namespace {
- // Maximum number of allowed moves per position
- const int MOVES_MAX = 256;
-
// Types
enum NodeType { NonPV, PV };
// 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; }
- void incrementNodeCounter(int threadID) { threads[threadID].nodes++; }
+ int min_split_depth() const { return minimumSplitDepth; }
+ int active_threads() const { return activeThreads; }
+ void set_active_threads(int cnt) { activeThreads = cnt; }
- void resetNodeCounters();
- int64_t nodes_searched() const;
+ 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;
- void wake_sleeping_threads();
- void put_threads_to_sleep();
+ 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(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
- Depth depth, Move threatMove, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
+ void split(Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
+ Depth depth, Move threatMove, bool mateThreat, int moveCount, MovePicker* mp, bool pvNode);
private:
- friend void poll();
-
- int ActiveThreads;
- volatile bool AllThreadsShouldExit, AllThreadsShouldSleep;
+ Depth minimumSplitDepth;
+ int maxThreadsPerSplitPoint;
+ bool useSleepingThreads;
+ int activeThreads;
+ volatile bool allThreadsShouldExit;
Thread threads[MAX_THREADS];
-
- Lock MPLock, WaitLock;
-
-#if !defined(_MSC_VER)
- pthread_cond_t WaitCond;
-#else
- HANDLE SitIdleEvent[MAX_THREADS];
-#endif
-
+ Lock mpLock, sleepLock[MAX_THREADS];
+ WaitCondition sleepCond[MAX_THREADS];
};
const Value EasyMoveMargin = Value(0x200);
- /// Global variables
+ /// Namespace variables
+
+ // Book object
+ Book OpeningBook;
// Iteration counter
int Iteration;
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
/// Local functions
- Value id_loop(const Position& pos, Move searchMoves[]);
+ Value id_loop(Position& pos, Move searchMoves[]);
Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
- template <NodeType PvNode>
+ template <NodeType PvNode, bool SpNode>
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>
- void sp_search(SplitPoint* sp, int threadID);
+ 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);
+ }
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, 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);
Value value_from_tt(Value v, int ply);
- bool move_is_killer(Move m, SearchStack* ss);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
bool connected_threat(const Position& pos, Move m, Move threat);
Value refine_eval(const TTEntry* tte, Value defaultEval, int ply);
int current_search_time();
std::string value_to_uci(Value v);
- int nps();
- void poll();
+ 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 extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
#if !defined(_MSC_VER)
- void *init_thread(void *threadID);
+ void* init_thread(void* threadID);
#else
DWORD WINAPI init_thread(LPVOID threadID);
#endif
void init_threads() { ThreadsMgr.init_threads(); }
void exit_threads() { ThreadsMgr.exit_threads(); }
-int64_t nodes_searched() { return ThreadsMgr.nodes_searched(); }
/// init_search() is called during startup. It initializes various lookup tables
// 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);
// Init futility move count array
for (d = 0; d < 32; d++)
- FutilityMoveCountArray[d] = 3 + (1 << (3 * d / 8));
+ FutilityMoveCountArray[d] = int(3.001 + 0.25 * pow(d, 2.0));
}
/// search-related global variables, and calls root_search(). It returns false
/// when a quit command is received during the search.
