////
#include <cassert>
+#include <cmath>
#include <cstring>
#include <fstream>
#include <iostream>
#include "book.h"
#include "evaluate.h"
#include "history.h"
+#include "maxgain.h"
#include "misc.h"
#include "movegen.h"
#include "movepick.h"
#include "tt.h"
#include "ucioption.h"
+using std::cout;
+using std::endl;
////
//// Local definitions
};
- // The RootMove class is used for moves at the root at the tree. For each
+ // The RootMove class 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).
struct RootMove {
- RootMove();
- bool operator<(const RootMove&); // used to sort
+ RootMove() { nodes = cumulativeNodes = ourBeta = theirBeta = 0ULL; }
+
+ // 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 node count.
+ bool operator<(const RootMove& m) const {
+
+ return score != m.score ? score < m.score : theirBeta <= m.theirBeta;
+ }
Move move;
Value score;
- int64_t nodes, cumulativeNodes;
+ int64_t nodes, cumulativeNodes, ourBeta, theirBeta;
Move pv[PLY_MAX_PLUS_2];
- int64_t ourBeta, theirBeta;
};
public:
RootMoveList(Position& pos, Move searchMoves[]);
- inline Move get_move(int moveNum) const;
- inline Value get_move_score(int moveNum) const;
- inline void set_move_score(int moveNum, Value score);
- inline void set_move_nodes(int moveNum, int64_t nodes);
- inline void set_beta_counters(int moveNum, int64_t our, int64_t their);
+
+ int move_count() const { return count; }
+ Move get_move(int moveNum) const { return moves[moveNum].move; }
+ Value get_move_score(int moveNum) const { return moves[moveNum].score; }
+ void set_move_score(int moveNum, Value score) { moves[moveNum].score = score; }
+ Move get_move_pv(int moveNum, int i) const { return moves[moveNum].pv[i]; }
+ int64_t get_move_cumulative_nodes(int moveNum) const { return moves[moveNum].cumulativeNodes; }
+
+ void set_move_nodes(int moveNum, int64_t nodes);
+ void set_beta_counters(int moveNum, int64_t our, int64_t their);
void set_move_pv(int moveNum, const Move pv[]);
- inline Move get_move_pv(int moveNum, int i) const;
- inline int64_t get_move_cumulative_nodes(int moveNum) const;
- inline int move_count() const;
- Move scan_for_easy_move() const;
- inline void sort();
+ void sort();
void sort_multipv(int n);
private:
/// Constants
// Search depth at iteration 1
- const Depth InitialDepth = OnePly /*+ OnePly/2*/;
+ const Depth InitialDepth = OnePly;
// Depth limit for selective search
const Depth SelectiveDepth = 7 * OnePly;
// Use internal iterative deepening?
const bool UseIIDAtPVNodes = true;
- const bool UseIIDAtNonPVNodes = false;
+ const bool UseIIDAtNonPVNodes = true;
// Internal iterative deepening margin. At Non-PV moves, when
// UseIIDAtNonPVNodes is true, we do an internal iterative deepening
// best move from the previous iteration, Problem is set back to false.
const Value NoProblemMargin = Value(0x14);
- // Null move margin. A null move search will not be done if the approximate
+ // Null move margin. A null move search will not be done if the static
// evaluation of the position is more than NullMoveMargin below beta.
- const Value NullMoveMargin = Value(0x300);
+ const Value NullMoveMargin = Value(0x200);
- // Pruning criterions. See the code and comments in ok_to_prune() to
- // understand their precise meaning.
- const bool PruneEscapeMoves = false;
- const bool PruneDefendingMoves = false;
- const bool PruneBlockingMoves = false;
+ // If the TT move is at least SingleReplyMargin better then the
+ // remaining ones we will extend it.
+ const Value SingleReplyMargin = Value(0x20);
// Margins for futility pruning in the quiescence search, and at frontier
// and near frontier nodes.
const Value FutilityMarginQS = Value(0x80);
// Each move futility margin is decreased
- const Value IncrementalFutilityMargin = Value(0xA);
-
- // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
- const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270),
- // 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply
- Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0) };
- // Razoring
- const Depth RazorDepth = 4*OnePly;
-
- // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
- const Value RazorMargins[6] = { Value(0x180), Value(0x300), Value(0x300), Value(0x3C0), Value(0x3C0), Value(0x3C0) };
-
- // Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
- const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) };
+ const Value IncrementalFutilityMargin = Value(0x8);
+ // Depth limit for razoring
+ const Depth RazorDepth = 4 * OnePly;
/// Variables initialized by UCI options
- // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes
- int LMRPVMoves, LMRNonPVMoves; // heavy SMP read access for the latter
-
// Depth limit for use of dynamic threat detection
- Depth ThreatDepth; // heavy SMP read access
+ Depth ThreatDepth;
// Last seconds noise filtering (LSN)
const bool UseLSNFiltering = true;
bool loseOnTime = false;
// Extensions. Array index 0 is used at non-PV nodes, index 1 at PV nodes.
- // There is heavy SMP read access on these arrays
- Depth CheckExtension[2], SingleReplyExtension[2], PawnPushTo7thExtension[2];
+ Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2];
Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
// Iteration counters
int Iteration;
- BetaCounterType BetaCounter; // has per-thread internal data
+ BetaCounterType BetaCounter;
// Scores and number of times the best move changed for each iteration
IterationInfoType IterationInfo[PLY_MAX_PLUS_2];
int MultiPV;
// Time managment variables
+ int RootMoveNumber;
int SearchStartTime;
int MaxNodes, MaxDepth;
int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
- int RootMoveNumber;
- bool InfiniteSearch;
- bool PonderSearch;
- bool StopOnPonderhit;
- bool AbortSearch; // heavy SMP read access
- bool Quit;
- bool FailHigh;
- bool FailLow;
- bool Problem;
+ bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
+ bool AbortSearch, Quit;
+ bool FailHigh, FailLow, Problem;
// Show current line?
bool ShowCurrentLine;
bool UseLogFile;
std::ofstream LogFile;
+ // Natural logarithmic lookup table and its getter function
+ double lnArray[512];
+ inline double ln(int i) { return lnArray[i]; }
+
// MP related variables
int ActiveThreads = 1;
Depth MinimumSplitDepth;
Lock MPLock;
Lock IOLock;
bool AllThreadsShouldExit = false;
- const int MaxActiveSplitPoints = 8;
- SplitPoint SplitPointStack[THREAD_MAX][MaxActiveSplitPoints];
+ SplitPoint SplitPointStack[THREAD_MAX][ACTIVE_SPLIT_POINTS_MAX];
bool Idle = true;
#if !defined(_MSC_VER)
// History table
History H;
+ // MaxGain table
+ MaxGain MG;
/// Functions
Value id_loop(const Position& pos, Move searchMoves[]);
Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta);
Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
- Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID);
+ Value search(Position& pos, SearchStack ss[], Value beta, Depth depth, int ply, bool allowNullmove, int threadID, Move excludedMove = MOVE_NONE);
Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
void sp_search(SplitPoint* sp, int threadID);
void sp_search_pv(SplitPoint* sp, int threadID);
bool connected_moves(const Position& pos, Move m1, Move m2);
bool value_is_mate(Value value);
bool move_is_killer(Move m, const SearchStack& ss);
- Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
+ Depth extension(const Position&, Move, bool, bool, bool, bool, bool, bool*);
bool ok_to_do_nullmove(const Position& pos);
- bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d);
+ bool ok_to_prune(const Position& pos, Move m, Move threat);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
- void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
+ 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);
bool fail_high_ply_1();
bool idle_thread_exists(int master);
bool split(const Position& pos, SearchStack* ss, int ply,
Value *alpha, Value *beta, Value *bestValue,
- const Value futilityValue, const Value approximateValue,
- Depth depth, int *moves,
+ const Value futilityValue, Depth depth, int *moves,
MovePicker *mp, int master, bool pvNode);
void wake_sleeping_threads();
////
-/// perft() is our utility to verify move generation is bug free. All the
-/// legal moves up to given depth are generated and counted and the sum returned.
+/// 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)
{
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"))
+ // Initialize global search variables
+ Idle = StopOnPonderhit = AbortSearch = Quit = false;
+ FailHigh = FailLow = Problem = false;
+ NodesSincePoll = 0;
+ SearchStartTime = get_system_time();
+ ExactMaxTime = maxTime;
+ MaxDepth = maxDepth;
+ MaxNodes = maxNodes;
+ InfiniteSearch = infinite;
+ PonderSearch = ponder;
+ UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
+
+ // Look for a book move, only during games, not tests
+ if (UseTimeManagement && !ponder && get_option_value_bool("OwnBook"))
{
Move bookMove;
if (get_option_value_string("Book File") != OpeningBook.file_name())
- OpeningBook.open("book.bin");
+ OpeningBook.open(get_option_value_string("Book File"));
bookMove = OpeningBook.get_move(pos);
if (bookMove != MOVE_NONE)
{
- std::cout << "bestmove " << bookMove << std::endl;
+ cout << "bestmove " << bookMove << endl;
return true;
}
}
- // Initialize global search variables
- Idle = false;
- SearchStartTime = get_system_time();
for (int i = 0; i < THREAD_MAX; i++)
{
Threads[i].nodes = 0ULL;
Threads[i].failHighPly1 = false;
}
- NodesSincePoll = 0;
- InfiniteSearch = infinite;
- PonderSearch = ponder;
- StopOnPonderhit = false;
- AbortSearch = false;
- Quit = false;
- FailHigh = false;
- FailLow = false;
- Problem = false;
- ExactMaxTime = maxTime;
+
+ if (button_was_pressed("New Game"))
+ loseOnTime = false; // Reset at the beginning of a new game
// Read UCI option values
TT.set_size(get_option_value_int("Hash"));
if (button_was_pressed("Clear Hash"))
- {
TT.clear();
- loseOnTime = false; // reset at the beginning of a new game
- }
bool 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)"));
- 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)"));
+ 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)"));
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;
Chess960 = get_option_value_bool("UCI_Chess960");
{
ActiveThreads = newActiveThreads;
init_eval(ActiveThreads);
+ // HACK: init_eval() destroys the static castleRightsMask[] array in the
+ // Position class. The below line repairs the damage.
