bool UseFutilityPruning = true;
// Margins for futility pruning in the quiescence search, at frontier
- // nodes, and at pre-frontier nodes:
+ // nodes, and at pre-frontier nodes
Value FutilityMargin0 = Value(0x80);
Value FutilityMargin1 = Value(0x100);
Value FutilityMargin2 = Value(0x300);
Depth PawnEndgameExtension[2] = {OnePly, OnePly};
Depth MateThreatExtension[2] = {Depth(0), Depth(0)};
- // Search depth at iteration 1:
+ // Search depth at iteration 1
const Depth InitialDepth = OnePly /*+ OnePly/2*/;
// Node counters
int NodesSincePoll;
int NodesBetweenPolls = 30000;
- // Iteration counter:
+ // Iteration counter
int Iteration;
+ bool LastIterations;
// Scores and number of times the best move changed for each iteration:
Value ValueByIteration[PLY_MAX_PLUS_2];
int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
- // MultiPV mode:
+ // MultiPV mode
int MultiPV = 1;
// Time managment variables
int time[], int increment[], int movesToGo, int maxDepth,
int maxNodes, int maxTime, Move searchMoves[]) {
- // Look for a book move:
- if(!infinite && !ponder && get_option_value_bool("OwnBook")) {
- Move bookMove;
- if(get_option_value_string("Book File") != OpeningBook.file_name()) {
- OpeningBook.close();
- OpeningBook.open("book.bin");
- }
- bookMove = OpeningBook.get_move(pos);
- if(bookMove != MOVE_NONE) {
- std::cout << "bestmove " << bookMove << std::endl;
- return;
- }
+ // Look for a book move
+ if (!infinite && !ponder && get_option_value_bool("OwnBook"))
+ {
+ Move bookMove;
+ if (get_option_value_string("Book File") != OpeningBook.file_name())
+ {
+ OpeningBook.close();
+ OpeningBook.open("book.bin");
+ }
+ bookMove = OpeningBook.get_move(pos);
+ if (bookMove != MOVE_NONE)
+ {
+ std::cout << "bestmove " << bookMove << std::endl;
+ return;
+ }
}
- // Initialize global search variables:
+ // Initialize global search variables
Idle = false;
SearchStartTime = get_system_time();
BestRootMove = MOVE_NONE;
PonderMove = MOVE_NONE;
EasyMove = MOVE_NONE;
- for(int i = 0; i < THREAD_MAX; i++) {
- Threads[i].nodes = 0ULL;
- Threads[i].failHighPly1 = false;
+ for (int i = 0; i < THREAD_MAX; i++)
+ {
+ Threads[i].nodes = 0ULL;
+ Threads[i].failHighPly1 = false;
}
NodesSincePoll = 0;
InfiniteSearch = infinite;
Problem = false;
ExactMaxTime = maxTime;
- // Read UCI option values:
+ // Read UCI option values
TT.set_size(get_option_value_int("Hash"));
- if(button_was_pressed("Clear Hash"))
- TT.clear();
+ if (button_was_pressed("Clear Hash"))
+ TT.clear();
+
PonderingEnabled = get_option_value_bool("Ponder");
MultiPV = get_option_value_int("MultiPV");
CheckExtension[1] = Depth(get_option_value_int("Check Extension (PV nodes)"));
- CheckExtension[0] =
- Depth(get_option_value_int("Check Extension (non-PV nodes)"));
+ CheckExtension[0] = Depth(get_option_value_int("Check Extension (non-PV nodes)"));
+
SingleReplyExtension[1] = Depth(get_option_value_int("Single Reply Extension (PV nodes)"));
- SingleReplyExtension[0] =
- Depth(get_option_value_int("Single Reply 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)"));
-
- LMRPVMoves = get_option_value_int("Full Depth Moves (PV nodes)") + 1;
- LMRNonPVMoves = get_option_value_int("Full Depth Moves (non-PV nodes)") + 1;
- ThreatDepth = get_option_value_int("Threat Depth") * OnePly;
+ SingleReplyExtension[0] = Depth(get_option_value_int("Single Reply 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)"));
+
+ LMRPVMoves = get_option_value_int("Full Depth Moves (PV nodes)") + 1;
+ LMRNonPVMoves = get_option_value_int("Full Depth Moves (non-PV nodes)") + 1;
+ ThreatDepth = get_option_value_int("Threat Depth") * OnePly;
SelectiveDepth = get_option_value_int("Selective Plies") * OnePly;
Chess960 = get_option_value_bool("UCI_Chess960");
ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine");
UseLogFile = get_option_value_bool("Use Search Log");
- if(UseLogFile)
- LogFile.open(get_option_value_string("Search Log Filename").c_str(),
- std::ios::out | std::ios::app);
-
- UseQSearchFutilityPruning =
- get_option_value_bool("Futility Pruning (Quiescence Search)");
- UseFutilityPruning =
- get_option_value_bool("Futility Pruning (Main Search)");
-
- FutilityMargin0 =
- value_from_centipawns(get_option_value_int("Futility Margin 0"));
- FutilityMargin1 =
- value_from_centipawns(get_option_value_int("Futility Margin 1"));
- FutilityMargin2 =
- value_from_centipawns(get_option_value_int("Futility Margin 2"));
+ if (UseLogFile)
+ LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
+
+ UseQSearchFutilityPruning = get_option_value_bool("Futility Pruning (Quiescence Search)");
+ UseFutilityPruning = get_option_value_bool("Futility Pruning (Main Search)");
+
+ FutilityMargin0 = value_from_centipawns(get_option_value_int("Futility Margin 0"));
+ FutilityMargin1 = value_from_centipawns(get_option_value_int("Futility Margin 1"));
+ FutilityMargin2 = value_from_centipawns(get_option_value_int("Futility Margin 2"));
RazorDepth = (get_option_value_int("Maximum Razoring Depth") + 1) * OnePly;
RazorMargin = value_from_centipawns(get_option_value_int("Razoring Margin"));
LSNValue = value_from_centipawns(get_option_value_int("LSN Value Margin"));
MinimumSplitDepth = get_option_value_int("Minimum Split Depth") * OnePly;
- MaxThreadsPerSplitPoint =
- get_option_value_int("Maximum Number of Threads per Split Point");
+ MaxThreadsPerSplitPoint = get_option_value_int("Maximum Number of Threads per Split Point");
read_weights(pos.side_to_move());
int newActiveThreads = get_option_value_int("Threads");
- if(newActiveThreads != ActiveThreads) {
- ActiveThreads = newActiveThreads;
- init_eval(ActiveThreads);
+ if (newActiveThreads != ActiveThreads)
+ {
+ ActiveThreads = newActiveThreads;
+ init_eval(ActiveThreads);
}
// Wake up sleeping threads:
wake_sleeping_threads();
- for(int i = 1; i < ActiveThreads; i++)
- assert(thread_is_available(i, 0));
+ for (int i = 1; i < ActiveThreads; i++)
+ assert(thread_is_available(i, 0));
// Set thinking time:
int myTime = time[side_to_move];
TimeAdvantage = myTime - oppTime;
- if(!movesToGo) { // Sudden death time control
- if(increment) {
- MaxSearchTime = myTime / 30 + myIncrement;
- AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
- }
- else { // Blitz game without increment
- MaxSearchTime = myTime / 40;
- AbsoluteMaxSearchTime = myTime / 8;
- }
+ if (!movesToGo) // Sudden death time control
+ {
+ if (increment)
+ {
+ MaxSearchTime = myTime / 30 + myIncrement;
+ AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
+ } else { // Blitz game without increment
+ MaxSearchTime = myTime / 40;
+ AbsoluteMaxSearchTime = myTime / 8;
+ }
}
- else { // (x moves) / (y minutes)
- if(movesToGo == 1) {
- MaxSearchTime = myTime / 2;
- AbsoluteMaxSearchTime = Min(myTime / 2, myTime - 500);
- }
- else {
- MaxSearchTime = myTime / Min(movesToGo, 20);
- AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
- }
+ else // (x moves) / (y minutes)
+ {
+ if (movesToGo == 1)
+ {
+ MaxSearchTime = myTime / 2;
+ AbsoluteMaxSearchTime = Min(myTime / 2, myTime - 500);
+ } else {
+ MaxSearchTime = myTime / Min(movesToGo, 20);
+ AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
+ }
}
- if(PonderingEnabled) {
- MaxSearchTime += MaxSearchTime / 4;
- MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
+
+ if (PonderingEnabled)
+ {
+ MaxSearchTime += MaxSearchTime / 4;
+ MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
}
// Fixed depth or fixed number of nodes?
