration[Iteration] = 0;
-
- cout << "info depth " << Iteration << endl;
+ Rml.bestMoveChanges = researchCountFL = researchCountFH = 0;
+ cout << "info depth " << depth << endl;
// Calculate dynamic aspiration window based on previous iterations
- if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN)
+ if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN)
{
- int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2];
- int prevDelta2 = ValueByIteration[Iteration - 2] - ValueByIteration[Iteration - 3];
+ int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2];
+ int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3];
- AspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
- AspirationDelta = (AspirationDelta + 7) / 8 * 8; // Round to match grainSize
+ aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
+ aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
- alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE);
- beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
+ alpha = Max(bestValues[depth - 1] - aspirationDelta, -VALUE_INFINITE);
+ beta = Min(bestValues[depth - 1] + aspirationDelta, VALUE_INFINITE);
}
- // Search to the current depth, rml is updated and sorted, alpha and beta could change
- value = root_search(pos, ss, pv, rml, &alpha, &beta);
+ // 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)
+ {
+ // Search starting from ss+1 to allow calling update_gains()
+ value = search<PV, false, true>(pos, ss+1, alpha, beta, depth * ONE_PLY, 0);
+
+ // Send PV line to GUI and write 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;
+ }
- // Write PV to transposition table, in case the relevant entries have
- // been overwritten during the search.
- insert_pv_in_tt(pos, pv);
+ // Value cannot be trusted. Break out immediately!
+ if (StopRequest)
+ break;
+
+ assert(value >= alpha);
+
+ // In case of failing high/low increase aspiration window and research,
+ // otherwise exit the fail high/low loop.
+ if (value >= beta)
+ {
+ beta = Min(beta + aspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
+ researchCountFH++;
+ }
+ else if (value <= alpha)
+ {
+ AspirationFailLow = true;
+ StopOnPonderhit = false;
- if (AbortSearch)
- break; // Value cannot be trusted. Break out immediately!
+ alpha = Max(alpha - aspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
+ researchCountFL++;
+ }
+ else
+ break;
+ }
- //Save info about search result
- ValueByIteration[Iteration] = value;
+ // Collect info about search result
+ bestMove = Rml[0].pv[0];
+ bestValues[depth] = value;
+ bestMoveChanges[depth] = Rml.bestMoveChanges;
// Drop the easy move if differs from the new best move
- if (pv[0] != EasyMove)
- EasyMove = MOVE_NONE;
+ if (bestMove != easyMove)
+ easyMove = MOVE_NONE;
- if (UseTimeManagement)
+ if (UseTimeManagement && !StopRequest)
{
// Time to stop?
- bool stopSearch = false;
-
- // Stop search early if there is only a single legal move,
- // we search up to Iteration 6 anyway to get a proper score.
- if (Iteration >= 6 && rml.move_count() == 1)
- stopSearch = true;
+ bool noMoreTime = false;
// Stop search early when the last two iterations returned a mate score
- if ( Iteration >= 6
- && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100
- && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100)
- stopSearch = true;
-
- // Stop search early if one move seems to be much better than the others
- if ( Iteration >= 8
- && EasyMove == pv[0]
- && ( ( rml.move_nodes(0) > (pos.nodes_searched() * 85) / 100
+ if ( depth >= 5
+ && abs(bestValues[depth]) >= abs(VALUE_MATE) - 100
+ && abs(bestValues[depth - 1]) >= abs(VALUE_MATE) - 100)
+ noMoreTime = 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.
+ if ( depth >= 7
+ && easyMove == bestMove
+ && ( Rml.size() == 1
+ ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100
&& current_search_time() > TimeMgr.available_time() / 16)
- ||( rml.move_nodes(0) > (pos.nodes_searched() * 98) / 100
+ ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100
&& current_search_time() > TimeMgr.available_time() / 32)))
- stopSearch = true;
+ noMoreTime = true;
// Add some extra time if the best move has changed during the last two iterations
- if (Iteration > 5 && Iteration <= 50)
- TimeMgr.pv_instability(BestMoveChangesByIteration[Iteration],
- BestMoveChangesByIteration[Iteration-1]);
+ if (depth > 4 && depth < 50)
+ 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)
- stopSearch = true;
+ noMoreTime = true;
- if (stopSearch)
+ if (noMoreTime)
{
- if (PonderSearch)
+ if (Pondering)
StopOnPonderhit = true;
else
break;
}
}
-
- if (MaxDepth && Iteration >= MaxDepth)
- break;
- }
-
- // If we are pondering or in infinite search, we shouldn't print the
- // best move before we are told to do so.
- if (!AbortSearch && (PonderSearch || InfiniteSearch))
- wait_for_stop_or_ponderhit();
- else
- // Print final search statistics
- cout << "info nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " time " << current_search_time() << endl;
-
- // Print the best move and the ponder move to the standard output
- if (pv[0] == MOVE_NONE)
- {
- pv[0] = rml.move(0);
- pv[1] = MOVE_NONE;
}
- assert(pv[0] != MOVE_NONE);
-
- cout << "bestmove " << pv[0];
-
- if (pv[1] != MOVE_NONE)
- cout << " ponder " << pv[1];
-
- cout << endl;
-
- if (UseLogFile)
- {
- if (dbg_show_mean)
- dbg_print_mean(LogFile);
-
- if (dbg_show_hit_rate)
- dbg_print_hit_rate(LogFile);
-
- LogFile << "\nNodes: " << pos.nodes_searched()
- << "\nNodes/second: " << nps(pos)
- << "\nBest move: " << move_to_san(pos, pv[0]);
-
- StateInfo st;
- pos.do_move(pv[0], st);
- LogFile << "\nPonder move: "
- << move_to_san(pos, pv[1]) // Works also with MOVE_NONE
- << endl;
- }
- return rml.move_score(0);
- }
-
-
- // root_search() is the function which searches the root node. It is
- // similar to search_pv except that it uses a different move ordering
- // scheme, prints some information to the standard output and handles
- // the fail low/high loops.