+ Position p(pos.to_fen());
+ assert(pos.is_ok());
}
// Wake up sleeping threads
// Set thinking time
int myTime = time[side_to_move];
int myIncrement = increment[side_to_move];
-
- if (!movesToGo) // Sudden death time control
+ if (UseTimeManagement)
{
- if (myIncrement)
+ if (!movesToGo) // Sudden death time control
{
- MaxSearchTime = myTime / 30 + myIncrement;
- AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
- } else { // Blitz game without increment
- MaxSearchTime = myTime / 30;
- AbsoluteMaxSearchTime = myTime / 8;
+ if (myIncrement)
+ {
+ MaxSearchTime = myTime / 30 + myIncrement;
+ AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
+ }
+ else // Blitz game without increment
+ {
+ MaxSearchTime = myTime / 30;
+ AbsoluteMaxSearchTime = myTime / 8;
+ }
}
- }
- else // (x moves) / (y minutes)
- {
- if (movesToGo == 1)
+ else // (x moves) / (y minutes)
{
- MaxSearchTime = myTime / 2;
- AbsoluteMaxSearchTime =
- (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
- } else {
- MaxSearchTime = myTime / Min(movesToGo, 20);
- AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
+ if (movesToGo == 1)
+ {
+ MaxSearchTime = myTime / 2;
+ AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
+ }
+ 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
-
- MaxNodes = maxNodes;
+ // Set best NodesBetweenPolls interval
if (MaxNodes)
- {
NodesBetweenPolls = Min(MaxNodes, 30000);
- InfiniteSearch = true; // HACK
- }
else if (myTime && myTime < 1000)
NodesBetweenPolls = 1000;
else if (myTime && myTime < 5000)
// Write information to search log file
if (UseLogFile)
- LogFile << "Searching: " << pos.to_fen() << std::endl
+ LogFile << "Searching: " << pos.to_fen() << endl
<< "infinite: " << infinite
<< " ponder: " << ponder
<< " time: " << myTime
<< " increment: " << myIncrement
- << " moves to go: " << movesToGo << std::endl;
-
+ << " moves to go: " << movesToGo << endl;
- // We're ready to start thinking. Call the iterative deepening loop function
- //
- // FIXME we really need to cleanup all this LSN ugliness
- if (!loseOnTime)
+ // LSN filtering. Used only for developing purpose. Disabled by default.
+ if ( UseLSNFiltering
+ && loseOnTime)
{
- Value v = id_loop(pos, searchMoves);
- loseOnTime = ( UseLSNFiltering
- && myTime < LSNTime
- && myIncrement == 0
- && v < -LSNValue);
+ // Step 2. If after last move we decided to lose on time, do it now!
+ while (SearchStartTime + myTime + 1000 > get_system_time())
+ /* wait here */;
}
- else
+
+ // We're ready to start thinking. Call the iterative deepening loop function
+ Value v = id_loop(pos, searchMoves);
+
+
+ if (UseLSNFiltering)
{
- loseOnTime = false; // reset for next match
- while (SearchStartTime + myTime + 1000 > get_system_time())
- ; // wait here
- id_loop(pos, searchMoves); // to fail gracefully
+ // Step 1. If this is sudden death game and our position is hopeless,
+ // decide to lose on time.
+ if ( !loseOnTime // If we already lost on time, go to step 3.
+ && myTime < LSNTime
+ && myIncrement == 0
+ && movesToGo == 0
+ && v < -LSNValue)
+ {
+ loseOnTime = true;
+ }
+ else if (loseOnTime)
+ {
+ // Step 3. Now after stepping over the time limit, reset flag for next match.
+ loseOnTime = false;
+ }
}
if (UseLogFile)
}
-/// init_threads() is called during startup. It launches all helper threads,
+/// init_threads() is called during startup. It launches all helper threads,
/// and initializes the split point stack and the global locks and condition
/// objects.
void init_threads() {
volatile int i;
+ bool ok;
#if !defined(_MSC_VER)
pthread_t pthread[1];
#endif
+ // Init our logarithmic lookup table
+ for (i = 0; i < 512; i++)
+ lnArray[i] = log(double(i)); // log() returns base-e logarithm
+
for (i = 0; i < THREAD_MAX; i++)
Threads[i].activeSplitPoints = 0;
}
// Launch the helper threads
- for(i = 1; i < THREAD_MAX; i++)
+ for (i = 1; i < THREAD_MAX; i++)
{
#if !defined(_MSC_VER)
- pthread_create(pthread, NULL, init_thread, (void*)(&i));
+ ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0);
#else
DWORD iID[1];
- CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID);
+ ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID) != NULL);
#endif
+ if (!ok)
+ {
+ cout << "Failed to create thread number " << i << endl;
+ Application::exit_with_failure();
+ }
+
// Wait until the thread has finished launching
while (!Threads[i].running);
}
}
-/// stop_threads() is called when the program exits. It makes all the
+/// stop_threads() is called when the program exits. It makes all the
/// helper threads exit cleanly.
void stop_threads() {
for (int i = 1; i < THREAD_MAX; i++)
{
Threads[i].stop = true;
- while(Threads[i].running);
+ while (Threads[i].running);
}
destroy_split_point_stack();
}
pv[ply] = pv[ply + 1] = MOVE_NONE;
currentMove = threatMove = MOVE_NONE;
reduction = Depth(0);
+ eval = VALUE_NONE;
+ evalInfo = NULL;
}
void SearchStack::initKillers() {
namespace {
- // id_loop() is the main iterative deepening loop. It calls root_search
+ // 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.
// searchMoves are verified, copied, scored and sorted
RootMoveList rml(p, searchMoves);
+ if (rml.move_count() == 0)
+ {
+ if (PonderSearch)
+ wait_for_stop_or_ponderhit();
+
+ return pos.is_check()? -VALUE_MATE : VALUE_DRAW;
+ }
+
// Print RootMoveList c'tor startup scoring to the standard output,
// so that we print information also for iteration 1.
- std::cout << "info depth " << 1 << "\ninfo depth " << 1
- << " score " << value_to_string(rml.get_move_score(0))
- << " time " << current_search_time()
- << " nodes " << nodes_searched()
- << " nps " << nps()
- << " pv " << rml.get_move(0) << "\n";
+ cout << "info depth " << 1 << "\ninfo depth " << 1
+ << " score " << value_to_string(rml.get_move_score(0))
+ << " time " << current_search_time()
+ << " nodes " << nodes_searched()
+ << " nps " << nps()
+ << " pv " << rml.get_move(0) << "\n";
// Initialize
TT.new_search();
H.clear();
+ MG.clear();
init_ss_array(ss);
IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0));
Iteration = 1;
- Move EasyMove = rml.scan_for_easy_move();
+ // Is one move significantly better than others after initial scoring ?
+ Move EasyMove = MOVE_NONE;
+ if ( rml.move_count() == 1
+ || rml.get_move_score(0) > rml.get_move_score(1) + EasyMoveMargin)
+ EasyMove = rml.get_move(0);
// Iterative deepening loop
while (Iteration < PLY_MAX)
if (Iteration <= 5)
ExtraSearchTime = 0;
- std::cout << "info depth " << Iteration << std::endl;
+ cout << "info depth " << Iteration << endl;
// Calculate dynamic search window based on previous iterations
Value alpha, beta;
speculatedValue = Min(Max(speculatedValue, -VALUE_INFINITE), VALUE_INFINITE);
IterationInfo[Iteration] = IterationInfoType(value, speculatedValue);
- // Erase the easy move if it differs from the new best move
+ // Drop the easy move if it differs from the new best move
if (ss[0].pv[0] != EasyMove)
EasyMove = MOVE_NONE;
Problem = false;
- if (!InfiniteSearch)
+ if (UseTimeManagement)
{
// Time to stop?
bool stopSearch = false;
- // Stop search early if there is only a single legal move
+ // 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;
+ BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
// 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
+ // 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)
+ if (current_search_time() > ((MaxSearchTime + ExtraSearchTime) * 80) / 128)
stopSearch = true;
if (stopSearch)
{
- //FIXME: Implement fail-low emergency measures
if (!PonderSearch)
break;
else
rml.sort();
- // If we are pondering, we shouldn't print the best move before we
- // are told to do so
- if (PonderSearch)
+ // 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
- std::cout << "info nodes " << nodes_searched()
- << " nps " << nps()
- << " time " << current_search_time()
- << " hashfull " << TT.full() << std::endl;
+ cout << "info nodes " << nodes_searched()
+ << " nps " << nps()
+ << " time " << current_search_time()
+ << " hashfull " << TT.full() << endl;
// Print the best move and the ponder move to the standard output
if (ss[0].pv[0] == MOVE_NONE)
ss[0].pv[0] = rml.get_move(0);
ss[0].pv[1] = MOVE_NONE;
}
- std::cout << "bestmove " << ss[0].pv[0];
+ cout << "bestmove " << ss[0].pv[0];
if (ss[0].pv[1] != MOVE_NONE)
- std::cout << " ponder " << ss[0].pv[1];
+ cout << " ponder " << ss[0].pv[1];
- std::cout << std::endl;
+ cout << endl;
if (UseLogFile)
{
if (dbg_show_hit_rate)
dbg_print_hit_rate(LogFile);
- StateInfo st;
- LogFile << "Nodes: " << nodes_searched() << std::endl
- << "Nodes/second: " << nps() << std::endl
- << "Best move: " << move_to_san(p, ss[0].pv[0]) << std::endl;
+ LogFile << "\nNodes: " << nodes_searched()
+ << "\nNodes/second: " << nps()
+ << "\nBest move: " << move_to_san(p, ss[0].pv[0]);
+ StateInfo st;
p.do_move(ss[0].pv[0], st);
- LogFile << "Ponder move: " << move_to_san(p, ss[0].pv[1])
- << std::endl << std::endl;
+ LogFile << "\nPonder move: " << move_to_san(p, ss[0].pv[1]) << endl;
}
return rml.get_move_score(0);
}
- // root_search() is the function which searches the root node. It is
+ // 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 (perhaps we should try to use this at internal PV nodes, too?)