MaxDepth = maxDepth;
- if(MaxDepth)
- InfiniteSearch = true; // HACK
+ if (MaxDepth)
+ InfiniteSearch = true; // HACK
MaxNodes = maxNodes;
- if(MaxNodes) {
- NodesBetweenPolls = Min(MaxNodes, 30000);
- InfiniteSearch = true; // HACK
+ if (MaxNodes)
+ {
+ NodesBetweenPolls = Min(MaxNodes, 30000);
+ InfiniteSearch = true; // HACK
}
else
- NodesBetweenPolls = 30000;
+ NodesBetweenPolls = 30000;
// Write information to search log file:
- if(UseLogFile) {
- LogFile << "Searching: " << pos.to_fen() << '\n';
- LogFile << "infinite: " << infinite << " ponder: " << ponder
- << " time: " << myTime << " increment: " << myIncrement
- << " moves to go: " << movesToGo << '\n';
- }
+ if (UseLogFile)
+ LogFile << "Searching: " << pos.to_fen() << std::endl
+ << "infinite: " << infinite
+ << " ponder: " << ponder
+ << " time: " << myTime
+ << " increment: " << myIncrement
+ << " moves to go: " << movesToGo << std::endl;
+
// We're ready to start thinking. Call the iterative deepening loop
// function:
id_loop(pos, searchMoves); // to fail gracefully
}
- if(UseLogFile)
- LogFile.close();
+ if (UseLogFile)
+ LogFile.close();
- if(Quit) {
- OpeningBook.close();
- stop_threads();
- quit_eval();
- exit(0);
+ if (Quit)
+ {
+ OpeningBook.close();
+ stop_threads();
+ quit_eval();
+ exit(0);
}
-
Idle = true;
}
/// objects.
void init_threads() {
+
volatile int i;
+
#if !defined(_MSC_VER)
pthread_t pthread[1];
#endif
- for(i = 0; i < THREAD_MAX; i++)
- Threads[i].activeSplitPoints = 0;
+ for (i = 0; i < THREAD_MAX; i++)
+ Threads[i].activeSplitPoints = 0;
// Initialize global locks:
lock_init(&MPLock, NULL);
pthread_mutex_init(&WaitLock, NULL);
pthread_cond_init(&WaitCond, NULL);
#else
- for(i = 0; i < THREAD_MAX; i++)
- SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
+ for (i = 0; i < THREAD_MAX; i++)
+ SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
#endif
- // All threads except the main thread should be initialized to idle state:
- for(i = 1; i < THREAD_MAX; i++) {
- Threads[i].stop = false;
- Threads[i].workIsWaiting = false;
- Threads[i].idle = true;
- Threads[i].running = false;
+ // All threads except the main thread should be initialized to idle state
+ for (i = 1; i < THREAD_MAX; i++)
+ {
+ Threads[i].stop = false;
+ Threads[i].workIsWaiting = false;
+ Threads[i].idle = true;
+ Threads[i].running = false;
}
- // Launch the helper threads:
- for(i = 1; i < THREAD_MAX; i++) {
+ // Launch the helper threads
+ for(i = 1; i < THREAD_MAX; i++)
+ {
#if !defined(_MSC_VER)
- pthread_create(pthread, NULL, init_thread, (void*)(&i));
+ pthread_create(pthread, NULL, init_thread, (void*)(&i));
#else
- {
DWORD iID[1];
CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID);
- }
#endif
- // Wait until the thread has finished launching:
- while(!Threads[i].running);
+ // Wait until the thread has finished launching:
+ while (!Threads[i].running);
}
}
/// helper threads exit cleanly.
void stop_threads() {
+
ActiveThreads = THREAD_MAX; // HACK
Idle = false; // HACK
wake_sleeping_threads();
AllThreadsShouldExit = true;
- for(int i = 1; i < THREAD_MAX; i++) {
- Threads[i].stop = true;
- while(Threads[i].running);
+ for (int i = 1; i < THREAD_MAX; i++)
+ {
+ Threads[i].stop = true;
+ while(Threads[i].running);
}
destroy_split_point_stack();
}
/// the current search.
int64_t nodes_searched() {
+
int64_t result = 0ULL;
- for(int i = 0; i < ActiveThreads; i++)
- result += Threads[i].nodes;
+ for (int i = 0; i < ActiveThreads; i++)
+ result += Threads[i].nodes;
return result;
}
// reached.