-bool think(const Position& pos, bool infinite, bool ponder, int time[], int increment[],
+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;
NodesSincePoll = 0;
- ThreadsMgr.resetNodeCounters();
SearchStartTime = get_system_time();
ExactMaxTime = maxTime;
MaxDepth = maxDepth;
UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
// Look for a book move, only during games, not tests
- if (UseTimeManagement && get_option_value_bool("OwnBook"))
+ if (UseTimeManagement && Options["OwnBook"].value<bool>())
{
- if (get_option_value_string("Book File") != OpeningBook.file_name())
- OpeningBook.open(get_option_value_string("Book File"));
+ if (Options["Book File"].value<std::string>() != OpeningBook.file_name())
+ OpeningBook.open(Options["Book File"].value<std::string>());
- Move bookMove = OpeningBook.get_move(pos, get_option_value_bool("Best Book Move"));
+ Move bookMove = OpeningBook.get_move(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE)
{
if (PonderSearch)
}
// Read UCI option values
- TT.set_size(get_option_value_int("Hash"));
- if (button_was_pressed("Clear Hash"))
+ TT.set_size(Options["Hash"].value<int>());
+ if (Options["Clear Hash"].value<bool>())
+ {
+ Options["Clear Hash"].set_value("false");
TT.clear();
+ }
- CheckExtension[1] = Depth(get_option_value_int("Check Extension (PV nodes)"));
- CheckExtension[0] = Depth(get_option_value_int("Check Extension (non-PV nodes)"));
- SingleEvasionExtension[1] = Depth(get_option_value_int("Single Evasion Extension (PV nodes)"));
- SingleEvasionExtension[0] = Depth(get_option_value_int("Single Evasion Extension (non-PV nodes)"));
- PawnPushTo7thExtension[1] = Depth(get_option_value_int("Pawn Push to 7th Extension (PV nodes)"));
- PawnPushTo7thExtension[0] = Depth(get_option_value_int("Pawn Push to 7th Extension (non-PV nodes)"));
- PassedPawnExtension[1] = Depth(get_option_value_int("Passed Pawn Extension (PV nodes)"));
- PassedPawnExtension[0] = Depth(get_option_value_int("Passed Pawn Extension (non-PV nodes)"));
- PawnEndgameExtension[1] = Depth(get_option_value_int("Pawn Endgame Extension (PV nodes)"));
- PawnEndgameExtension[0] = Depth(get_option_value_int("Pawn Endgame Extension (non-PV nodes)"));
- MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)"));
- MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)"));
-
- MinimumSplitDepth = get_option_value_int("Minimum Split Depth") * ONE_PLY;
- MaxThreadsPerSplitPoint = get_option_value_int("Maximum Number of Threads per Split Point");
- MultiPV = get_option_value_int("MultiPV");
- UseLogFile = get_option_value_bool("Use Search Log");
+ 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>();
+ PassedPawnExtension[0] = Options["Passed Pawn Extension (non-PV nodes)"].value<Depth>();
+ PawnEndgameExtension[1] = Options["Pawn Endgame Extension (PV nodes)"].value<Depth>();
+ PawnEndgameExtension[0] = Options["Pawn Endgame Extension (non-PV nodes)"].value<Depth>();
+ MateThreatExtension[1] = Options["Mate Threat Extension (PV nodes)"].value<Depth>();
+ MateThreatExtension[0] = Options["Mate Threat Extension (non-PV nodes)"].value<Depth>();
+ MultiPV = Options["MultiPV"].value<int>();
+ UseLogFile = Options["Use Search Log"].value<bool>();
if (UseLogFile)
- LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
+ LogFile.open(Options["Search Log Filename"].value<std::string>().c_str(), std::ios::out | std::ios::app);
read_weights(pos.side_to_move());
// Set the number of active threads
- int newActiveThreads = get_option_value_int("Threads");
- 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 sleeping threads
- ThreadsMgr.wake_sleeping_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()];
if (UseLogFile)
LogFile.close();
- ThreadsMgr.put_threads_to_sleep();
+ // This makes all the threads to go to sleep
+ ThreadsMgr.set_active_threads(1);
return !Quit;
}
// been consumed, the user stops the search, or the maximum search depth is
// reached.
- Value id_loop(const Position& pos, Move searchMoves[]) {
+ Value id_loop(Position& pos, Move searchMoves[]) {
- Position p(pos, pos.thread());
SearchStack ss[PLY_MAX_PLUS_2];
Move pv[PLY_MAX_PLUS_2];
Move EasyMove = MOVE_NONE;
Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
// Moves to search are verified, copied, scored and sorted
- RootMoveList rml(p, searchMoves);
+ RootMoveList rml(pos, searchMoves);
// Handle special case of searching on a mate/stale position
if (rml.move_count() == 0)
// Print RootMoveList startup scoring to the standard output,
// so to output information also for iteration 1.
- cout << set960(p.is_chess960()) // Is enough to set once at the beginning
+ 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 " << ThreadsMgr.nodes_searched()
- << " nps " << nps()
+ << " nodes " << pos.nodes_searched()
+ << " nps " << nps(pos)
<< " pv " << rml.move(0) << "\n";
// Initialize
}
// Search to the current depth, rml is updated and sorted, alpha and beta could change
- value = root_search(p, ss, pv, rml, &alpha, &beta);
+ value = root_search(pos, ss, pv, rml, &alpha, &beta);
// Write PV to transposition table, in case the relevant entries have
// been overwritten during the search.