-
- Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
-
- StateInfo st;
- CheckInfo ci(pos);
- int64_t nodes;
- Move move;
- Depth depth, ext, newDepth;
- Value value, alpha, beta;
- bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
- int researchCountFH, researchCountFL;
-
- researchCountFH = researchCountFL = 0;
- alpha = *alphaPtr;
- beta = *betaPtr;
- isCheck = pos.is_check();
- depth = (Iteration - 2) * ONE_PLY + InitialDepth;
-
- // Step 1. Initialize node (polling is omitted at root)
- ss->currentMove = ss->bestMove = MOVE_NONE;
-
- // Step 2. Check for aborted search (omitted at root)
- // Step 3. Mate distance pruning (omitted at root)
- // Step 4. Transposition table lookup (omitted at root)
-
- // Step 5. Evaluate the position statically
- // At root we do this only to get reference value for child nodes
- ss->evalMargin = VALUE_NONE;
- ss->eval = isCheck ? VALUE_NONE : evaluate(pos, ss->evalMargin);
-
- // Step 6. Razoring (omitted at root)
- // Step 7. Static null move pruning (omitted at root)
- // Step 8. Null move search with verification search (omitted at root)
- // Step 9. Internal iterative deepening (omitted at root)
-
- // Step extra. Fail low loop
- // We start with small aspiration window and in case of fail low, we research
- // with bigger window until we are not failing low anymore.
- while (1)
- {
- // Sort the moves before to (re)search
- rml.score_moves(pos);
- rml.sort();
-
- // Step 10. Loop through all moves in the root move list
- for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
- {
- // This is used by time management
- FirstRootMove = (i == 0);
-
- // Save the current node count before the move is searched
- nodes = pos.nodes_searched();
-
- // Pick the next root move, and print the move and the move number to
- // the standard output.
- move = ss->currentMove = rml.move(i);
-
- if (current_search_time() >= 1000)
- cout << "info currmove " << move
- << " currmovenumber " << i + 1 << endl;
-
- moveIsCheck = pos.move_is_check(move);
- captureOrPromotion = pos.move_is_capture_or_promotion(move);
-
- // Step 11. Decide the new search depth
- ext = extension<PV>(pos, move, captureOrPromotion, moveIsCheck, false, false, &dangerous);
- newDepth = depth + ext;
-
- // Step 12. Futility pruning (omitted at root)
-
- // Step extra. Fail high loop
- // If move fails high, we research with bigger window until we are not failing
- // high anymore.
- value = - VALUE_INFINITE;
-
- while (1)
- {
- // Step 13. Make the move
- pos.do_move(move, st, ci, moveIsCheck);
-
- // Step extra. pv search
- // We do pv search for first moves (i < MultiPV)
- // and for fail high research (value > alpha)
- if (i < MultiPV || value > alpha)
- {
- // Aspiration window is disabled in multi-pv case
- if (MultiPV > 1)
- alpha = -VALUE_INFINITE;
-
- // Full depth PV search, done on first move or after a fail high
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
- }
- else
- {
- // Step 14. Reduced search
- // if the move fails high will be re-searched at full depth
- bool doFullDepthSearch = true;
-
- if ( depth >= 3 * ONE_PLY
- && !dangerous
- && !captureOrPromotion
- && !move_is_castle(move))
- {
- ss->reduction = reduction<PV>(depth, i - MultiPV + 2);
- if (ss->reduction)
- {
- assert(newDepth-ss->reduction >= ONE_PLY);
-
- // Reduced depth non-pv search using alpha as upperbound
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
- doFullDepthSearch = (value > alpha);
- }
-
- // The move failed high, but if reduction is very big we could
- // face a false positive, retry with a less aggressive reduction,
- // if the move fails high again then go with full depth search.
- if (doFullDepthSearch && ss->reduction > 2 * ONE_PLY)
- {
- assert(newDepth - ONE_PLY >= ONE_PLY);
-
- ss->reduction = ONE_PLY;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
- doFullDepthSearch = (value > alpha);
- }
- ss->reduction = DEPTH_ZERO; // Restore original reduction
- }
-
- // Step 15. Full depth search
- if (doFullDepthSearch)
- {
- // Full depth non-pv search using alpha as upperbound
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, 1);
-
- // If we are above alpha then research at same depth but as PV
- // to get a correct score or eventually a fail high above beta.
- if (value > alpha)
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
- }
- }
-
- // Step 16. Undo move
- pos.undo_move(move);
-
- // Can we exit fail high loop ?
- if (AbortSearch || value < beta)
- break;
-
- // We are failing high and going to do a research. It's important to update
- // the score before research in case we run out of time while researching.
- rml.set_move_score(i, value);
- ss->bestMove = move;
- extract_pv_from_tt(pos, move, pv);
- rml.set_move_pv(i, pv);
-
- // Print information to the standard output
- print_pv_info(pos, pv, alpha, beta, value);
-
- // Prepare for a research after a fail high, each time with a wider window
- *betaPtr = beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
- researchCountFH++;
-
- } // End of fail high loop
-
- // Finished searching the move. If AbortSearch is true, the search
- // was aborted because the user interrupted the search or because we
- // ran out of time. In this case, the return value of the search cannot
- // be trusted, and we break out of the loop without updating the best
- // move and/or PV.
- if (AbortSearch)
- break;
-
- // Remember searched nodes counts for this move
- rml.add_move_nodes(i, pos.nodes_searched() - nodes);
-
- assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
- assert(value < beta);
-
- // Step 17. Check for new best move
- if (value <= alpha && i >= MultiPV)
- rml.set_move_score(i, -VALUE_INFINITE);
- else
- {
- // PV move or new best move!
-
- // Update PV
- rml.set_move_score(i, value);
- ss->bestMove = move;
- extract_pv_from_tt(pos, move, pv);
- rml.set_move_pv(i, pv);
-
- if (MultiPV == 1)
- {
- // We record how often the best move has been changed in each
- // iteration. This information is used for time managment: When
- // the best move changes frequently, we allocate some more time.