- // and prints some information to the standard output.
+ // scheme and prints some information to the standard output.
- Value root_search(Position& pos, SearchStack ss[], RootMoveList &rml, Value alpha, Value beta) {
+ Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value alpha, Value beta) {
Value oldAlpha = alpha;
- Value value;
+ Value value = -VALUE_INFINITE;
CheckInfo ci(pos);
+ bool isCheck = pos.is_check();
+
+ // Evaluate the position statically
+ EvalInfo ei;
+ if (!isCheck)
+ ss[0].eval = evaluate(pos, ei, 0);
+ else
+ ss[0].eval = VALUE_NONE;
// 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;
StateInfo st;
- Depth ext, newDepth;
+ Depth depth, ext, newDepth;
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.
+ // Save the current node count before the move is searched
nodes = nodes_searched();
// Reset beta cut-off counters
// 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;
+ cout << "info currmove " << move
+ << " currmovenumber " << RootMoveNumber << endl;
// Decide search depth for this move
bool moveIsCheck = pos.move_is_check(move);
bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
bool dangerous;
+ depth = (Iteration - 2) * OnePly + InitialDepth;
ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
- newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
+ newDepth = depth + ext;
// Make the move, and search it
pos.do_move(move, st, ci, moveIsCheck);
alpha = -VALUE_INFINITE;
value = -search_pv(pos, ss, -beta, -alpha, 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 <= IterationInfo[Iteration-1].value - ProblemMargin);
+ Problem = ( Iteration >= 2
+ && value <= IterationInfo[Iteration - 1].value - ProblemMargin);
if (Problem && StopOnPonderhit)
StopOnPonderhit = false;
}
else
{
- if ( newDepth >= 3*OnePly
- && i >= MultiPV + LMRPVMoves
+ // Try to reduce non-pv search depth by one ply if move seems not problematic,
+ // if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
+ if ( depth >= 3*OnePly // FIXME was newDepth
&& !dangerous
&& !captureOrPromotion
&& !move_is_castle(move))
{
- ss[0].reduction = OnePly;
- value = -search(pos, ss, -alpha, newDepth-OnePly, 1, true, 0);
- } else
- value = alpha + 1; // Just to trigger next condition
+ double red = 0.5 + ln(RootMoveNumber - MultiPV + 1) * ln(depth / 2) / 6.0;
+ if (red >= 1.0)
+ {
+ ss[0].reduction = Depth(int(floor(red * int(OnePly))));
+ value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0);
+ doFullDepthSearch = (value > alpha);
+ }
+ }
- if (value > alpha)
+ if (doFullDepthSearch)
{
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.
+ // re-search the move using a PV search. 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 (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 beta-cutoff statistics
+ // Remember beta-cutoff and searched nodes counts for this move. The
+ // info is used to sort the root moves at the next iteration.
int64_t our, their;
BetaCounter.read(pos.side_to_move(), our, their);
rml.set_beta_counters(i, our, their);
+ rml.set_move_nodes(i, nodes_searched() - nodes);
assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
BestMoveChangesByIteration[Iteration]++;
// Print search information to the standard output
- std::cout << "info depth " << Iteration
- << " score " << value_to_string(value)
- << ((value >= beta)?
- " lowerbound" : ((value <= alpha)? " upperbound" : ""))
- << " time " << current_search_time()
- << " nodes " << nodes_searched()
- << " nps " << nps()
- << " pv ";
+ cout << "info depth " << Iteration
+ << " score " << value_to_string(value)
+ << ((value >= beta) ? " lowerbound" :
+ ((value <= alpha)? " upperbound" : ""))
+ << " 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] << " ";
+ cout << ss[0].pv[j] << " ";
- std::cout << std::endl;
+ cout << endl;
if (UseLogFile)
- LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value,
- ((value >= beta)? VALUE_TYPE_LOWER
- : ((value <= alpha)? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT)),
- ss[0].pv)
- << std::endl;
+ {
+ ValueType type = (value >= beta ? VALUE_TYPE_LOWER
+ : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
+ LogFile << pretty_pv(pos, current_search_time(), Iteration,
+ nodes_searched(), value, type, ss[0].pv) << endl;
+ }
if (value > alpha)
alpha = value;
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;
+ 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 (int k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
+ cout << rml.get_move_pv(j, k) << " ";
+
+ cout << endl;
}
alpha = rml.get_move_score(Min(i, MultiPV-1));
}
- } // New best move case
+ } // PV move or new best move
assert(alpha >= oldAlpha);
assert(threadID >= 0 && threadID < ActiveThreads);
Move movesSearched[256];
- EvalInfo ei;
StateInfo st;
const TTEntry* tte;
Move ttMove, move;
Depth ext, newDepth;
Value oldAlpha, value;
- bool isCheck, mateThreat, singleReply, moveIsCheck, captureOrPromotion, dangerous;
+ bool isCheck, mateThreat, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
int moveCount = 0;
- Value bestValue = -VALUE_INFINITE;
+ Value bestValue = value = -VALUE_INFINITE;
if (depth < OnePly)
return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID);
if (AbortSearch || thread_should_stop(threadID))
return Value(0);
- if (pos.is_draw())
+ if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
- if (ply >= PLY_MAX - 1)
- return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID);
-
// Mate distance pruning
oldAlpha = alpha;
alpha = Max(value_mated_in(ply), alpha);
return alpha;
// Transposition table lookup. At PV nodes, we don't use the TT for
- // pruning, but only for move ordering.
+ // 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
+ //
tte = TT.retrieve(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE);
// Go with internal iterative deepening if we don't have a TT move
- if (UseIIDAtPVNodes && ttMove == MOVE_NONE && depth >= 5*OnePly)
+ if ( UseIIDAtPVNodes
+ && depth >= 5*OnePly
+ && ttMove == MOVE_NONE)
{
search_pv(pos, ss, alpha, beta, depth-2*OnePly, ply, threadID);
ttMove = ss[ply].pv[ply];
+ tte = TT.retrieve(pos.get_key());
+ }
+
+ // Evaluate the position statically
+ isCheck = pos.is_check();
+ EvalInfo ei;
+ if (!isCheck)
+ {
+ ss[ply].eval = evaluate(pos, ei, threadID);
+
+ // Store gain statistics
+ Move m = ss[ply - 1].currentMove;
+ if ( m != MOVE_NULL
+ && pos.captured_piece() == NO_PIECE_TYPE
+ && !move_is_castle(m)
+ && !move_is_promotion(m))
+ MG.store(pos.piece_on(move_to(m)), move_from(m), move_to(m), ss[ply - 1].eval, -ss[ply].eval);
+
}
// Initialize a MovePicker object for the current position, and prepare
// to search all moves
- isCheck = pos.is_check();
mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
CheckInfo ci(pos);
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
{
assert(move_is_ok(move));
- singleReply = (isCheck && mp.number_of_evasions() == 1);
+ singleEvasion = (isCheck && mp.number_of_evasions() == 1);
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
- movesSearched[moveCount++] = ss[ply].currentMove = move;
-
// Decide the new search depth
- ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
+ ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous);
+
+ // Singular extension search. We extend the TT move if its value is much better than
+ // its siblings. To verify this we do a reduced search on all the other moves but the
+ // ttMove, if result is lower then ttValue minus a margin then we extend ttMove.
+ if ( depth >= 6 * OnePly
+ && tte
+ && move == tte->move()
+ && ext < OnePly
+ && is_lower_bound(tte->type())
+ && tte->depth() >= depth - 3 * OnePly)
+ {
+ Value ttValue = value_from_tt(tte->value(), ply);
+
+ if (abs(ttValue) < VALUE_KNOWN_WIN)
+ {
+ Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move);
+
+ if (excValue < ttValue - SingleReplyMargin)
+ ext = OnePly;
+ }
+ }
+
newDepth = depth - OnePly + ext;
+ // Update current move
+ movesSearched[moveCount++] = ss[ply].currentMove = move;
+
// Make and search the move
pos.do_move(move, st, ci, moveIsCheck);
{
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( depth >= 3*OnePly
- && moveCount >= LMRPVMoves
&& !dangerous
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
{
- ss[ply].reduction = OnePly;
- value = -search(pos, ss, -alpha, newDepth-OnePly, ply+1, true, threadID);
+ double red = 0.5 + ln(moveCount) * ln(depth / 2) / 6.0;
+ if (red >= 1.0)
+ {
+ ss[ply].reduction = Depth(int(floor(red * int(OnePly))));
+ value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID);
+ doFullDepthSearch = (value > alpha);
+ }
}
- else
- value = alpha + 1; // Just to trigger next condition
- if (value > alpha) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -alpha, newDepth, ply+1, true, threadID);
&& idle_thread_exists(threadID)
&& !AbortSearch
&& !thread_should_stop(threadID)
- && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, VALUE_NONE,
+ && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE,
depth, &moveCount, &mp, threadID, true))
break;
}
// search() is the search function for zero-width nodes.