- insert_pv_in_tt(p, pv);
+ insert_pv_in_tt(pos, pv);
if (AbortSearch)
break; // Value cannot be trusted. Break out immediately!
stopSearch = true;
// Stop search early if one move seems to be much better than the others
- int64_t nodes = ThreadsMgr.nodes_searched();
if ( Iteration >= 8
&& EasyMove == pv[0]
- && ( ( rml.move_nodes(0) > (nodes * 85) / 100
+ && ( ( rml.move_nodes(0) > (pos.nodes_searched() * 85) / 100
&& current_search_time() > TimeMgr.available_time() / 16)
- ||( rml.move_nodes(0) > (nodes * 98) / 100
+ ||( rml.move_nodes(0) > (pos.nodes_searched() * 98) / 100
&& current_search_time() > TimeMgr.available_time() / 32)))
stopSearch = true;
// Add some extra time if the best move has changed during the last two iterations
if (Iteration > 5 && Iteration <= 50)
- TimeMgr.pv_unstability(BestMoveChangesByIteration[Iteration],
+ TimeMgr.pv_instability(BestMoveChangesByIteration[Iteration],
BestMoveChangesByIteration[Iteration-1]);
// Stop search if most of MaxSearchTime is consumed at the end of the
wait_for_stop_or_ponderhit();
else
// Print final search statistics
- cout << "info nodes " << ThreadsMgr.nodes_searched()
- << " nps " << nps()
+ 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)
+ if (pv[0] == MOVE_NONE || MultiPV > 1)
{
pv[0] = rml.move(0);
pv[1] = MOVE_NONE;
if (dbg_show_hit_rate)
dbg_print_hit_rate(LogFile);
- LogFile << "\nNodes: " << ThreadsMgr.nodes_searched()
- << "\nNodes/second: " << nps()
- << "\nBest move: " << move_to_san(p, pv[0]);
+ LogFile << "\nNodes: " << pos.nodes_searched()
+ << "\nNodes/second: " << nps(pos)
+ << "\nBest move: " << move_to_san(pos, pv[0]);
StateInfo st;
- p.do_move(pv[0], st);
+ pos.do_move(pv[0], st);
LogFile << "\nPonder move: "
- << move_to_san(p, pv[1]) // Works also with MOVE_NONE
+ << move_to_san(pos, pv[1]) // Works also with MOVE_NONE
<< endl;
}
return rml.move_score(0);
int64_t nodes;
Move move;
Depth depth, ext, newDepth;
- Value value, evalMargin, alpha, beta;
+ Value value, alpha, beta;
bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
int researchCountFH, researchCountFL;
// Step 5. Evaluate the position statically
// At root we do this only to get reference value for child nodes
- ss->eval = isCheck ? VALUE_NONE : evaluate(pos, evalMargin);
+ 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)
FirstRootMove = (i == 0);
// Save the current node count before the move is searched
- nodes = ThreadsMgr.nodes_searched();
+ nodes = pos.nodes_searched();
// Pick the next root move, and print the move and the move number to
// the standard output.
break;
// Remember searched nodes counts for this move
- rml.add_move_nodes(i, ThreadsMgr.nodes_searched() - nodes);
+ rml.add_move_nodes(i, pos.nodes_searched() - nodes);
assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
assert(value < beta);
<< " score " << value_to_uci(rml.move_score(j))
<< " depth " << (j <= i ? Iteration : Iteration - 1)
<< " time " << current_search_time()
- << " nodes " << ThreadsMgr.nodes_searched()
- << " nps " << nps()
+ << " nodes " << pos.nodes_searched()
+ << " nps " << nps(pos)
<< " pv ";
for (int k = 0; rml.move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
}
- // search<>() is the main search function for both PV and non-PV nodes
+ // search<>() is the main search function for both PV and non-PV nodes and for
+ // normal and SplitPoint nodes. When called just after a split point the search
+ // is simpler because we have already probed the hash table, done a null move
+ // search, and searched the first move before splitting, we don't have to repeat
+ // 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>
+ template <NodeType PvNode, bool SpNode>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
Key posKey;
Move ttMove, move, excludedMove, threatMove;
Depth ext, newDepth;
- Value bestValue, value, evalMargin, oldAlpha;
+ ValueType vt;
+ Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
int moveCount = 0;
int threadID = pos.thread();
+ SplitPoint* sp = NULL;
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
+ isCheck = pos.is_check();
+
+ if (SpNode)
+ {
+ sp = ss->sp;
+ tte = NULL;
+ ttMove = excludedMove = MOVE_NONE;
+ threatMove = sp->threatMove;
+ mateThreat = sp->mateThreat;
+ goto split_point_start;
+ }
+ else {} // Hack to fix icc's "statement is unreachable" warning
// Step 1. Initialize node and poll. Polling can abort search
- ThreadsMgr.incrementNodeCounter(threadID);
ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
(ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
{
NodesSincePoll = 0;
- poll();
+ poll(pos);
}
// Step 2. Check for aborted search and immediate draw
- if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
- return VALUE_ZERO;
-
- if (pos.is_draw() || ply >= PLY_MAX - 1)
+ if ( AbortSearch
+ || ThreadsMgr.cutoff_at_splitpoint(threadID)
+ || pos.is_draw()
+ || ply >= PLY_MAX - 1)
return VALUE_DRAW;
// Step 3. Mate distance pruning
posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
tte = TT.retrieve(posKey);
- ttMove = (tte ? tte->move() : MOVE_NONE);
+ 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:
// * Fifty move rule detection
// * Searching for a mate
// * Printing of full PV line
-
if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
{
- // Refresh tte entry to avoid aging
- TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove, tte->static_value(), tte->static_value_margin());
-
+ TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
// Step 5. Evaluate the position statically and
// update gain statistics of parent move.