Value id_loop(const Position &pos, Move searchMoves[]) {
+
Position p(pos);
SearchStack ss[PLY_MAX_PLUS_2];
ValueByIteration[0] = Value(0);
ValueByIteration[1] = rml.get_move_score(0);
Iteration = 1;
+ LastIterations = false;
EasyMove = rml.scan_for_easy_move();
// Iterative deepening loop
- while(!AbortSearch && Iteration < PLY_MAX) {
-
- // Initialize iteration
- rml.sort();
- Iteration++;
- BestMoveChangesByIteration[Iteration] = 0;
- if(Iteration <= 5)
- ExtraSearchTime = 0;
-
- std::cout << "info depth " << Iteration << std::endl;
-
- // Search to the current depth
- ValueByIteration[Iteration] = root_search(p, ss, rml);
-
- // Erase the easy move if it differs from the new best move
- if(ss[0].pv[0] != EasyMove)
- EasyMove = MOVE_NONE;
-
- Problem = false;
-
- if(!InfiniteSearch) {
- // Time to stop?
- bool stopSearch = false;
-
- // Stop search early if there is only a single legal move:
- if(Iteration >= 6 && rml.move_count() == 1)
- stopSearch = true;
-
- // 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
- // rest:
- int64_t nodes = nodes_searched();
- if(Iteration >= 8 && EasyMove == ss[0].pv[0] &&
- ((rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100 &&
- current_search_time() > MaxSearchTime / 16) ||
- (rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100 &&
- current_search_time() > MaxSearchTime / 32)))
- stopSearch = true;
-
- // Add some extra time if the best move has changed during the last
- // two iterations:
- if(Iteration > 5 && Iteration <= 50)
- ExtraSearchTime =
- BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2) +
- BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
-
- // If we need some more and we are in time advantage take it.
- if (ExtraSearchTime > 0 && TimeAdvantage > 2 * MaxSearchTime)
- ExtraSearchTime += MaxSearchTime / 2;
-
- // 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() > ((MaxSearchTime + ExtraSearchTime)*80) / 128)
- stopSearch = true;
-
- if(stopSearch) {
- if(!PonderSearch)
- break;
- else
- StopOnPonderhit = true;
- }
- }
+ while (!AbortSearch && Iteration < PLY_MAX)
+ {
+ // Initialize iteration
+ rml.sort();
+ Iteration++;
+ BestMoveChangesByIteration[Iteration] = 0;
+ if (Iteration <= 5)
+ ExtraSearchTime = 0;
- // Write PV to transposition table, in case the relevant entries have
- // been overwritten during the search:
- TT.insert_pv(p, ss[0].pv);
+ std::cout << "info depth " << Iteration << std::endl;
- if(MaxDepth && Iteration >= MaxDepth)
- break;
+ // Search to the current depth
+ ValueByIteration[Iteration] = root_search(p, ss, rml);
+
+ // Erase the easy move if it differs from the new best move
+ if (ss[0].pv[0] != EasyMove)
+ EasyMove = MOVE_NONE;
+
+ Problem = false;
+
+ if (!InfiniteSearch)
+ {
+ // Time to stop?