- if (i > 0)
- BestMoveChangesByIteration[Iteration]++;
-
- // Print information to the standard output
- print_pv_info(pos, pv, alpha, beta, value);
-
- // Raise alpha to setup proper non-pv search upper bound
- if (value > alpha)
- alpha = value;
- }
- else // MultiPV > 1
- {
- rml.sort_multipv(i);
- for (int j = 0; j < Min(MultiPV, rml.move_count()); j++)
- {
- cout << "info multipv " << j + 1
- << " score " << value_to_uci(rml.move_score(j))
- << " depth " << (j <= i ? Iteration : Iteration - 1)
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv ";
-
- for (int k = 0; rml.move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
- cout << rml.move_pv(j, k) << " ";
-
- cout << endl;
- }
- alpha = rml.move_score(Min(i, MultiPV - 1));
- }
- } // PV move or new best move
-
- assert(alpha >= *alphaPtr);
-
- AspirationFailLow = (alpha == *alphaPtr);
-
- if (AspirationFailLow && StopOnPonderhit)
- StopOnPonderhit = false;
- }
-
- // Can we exit fail low loop ?
- if (AbortSearch || !AspirationFailLow)
- break;
-
- // Prepare for a research after a fail low, each time with a wider window
- *alphaPtr = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
- researchCountFL++;
-
- } // Fail low loop
-
- // Sort the moves before to return
- rml.sort();
-
- return alpha;
+ *ponderMove = Rml[0].pv[1];
+ return bestMove;
}
// 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>
+ template <NodeType PvNode, bool SpNode, bool Root>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta > alpha && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
- assert(ply > 0 && ply < PLY_MAX);
+ assert((Root || ply > 0) && ply < PLY_MAX);
assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
Move movesSearched[MOVES_MAX];
+ int64_t nodes;
StateInfo st;
const TTEntry *tte;
Key posKey;
ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
- bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
+ bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
- int moveCount = 0;
+ int moveCount = 0, playedMoveCount = 0;
int threadID = pos.thread();
SplitPoint* sp = NULL;
+
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
isCheck = pos.is_check();
threatMove = sp->threatMove;
mateThreat = sp->mateThreat;
goto split_point_start;
- } else {} // Hack to fix icc's "statement is unreachable" warning
+ }
+ else if (Root)
+ bestValue = alpha;
// Step 1. Initialize node and poll. Polling can abort search
ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
}
// Step 2. Check for aborted search and immediate draw
- if ( AbortSearch || ThreadsMgr.thread_should_stop(threadID)
- || pos.is_draw() || ply >= PLY_MAX - 1)
+ if (( StopRequest
+ || ThreadsMgr.cutoff_at_splitpoint(threadID)
+ || pos.is_draw()
+ || ply >= PLY_MAX - 1) && !Root)
return VALUE_DRAW;
// Step 3. Mate distance pruning
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 exists.
excludedMove = ss->excludedMove;
tte = TT.retrieve(posKey);
ttMove = tte ? tte->move() : MOVE_NONE;
- // At PV nodes, we don't use the TT for pruning, but only for move ordering.
- // This is to avoid problems in the following areas:
- //
- // * Repetition draw detection
- // * Fifty move rule detection
- // * Searching for a mate
- // * Printing of full PV line
- if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
+ // 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.
+ if ( !Root
+ && tte
+ && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT
+ : ok_to_use_TT(tte, depth, beta, ply)))
{
TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
&& !isCheck
&& refinedValue < beta - razor_margin(depth)
&& ttMove == MOVE_NONE
- && (ss-1)->currentMove != MOVE_NULL
&& !value_is_mate(beta)
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
threatMove = (ss+1)->bestMove;
if ( depth < ThreatDepth
&& (ss-1)->reduction
+ && threatMove != MOVE_NONE
&& connected_moves(pos, (ss-1)->currentMove, threatMove))
return beta - 1;
}
}
// Step 9. Internal iterative deepening
- if ( depth >= IIDDepth[PvNode]
- && ttMove == MOVE_NONE
+ if ( depth >= IIDDepth[PvNode]
+ && ttMove == MOVE_NONE
&& (PvNode || (!isCheck && ss->eval >= beta - IIDMargin)))
{
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
- // FIXME currently MovePicker() c'tor is needless called also in SplitPoint
- MovePicker mpBase(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
- MovePicker& mp = SpNode ? *sp->mp : mpBase;
+ MovePickerExt<SpNode, Root> mp(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
- singleEvasion = !SpNode && isCheck && mp.number_of_evasions() == 1;
futilityBase = ss->eval + ss->evalMargin;
- singularExtensionNode = !SpNode
+ singularExtensionNode = !Root
+ && !SpNode
&& depth >= SingularExtensionDepth[PvNode]
&& tte
&& tte->move()
// Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE
- && !ThreadsMgr.thread_should_stop(threadID))
+ && !ThreadsMgr.cutoff_at_splitpoint(threadID))
{
assert(move_is_ok(move));
else if (move == excludedMove)
continue;
else
- movesSearched[moveCount++] = move;
+ moveCount++;
+ if (Root)
+ {
+ // This is used by time management
+ FirstRootMove = (moveCount == 1);
+
+ // Save the current node count before the move is searched
+ nodes = pos.nodes_searched();
+
+ // If it's time to send nodes info, do it here where we have the
+ // correct accumulated node counts searched by each thread.
+ if (SendSearchedNodes)
+ {
+ SendSearchedNodes = false;
+ cout << "info nodes " << nodes
+ << " nps " << nps(pos)
+ << " time " << current_search_time() << endl;
+ }
+
+ if (current_search_time() >= 1000)
+ cout << "info currmove " << move
+ << " currmovenumber " << moveCount << endl;
+ }
+
+ isPvMove = (PvNode && moveCount <= (Root ? 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, singleEvasion, mateThreat, &dangerous);
+ ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, mateThreat, &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.