- isCheck = pos.is_check();
if (isCheck)
- ss->eval = evalMargin = VALUE_NONE;
+ ss->eval = ss->evalMargin = VALUE_NONE;
else if (tte)
{
assert(tte->static_value() != VALUE_NONE);
ss->eval = tte->static_value();
- evalMargin = tte->static_value_margin();
+ ss->evalMargin = tte->static_value_margin();
refinedValue = refine_eval(tte, ss->eval, ply);
}
else
{
- refinedValue = ss->eval = evaluate(pos, evalMargin);
- TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
+ refinedValue = ss->eval = evaluate(pos, ss->evalMargin);
+ TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ss->evalMargin);
}
// Save gain for the parent non-capture move
&& !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()))
{
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
-
- nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
+ nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY, ply+1);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
threatMove = (ss+1)->bestMove;
if ( depth < ThreatDepth
&& (ss-1)->reduction
+ && threatMove != MOVE_NONE
&& connected_moves(pos, (ss-1)->currentMove, threatMove))
return beta - 1;
}
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
- MovePicker mp = MovePicker(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
+ // 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;
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
- singleEvasion = isCheck && mp.number_of_evasions() == 1;
- futilityBase = ss->eval + evalMargin;
- singularExtensionNode = depth >= SingularExtensionDepth[PvNode]
+ singleEvasion = !SpNode && isCheck && mp.number_of_evasions() == 1;
+ futilityBase = ss->eval + ss->evalMargin;
+ singularExtensionNode = !SpNode
+ && depth >= SingularExtensionDepth[PvNode]
&& tte
&& tte->move()
&& !excludedMove // Do not allow recursive singular extension search
&& (tte->type() & VALUE_TYPE_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;
+ if (SpNode)
+ {
+ lock_grab(&(sp->lock));
+ bestValue = sp->bestValue;
+ }
// Step 10. Loop through moves
// 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));
- if (move == excludedMove)
+ if (SpNode)
+ {
+ moveCount = ++sp->moveCount;
+ lock_release(&(sp->lock));
+ }
+ else if (move == excludedMove)
continue;
+ else
+ movesSearched[moveCount++] = move;
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
}
}
- newDepth = depth - ONE_PLY + ext;
-
// Update current move (this must be done after singular extension search)
- movesSearched[moveCount++] = ss->currentMove = move;
+ ss->currentMove = move;
+ newDepth = depth - ONE_PLY + ext;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
// Move count based pruning
if ( moveCount >= futility_move_count(depth)
&& !(threatMove && connected_threat(pos, move, threatMove))
- && bestValue > value_mated_in(PLY_MAX))
+ && bestValue > value_mated_in(PLY_MAX)) // FIXME bestValue is racy
+ {
+ if (SpNode)
+ lock_grab(&(sp->lock));
+
continue;
+ }
// Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
if (futilityValueScaled < beta)
{
- if (futilityValueScaled > bestValue)
+ if (SpNode)
+ {
+ lock_grab(&(sp->lock));
+ if (futilityValueScaled > sp->bestValue)
+ sp->bestValue = bestValue = futilityValueScaled;
+ }
+ else if (futilityValueScaled > bestValue)
bestValue = futilityValueScaled;
+
+ 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 extra. pv search (only in PV nodes)
// The first move in list is the expected PV
if (PvNode && moveCount == 1)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
else
{
// Step 14. Reduced depth search
&& !captureOrPromotion
&& !dangerous
&& !move_is_castle(move)
- && !move_is_killer(move, ss))
+ && ss->killers[0] != move
+ && ss->killers[1] != move)
{
ss->reduction = reduction<PvNode>(depth, moveCount);
+
if (ss->reduction)
{
+ alpha = SpNode ? sp->alpha : alpha;
Depth d = newDepth - ss->reduction;
- value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
doFullDepthSearch = (value > alpha);
}
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);
}
// Step 15. Full depth search
if (doFullDepthSearch)
{
- value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO, ply+1)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
+ alpha = SpNode ? sp->alpha : alpha;
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
// 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)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO, ply+1)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
}
}
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
// Step 17. Check for new best move
- if (value > bestValue)
+ if (SpNode)
+ {
+ lock_grab(&(sp->lock));
+ bestValue = sp->bestValue;
+ alpha = sp->alpha;
+ }
+
+ if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID)))
{
bestValue = value;
+
+ if (SpNode)
+ sp->bestValue = value;
+
if (value > alpha)
{
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->parentSstack->bestMove = move;
}
}
// Step 18. Check for split
- if ( depth >= MinimumSplitDepth
+ if ( !SpNode