+ bool stopSearch = false;
+
+ // Stop search early if there is only a single legal move:
+ if (Iteration >= 6 && rml.move_count() == 1)
+ stopSearch = true;
+
+ // 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 rest
+ int64_t nodes = nodes_searched();
+ if ( Iteration >= 8
+ && EasyMove == ss[0].pv[0]
+ && ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
+ && current_search_time() > MaxSearchTime / 16)
+ ||( rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100
+ && current_search_time() > MaxSearchTime / 32)))
+ stopSearch = true;
+
+ // Add some extra time if the best move has changed during the last two iterations
+ if (Iteration > 5 && Iteration <= 50)
+ ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2)
+ + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
+
+ // If we need some more and we are in time advantage take it
+ if (ExtraSearchTime > 0 && TimeAdvantage > 2 * MaxSearchTime)
+ ExtraSearchTime += MaxSearchTime / 2;
+
+ // Try to guess if the current iteration is the last one or the last two
+ LastIterations = (current_search_time() > ((MaxSearchTime + ExtraSearchTime)*58) / 128);
+
+ // 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() > ((MaxSearchTime + ExtraSearchTime)*80) / 128)
+ stopSearch = true;
+
+ if (stopSearch)
+ {
+ if (!PonderSearch)
+ break;
+ else
+ StopOnPonderhit = true;
+ }
+ }
+ // Write PV to transposition table, in case the relevant entries have
+ // been overwritten during the search:
+ TT.insert_pv(p, ss[0].pv);
+
+ if (MaxDepth && Iteration >= MaxDepth)
+ break;
}
rml.sort();
// If we are pondering, we shouldn't print the best move before we
// are told to do so
- if(PonderSearch)
- wait_for_stop_or_ponderhit();
+ if (PonderSearch)
+ wait_for_stop_or_ponderhit();
else
- // Print final search statistics
- std::cout << "info nodes " << nodes_searched() << " nps " << nps()
- << " time " << current_search_time()
- << " hashfull " << TT.full() << std::endl;
+ // Print final search statistics
+ std::cout << "info nodes " << nodes_searched()
+ << " nps " << nps()
+ << " time " << current_search_time()
+ << " hashfull " << TT.full() << std::endl;
- // Print the best move and the ponder move to the standard output:
+ // Print the best move and the ponder move to the standard output
std::cout << "bestmove " << ss[0].pv[0];
- if(ss[0].pv[1] != MOVE_NONE)
- std::cout << " ponder " << ss[0].pv[1];
+ if (ss[0].pv[1] != MOVE_NONE)
+ std::cout << " ponder " << ss[0].pv[1];
+
std::cout << std::endl;
- if(UseLogFile) {
- UndoInfo u;
- LogFile << "Nodes: " << nodes_searched() << '\n';
- LogFile << "Nodes/second: " << nps() << '\n';
- LogFile << "Best move: " << move_to_san(p, ss[0].pv[0]) << '\n';
- p.do_move(ss[0].pv[0], u);
- LogFile << "Ponder move: " << move_to_san(p, ss[0].pv[1]) << '\n';
- LogFile << std::endl;
+ if (UseLogFile)
+ {
+ UndoInfo u;
+ LogFile << "Nodes: " << nodes_searched() << std::endl
+ << "Nodes/second: " << nps() << std::endl
+ << "Best move: " << move_to_san(p, ss[0].pv[0]) << std::endl;
+
+ p.do_move(ss[0].pv[0], u);
+ LogFile << "Ponder move: " << move_to_san(p, ss[0].pv[1])
+ << std::endl << std::endl;
}
return rml.get_move_score(0);
}
// and prints some information to the standard output.
Value root_search(Position &pos, SearchStack ss[], RootMoveList &rml) {
- Value alpha = -VALUE_INFINITE, beta = VALUE_INFINITE, value;
+
+ Value alpha = -VALUE_INFINITE;
+ Value beta = VALUE_INFINITE, value;
Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
- // Loop through all the moves in the root move list:
- for(int i = 0; i < rml.move_count() && !AbortSearch; i++) {
- int64_t nodes;
- Move move;
- UndoInfo u;
- Depth ext, newDepth;
+ // Loop through all the moves in the root move list
+ for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
+ {
+ int64_t nodes;
+ Move move;
+ UndoInfo u;
+ Depth ext, newDepth;
- RootMoveNumber = i + 1;
- FailHigh = false;
+ RootMoveNumber = i + 1;
+ FailHigh = false;
- // Remember the node count before the move is searched. The node counts
- // are used to sort the root moves at the next iteration.
- nodes = nodes_searched();
+ // Remember the node count before the move is searched. The node counts
+ // are used to sort the root moves at the next iteration.
+ nodes = nodes_searched();
- // Pick the next root move, and print the move and the move number to
- // the standard output:
- move = ss[0].currentMove = rml.get_move(i);
- if(current_search_time() >= 1000)
- std::cout << "info currmove " << move
- << " currmovenumber " << i + 1 << std::endl;
+ // Pick the next root move, and print the move and the move number to
+ // the standard output.
+ move = ss[0].currentMove = rml.get_move(i);
+ if (current_search_time() >= 1000)
+ std::cout << "info currmove " << move
+ << " currmovenumber " << i + 1 << std::endl;
- // Decide search depth for this move:
- ext = extension(pos, move, true, pos.move_is_check(move), false, false);
- newDepth = (Iteration-2)*OnePly + ext + InitialDepth;
+ // Decide search depth for this move
+ ext = extension(pos, move, true, pos.move_is_check(move), false, false);
+ newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
- // Make the move, and search it.