// Update current move (this must be done after singular extension search)
ss->currentMove = move;
- newDepth = depth - ONE_PLY + ext;
+ newDepth = depth - (!Root ? ONE_PLY : DEPTH_ZERO) + ext;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
continue;
}
+
+ // Prune moves with negative SEE at low depths
+ if ( predictedDepth < 2 * ONE_PLY
+ && bestValue > value_mated_in(PLY_MAX)
+ && pos.see_sign(move) < 0)
+ {
+ if (SpNode)
+ lock_grab(&(sp->lock));
+
+ continue;
+ }
}
// Step 13. Make the move
pos.do_move(move, st, ci, moveIsCheck);
+ if (!SpNode && !captureOrPromotion)
+ movesSearched[playedMoveCount++] = move;
+
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
- if (!SpNode && PvNode && moveCount == 1)
+ if (isPvMove)
+ {
+ // Aspiration window is disabled in multi-pv case
+ if (Root && MultiPV > 1)
+ alpha = -VALUE_INFINITE;
+
value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ }
else
{
// Step 14. Reduced depth search
&& !captureOrPromotion
&& !dangerous
&& !move_is_castle(move)
- && !(ss->killers[0] == move || ss->killers[1] == move))
+ && ss->killers[0] != move
+ && ss->killers[1] != move)
{
- ss->reduction = reduction<PvNode>(depth, moveCount);
+ ss->reduction = Root ? reduction<PvNode>(depth, moveCount - MultiPV + 1)
+ : reduction<PvNode>(depth, moveCount);
if (ss->reduction)
{
alpha = SpNode ? sp->alpha : alpha;
doFullDepthSearch = (value > alpha);
}
-
- // The move failed high, but if reduction is very big we could
- // face a false positive, retry with a less aggressive reduction,
- // if the move fails high again then go with full depth search.
- if (doFullDepthSearch && ss->reduction > 2 * ONE_PLY)
- {
- assert(newDepth - ONE_PLY >= ONE_PLY);
-
- ss->reduction = ONE_PLY;
- alpha = SpNode ? sp->alpha : alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, ply+1);
- doFullDepthSearch = (value > alpha);
- }
ss->reduction = DEPTH_ZERO; // Restore original reduction
}
// 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 && value < beta)
+ if (PvNode && value > alpha && (Root || value < beta))
value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
}
}
alpha = sp->alpha;
}
- if (value > bestValue && !(SpNode && ThreadsMgr.thread_should_stop(threadID)))
+ if (!Root && value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID)))
{
bestValue = value;
if (value > alpha)
{
- if (SpNode && (!PvNode || value >= beta))
- sp->stopRequest = true;
-
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;
}
}
+ if (Root)
+ {
+ // To avoid to exit with bestValue == -VALUE_INFINITE
+ if (value > bestValue)
+ bestValue = value;
+
+ // Finished searching the move. If StopRequest is true, the search
+ // was aborted because the user interrupted the search or because we
+ // ran out of time. In this case, the return value of the search cannot
+ // be trusted, and we break out of the loop without updating the best
+ // move and/or PV.
+ if (StopRequest)
+ break;
+
+ // Remember searched nodes counts for this move
+ mp.rm->nodes += pos.nodes_searched() - nodes;
+
+ // Step 17. Check for new best move
+ if (!isPvMove && value <= alpha)
+ mp.rm->pv_score = -VALUE_INFINITE;
+ else
+ {
+ // PV move or new best move!
+
+ // Update PV
+ ss->bestMove = move;
+ mp.rm->pv_score = value;
+ mp.rm->extract_pv_from_tt(pos);
+
+ // We record how often the best move has been changed in each
+ // iteration. This information is used for time managment: When
+ // the best move changes frequently, we allocate some more time.
+ if (!isPvMove && MultiPV == 1)
+ Rml.bestMoveChanges++;
+
+ Rml.sort_multipv(moveCount);
+
+ // Update alpha. In multi-pv we don't use aspiration window, so
+ // set alpha equal to minimum score among the PV lines.
+ if (MultiPV > 1)
+ alpha = Rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount?
+ else if (value > alpha)
+ alpha = value;
+
+ } // PV move or new best move
+ }
+
// Step 18. Check for split
- if ( !SpNode
- && depth >= MinimumSplitDepth
+ if ( !Root
+ && !SpNode
+ && depth >= ThreadsMgr.min_split_depth()
&& ThreadsMgr.active_threads() > 1
&& bestValue < beta
&& ThreadsMgr.available_thread_exists(threadID)
- && !AbortSearch
- && !ThreadsMgr.thread_should_stop(threadID)
- && Iteration <= 99)
+ && !StopRequest
+ && !ThreadsMgr.cutoff_at_splitpoint(threadID))
ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
threatMove, mateThreat, moveCount, &mp, PvNode);
}
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (!SpNode && !AbortSearch && !ThreadsMgr.thread_should_stop(threadID))
+ if (!SpNode && !StopRequest && !ThreadsMgr.cutoff_at_splitpoint(threadID))
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
if ( bestValue >= beta
&& !pos.move_is_capture_or_promotion(move))
{
- update_history(pos, move, depth, movesSearched, moveCount);
- update_killers(move, ss);
+ update_history(pos, move, depth, movesSearched, playedMoveCount);
+ update_killers(move, ss->killers);
}
}
return bestValue;
}
-
// qsearch() is the quiescence search function, which is called by the main
// search function when the remaining depth is zero (or, to be more precise,
// less than ONE_PLY).
StateInfo st;
Move ttMove, move;
Value bestValue, value, evalMargin, futilityValue, futilityBase;
- bool isCheck, deepChecks, enoughMaterial, moveIsCheck, evasionPrunable;
+ bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
const TTEntry* tte;
+ Depth ttDepth;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
+ // 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);
+
// 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());
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
+ if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ply))
{
ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
- isCheck = pos.is_check();
-
// Evaluate the position statically
if (isCheck)
{
bestValue = futilityBase = -VALUE_INFINITE;
ss->eval = evalMargin = VALUE_NONE;
- deepChecks = enoughMaterial = false;
+ enoughMaterial = false;
}
else
{
if (PvNode && bestValue > alpha)
alpha = bestValue;
- // If we are near beta then try to get a cutoff pushing checks a bit further
- deepChecks = (depth == -ONE_PLY && bestValue >= beta - PawnValueMidgame / 8);
-
// Futility pruning parameters, not needed when in check
futilityBase = ss->eval + evalMargin + FutilityMarginQS;
enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
// Initialize a MovePicker object for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
- // queen promotions and checks (only if depth == 0 or depth == -ONE_PLY
- // and we are near beta) will be generated.
- MovePicker mp = MovePicker(pos, ttMove, deepChecks ? DEPTH_ZERO : depth, H);
+ // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
+ // be generated.