+ && depth >= ThreadsMgr.min_split_depth()
&& ThreadsMgr.active_threads() > 1
&& bestValue < beta
&& ThreadsMgr.available_thread_exists(threadID)
&& !AbortSearch
- && !ThreadsMgr.thread_should_stop(threadID)
+ && !ThreadsMgr.cutoff_at_splitpoint(threadID)
&& Iteration <= 99)
ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
- threatMove, mateThreat, &moveCount, &mp, PvNode);
+ threatMove, mateThreat, moveCount, &mp, PvNode);
}
// Step 19. 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 (!moveCount)
+ if (!SpNode && !moveCount)
return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW;
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
- return bestValue;
+ if (!SpNode && !AbortSearch && !ThreadsMgr.cutoff_at_splitpoint(threadID))
+ {
+ move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
+ vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
+ : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
- ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
- move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove);
- TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, evalMargin);
+ TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ss->evalMargin);
- // Update killers and history only for non capture moves that fails high
- if ( bestValue >= beta
- && !pos.move_is_capture_or_promotion(move))
- {
+ // Update killers and history only for non capture moves that fails high
+ if ( bestValue >= beta
+ && !pos.move_is_capture_or_promotion(move))
+ {
update_history(pos, move, depth, movesSearched, moveCount);
update_killers(move, ss);
+ }
+ }
+
+ if (SpNode)
+ {
+ // Here we have the lock still grabbed
+ sp->slaves[threadID] = 0;
+ sp->nodes += pos.nodes_searched();
+ lock_release(&(sp->lock));
}
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
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;
- ThreadsMgr.incrementNodeCounter(pos.thread());
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;
+ // 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 = MovePicker(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);
}
- // sp_search() is used to search from a split point. This function is called
- // by each thread working at the split point. It is similar to the normal
- // search() function, but simpler. Because we have already probed the hash
- // table, done a null move search, and searched the first move before
- // splitting, we don't have to repeat all this work in sp_search(). 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.
+ // 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.
- template <NodeType PvNode>
- void sp_search(SplitPoint* sp, int threadID) {
-
- assert(threadID >= 0 && threadID < ThreadsMgr.active_threads());
- assert(ThreadsMgr.active_threads() > 1);
-
- StateInfo st;
- Move move;
- Depth ext, newDepth;
- Value value;
- Value futilityValueScaled; // NonPV specific
- bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
- int moveCount;
- value = -VALUE_INFINITE;
+ 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;
- Position pos(*sp->pos, threadID);
- CheckInfo ci(pos);
- SearchStack* ss = sp->sstack[threadID] + 1;
- isCheck = pos.is_check();
+ // Rule 2. Queen contact check is very dangerous
+ if ( type_of_piece(pc) == QUEEN
+ && bit_is_set(kingAtt, to))
+ return true;
- // Step 10. Loop through moves
- // Loop through all legal moves until no moves remain or a beta cutoff occurs
- lock_grab(&(sp->lock));
+ // Rule 3. Creating new double threats with checks
+ b = pos.pieces_of_color(them) & newAtt & ~oldAtt & ~(1ULL << ksq);
- while ( sp->bestValue < sp->beta
- && (move = sp->mp->get_next_move()) != MOVE_NONE
- && !ThreadsMgr.thread_should_stop(threadID))
+ while (b)
{
- moveCount = ++sp->moveCount;
- lock_release(&(sp->lock));
-
- assert(move_is_ok(move));
-
- 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, false, sp->mateThreat, &dangerous);
- newDepth = sp->depth - ONE_PLY + ext;
-
- // Update current move
- ss->currentMove = move;
-
- // Step 12. Futility pruning (is omitted in PV nodes)
- if ( !PvNode
- && !captureOrPromotion
- && !isCheck
- && !dangerous
- && !move_is_castle(move))
- {
- // Move count based pruning
- if ( moveCount >= futility_move_count(sp->depth)
- && !(sp->threatMove && connected_threat(pos, move, sp->threatMove))
- && sp->bestValue > value_mated_in(PLY_MAX))
- {
- lock_grab(&(sp->lock));
- continue;
- }
-
- // Value based pruning
- Depth predictedDepth = newDepth - reduction<NonPV>(sp->depth, moveCount);
- futilityValueScaled = ss->eval + futility_margin(predictedDepth, moveCount)
- + H.gain(pos.piece_on(move_from(move)), move_to(move));
-
- if (futilityValueScaled < sp->beta)
- {
- lock_grab(&(sp->lock));
-
- if (futilityValueScaled > sp->bestValue)
- sp->bestValue = futilityValueScaled;
- continue;
- }
- }
-
- // Step 13. Make the move
- pos.do_move(move, st, ci, moveIsCheck);
-
- // Step 14. Reduced search
- // If the move fails high will be re-searched at full depth.