- pos.do_move(move, u, dcCandidates);
+ // Make the move, and search it
+ pos.do_move(move, u, dcCandidates);
- if(i < MultiPV) {
- value = -search_pv(pos, ss, -beta, VALUE_INFINITE, newDepth, 1, 0);
- // If the value has dropped a lot compared to the last iteration,
- // set the boolean variable Problem to true. This variable is used
- // for time managment: When Problem is true, we try to complete the
- // current iteration before playing a move.
- Problem = (Iteration >= 2 &&
- value <= ValueByIteration[Iteration-1] - ProblemMargin);
- if(Problem && StopOnPonderhit)
- StopOnPonderhit = false;
- }
- else {
- value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
- if(value > alpha) {
- // Fail high! Set the boolean variable FailHigh to true, and
- // re-search the move with a big window. The variable FailHigh is
- // used for time managment: We try to avoid aborting the search
- // prematurely during a fail high research.
- FailHigh = true;
- value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
+ if (i < MultiPV)
+ {
+ value = -search_pv(pos, ss, -beta, VALUE_INFINITE, newDepth, 1, 0);
+ // If the value has dropped a lot compared to the last iteration,
+ // set the boolean variable Problem to true. This variable is used
+ // for time managment: When Problem is true, we try to complete the
+ // current iteration before playing a move.
+ Problem = (Iteration >= 2 && value <= ValueByIteration[Iteration-1] - ProblemMargin);
+
+ if (Problem && StopOnPonderhit)
+ StopOnPonderhit = false;
+ }
+ else
+ {
+ value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
+ if (value > alpha)
+ {
+ // Fail high! Set the boolean variable FailHigh to true, and
+ // re-search the move with a big window. The variable FailHigh is
+ // used for time managment: We try to avoid aborting the search
+ // prematurely during a fail high research.
+ FailHigh = true;
+ value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
+ }
}
- }
- pos.undo_move(move, u);
+ pos.undo_move(move, u);
- // 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;
+ // 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 the node count for this move. The node counts are used to
- // sort the root moves at the next iteration.
- rml.set_move_nodes(i, nodes_searched() - nodes);
+ // Remember the node count for this move. The node counts are used to
+ // sort the root moves at the next iteration.
+ rml.set_move_nodes(i, nodes_searched() - nodes);
- assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
+ assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
- if(value <= alpha && i >= MultiPV)
- rml.set_move_score(i, -VALUE_INFINITE);
- else {
- // New best move!
-
- // Update PV:
- rml.set_move_score(i, value);
- update_pv(ss, 0);
- rml.set_move_pv(i, ss[0].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 search information to the standard output:
- std::cout << "info depth " << Iteration
- << " score " << value_to_string(value)
- << " time " << current_search_time()
- << " nodes " << nodes_searched()
- << " nps " << nps()
- << " pv ";
- for(int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++)
- std::cout << ss[0].pv[j] << " ";
- std::cout << std::endl;
-
- if(UseLogFile)
- LogFile << pretty_pv(pos, current_search_time(), Iteration,
- nodes_searched(), value, ss[0].pv)
- << std::endl;
-
- alpha = value;
-
- // Reset the global variable Problem to false if the value isn't too
- // far below the final value from the last iteration.
- if(value > ValueByIteration[Iteration - 1] - NoProblemMargin)
- Problem = false;
- }
- else { // MultiPV > 1
- rml.sort_multipv(i);
- for(int j = 0; j < Min(MultiPV, rml.move_count()); j++) {
- int k;
- std::cout << "info multipv " << j + 1
- << " score " << value_to_string(rml.get_move_score(j))
- << " depth " << ((j <= i)? Iteration : Iteration - 1)
- << " time " << current_search_time()
- << " nodes " << nodes_searched()
- << " nps " << nps()
- << " pv ";
- for(k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
- std::cout << rml.get_move_pv(j, k) << " ";
- std::cout << std::endl;
- }
- alpha = rml.get_move_score(Min(i, MultiPV-1));
+ if (value <= alpha && i >= MultiPV)
+ rml.set_move_score(i, -VALUE_INFINITE);
+ else
+ {
+ // New best move!