+ MovePicker mp(pos, ttMove, depth, H);
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
&& pos.see_sign(move) < 0)
continue;
+ // Don't search useless checks
+ if ( !PvNode
+ && !isCheck
+ && moveIsCheck
+ && move != ttMove
+ && !pos.move_is_capture_or_promotion(move)
+ && ss->eval + PawnValueMidgame / 4 < beta
+ && !check_is_dangerous(pos, move, futilityBase, beta, &bestValue))
+ {
+ if (ss->eval + PawnValueMidgame / 4 > bestValue)
+ bestValue = ss->eval + PawnValueMidgame / 4;
+
+ continue;
+ }
+
// Update current move
ss->currentMove = move;
return value_mated_in(ply);
// Update transposition table
- Depth d = (depth == DEPTH_ZERO ? DEPTH_ZERO : DEPTH_ZERO - ONE_PLY);
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, d, ss->bestMove, ss->eval, evalMargin);
+ TT.store(pos.get_key(), value_to_tt(bestValue, 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.
+
+ bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bestValue)
+ {
+ Bitboard b, occ, oldAtt, newAtt, kingAtt;
+ Square from, to, ksq, victimSq;
+ Piece pc;
+ Color them;
+ Value futilityValue, bv = *bestValue;
+
+ from = move_from(move);
+ to = move_to(move);
+ them = opposite_color(pos.side_to_move());
+ ksq = pos.king_square(them);
+ kingAtt = pos.attacks_from<KING>(ksq);
+ pc = pos.piece_on(from);
+
+ occ = pos.occupied_squares() & ~(1ULL << from) & ~(1ULL << ksq);
+ oldAtt = pos.attacks_from(pc, from, occ);
+ 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);
+
+ if (!(b && (b & (b - 1))))
+ return true;
+
+ // Rule 2. Queen contact check is very dangerous
+ if ( type_of_piece(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);
+
+ while (b)
+ {
+ victimSq = pop_1st_bit(&b);
+ futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq);
+
+ // Note that here we generate illegal "double move"!
+ if ( futilityValue >= beta
+ && pos.see_sign(make_move(from, victimSq)) >= 0)
+ return true;
+
+ if (futilityValue > bv)
+ bv = futilityValue;
+ }
+
+ // Update bestValue only if check is not dangerous (because we will prune the move)
+ *bestValue = bv;
+ return false;
+ }
+
+
// connected_moves() tests whether two moves are 'connected' in the sense
// that the first move somehow made the second move possible (for instance
// if the moving piece is the same in both moves). The first move is assumed
Square f1, t1, f2, t2;
Piece p;
- assert(move_is_ok(m1));
- assert(move_is_ok(m2));
-
- if (m2 == MOVE_NONE)
- return false;
+ assert(m1 && move_is_ok(m1));
+ assert(m2 && move_is_ok(m2));
// Case 1: The moving piece is the same in both moves
f2 = move_from(m2);
// 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 singleEvasion, bool mateThreat, bool* dangerous) {
+ Depth extension(const Position& pos, Move m, bool captureOrPromotion,
+ bool moveIsCheck, bool mateThreat, bool* dangerous) {
assert(m != MOVE_NONE);
Depth result = DEPTH_ZERO;
- *dangerous = moveIsCheck | singleEvasion | mateThreat;
+ *dangerous = moveIsCheck | mateThreat;
if (*dangerous)
{
if (moveIsCheck && pos.see_sign(m) >= 0)
result += CheckExtension[PvNode];
- if (singleEvasion)
- result += SingleEvasionExtension[PvNode];
-
if (mateThreat)
result += MateThreatExtension[PvNode];
}
void update_history(const Position& pos, Move move, Depth depth,
Move movesSearched[], int moveCount) {
Move m;
+ Value bonus = Value(int(depth) * int(depth));
- H.success(pos.piece_on(move_from(move)), move_to(move), depth);
+ H.update(pos.piece_on(move_from(move)), move_to(move), bonus);
for (int i = 0; i < moveCount - 1; i++)
{
assert(m != move);
- if (!pos.move_is_capture_or_promotion(m))
- H.failure(pos.piece_on(move_from(m)), move_to(m), depth);
+ H.update(pos.piece_on(move_from(m)), move_to(m), -bonus);
}
}
// update_killers() add a good move that produced a beta-cutoff
// among the killer moves of that ply.
- void update_killers(Move m, SearchStack* ss) {
-
- if (m == ss->killers[0])
- return;
+ void update_killers(Move m, Move killers[]) {
- ss->killers[1] = ss->killers[0];
- ss->killers[0] = m;
+ if (m != killers[0])
+ {
+ killers[1] = killers[0];
+ killers[0] = m;
+ }
}
&& after != VALUE_NONE
&& pos.captured_piece_type() == PIECE_TYPE_NONE
&& !move_is_special(m))
- H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
+ H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
}
- // 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;
- }
-
-
- // value_to_uci() converts a value to a string suitable for use with the UCI protocol
+ // value_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::stringstream s;
if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to pawn = 100
+ s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
else
s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2 );
return s.str();
}
- // nps() computes the current nodes/second count.
+
+ // 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;
+ }
+
+
+ // nps() computes the current nodes/second count
int nps(const Position& pos) {
int t = current_search_time();
// Poll for input
- if (Bioskey())
+ if (input_available())
{
// We are line oriented, don't read single chars
std::string command;
if (command == "quit")
{
- AbortSearch = true;
- PonderSearch = false;
- Quit = true;
+ // Quit the program as soon as possible
+ Pondering = false;
+ QuitRequest = StopRequest = true;
return;
}
else if (command == "stop")
{
- AbortSearch = true;
- PonderSearch = false;
+ // Stop calculating as soon as possible, but still send the "bestmove"
+ // and possibly the "ponder" token when finishing the search.
+ Pondering = false;
+ StopRequest = true;
}
else if (command == "ponderhit")
- 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;
+
+ if (StopOnPonderhit)
+ StopRequest = true;
+ }
}
// Print search information
if (dbg_show_hit_rate)
dbg_print_hit_rate();
- cout << "info nodes " << pos.nodes_searched() << " nps " << nps(pos)
- << " time " << t << endl;
+ // Send info on searched nodes as soon as we return to root
+ SendSearchedNodes = true;
}
// Should we stop the search?