Value search(Position& pos, SearchStack ss[], Value beta, Depth depth,
- int ply, bool allowNullmove, int threadID) {
+ int ply, bool allowNullmove, int threadID, Move excludedMove) {
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(ply >= 0 && ply < PLY_MAX);
const TTEntry* tte;
Move ttMove, move;
Depth ext, newDepth;
- Value approximateEval, nullValue, value, futilityValue, futilityValueScaled;
- bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous;
+ Value bestValue, staticValue, nullValue, value, futilityValue, futilityValueScaled;
+ bool isCheck, useFutilityPruning, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
int moveCount = 0;
- Value bestValue = -VALUE_INFINITE;
+ futilityValue = staticValue = bestValue = value = -VALUE_INFINITE;
if (depth < OnePly)
return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
if (AbortSearch || thread_should_stop(threadID))
return Value(0);
- if (pos.is_draw())
+ if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
- if (ply >= PLY_MAX - 1)
- return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID);
-
// Mate distance pruning
if (value_mated_in(ply) >= beta)
return beta;
if (value_mate_in(ply + 1) < beta)
return beta - 1;
+ // 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 exsists.
+ Key posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
+
// Transposition table lookup
- tte = TT.retrieve(pos.get_key());
+ tte = TT.retrieve(posKey);
ttMove = (tte ? tte->move() : MOVE_NONE);
if (tte && ok_to_use_TT(tte, depth, beta, ply))
{
- ss[ply].currentMove = ttMove; // can be MOVE_NONE
+ ss[ply].currentMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
- approximateEval = quick_evaluate(pos);
isCheck = pos.is_check();
+ // Calculate depth dependant futility pruning parameters
+ const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8));
+ const int PostFutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2);
+
+ // Evaluate the position statically
+ if (!isCheck)
+ {
+ if (tte && (tte->type() & VALUE_TYPE_EVAL))
+ staticValue = value_from_tt(tte->value(), ply);
+ else
+ {
+ staticValue = evaluate(pos, ei, threadID);
+ ss[ply].evalInfo = &ei;
+ }
+
+ ss[ply].eval = staticValue;
+ futilityValue = staticValue + PostFutilityValueMargin; //FIXME: Remove me, only for split
+ staticValue = refine_eval(tte, staticValue, ply); // Enhance accuracy with TT value if possible
+
+ // Store gain statistics
+ Move m = ss[ply - 1].currentMove;
+ if ( m != MOVE_NULL
+ && pos.captured_piece() == NO_PIECE_TYPE
+ && !move_is_castle(m)
+ && !move_is_promotion(m))
+ MG.store(pos.piece_on(move_to(m)), move_from(m), move_to(m), ss[ply - 1].eval, -ss[ply].eval);
+ }
+
+ // Post futility pruning
+ if (staticValue - PostFutilityValueMargin >= beta)
+ return (staticValue - PostFutilityValueMargin);
+
// Null move search
if ( allowNullmove
&& depth > OnePly
&& !isCheck
&& !value_is_mate(beta)
&& ok_to_do_nullmove(pos)
- && approximateEval >= beta - NullMoveMargin)
+ && staticValue >= beta - NullMoveMargin)
{
ss[ply].currentMove = MOVE_NULL;
pos.do_null_move(st);
// Null move dynamic reduction based on depth
- int R = (depth >= 5 * OnePly ? 4 : 3);
+ int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0);
// Null move dynamic reduction based on value
- if (approximateEval - beta > PawnValueMidgame)
+ if (staticValue - beta > PawnValueMidgame)
R++;
nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
}
// Null move search not allowed, try razoring
else if ( !value_is_mate(beta)
+ && !isCheck
&& depth < RazorDepth
- && approximateEval < beta - RazorApprMargins[int(depth) - 2]
+ && staticValue < beta - (NullMoveMargin + 16 * depth)
&& ss[ply - 1].currentMove != MOVE_NULL
&& ttMove == MOVE_NONE
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
- Value rbeta = beta - RazorMargins[int(depth) - 2];
+ Value rbeta = beta - (NullMoveMargin + 16 * depth);
Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID);
if (v < rbeta)
return v;
// Go with internal iterative deepening if we don't have a TT move
if (UseIIDAtNonPVNodes && ttMove == MOVE_NONE && depth >= 8*OnePly &&
- evaluate(pos, ei, threadID) >= beta - IIDMargin)
+ !isCheck && ss[ply].eval >= beta - IIDMargin)
{
search(pos, ss, beta, Min(depth/2, depth-2*OnePly), ply, false, threadID);
ttMove = ss[ply].pv[ply];
+ tte = TT.retrieve(pos.get_key());
}
// Initialize a MovePicker object for the current position, and prepare
// to search all moves.
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
CheckInfo ci(pos);
- futilityValue = VALUE_NONE;
useFutilityPruning = depth < SelectiveDepth && !isCheck;
- // Avoid calling evaluate() if we already have the score in TT
- if (tte && (tte->type() & VALUE_TYPE_EVAL))
- futilityValue = value_from_tt(tte->value(), ply) + FutilityMargins[int(depth) - 2];
-
- // Loop through all legal moves until no moves remain or a beta cutoff
- // occurs.
+ // Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE
&& !thread_should_stop(threadID))
{
assert(move_is_ok(move));
- singleReply = (isCheck && mp.number_of_evasions() == 1);
+ if (move == excludedMove)
+ continue;
+
moveIsCheck = pos.move_is_check(move, ci);
+ singleEvasion = (isCheck && mp.number_of_evasions() == 1);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
- movesSearched[moveCount++] = ss[ply].currentMove = move;
-
// Decide the new search depth
- ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
+ ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous);
+
+ // Singular extension search. We extend the TT move if its value is much better than
+ // its siblings. To verify this we do a reduced search on all the other moves but the
+ // ttMove, if result is lower then ttValue minus a margin then we extend ttMove.
+ if ( depth >= 8 * OnePly
+ && tte
+ && move == tte->move()
+ && !excludedMove // Do not allow recursive single-reply search
+ && ext < OnePly
+ && is_lower_bound(tte->type())
+ && tte->depth() >= depth - 3 * OnePly)
+ {
+ Value ttValue = value_from_tt(tte->value(), ply);
+
+ if (abs(ttValue) < VALUE_KNOWN_WIN)
+ {
+ Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move);
+
+ if (excValue < ttValue - SingleReplyMargin)
+ ext = OnePly;
+ }
+ }
+
newDepth = depth - OnePly + ext;
+ // Update current move
+ movesSearched[moveCount++] = ss[ply].currentMove = move;
+
+ // Futility pruning for captures
+ Color them = opposite_color(pos.side_to_move());
+
+ if ( useFutilityPruning
+ && !dangerous
+ && pos.move_is_capture(move)
+ && !pos.move_is_check(move, ci)
+ && !move_is_promotion(move)
+ && move != ttMove
+ && !move_is_ep(move)
+ && (pos.type_of_piece_on(move_to(move)) != PAWN || !pos.pawn_is_passed(them, move_to(move)))) // Do not prune passed pawn captures
+ {
+ int preFutilityValueMargin = 0;
+
+ if (newDepth >= OnePly)
+ preFutilityValueMargin = 112 * bitScanReverse32(int(newDepth) * int(newDepth) / 2);
+
+ if (ss[ply].eval + pos.endgame_value_of_piece_on(move_to(move)) + preFutilityValueMargin + ei.futilityMargin + 90 < beta)
+ continue;
+ }
+
+
// Futility pruning
if ( useFutilityPruning
&& !dangerous
&& !captureOrPromotion
+ && !move_is_castle(move)
&& move != ttMove)
{
- // History pruning. See ok_to_prune() definition
- if ( moveCount >= 2 + int(depth)
- && ok_to_prune(pos, move, ss[ply].threatMove, depth)
+ // Move count based pruning
+ if ( moveCount >= FutilityMoveCountMargin
+ && ok_to_prune(pos, move, ss[ply].threatMove)
&& bestValue > value_mated_in(PLY_MAX))
continue;
// Value based pruning
- if (approximateEval < beta)
- {
- if (futilityValue == VALUE_NONE)
- futilityValue = evaluate(pos, ei, threadID)
- + FutilityMargins[int(depth) - 2]
- + 4*IncrementalFutilityMargin;
+ Depth predictedDepth = newDepth;
- futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
+ //FIXME HACK: awful code duplication
+ double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0;
+ if (red >= 1.0)
+ predictedDepth -= int(floor(red * int(OnePly)));
- if (futilityValueScaled < beta)
- {
- if (futilityValueScaled > bestValue)
- bestValue = futilityValueScaled;
- continue;
- }
+ int preFutilityValueMargin = 0;
+ if (predictedDepth >= OnePly)
+ preFutilityValueMargin = 112 * bitScanReverse32(int(predictedDepth) * int(predictedDepth) / 2);
+
+ preFutilityValueMargin += MG.retrieve(pos.piece_on(move_from(move)), move_from(move), move_to(move)) + 45;
+
+ futilityValueScaled = ss[ply].eval + preFutilityValueMargin - moveCount * IncrementalFutilityMargin;
+
+ if (futilityValueScaled < beta)
+ {
+ if (futilityValueScaled > bestValue)
+ bestValue = futilityValueScaled;
+ continue;
}
}
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( depth >= 3*OnePly
- && moveCount >= LMRNonPVMoves
&& !dangerous
&& !captureOrPromotion
&& !move_is_castle(move)
- && !move_is_killer(move, ss[ply]))
+ && !move_is_killer(move, ss[ply])
+ /* && move != ttMove*/)
{
- ss[ply].reduction = OnePly;
- value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID);
+ double red = 0.5 + ln(moveCount) * ln(depth / 2) / 3.0;
+ if (red >= 1.0)
+ {
+ ss[ply].reduction = Depth(int(floor(red * int(OnePly))));
+ value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, true, threadID);
+ doFullDepthSearch = (value >= beta);
+ }
}
- else
- value = beta; // Just to trigger next condition
- if (value >= beta) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
ss[ply].reduction = Depth(0);
value = -search(pos, ss, -(beta-1), newDepth, ply+1, true, threadID);
// New best move?