+
+ // Update PV
+ rml.set_move_score(i, value);
+ update_pv(ss, 0);
+ rml.set_move_pv(i, ss[0].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 search information to the standard output:
+ std::cout << "info depth " << Iteration
+ << " score " << value_to_string(value)
+ << " time " << current_search_time()
+ << " nodes " << nodes_searched()
+ << " nps " << nps()
+ << " pv ";
+
+ for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++)
+ std::cout << ss[0].pv[j] << " ";
+
+ std::cout << std::endl;
+
+ if (UseLogFile)
+ LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ss[0].pv)
+ << std::endl;
+
+ alpha = value;
+
+ // Reset the global variable Problem to false if the value isn't too
+ // far below the final value from the last iteration.
+ if (value > ValueByIteration[Iteration - 1] - NoProblemMargin)
+ Problem = false;
+ }
+ else // MultiPV > 1
+ {
+ rml.sort_multipv(i);
+ for (int j = 0; j < Min(MultiPV, rml.move_count()); j++)
+ {
+ int k;
+ std::cout << "info multipv " << j + 1
+ << " score " << value_to_string(rml.get_move_score(j))
+ << " depth " << ((j <= i)? Iteration : Iteration - 1)
+ << " time " << current_search_time()
+ << " nodes " << nodes_searched()
+ << " nps " << nps()
+ << " pv ";
+
+ for (k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
+ std::cout << rml.get_move_pv(j, k) << " ";
+
+ std::cout << std::endl;
+ }
+ alpha = rml.get_move_score(Min(i, MultiPV-1));
+ }
}
- }
}
return alpha;
}
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
- EvalInfo ei;
-
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
- Value oldAlpha = alpha;
-
if (AbortSearch || thread_should_stop(threadID))
return Value(0);
if (pos.is_draw())
return VALUE_DRAW;
+ EvalInfo ei;
+
if (ply >= PLY_MAX - 1)
return evaluate(pos, ei, threadID);
// Mate distance pruning
+ Value oldAlpha = alpha;
alpha = Max(value_mated_in(ply), alpha);
beta = Min(value_mate_in(ply+1), beta);
if (alpha >= beta)
return alpha;
- // Transposition table lookup. At PV nodes, we don't use the TT for
+ // Transposition table lookup. At PV nodes, we don't use the TT for
// pruning, but only for move ordering.
const TTEntry* tte = TT.retrieve(pos);
-
Move ttMove = (tte ? tte->move() : MOVE_NONE);
// Go with internal iterative deepening if we don't have a TT move
}
// Initialize a MovePicker object for the current position, and prepare
- // to search all moves:
+ // to search all moves
MovePicker mp = MovePicker(pos, true, ttMove, ss[ply].mateKiller,
ss[ply].killer1, ss[ply].killer2, depth);
int moveCount = 0;
Value value, bestValue = -VALUE_INFINITE;
Bitboard dcCandidates = mp.discovered_check_candidates();
+ bool isCheck = pos.is_check();
bool mateThreat = MateThreatExtension[1] > Depth(0)
&& pos.has_mate_threat(opposite_color(pos.side_to_move()));
{
assert(move_is_ok(move));
- bool singleReply = (pos.is_check() && mp.number_of_moves() == 1);
+ bool singleReply = (isCheck && mp.number_of_moves() == 1);
bool moveIsCheck = pos.move_is_check(move, dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
movesSearched[moveCount++] = ss[ply].currentMove = move;
- ss[ply].currentMoveCaptureValue = move_is_ep(move) ?
- PawnValueMidgame : pos.midgame_value_of_piece_on(move_to(move));
+ if (moveIsCapture)
+ ss[ply].currentMoveCaptureValue = pos.midgame_value_of_piece_on(move_to(move));
+ else if (move_is_ep(move))
+ ss[ply].currentMoveCaptureValue = PawnValueMidgame;
+ else
+ ss[ply].currentMoveCaptureValue = Value(0);
// Decide the new search depth
Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat);
// All legal moves have been searched. A special case: If there were
// no legal moves, it must be mate or stalemate:
if (moveCount == 0)
- return (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW);
+ return (isCheck ? value_mated_in(ply) : VALUE_DRAW);
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
// Transposition table lookup
const TTEntry* tte = TT.retrieve(pos);
-
Move ttMove = (tte ? tte->move() : MOVE_NONE);
if (tte && ok_to_use_TT(tte, depth, beta, ply))
Value approximateEval = quick_evaluate(pos);
bool mateThreat = false;
+ bool isCheck = pos.is_check();
// Null move search
if ( allowNullmove
- && !pos.is_check()
+ && !isCheck
&& ok_to_do_nullmove(pos)
&& approximateEval >= beta - NullMoveMargin)
{
UndoInfo u;
pos.do_null_move(u);
- Value nullValue = -search(pos, ss, -(beta-1), depth-4*OnePly, ply+1, false, threadID);
+ int R = (depth > 7 ? 4 : 3);
+ Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move(u);
if (nullValue >= beta)
Value value, bestValue = -VALUE_INFINITE;
Bitboard dcCandidates = mp.discovered_check_candidates();
Value futilityValue = VALUE_NONE;
- bool isCheck = pos.is_check();
bool useFutilityPruning = UseFutilityPruning
&& depth < SelectiveDepth
&& !isCheck;
}
// All legal moves have been searched. A special case: If there were
- // no legal moves, it must be mate or stalemate:
+ // no legal moves, it must be mate or stalemate.