- if (PonderSearch)
+ if (Pondering)
return;
bool stillAtFirstMove = FirstRootMove
bool noMoreTime = t > TimeMgr.maximum_time()
|| stillAtFirstMove;
- if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
+ if ( (UseTimeManagement && noMoreTime)
|| (ExactMaxTime && t >= ExactMaxTime)
- || (Iteration >= 3 && MaxNodes && pos.nodes_searched() >= MaxNodes))
- AbortSearch = true;
- }
-
-
- // ponderhit() is called when the program is pondering (i.e. thinking while
- // it's the opponent's turn to move) in order to let the engine know that
- // it correctly predicted the opponent's move.
-
- void ponderhit() {
-
- int t = current_search_time();
- PonderSearch = false;
-
- bool stillAtFirstMove = FirstRootMove
- && !AspirationFailLow
- && t > TimeMgr.available_time();
-
- bool noMoreTime = t > TimeMgr.maximum_time()
- || stillAtFirstMove;
-
- if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
- AbortSearch = true;
- }
-
-
- // init_ss_array() does a fast reset of the first entries of a SearchStack
- // array and of all the excludedMove and skipNullMove entries.
-
- void init_ss_array(SearchStack* ss, int size) {
-
- for (int i = 0; i < size; i++, ss++)
- {
- ss->excludedMove = MOVE_NONE;
- ss->skipNullMove = false;
- ss->reduction = DEPTH_ZERO;
- ss->sp = NULL;
-
- if (i < 3)
- ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE;
- }
+ || (MaxNodes && pos.nodes_searched() >= MaxNodes)) // FIXME
+ StopRequest = true;
}
// the UCI protocol: When pondering, the engine is not allowed to give a
// "bestmove" before the GUI sends it a "stop" or "ponderhit" command.
// We simply wait here until one of these commands is sent, and return,
- // after which the bestmove and pondermove will be printed (in id_loop()).
+ // after which the bestmove and pondermove will be printed.
void wait_for_stop_or_ponderhit() {
while (true)
{
+ // Wait for a command from stdin
if (!std::getline(std::cin, command))
command = "quit";
if (command == "quit")
{
- Quit = true;
+ QuitRequest = true;
break;
}
else if (command == "ponderhit" || command == "stop")
}
- // print_pv_info() prints to standard output and eventually to log file information on
- // the current PV line. It is called at each iteration or after a new pv is found.
-
- void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value) {
-
- cout << "info depth " << Iteration
- << " score " << value_to_uci(value)
- << (value >= beta ? " lowerbound" : value <= alpha ? " upperbound" : "")
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv ";
-
- for (Move* m = pv; *m != MOVE_NONE; m++)
- cout << *m << " ";
-
- cout << endl;
-
- if (UseLogFile)
- {
- ValueType t = value >= beta ? VALUE_TYPE_LOWER :
- value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
-
- LogFile << pretty_pv(pos, current_search_time(), Iteration, value, t, pv) << endl;
- }
- }
-
-
- // insert_pv_in_tt() is called at the end of a search iteration, and inserts
- // the PV back into the TT. This makes sure the old PV moves are searched
- // first, even if the old TT entries have been overwritten.
-
- void insert_pv_in_tt(const Position& pos, Move pv[]) {
-
- StateInfo st;
- TTEntry* tte;
- Position p(pos, pos.thread());
- Value v, m = VALUE_NONE;
-
- for (int i = 0; pv[i] != MOVE_NONE; i++)
- {
- tte = TT.retrieve(p.get_key());
- if (!tte || tte->move() != pv[i])
- {
- v = (p.is_check() ? VALUE_NONE : evaluate(p, m));
- TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, m);
- }
- p.do_move(pv[i], st);
- }
- }
-
-
- // 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
- // long PV to print that is important for position analysis.
-
- void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) {
-
- StateInfo st;
- TTEntry* tte;
- Position p(pos, pos.thread());
- int ply = 0;
-
- assert(bestMove != MOVE_NONE);
-
- pv[ply] = bestMove;
- p.do_move(pv[ply++], st);
-
- while ( (tte = TT.retrieve(p.get_key())) != NULL
- && tte->move() != MOVE_NONE
- && move_is_legal(p, tte->move())
- && ply < PLY_MAX
- && (!p.is_draw() || ply < 2))
- {
- pv[ply] = tte->move();
- p.do_move(pv[ply++], st);
- }
- pv[ply] = MOVE_NONE;
- }
-
-
// 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
/// 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.
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)
+ if (allThreadsShouldExit)
{
assert(!sp);
threads[threadID].state = THREAD_TERMINATED;
// 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
- || (!sp && threads[threadID].state == THREAD_AVAILABLE))
+ while ( threadID >= activeThreads || threads[threadID].state == THREAD_INITIALIZING
+ || (useSleepingThreads && threads[threadID].state == THREAD_AVAILABLE))
{
- assert(!sp);
- assert(threadID != 0);
+ assert(!sp || useSleepingThreads);
+ assert(threadID != 0 || useSleepingThreads);
- if (AllThreadsShouldExit)
- break;
+ 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]);
- lock_grab(&MPLock);
+ // 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);
- // Retest condition under lock protection
- if (!( threadID >= ActiveThreads
- || threads[threadID].state == THREAD_INITIALIZING
- || (!sp && threads[threadID].state == THREAD_AVAILABLE)))
+ if (allFinished || allThreadsShouldExit)
{
- lock_release(&MPLock);
- continue;
+ lock_release(&sleepLock[threadID]);
+ break;
}
- // Put thread to sleep
- threads[threadID].state = THREAD_AVAILABLE;
- cond_wait(&WaitCond[threadID], &MPLock);
- lock_release(&MPLock);
+ // 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);
+ assert(!allThreadsShouldExit);
threads[threadID].state = THREAD_SEARCHING;
ss->sp = tsp;
if (tsp->pvNode)
- search<PV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
- else {
- search<NonPV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
- }
+ search<PV, true, false>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ else
+ search<NonPV, true, false>(pos, ss, 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.