- bool doFullDepthSearch = true;
-
- if ( !captureOrPromotion
- && !dangerous
- && !move_is_castle(move)
- && !move_is_killer(move, ss))
- {
- ss->reduction = reduction<PvNode>(sp->depth, moveCount);
- if (ss->reduction)
- {
- Value localAlpha = sp->alpha;
- Depth d = newDepth - ss->reduction;
- value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, DEPTH_ZERO, sp->ply+1)
- : - search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, d, sp->ply+1);
-
- doFullDepthSearch = (value > localAlpha);
- }
-
- // 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 localAlpha = sp->alpha;
- value = -search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth-ss->reduction, sp->ply+1);
- doFullDepthSearch = (value > localAlpha);
- }
- ss->reduction = DEPTH_ZERO; // Restore original reduction
- }
-
- // Step 15. Full depth search
- if (doFullDepthSearch)
- {
- Value localAlpha = sp->alpha;
- value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, DEPTH_ZERO, sp->ply+1)
- : - search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth, sp->ply+1);
-
- // 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 > localAlpha && value < sp->beta)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -sp->beta, -sp->alpha, DEPTH_ZERO, sp->ply+1)
- : - search<PV>(pos, ss+1, -sp->beta, -sp->alpha, newDepth, sp->ply+1);
- }
-
- // Step 16. Undo move
- pos.undo_move(move);
+ victimSq = pop_1st_bit(&b);
+ futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq);
- assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
-
- // Step 17. Check for new best move
- lock_grab(&(sp->lock));
-
- if (value > sp->bestValue && !ThreadsMgr.thread_should_stop(threadID))
- {
- sp->bestValue = value;
-
- if (sp->bestValue > sp->alpha)
- {
- if (!PvNode || value >= sp->beta)
- sp->stopRequest = true;
-
- if (PvNode && value < sp->beta) // This guarantees that always: sp->alpha < sp->beta
- sp->alpha = value;
+ // Note that here we generate illegal "double move"!
+ if ( futilityValue >= beta
+ && pos.see_sign(make_move(from, victimSq)) >= 0)
+ return true;
- sp->parentSstack->bestMove = ss->bestMove = move;
- }
- }
+ if (futilityValue > bv)
+ bv = futilityValue;
}
- /* Here we have the lock still grabbed */
-
- sp->slaves[threadID] = 0;
-
- lock_release(&(sp->lock));
+ // Update bestValue only if check is not dangerous (because we will prune the move)
+ *bestValue = bv;
+ return false;
}
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);
}
- // move_is_killer() checks if the given move is among the killer moves
-
- bool move_is_killer(Move m, SearchStack* ss) {
-
- if (ss->killers[0] == m || ss->killers[1] == m)
- 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
void update_history(const Position& pos, Move move, Depth depth,
Move movesSearched[], int moveCount) {
-
Move m;
H.success(pos.piece_on(move_from(move)), move_to(move), depth);
// nps() computes the current nodes/second count.
- int nps() {
+ int nps(const Position& pos) {
int t = current_search_time();
- return (t > 0 ? int((ThreadsMgr.nodes_searched() * 1000) / t) : 0);
+ return (t > 0 ? int((pos.nodes_searched() * 1000) / t) : 0);
}
// looks at the time consumed so far and decides if it's time to abort the
// search.