if (value > bestValue)
{
- bestValue = value;
- if (value >= beta)
- update_pv(ss, ply);
+ bestValue = value;
+ if (value >= beta)
+ update_pv(ss, ply);
- if (value == value_mate_in(ply + 1))
- ss[ply].mateKiller = move;
+ if (value == value_mate_in(ply + 1))
+ ss[ply].mateKiller = move;
}
// Split?
&& idle_thread_exists(threadID)
&& !AbortSearch
&& !thread_should_stop(threadID)
- && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval,
+ && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue
depth, &moveCount, &mp, threadID, false))
- break;
+ break;
}
- // All legal moves have been searched. A special case: If there were
+ // 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);
+ if (!moveCount)
+ return excludedMove ? beta - 1 : (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW);
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
return bestValue;
if (bestValue < beta)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
+ TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
else
{
BetaCounter.add(pos.side_to_move(), depth, threadID);
move = ss[ply].pv[ply];
+ TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
if (!pos.move_is_capture_or_promotion(move))
{
update_history(pos, move, depth, movesSearched, moveCount);
update_killers(move, ss[ply]);
}
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
+
}
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
EvalInfo ei;
StateInfo st;
Move ttMove, move;
- Value staticValue, bestValue, value, futilityValue;
- bool isCheck, enoughMaterial, moveIsCheck;
+ Value staticValue, bestValue, value, futilityBase, futilityValue;
+ bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
const TTEntry* tte = NULL;
int moveCount = 0;
bool pvNode = (beta - alpha != 1);
if (AbortSearch || thread_should_stop(threadID))
return Value(0);
- if (pos.is_draw())
+ if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
- // Transposition table lookup, only when not in PV
- if (!pvNode)
+ // 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))
{
- tte = TT.retrieve(pos.get_key());
- if (tte && ok_to_use_TT(tte, depth, beta, ply))
- {
- assert(tte->type() != VALUE_TYPE_EVAL);
+ assert(tte->type() != VALUE_TYPE_EVAL);
- return value_from_tt(tte->value(), ply);
- }
+ ss[ply].currentMove = ttMove; // Can be MOVE_NONE
+ return value_from_tt(tte->value(), ply);
}
- ttMove = (tte ? tte->move() : MOVE_NONE);
- // Evaluate the position statically
isCheck = pos.is_check();
- ei.futilityMargin = Value(0); // Manually initialize futilityMargin
+ // Evaluate the position statically
if (isCheck)
staticValue = -VALUE_INFINITE;
-
else if (tte && (tte->type() & VALUE_TYPE_EVAL))
- {
- // Use the cached evaluation score if possible
- assert(ei.futilityMargin == Value(0));
-
- staticValue = tte->value();
- }
+ staticValue = value_from_tt(tte->value(), ply);
else
staticValue = evaluate(pos, ei, threadID);
- if (ply >= PLY_MAX - 1)
- return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID);
+ if (!isCheck)
+ {
+ ss[ply].eval = staticValue;
+ // Store gain statistics
+ Move m = ss[ply - 1].currentMove;
+ if ( m != MOVE_NULL
+ && pos.captured_piece() == NO_PIECE_TYPE
+ && !move_is_castle(m)
+ && !move_is_promotion(m))
+ MG.store(pos.piece_on(move_to(m)), move_from(m), move_to(m), ss[ply - 1].eval, -ss[ply].eval);
+ }
+
// Initialize "stand pat score", and return it immediately if it is
// at least beta.
if (bestValue > alpha)
alpha = bestValue;
+ // If we are near beta then try to get a cutoff pushing checks a bit further
+ bool deepChecks = depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8;
+
// 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) will be generated.
- MovePicker mp = MovePicker(pos, ttMove, depth, H);
+ // to search the moves. Because the depth is <= 0 here, only captures,
+ // queen promotions and checks (only if depth == 0 or depth == -OnePly
+ // and we are near beta) will be generated.
+ MovePicker mp = MovePicker(pos, ttMove, deepChecks ? Depth(0) : depth, H);
CheckInfo ci(pos);
enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
+ futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin;
// Loop through the moves until no moves remain or a beta cutoff
// occurs.
{
assert(move_is_ok(move));
+ moveIsCheck = pos.move_is_check(move, ci);
+
+ // Update current move
moveCount++;
ss[ply].currentMove = move;
- moveIsCheck = pos.move_is_check(move, ci);
-
// Futility pruning
if ( enoughMaterial
&& !isCheck
&& !move_is_promotion(move)
&& !pos.move_is_passed_pawn_push(move))
{
- futilityValue = staticValue
- + Max(pos.midgame_value_of_piece_on(move_to(move)),
- pos.endgame_value_of_piece_on(move_to(move)))
- + (move_is_ep(move) ? PawnValueEndgame : Value(0))
- + FutilityMarginQS
- + ei.futilityMargin;
+ futilityValue = futilityBase
+ + pos.endgame_value_of_piece_on(move_to(move))
+ + (move_is_ep(move) ? PawnValueEndgame : Value(0));
if (futilityValue < alpha)
{
}
}
- // Don't search captures and checks with negative SEE values
- if ( !isCheck
+ // Detect blocking evasions that are candidate to be pruned
+ evasionPrunable = isCheck
+ && bestValue != -VALUE_INFINITE
+ && !pos.move_is_capture(move)
+ && pos.type_of_piece_on(move_from(move)) != KING
+ && !pos.can_castle(pos.side_to_move());
+
+ // Don't search moves with negative SEE values
+ if ( (!isCheck || evasionPrunable)
&& move != ttMove
&& !move_is_promotion(move)
&& pos.see_sign(move) < 0)
}
}
- // All legal moves have been searched. A special case: If we're in check
+ // All legal moves have been searched. A special case: If we're in check
// and no legal moves were found, it is checkmate.
if (!moveCount && pos.is_check()) // Mate!
return value_mated_in(ply);
- assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
-
// Update transposition table
- move = ss[ply].pv[ply];
- if (!pvNode)
+ Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
+ if (bestValue < beta)
{
- // If bestValue isn't changed it means it is still the static evaluation of
- // the node, so keep this info to avoid a future costly evaluation() call.
+ // If bestValue isn't changed it means it is still the static evaluation
+ // of the node, so keep this info to avoid a future evaluation() call.
ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
- Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE);
+ }
+ else
+ {
+ move = ss[ply].pv[ply];
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
- if (bestValue < beta)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE);
- else
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
+ // Update killers only for good checking moves
+ if (!pos.move_is_capture_or_promotion(move))
+ update_killers(move, ss[ply]);
}
- // Update killers only for good check moves
- if (alpha >= beta && !pos.move_is_capture_or_promotion(move))
- update_killers(move, ss[ply]);
+ assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
return bestValue;
}
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
- Position pos = Position(sp->pos);
+ Position pos(*sp->pos);
CheckInfo ci(pos);
SearchStack* ss = sp->sstack[threadID];
- Value value;
+ Value value = -VALUE_INFINITE;
Move move;
bool isCheck = pos.is_check();
bool useFutilityPruning = sp->depth < SelectiveDepth
&& !isCheck;
+ const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8));
+
while ( sp->bestValue < sp->beta
&& !thread_should_stop(threadID)
&& (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
&& !dangerous
&& !captureOrPromotion)
{
- // History pruning. See ok_to_prune() definition
- if ( moveCount >= 2 + int(sp->depth)
- && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth)
+ // Move count based pruning
+ if ( moveCount >= FutilityMoveCountMargin
+ && ok_to_prune(pos, move, ss[sp->ply].threatMove)
&& sp->bestValue > value_mated_in(PLY_MAX))
continue;
// Value based pruning
- if (sp->approximateEval < sp->beta)
+ Value futilityValueScaled = sp->futilityValue - moveCount * IncrementalFutilityMargin;
+
+ if (futilityValueScaled < sp->beta)
{
- if (sp->futilityValue == VALUE_NONE)
+ if (futilityValueScaled > sp->bestValue) // Less then 1% of cases
{
- EvalInfo ei;
- sp->futilityValue = evaluate(pos, ei, threadID)
- + FutilityMargins[int(sp->depth) - 2];
- }
-
- if (sp->futilityValue < sp->beta)
- {
- if (sp->futilityValue > sp->bestValue) // Less then 1% of cases
- {
- lock_grab(&(sp->lock));
- if (sp->futilityValue > sp->bestValue)
- sp->bestValue = sp->futilityValue;
- lock_release(&(sp->lock));
- }
- continue;
+ lock_grab(&(sp->lock));
+ if (futilityValueScaled > sp->bestValue)
+ sp->bestValue = futilityValueScaled;
+ lock_release(&(sp->lock));
}
+ continue;
}
}
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( !dangerous
- && moveCount >= LMRNonPVMoves
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
- ss[sp->ply].reduction = OnePly;
- value = -search(pos, ss, -(sp->beta-1), newDepth - OnePly, sp->ply+1, true, threadID);
+ double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 3.0;
+ if (red >= 1.0)
+ {
+ ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly))));
+ value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
+ doFullDepthSearch = (value >= sp->beta);
+ }
}
- else
- value = sp->beta; // Just to trigger next condition
- if (value >= sp->beta) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
ss[sp->ply].reduction = Depth(0);
value = -search(pos, ss, -(sp->beta - 1), newDepth, sp->ply+1, true, threadID);
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
- Position pos = Position(sp->pos);
+ Position pos(*sp->pos);
CheckInfo ci(pos);
SearchStack* ss = sp->sstack[threadID];
- Value value;
+ Value value = -VALUE_INFINITE;
Move move;
while ( sp->alpha < sp->beta
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
+ bool doFullDepthSearch = true;
+
if ( !dangerous
- && moveCount >= LMRPVMoves
&& !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
- ss[sp->ply].reduction = OnePly;
- value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1, true, threadID);
+ double red = 0.5 + ln(moveCount) * ln(sp->depth / 2) / 6.0;
+ if (red >= 1.0)
+ {
+ Value localAlpha = sp->alpha;
+ ss[sp->ply].reduction = Depth(int(floor(red * int(OnePly))));
+ value = -search(pos, ss, -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
+ doFullDepthSearch = (value > localAlpha);
+ }
}
- else
- value = sp->alpha + 1; // Just to trigger next condition
- if (value > sp->alpha) // Go with full depth non-pv search
+ if (doFullDepthSearch) // Go with full depth non-pv search
{
+ Value localAlpha = sp->alpha;
ss[sp->ply].reduction = Depth(0);
- value = -search(pos, ss, -sp->alpha, newDepth, sp->ply+1, true, threadID);
+ value = -search(pos, ss, -localAlpha, newDepth, sp->ply+1, true, threadID);
- if (value > sp->alpha && value < sp->beta)
+ if (value > localAlpha && value < sp->beta)
{
// When the search fails high at ply 1 while searching the first
- // move at the root, set the flag failHighPly1. This is used for
+ // move at the root, set the flag failHighPly1. This is used for
// time managment: We don't want to stop the search early in
// such cases, because resolving the fail high at ply 1 could
// result in a big drop in score at the root.
if (sp->ply == 1 && RootMoveNumber == 1)
Threads[threadID].failHighPly1 = true;
- value = -search_pv(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, threadID);
+ // If another thread has failed high then sp->alpha has been increased
+ // to be higher or equal then beta, if so, avoid to start a PV search.
+ localAlpha = sp->alpha;
+ if (localAlpha < sp->beta)
+ value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID);
+ else
+ assert(thread_should_stop(threadID));
+
Threads[threadID].failHighPly1 = false;
}
}
break;
// New best move?
- lock_grab(&(sp->lock));
- if (value > sp->bestValue && !thread_should_stop(threadID))
+ if (value > sp->bestValue) // Less then 2% of cases
{
- sp->bestValue = value;
- if (value > sp->alpha)
+ lock_grab(&(sp->lock));
+ if (value > sp->bestValue && !thread_should_stop(threadID))
{
- sp->alpha = value;
- sp_update_pv(sp->parentSstack, ss, sp->ply);
- if (value == value_mate_in(sp->ply + 1))
- ss[sp->ply].mateKiller = move;
-
- if (value >= sp->beta)
+ sp->bestValue = value;
+ if (value > sp->alpha)
{
- for (int i = 0; i < ActiveThreads; i++)
- if (i != threadID && (i == sp->master || sp->slaves[i]))
- Threads[i].stop = true;
+ // Ask threads to stop before to modify sp->alpha
+ if (value >= sp->beta)
+ {
+ for (int i = 0; i < ActiveThreads; i++)
+ if (i != threadID && (i == sp->master || sp->slaves[i]))
+ Threads[i].stop = true;
- sp->finished = true;
+ sp->finished = true;
+ }
+
+ sp->alpha = value;
+
+ sp_update_pv(sp->parentSstack, ss, sp->ply);
+ if (value == value_mate_in(sp->ply + 1))
+ ss[sp->ply].mateKiller = move;
}
- }
- // If we are at ply 1, and we are searching the first root move at
- // ply 0, set the 'Problem' variable if the score has dropped a lot
- // (from the computer's point of view) since the previous iteration.
- if ( sp->ply == 1
- && Iteration >= 2
- && -value <= IterationInfo[Iteration-1].value - ProblemMargin)
- Problem = true;
+ // If we are at ply 1, and we are searching the first root move at
+ // ply 0, set the 'Problem' variable if the score has dropped a lot
+ // (from the computer's point of view) since the previous iteration.
+ if ( sp->ply == 1
+ && Iteration >= 2
+ && -value <= IterationInfo[Iteration-1].value - ProblemMargin)
+ Problem = true;
+ }
+ lock_release(&(sp->lock));
}
- lock_release(&(sp->lock));
}
lock_grab(&(sp->lock));
}
- /// The RootMove class
-
- // Constructor
-
- RootMove::RootMove() {
- nodes = cumulativeNodes = ourBeta = theirBeta = 0ULL;
- }
-
- // 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 node count.
-
- bool RootMove::operator<(const RootMove& m) {
-
- if (score != m.score)
- return (score < m.score);
-
- return theirBeta <= m.theirBeta;
- }
-
/// The RootMoveList class
- // Constructor
+ // RootMoveList c'tor
RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) : count(0) {
moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
pos.undo_move(moves[count].move);
moves[count].pv[0] = moves[count].move;
- moves[count].pv[1] = MOVE_NONE; // FIXME
+ moves[count].pv[1] = MOVE_NONE;
count++;
}
sort();
}
- // Simple accessor methods for the RootMoveList class
-
- inline Move RootMoveList::get_move(int moveNum) const {
- return moves[moveNum].move;
- }
+ // RootMoveList simple methods definitions
- inline Value RootMoveList::get_move_score(int moveNum) const {
- return moves[moveNum].score;
- }
+ void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) {
- inline void RootMoveList::set_move_score(int moveNum, Value score) {
- moves[moveNum].score = score;
- }
-
- inline void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) {
moves[moveNum].nodes = nodes;
moves[moveNum].cumulativeNodes += nodes;
}
- inline void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) {
+ void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) {
+
moves[moveNum].ourBeta = our;
moves[moveNum].theirBeta = their;
}
void RootMoveList::set_move_pv(int moveNum, const Move pv[]) {
- int j;
- for(j = 0; pv[j] != MOVE_NONE; j++)
- moves[moveNum].pv[j] = pv[j];
- moves[moveNum].pv[j] = MOVE_NONE;
- }
- inline Move RootMoveList::get_move_pv(int moveNum, int i) const {
- return moves[moveNum].pv[i];
- }
+ int j;
- inline int64_t RootMoveList::get_move_cumulative_nodes(int moveNum) const {
- return moves[moveNum].cumulativeNodes;
- }
+ for (j = 0; pv[j] != MOVE_NONE; j++)
+ moves[moveNum].pv[j] = pv[j];
- inline int RootMoveList::move_count() const {
- return count;
+ moves[moveNum].pv[j] = MOVE_NONE;
}
- // RootMoveList::scan_for_easy_move() is called at the end of the first
- // iteration, and is used to detect an "easy move", i.e. a move which appears
- // to be much bester than all the rest. If an easy move is found, the move
- // is returned, otherwise the function returns MOVE_NONE. It is very
- // important that this function is called at the right moment: The code
- // assumes that the first iteration has been completed and the moves have
- // been sorted. This is done in RootMoveList c'tor.
-
- Move RootMoveList::scan_for_easy_move() const {
-
- assert(count);
-
- if (count == 1)
- return get_move(0);
-
- // moves are sorted so just consider the best and the second one
- if (get_move_score(0) > get_move_score(1) + EasyMoveMargin)
- return get_move(0);
-
- return MOVE_NONE;
- }
-
// RootMoveList::sort() sorts the root move list at the beginning of a new
// iteration.
- inline void RootMoveList::sort() {
+ void RootMoveList::sort() {
- sort_multipv(count - 1); // all items
+ sort_multipv(count - 1); // Sort all items
}
void RootMoveList::sort_multipv(int n) {
- for (int i = 1; i <= n; i++)
+ int i,j;
+
+ for (i = 1; i <= n; i++)
{
- RootMove rm = moves[i];
- int j;
- for (j = i; j > 0 && moves[j-1] < rm; j--)
- moves[j] = moves[j-1];
- moves[j] = rm;
+ RootMove rm = moves[i];
+ for (j = i; j > 0 && moves[j - 1] < rm; j--)
+ moves[j] = moves[j - 1];
+
+ moves[j] = rm;
}
}
// init_node() is called at the beginning of all the search functions
- // (search(), search_pv(), qsearch(), and so on) and initializes the search
- // stack object corresponding to the current node. Once every
+ // (search(), search_pv(), qsearch(), and so on) and initializes the
+ // search stack object corresponding to the current node. Once every
// NodesBetweenPolls nodes, init_node() also calls poll(), which polls
// for user input and checks whether it is time to stop the search.