- int i = 0;
- for ( ; sp && i < ActiveThreads && !sp->slaves[i]; i++) {}
+ for (i = 0; sp && i < activeThreads && !sp->slaves[i]; i++) {}
+ allFinished = (i == activeThreads);
- if (i == ActiveThreads)
+ if (allFinished)
{
// Because sp->slaves[] is reset under lock protection,
// be sure sp->lock has been released before to return.
bool ok;
// Initialize global locks
- lock_init(&MPLock);
+ lock_init(&mpLock);
for (i = 0; i < MAX_THREADS; i++)
- cond_init(&WaitCond[i]);
+ {
+ lock_init(&sleepLock[i]);
+ cond_init(&sleepCond[i]);
+ }
// Initialize splitPoints[] locks
for (i = 0; i < MAX_THREADS; i++)
lock_init(&(threads[i].splitPoints[j].lock));
// Will be set just before program exits to properly end the threads
- AllThreadsShouldExit = false;
+ allThreadsShouldExit = false;
// Threads will be put all threads to sleep as soon as created
- ActiveThreads = 1;
+ activeThreads = 1;
// All threads except the main thread should be initialized to THREAD_INITIALIZING
threads[0].state = THREAD_SEARCHING;
if (!ok)
{
cout << "Failed to create thread number " << i << endl;
- Application::exit_with_failure();
+ exit(EXIT_FAILURE);
}
// Wait until the thread has finished launching and is gone to sleep
void ThreadsManager::exit_threads() {
- AllThreadsShouldExit = true; // Let the woken up threads to exit idle_loop()
+ 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++)
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
lock_destroy(&(threads[i].splitPoints[j].lock));
- lock_destroy(&MPLock);
+ lock_destroy(&mpLock);
// Now we can safely destroy the wait conditions
for (int i = 0; i < MAX_THREADS; i++)
- cond_destroy(&WaitCond[i]);
+ {
+ lock_destroy(&sleepLock[i]);
+ cond_destroy(&sleepCond[i]);
+ }
}
- // thread_should_stop() checks whether the thread should stop its search.
- // This can happen if a beta cutoff has occurred in the thread's currently
- // active split point, or in some ancestor of the current split point.
+ // 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::thread_should_stop(int threadID) const {
+ bool ThreadsManager::cutoff_at_splitpoint(int threadID) const {
- assert(threadID >= 0 && threadID < ActiveThreads);
+ assert(threadID >= 0 && threadID < activeThreads);
SplitPoint* sp = threads[threadID].splitPoint;
- for ( ; sp && !sp->stopRequest; sp = sp->parent) {}
+ for ( ; sp && !sp->betaCutoff; sp = sp->parent) {}
return sp != NULL;
}
bool ThreadsManager::thread_is_available(int slave, int master) const {
- assert(slave >= 0 && slave < ActiveThreads);
- assert(master >= 0 && master < ActiveThreads);
- assert(ActiveThreads > 1);
+ assert(slave >= 0 && slave < activeThreads);
+ assert(master >= 0 && master < activeThreads);
+ assert(activeThreads > 1);
if (threads[slave].state != THREAD_AVAILABLE || slave == master)
return false;
// No active split points means that the thread is available as
// a slave for any other thread.
- if (localActiveSplitPoints == 0 || ActiveThreads == 2)
+ if (localActiveSplitPoints == 0 || activeThreads == 2)
return true;
// Apply the "helpful master" concept if possible. Use localActiveSplitPoints
bool ThreadsManager::available_thread_exists(int master) const {
- assert(master >= 0 && master < ActiveThreads);
- assert(ActiveThreads > 1);
+ assert(master >= 0 && master < activeThreads);
+ assert(activeThreads > 1);
- for (int i = 0; i < ActiveThreads; i++)
+ for (int i = 0; i < activeThreads; i++)
if (thread_is_available(i, master))
return true;
assert(*alpha < beta);
assert(beta <= VALUE_INFINITE);
assert(depth > DEPTH_ZERO);
- assert(pos.thread() >= 0 && pos.thread() < ActiveThreads);
- assert(ActiveThreads > 1);
+ assert(pos.thread() >= 0 && pos.thread() < activeThreads);
+ assert(activeThreads > 1);
int i, master = pos.thread();
Thread& masterThread = threads[master];
- lock_grab(&MPLock);
+ 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);
+ lock_release(&mpLock);
return;
}
// Initialize the split point object
splitPoint.parent = masterThread.splitPoint;
- splitPoint.stopRequest = false;
+ splitPoint.master = master;
+ splitPoint.betaCutoff = false;
splitPoint.ply = ply;
splitPoint.depth = depth;
splitPoint.threatMove = threatMove;
splitPoint.pos = &pos;
splitPoint.nodes = 0;
splitPoint.parentSstack = ss;
- for (i = 0; i < ActiveThreads; i++)
+ for (i = 0; i < activeThreads; i++)
splitPoint.slaves[i] = 0;
masterThread.splitPoint = &splitPoint;
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++)
+ for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
if (thread_is_available(i, master))
{
threads[i].state = THREAD_BOOKED;
assert(Fake || workersCnt > 1);
// We can release the lock because slave threads are already booked and master is not available
- lock_release(&MPLock);
+ 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.
- for (i = 0; i < ActiveThreads; i++)
+ 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 (i != master)
+
+ if (useSleepingThreads && i != master)
wake_sleeping_thread(i);
}
// We have returned from the idle loop, which means that all threads are
// finished. Update alpha and bestValue, and return.
- lock_grab(&MPLock);
+ lock_grab(&mpLock);
*alpha = splitPoint.alpha;
*bestValue = splitPoint.bestValue;
masterThread.splitPoint = splitPoint.parent;
pos.set_nodes_searched(pos.nodes_searched() + splitPoint.nodes);
- lock_release(&MPLock);
+ lock_release(&mpLock);
}
- // wake_sleeping_thread() wakes up all sleeping threads when it is time
- // to start a new search from the root.