if (moveCount == 0)
return (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW);
if (tte && ok_to_use_TT(tte, depth, beta, ply))
return value_from_tt(tte->value(), ply);
- // Evaluate the position statically:
+ // Evaluate the position statically
Value staticValue = evaluate(pos, ei, threadID);
if (ply == PLY_MAX - 1)
// Update transposition table
TT.store(pos, value_to_tt(bestValue, ply), depth, MOVE_NONE, VALUE_TYPE_EXACT);
+ // Update killers only for good check moves
+ Move m = ss[ply].currentMove;
+ if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered
+ {
+ // Wrong to update history when depth is <= 0
+
+ if (m != ss[ply].killer1)
+ {
+ ss[ply].killer2 = ss[ply].killer1;
+ ss[ply].killer1 = m;
+ }
+ }
return bestValue;
}
Depth extension(const Position &pos, Move m, bool pvNode,
bool check, bool singleReply, bool mateThreat) {
+
Depth result = Depth(0);
- if(check)
- result += CheckExtension[pvNode];
- if(singleReply)
- result += SingleReplyExtension[pvNode];
- if(pos.move_is_pawn_push_to_7th(m))
- result += PawnPushTo7thExtension[pvNode];
- if(pos.move_is_passed_pawn_push(m))
- result += PassedPawnExtension[pvNode];
- if(mateThreat)
- result += MateThreatExtension[pvNode];
- if(pos.midgame_value_of_piece_on(move_to(m)) >= RookValueMidgame
- && (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- - pos.midgame_value_of_piece_on(move_to(m)) == Value(0))
- && !move_promotion(m))
- result += PawnEndgameExtension[pvNode];
- if(pvNode && pos.move_is_capture(m)
- && pos.type_of_piece_on(move_to(m)) != PAWN && pos.see(m) >= 0)
- result += OnePly/2;
+ if (check)
+ result += CheckExtension[pvNode];
+
+ if (singleReply)
+ result += SingleReplyExtension[pvNode];
+
+ if (pos.move_is_pawn_push_to_7th(m))
+ result += PawnPushTo7thExtension[pvNode];
+
+ if (pos.move_is_passed_pawn_push(m))
+ result += PassedPawnExtension[pvNode];
+
+ if (mateThreat)
+ result += MateThreatExtension[pvNode];
+
+ if ( pos.midgame_value_of_piece_on(move_to(m)) >= RookValueMidgame\r
+ && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)\r
+ - pos.midgame_value_of_piece_on(move_to(m)) == Value(0))\r
+ && !move_promotion(m))
+ result += PawnEndgameExtension[pvNode];
+
+ if ( pvNode
+ && pos.move_is_capture(m)
+ && pos.type_of_piece_on(move_to(m)) != PAWN
+ && pos.see(m) >= 0)
+ result += OnePly/2;
return Min(result, OnePly);
}
H.success(pos.piece_on(move_from(m)), m, depth);
for (int i = 0; i < moveCount - 1; i++)
- if (ok_to_history(pos, movesSearched[i]) && m != movesSearched[i])
+ {
+ assert(m != movesSearched[i]);
+ if (ok_to_history(pos, movesSearched[i]))
H.failure(pos.piece_on(move_from(movesSearched[i])), movesSearched[i]);
+ }
}
// fail_high_ply_1() checks if some thread is currently resolving a fail
projects / stockfish / blobdiff