}
}
ss[ply].init(ply);
- ss[ply+2].initKillers();
+ ss[ply + 2].initKillers();
if (Threads[threadID].printCurrentLine)
print_current_line(ss, ply, threadID);
}
- // update_pv() is called whenever a search returns a value > alpha. It
- // updates the PV in the SearchStack object corresponding to the current
- // node.
+ // update_pv() is called whenever a search returns a value > alpha.
+ // It updates the PV in the SearchStack object corresponding to the
+ // current node.
void update_pv(SearchStack ss[], int ply) {
+
assert(ply >= 0 && ply < PLY_MAX);
- ss[ply].pv[ply] = ss[ply].currentMove;
int p;
- for(p = ply + 1; ss[ply+1].pv[p] != MOVE_NONE; p++)
- ss[ply].pv[p] = ss[ply+1].pv[p];
+
+ ss[ply].pv[ply] = ss[ply].currentMove;
+
+ for (p = ply + 1; ss[ply + 1].pv[p] != MOVE_NONE; p++)
+ ss[ply].pv[p] = ss[ply + 1].pv[p];
+
ss[ply].pv[p] = MOVE_NONE;
}
- // sp_update_pv() is a variant of update_pv for use at split points. The
+ // sp_update_pv() is a variant of update_pv for use at split points. The
// difference between the two functions is that sp_update_pv also updates
// the PV at the parent node.
void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply) {
+
assert(ply >= 0 && ply < PLY_MAX);
- ss[ply].pv[ply] = pss[ply].pv[ply] = ss[ply].currentMove;
int p;
- for(p = ply + 1; ss[ply+1].pv[p] != MOVE_NONE; p++)
- ss[ply].pv[p] = pss[ply].pv[p] = ss[ply+1].pv[p];
+
+ ss[ply].pv[ply] = pss[ply].pv[ply] = ss[ply].currentMove;
+
+ for (p = ply + 1; ss[ply + 1].pv[p] != MOVE_NONE; p++)
+ ss[ply].pv[p] = pss[ply].pv[p] = ss[ply + 1].pv[p];
+
ss[ply].pv[p] = pss[ply].pv[p] = MOVE_NONE;
}
// 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 to be the move that was made to reach the current position, while
- // the second move is assumed to be a move from the current position.
+ // if the moving piece is the same in both moves). The first move is assumed
+ // to be the move that was made to reach the current position, while the
+ // second move is assumed to be a move from the current position.
bool connected_moves(const Position& pos, Move m1, Move m2) {
&& bit_is_set(squares_between(f2, t2), f1))
return true;
- // Case 4: The destination square for m2 is attacked by the moving piece in m1
+ // Case 4: The destination square for m2 is defended by the moving piece in m1
p = pos.piece_on(t1);
if (bit_is_set(pos.attacks_from(p, t1), t2))
return true;
// Case 5: Discovered check, checking piece is the piece moved in m1
- if ( piece_is_slider(p)
- && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
+ if ( piece_is_slider(p)
+ && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
&& !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2))
{
- Bitboard occ = pos.occupied_squares();
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(us);
- clear_bit(&occ, f2);
- if (type_of_piece(p) == BISHOP)
- {
- if (bit_is_set(bishop_attacks_bb(ksq, occ), t1))
- return true;
- }
- else if (type_of_piece(p) == ROOK)
- {
- if (bit_is_set(rook_attacks_bb(ksq, occ), t1))
- return true;
- }
- else
- {
- assert(type_of_piece(p) == QUEEN);
- if (bit_is_set(queen_attacks_bb(ksq, occ), t1))
- return true;
- }
+ // discovered_check_candidates() works also if the Position's side to
+ // move is the opposite of the checking piece.
+ Color them = opposite_color(pos.side_to_move());
+ Bitboard dcCandidates = pos.discovered_check_candidates(them);
+
+ if (bit_is_set(dcCandidates, f2))
+ 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
+ // or with extended depth. Certain classes of moves (checking moves, in
// particular) are searched with bigger depth than ordinary moves and in
// any case are marked as 'dangerous'. Note that also if a move is not
// extended, as example because the corresponding UCI option is set to zero,
// the move is marked as 'dangerous' so, at least, we avoid to prune it.
Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion,
- bool check, bool singleReply, bool mateThreat, bool* dangerous) {
+ bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous) {
assert(m != MOVE_NONE);
Depth result = Depth(0);
- *dangerous = check | singleReply | mateThreat;
+ *dangerous = moveIsCheck | singleEvasion | mateThreat;
if (*dangerous)
{
- if (check)
+ if (moveIsCheck)
result += CheckExtension[pvNode];
- if (singleReply)
- result += SingleReplyExtension[pvNode];
+ if (singleEvasion)
+ result += SingleEvasionExtension[pvNode];
if (mateThreat)
result += MateThreatExtension[pvNode];
// ok_to_do_nullmove() looks at the current position and decides whether
- // doing a 'null move' should be allowed. In order to avoid zugzwang
+ // doing a 'null move' should be allowed. In order to avoid zugzwang
// problems, null moves are not allowed when the side to move has very
- // little material left. Currently, the test is a bit too simple: Null
- // moves are avoided only when the side to move has only pawns left. It's
- // probably a good idea to avoid null moves in at least some more
+ // little material left. Currently, the test is a bit too simple: Null
+ // moves are avoided only when the side to move has only pawns left.
+ // It's probably a good idea to avoid null moves in at least some more
// complicated endgames, e.g. KQ vs KR. FIXME
bool ok_to_do_nullmove(const Position& pos) {
}
- // ok_to_prune() tests whether it is safe to forward prune a move. Only
+ // ok_to_prune() tests whether it is safe to forward prune a move. Only
// non-tactical moves late in the move list close to the leaves are
// candidates for pruning.
- bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d) {
+ bool ok_to_prune(const Position& pos, Move m, Move threat) {
assert(move_is_ok(m));
assert(threat == MOVE_NONE || move_is_ok(threat));
assert(!pos.move_is_check(m));
assert(!pos.move_is_capture_or_promotion(m));
assert(!pos.move_is_passed_pawn_push(m));
- assert(d >= OnePly);
Square mfrom, mto, tfrom, tto;
+ // Prune if there isn't any threat move
+ if (threat == MOVE_NONE)
+ return true;
+
mfrom = move_from(m);
mto = move_to(m);
tfrom = move_from(threat);
tto = move_to(threat);
- // Case 1: Castling moves are never pruned
- if (move_is_castle(m))
+ // Case 1: Don't prune moves which move the threatened piece
+ if (mfrom == tto)
return false;
- // Case 2: Don't prune moves which move the threatened piece
- if (!PruneEscapeMoves && threat != MOVE_NONE && mfrom == tto)
- return false;
-
- // Case 3: If the threatened piece has value less than or equal to the
+ // Case 2: If the threatened piece has value less than or equal to the
// value of the threatening piece, don't prune move which defend it.
- if ( !PruneDefendingMoves
- && threat != MOVE_NONE
- && pos.move_is_capture(threat)
+ if ( pos.move_is_capture(threat)
&& ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto)
|| pos.type_of_piece_on(tfrom) == KING)
&& pos.move_attacks_square(m, tto))
return false;
- // Case 4: Don't prune moves with good history
- if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d))
- return false;
-
- // Case 5: If the moving piece in the threatened move is a slider, don't
+ // Case 3: If the moving piece in the threatened move is a slider, don't
// prune safe moves which block its ray.
- if ( !PruneBlockingMoves
- && threat != MOVE_NONE
- && piece_is_slider(pos.piece_on(tfrom))
+ if ( piece_is_slider(pos.piece_on(tfrom))
&& bit_is_set(squares_between(tfrom, tto), mto)
&& pos.see_sign(m) >= 0)
return false;
Value v = value_from_tt(tte->value(), ply);
return ( tte->depth() >= depth
- || v >= Max(value_mate_in(100), beta)
- || v < Min(value_mated_in(100), beta))
+ || v >= Max(value_mate_in(PLY_MAX), beta)
+ || v < Min(value_mated_in(PLY_MAX), beta))
&& ( (is_lower_bound(tte->type()) && v >= beta)
|| (is_upper_bound(tte->type()) && v < beta));
}
+ // refine_eval() returns the transposition table score if
+ // possible otherwise falls back on static position evaluation.
+
+ Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) {
+
+ if (!tte)
+ return defaultEval;
+
+ Value v = value_from_tt(tte->value(), ply);
+
+ if ( (is_lower_bound(tte->type()) && v >= defaultEval)
+ || (is_upper_bound(tte->type()) && v < defaultEval))
+ return v;
+
+ return defaultEval;
+ }
+
// update_history() registers a good move that produced a beta-cutoff
// in history and marks as failures all the other moves of that ply.
- void update_history(const Position& pos, Move m, Depth depth,
+ void update_history(const Position& pos, Move move, Depth depth,
Move movesSearched[], int moveCount) {
- H.success(pos.piece_on(move_from(m)), move_to(m), depth);
+ Move m;
+
+ H.success(pos.piece_on(move_from(move)), move_to(move), depth);
for (int i = 0; i < moveCount - 1; i++)
{
- assert(m != movesSearched[i]);
- if (!pos.move_is_capture_or_promotion(movesSearched[i]))
- H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
+ m = movesSearched[i];
+
+ assert(m != move);
+
+ if (!pos.move_is_capture_or_promotion(m))
+ H.failure(pos.piece_on(move_from(m)), move_to(m), depth);
}
}
// fail_high_ply_1() checks if some thread is currently resolving a fail
// high at ply 1 at the node below the first root node. This information
- // is used for time managment.