+ // 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(&MPLock);
- cond_signal(&WaitCond[threadID]);
- lock_release(&MPLock);
+ lock_grab(&sleepLock[threadID]);
+ cond_signal(&sleepCond[threadID]);
+ lock_release(&sleepLock[threadID]);
}
- /// The RootMoveList class
+ /// RootMove and RootMoveList method's definitions
- // RootMoveList c'tor
+ RootMove::RootMove() {
- RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) {
+ nodes = 0;
+ pv_score = non_pv_score = -VALUE_INFINITE;
+ pv[0] = MOVE_NONE;
+ }
- SearchStack ss[PLY_MAX_PLUS_2];
- MoveStack mlist[MOVES_MAX];
- StateInfo st;
- bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
+ RootMove& RootMove::operator=(const RootMove& rm) {
- // Initialize search stack
- init_ss_array(ss, PLY_MAX_PLUS_2);
- ss[0].eval = ss[0].evalMargin = VALUE_NONE;
- count = 0;
+ const Move* src = rm.pv;
+ Move* dst = pv;
- // Generate all legal moves
- MoveStack* last = generate_moves(pos, mlist);
+ // Avoid a costly full rm.pv[] copy
+ do *dst++ = *src; while (*src++ != MOVE_NONE);
- // Add each move to the moves[] array
- for (MoveStack* cur = mlist; cur != last; cur++)
- {
- bool includeMove = includeAllMoves;
+ nodes = rm.nodes;
+ pv_score = rm.pv_score;
+ non_pv_score = rm.non_pv_score;
+ return *this;
+ }
- for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
- includeMove = (searchMoves[k] == cur->move);
+ // 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
+ // long PV to print that is important for position analysis.
- if (!includeMove)
- continue;
+ void RootMove::extract_pv_from_tt(Position& pos) {
- // Find a quick score for the move
- moves[count].move = ss[0].currentMove = moves[count].pv[0] = cur->move;
- moves[count].pv[1] = MOVE_NONE;
- pos.do_move(cur->move, st);
- moves[count].score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
- pos.undo_move(cur->move);
- count++;
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ TTEntry* tte;
+ int ply = 1;
+
+ assert(pv[0] != MOVE_NONE && move_is_legal(pos, 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())
+ && ply < PLY_MAX
+ && (!pos.is_draw() || ply < 2))
+ {
+ pv[ply] = tte->move();
+ pos.do_move(pv[ply++], *st++);
}
- sort();
+ pv[ply] = MOVE_NONE;
+
+ do pos.undo_move(pv[--ply]); while (ply);
}
- // Score root moves using the standard way used in main search, the moves
- // are scored according to the order in which are returned by MovePicker.
+ // insert_pv_in_tt() is called at the end of a search iteration, and inserts
+ // the PV back into the TT. This makes sure the old PV moves are searched
+ // first, even if the old TT entries have been overwritten.
- void RootMoveList::score_moves(const Position& pos)
- {
- Move move;
- int score = 1000;
- MovePicker mp = MovePicker(pos, MOVE_NONE, ONE_PLY, H);
+ void RootMove::insert_pv_in_tt(Position& pos) {
- while ((move = mp.get_next_move()) != MOVE_NONE)
- for (int i = 0; i < count; i++)
- if (moves[i].move == move)
- {
- moves[i].mp_score = score--;
- break;
- }
- }
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ TTEntry* tte;
+ Key k;
+ Value v, m = VALUE_NONE;
+ int ply = 0;
- // RootMoveList simple methods definitions
+ assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
- void RootMoveList::set_move_pv(int moveNum, const Move pv[]) {
+ do {
+ k = pos.get_key();
+ tte = TT.retrieve(k);
- int j;
+ // Don't overwrite exsisting correct entries
+ if (!tte || tte->move() != pv[ply])
+ {
+ v = (pos.is_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++);
- for (j = 0; pv[j] != MOVE_NONE; j++)
- moves[moveNum].pv[j] = pv[j];
+ } while (pv[++ply] != MOVE_NONE);
- moves[moveNum].pv[j] = MOVE_NONE;
+ 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 and eventually writes the info
+ // to a log file. It is called at each iteration or after a new pv is found.
- // RootMoveList::sort() sorts the root move list at the beginning of a new
- // iteration.
+ std::string RootMove::pv_info_to_uci(Position& pos, int depth, Value alpha, Value beta, int pvLine) {
- void RootMoveList::sort() {
+ std::stringstream s, l;
+ Move* m = pv;
- sort_multipv(count - 1); // Sort all items
+ while (*m != MOVE_NONE)
+ l << *m++ << " ";
+
+ s << "info depth " << depth
+ << " seldepth " << int(m - pv)
+ << " multipv " << pvLine + 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();
+
+ if (UseLogFile && pvLine == 0)
+ {
+ ValueType t = pv_score >= beta ? VALUE_TYPE_LOWER :
+ pv_score <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
+
+ LogFile << pretty_pv(pos, current_search_time(), depth, pv_score, t, pv) << endl;
+ }
+ return s.str();
}
- // RootMoveList::sort_multipv() sorts the first few moves in the root move
- // list by their scores and depths. It is used to order the different PVs
- // correctly in MultiPV mode.
+ void RootMoveList::init(Position& pos, Move searchMoves[]) {
- void RootMoveList::sort_multipv(int n) {
+ MoveStack mlist[MOVES_MAX];
+ Move* sm;
+
+ clear();
+ bestMoveChanges = 0;
- int i,j;
+ // Generate all legal moves and score them
+ MoveStack* last = generate<MV_LEGAL>(pos, mlist);
+ qsearch_scoring(pos, mlist, last);
- for (i = 1; i <= n; i++)
+ // Add each move to the RootMoveList's vector
+ for (MoveStack* cur = mlist; cur != last; cur++)
{
- RootMove rm = moves[i];
- for (j = i; j > 0 && moves[j - 1] < rm; j--)
- moves[j] = moves[j - 1];
+ // 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++) {}
- moves[j] = rm;
+ if (searchMoves[0] && *sm != cur->move)
+ continue;
+
+ RootMove rm;
+ rm.pv[0] = cur->move;
+ rm.pv[1] = MOVE_NONE;
+ rm.pv_score = Value(cur->score);
+ push_back(rm);
}
+ sort();
}
} // namespace
projects / stockfish / blobdiff