- void poll() {
+ void poll(const Position& pos) {
static int lastInfoTime;
int t = current_search_time();
// Poll for input
- if (Bioskey())
+ if (data_available())
{
// We are line oriented, don't read single chars
std::string command;
if (dbg_show_hit_rate)
dbg_print_hit_rate();
- cout << "info nodes " << ThreadsMgr.nodes_searched() << " nps " << nps()
+ cout << "info nodes " << pos.nodes_searched() << " nps " << nps(pos)
<< " time " << t << endl;
}
if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
|| (ExactMaxTime && t >= ExactMaxTime)
- || (Iteration >= 3 && MaxNodes && ThreadsMgr.nodes_searched() >= MaxNodes))
+ || (Iteration >= 3 && MaxNodes && pos.nodes_searched() >= MaxNodes))
AbortSearch = true;
}
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;
<< " score " << value_to_uci(value)
<< (value >= beta ? " lowerbound" : value <= alpha ? " upperbound" : "")
<< " time " << current_search_time()
- << " nodes " << ThreadsMgr.nodes_searched()
- << " nps " << nps()
+ << " nodes " << pos.nodes_searched()
+ << " nps " << nps(pos)
<< " pv ";
for (Move* m = pv; *m != MOVE_NONE; m++)
ValueType t = value >= beta ? VALUE_TYPE_LOWER :
value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
- LogFile << pretty_pv(pos, current_search_time(), Iteration,
- ThreadsMgr.nodes_searched(), value, t, pv) << endl;
+ LogFile << pretty_pv(pos, current_search_time(), Iteration, value, t, pv) << endl;
}
}
#if !defined(_MSC_VER)
- void* init_thread(void *threadID) {
+ void* init_thread(void* threadID) {
ThreadsMgr.idle_loop(*(int*)threadID, NULL);
return NULL;
/// The ThreadsManager class
- // resetNodeCounters(), resetBetaCounters(), searched_nodes() and
- // get_beta_counters() are getters/setters for the per thread
- // counters used to sort the moves at root.
-
- void ThreadsManager::resetNodeCounters() {
- for (int i = 0; i < MAX_THREADS; i++)
- threads[i].nodes = 0ULL;
- }
+ // 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.
- int64_t ThreadsManager::nodes_searched() const {
+ void ThreadsManager::read_uci_options() {
- int64_t result = 0ULL;
- for (int i = 0; i < ActiveThreads; i++)
- result += threads[i].nodes;
-
- return result;
+ 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>();
}
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 (AllThreadsShouldSleep || threadID >= ActiveThreads)
+ while ( threadID >= activeThreads || threads[threadID].state == THREAD_INITIALIZING
+ || (useSleepingThreads && threads[threadID].state == THREAD_AVAILABLE))
{
- assert(!sp);
- assert(threadID != 0);
- threads[threadID].state = THREAD_SLEEPING;
+ assert(!sp || useSleepingThreads);
+ assert(threadID != 0 || useSleepingThreads);
-#if !defined(_MSC_VER)
- lock_grab(&WaitLock);
- if (AllThreadsShouldSleep || threadID >= ActiveThreads)
- pthread_cond_wait(&WaitCond, &WaitLock);
- lock_release(&WaitLock);
-#else
- WaitForSingleObject(SitIdleEvent[threadID], INFINITE);
-#endif
- }
+ if (threads[threadID].state == THREAD_INITIALIZING)
+ threads[threadID].state = THREAD_AVAILABLE;
- // If thread has just woken up, mark it as available
- if (threads[threadID].state == THREAD_SLEEPING)
- 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 && !AllThreadsShouldSleep);
+ assert(!allThreadsShouldExit);
threads[threadID].state = THREAD_SEARCHING;
- if (threads[threadID].splitPoint->pvNode)
- sp_search<PV>(threads[threadID].splitPoint, threadID);
+ // Here we call search() with SplitPoint template parameter set to true
+ SplitPoint* tsp = threads[threadID].splitPoint;
+ Position pos(*tsp->pos, threadID);
+ SearchStack* ss = tsp->sstack[threadID] + 1;
+ ss->sp = tsp;
+
+ if (tsp->pvNode)
+ search<PV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
else
- sp_search<NonPV>(threads[threadID].splitPoint, threadID);
+ search<NonPV, true>(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.
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;
void ThreadsManager::init_threads() {
- volatile int i;
+ int i, arg[MAX_THREADS];
bool ok;
-#if !defined(_MSC_VER)
- pthread_t pthread[1];
-#endif
-
// Initialize global locks
- lock_init(&MPLock);
- lock_init(&WaitLock);
+ lock_init(&mpLock);
-#if !defined(_MSC_VER)
- pthread_cond_init(&WaitCond, NULL);
-#else
for (i = 0; i < MAX_THREADS; i++)
- SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
-#endif
+ {
+ 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 to sleep as soon as created
- AllThreadsShouldSleep = true;
+ // Threads will be put all threads to sleep as soon as created
+ activeThreads = 1;
- // All threads except the main thread should be initialized to THREAD_AVAILABLE
- ActiveThreads = 1;
+ // All threads except the main thread should be initialized to THREAD_INITIALIZING
threads[0].state = THREAD_SEARCHING;
for (i = 1; i < MAX_THREADS; i++)
- threads[i].state = THREAD_AVAILABLE;
+ threads[i].state = THREAD_INITIALIZING;
// Launch the helper threads
for (i = 1; i < MAX_THREADS; i++)
{
+ arg[i] = i;
#if !defined(_MSC_VER)
- ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0);
+ 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)(&i), 0, NULL) != NULL);
+ ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&arg[i]), 0, NULL) != NULL);
#endif
-
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
- while (threads[i].state != THREAD_SLEEPING) {}
+ while (threads[i].state == THREAD_INITIALIZING) {}
}
}
void ThreadsManager::exit_threads() {
- ActiveThreads = MAX_THREADS; // HACK
- AllThreadsShouldSleep = true; // HACK
- wake_sleeping_threads();
+ allThreadsShouldExit = true; // Let the woken up threads to exit idle_loop()
- // This makes the threads to exit idle_loop()
- AllThreadsShouldExit = true;
-
- // Wait for thread termination
+ // 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(&WaitLock);
- lock_destroy(&MPLock);
+ 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]);
+ }
}
- // 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;
+ SplitPoint* sp = threads[threadID].splitPoint;
- for (sp = threads[threadID].splitPoint; 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;
// Make a local copy to be sure doesn't change under our feet
int localActiveSplitPoints = threads[slave].activeSplitPoints;
- if (localActiveSplitPoints == 0)
- // No active split points means that the thread is available as
- // a slave for any other thread.
- return true;
-
- if (ActiveThreads == 2)
+ // 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
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;
// 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 sp_search(). When all threads have returned from sp_search() then
- // split() returns.
+ // 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(const Position& p, SearchStack* ss, int ply, Value* alpha,
+ 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(p.is_ok());
+ 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(p.thread() >= 0 && p.thread() < ActiveThreads);
- assert(ActiveThreads > 1);
+ assert(pos.thread() >= 0 && pos.thread() < activeThreads);
+ assert(activeThreads > 1);
- int i, master = p.thread();
+ 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.pvNode = pvNode;
splitPoint.bestValue = *bestValue;
splitPoint.mp = mp;
- splitPoint.moveCount = *moveCount;
- splitPoint.pos = &p;
+ splitPoint.moveCount = moveCount;
+ 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 (useSleepingThreads && i != master)
+ wake_sleeping_thread(i);
}
// Everything is set up. The master thread enters the idle loop, from
// 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.activeSplitPoints--;
masterThread.splitPoint = splitPoint.parent;
+ pos.set_nodes_searched(pos.nodes_searched() + splitPoint.nodes);
- lock_release(&MPLock);
+ lock_release(&mpLock);
}
- // wake_sleeping_threads() 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_threads() {
-
- assert(AllThreadsShouldSleep);
- assert(ActiveThreads > 0);
-
- AllThreadsShouldSleep = false;
-
- if (ActiveThreads == 1)
- return;
-
-#if !defined(_MSC_VER)
- pthread_mutex_lock(&WaitLock);
- pthread_cond_broadcast(&WaitCond);
- pthread_mutex_unlock(&WaitLock);
-#else
- for (int i = 1; i < MAX_THREADS; i++)
- SetEvent(SitIdleEvent[i]);
-#endif
+ void ThreadsManager::wake_sleeping_thread(int threadID) {
+ lock_grab(&sleepLock[threadID]);
+ cond_signal(&sleepCond[threadID]);
+ lock_release(&sleepLock[threadID]);
}
- // put_threads_to_sleep() makes all the threads go to sleep just before
- // to leave think(), at the end of the search. Threads should have already
- // finished the job and should be idle.
-
- void ThreadsManager::put_threads_to_sleep() {
-
- assert(!AllThreadsShouldSleep);
-
- // This makes the threads to go to sleep
- AllThreadsShouldSleep = true;
- }
-
/// The RootMoveList class
// RootMoveList c'tor
// Initialize search stack
init_ss_array(ss, PLY_MAX_PLUS_2);
- ss[0].eval = VALUE_NONE;
+ ss[0].eval = ss[0].evalMargin = VALUE_NONE;
count = 0;
// Generate all legal moves
projects / stockfish / blobdiff