+ // is used for time management.
bool fail_high_ply_1() {
- for(int i = 0; i < ActiveThreads; i++)
+ for (int i = 0; i < ActiveThreads; i++)
if (Threads[i].failHighPly1)
return true;
// 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() {
+
int t = current_search_time();
- return (t > 0)? int((nodes_searched() * 1000) / t) : 0;
+ return (t > 0 ? int((nodes_searched() * 1000) / t) : 0);
}
- // poll() performs two different functions: It polls for user input, and it
+ // poll() performs two different functions: It polls for user input, and it
// looks at the time consumed so far and decides if it's time to abort the
// search.
{
// We are line oriented, don't read single chars
std::string command;
+
if (!std::getline(std::cin, command))
command = "quit";
else if (command == "ponderhit")
ponderhit();
}
+
// Print search information
if (t < 1000)
lastInfoTime = 0;
{
lastInfoTime = t;
lock_grab(&IOLock);
+
if (dbg_show_mean)
dbg_print_mean();
if (dbg_show_hit_rate)
dbg_print_hit_rate();
- std::cout << "info nodes " << nodes_searched() << " nps " << nps()
- << " time " << t << " hashfull " << TT.full() << std::endl;
+ cout << "info nodes " << nodes_searched() << " nps " << nps()
+ << " time " << t << " hashfull " << TT.full() << endl;
+
lock_release(&IOLock);
+
if (ShowCurrentLine)
Threads[0].printCurrentLine = true;
}
+
// Should we stop the search?
if (PonderSearch)
return;
- bool overTime = t > AbsoluteMaxSearchTime
- || (RootMoveNumber == 1 && t > MaxSearchTime + ExtraSearchTime && !FailLow) //FIXME: We are not checking any problem flags, BUG?
- || ( !FailHigh && !FailLow && !fail_high_ply_1() && !Problem
- && t > 6*(MaxSearchTime + ExtraSearchTime));
+ bool stillAtFirstMove = RootMoveNumber == 1
+ && !FailLow
+ && t > MaxSearchTime + ExtraSearchTime;
+
+ bool noProblemFound = !FailHigh
+ && !FailLow
+ && !fail_high_ply_1()
+ && !Problem
+ && t > 6 * (MaxSearchTime + ExtraSearchTime);
- if ( (Iteration >= 3 && (!InfiniteSearch && overTime))
+ bool noMoreTime = t > AbsoluteMaxSearchTime
+ || stillAtFirstMove //FIXME: We are not checking any problem flags, BUG?
+ || noProblemFound;
+
+ if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
|| (ExactMaxTime && t >= ExactMaxTime)
|| (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
AbortSearch = true;
int t = current_search_time();
PonderSearch = false;
- if (Iteration >= 3 &&
- (!InfiniteSearch && (StopOnPonderhit ||
- t > AbsoluteMaxSearchTime ||
- (RootMoveNumber == 1 &&
- t > MaxSearchTime + ExtraSearchTime && !FailLow) ||
- (!FailHigh && !FailLow && !fail_high_ply_1() && !Problem &&
- t > 6*(MaxSearchTime + ExtraSearchTime)))))
- AbortSearch = true;
+
+ bool stillAtFirstMove = RootMoveNumber == 1
+ && !FailLow
+ && t > MaxSearchTime + ExtraSearchTime;
+
+ bool noProblemFound = !FailHigh
+ && !FailLow
+ && !fail_high_ply_1()
+ && !Problem
+ && t > 6 * (MaxSearchTime + ExtraSearchTime);
+
+ bool noMoreTime = t > AbsoluteMaxSearchTime
+ || stillAtFirstMove
+ || noProblemFound;
+
+ if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
+ AbortSearch = true;
}
// print_current_line() prints the current line of search for a given
- // thread. Called when the UCI option UCI_ShowCurrLine is 'true'.
+ // thread. Called when the UCI option UCI_ShowCurrLine is 'true'.
void print_current_line(SearchStack ss[], int ply, int threadID) {
if (!Threads[threadID].idle)
{
lock_grab(&IOLock);
- std::cout << "info currline " << (threadID + 1);
+ cout << "info currline " << (threadID + 1);
for (int p = 0; p < ply; p++)
- std::cout << " " << ss[p].currentMove;
+ cout << " " << ss[p].currentMove;
- std::cout << std::endl;
+ cout << endl;
lock_release(&IOLock);
}
Threads[threadID].printCurrentLine = false;
// wait_for_stop_or_ponderhit() is called when the maximum depth is reached
- // while the program is pondering. The point is to work around a wrinkle in
- // the UCI protocol: When pondering, the engine is not allowed to give a
+ // while the program is pondering. The point is to work around a wrinkle in
+ // 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()).
// object for which the current thread is the master.
void idle_loop(int threadID, SplitPoint* waitSp) {
+
assert(threadID >= 0 && threadID < THREAD_MAX);
Threads[threadID].running = true;
- while(true) {
- if(AllThreadsShouldExit && threadID != 0)
- break;
+ while (true)
+ {
+ if (AllThreadsShouldExit && threadID != 0)
+ break;
+
+ // If we are not thinking, wait for a condition to be signaled
+ // instead of wasting CPU time polling for work.
+ while (threadID != 0 && (Idle || threadID >= ActiveThreads))
+ {
- // If we are not thinking, wait for a condition to be signaled instead
- // of wasting CPU time polling for work:
- while(threadID != 0 && (Idle || threadID >= ActiveThreads)) {
#if !defined(_MSC_VER)
- pthread_mutex_lock(&WaitLock);
- if(Idle || threadID >= ActiveThreads)
- pthread_cond_wait(&WaitCond, &WaitLock);
- pthread_mutex_unlock(&WaitLock);
+ pthread_mutex_lock(&WaitLock);
+ if (Idle || threadID >= ActiveThreads)
+ pthread_cond_wait(&WaitCond, &WaitLock);
+
+ pthread_mutex_unlock(&WaitLock);
#else
- WaitForSingleObject(SitIdleEvent[threadID], INFINITE);
+ WaitForSingleObject(SitIdleEvent[threadID], INFINITE);
#endif
- }
+ }
// If this thread has been assigned work, launch a search
- if(Threads[threadID].workIsWaiting) {
- Threads[threadID].workIsWaiting = false;
- if(Threads[threadID].splitPoint->pvNode)
- sp_search_pv(Threads[threadID].splitPoint, threadID);
- else
- sp_search(Threads[threadID].splitPoint, threadID);
- Threads[threadID].idle = true;
+ if (Threads[threadID].workIsWaiting)
+ {
+ assert(!Threads[threadID].idle);
+
+ Threads[threadID].workIsWaiting = false;
+ if (Threads[threadID].splitPoint->pvNode)
+ sp_search_pv(Threads[threadID].splitPoint, threadID);
+ else
+ sp_search(Threads[threadID].splitPoint, threadID);
+
+ Threads[threadID].idle = true;
}
// If this thread is the master of a split point and all threads have
// finished their work at this split point, return from the idle loop.
- if(waitSp != NULL && waitSp->cpus == 0)
- return;
+ if (waitSp != NULL && waitSp->cpus == 0)
+ return;
}
Threads[threadID].running = false;
// initializes all split point objects.
void init_split_point_stack() {
- for(int i = 0; i < THREAD_MAX; i++)
- for(int j = 0; j < MaxActiveSplitPoints; j++) {
- SplitPointStack[i][j].parent = NULL;
- lock_init(&(SplitPointStack[i][j].lock), NULL);
- }
+
+ for (int i = 0; i < THREAD_MAX; i++)
+ for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
+ {
+ SplitPointStack[i][j].parent = NULL;
+ lock_init(&(SplitPointStack[i][j].lock), NULL);
+ }
}
// destroys all locks in the precomputed split point objects.
void destroy_split_point_stack() {
- for(int i = 0; i < THREAD_MAX; i++)
- for(int j = 0; j < MaxActiveSplitPoints; j++)
- lock_destroy(&(SplitPointStack[i][j].lock));
+
+ for (int i = 0; i < THREAD_MAX; i++)
+ for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
+ lock_destroy(&(SplitPointStack[i][j].lock));
}
// thread_should_stop() checks whether the thread with a given threadID has
- // been asked to stop, directly or indirectly. This can happen if a beta
- // cutoff has occured in thre thread's currently active split point, or in
+ // been asked to stop, directly or indirectly. 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.
bool thread_should_stop(int threadID) {
+
assert(threadID >= 0 && threadID < ActiveThreads);
SplitPoint* sp;
- if(Threads[threadID].stop)
- return true;
- if(ActiveThreads <= 2)
- return false;
- for(sp = Threads[threadID].splitPoint; sp != NULL; sp = sp->parent)
- if(sp->finished) {
- Threads[threadID].stop = true;
+ if (Threads[threadID].stop)
return true;
- }
+ if (ActiveThreads <= 2)
+ return false;
+ for (sp = Threads[threadID].splitPoint; sp != NULL; sp = sp->parent)
+ if (sp->finished)
+ {
+ Threads[threadID].stop = true;
+ return true;
+ }
return false;
}
// thread_is_available() checks whether the thread with threadID "slave" is
- // available to help the thread with threadID "master" at a split point. An
- // obvious requirement is that "slave" must be idle. With more than two
+ // available to help the thread with threadID "master" at a split point. An
+ // obvious requirement is that "slave" must be idle. With more than two
// threads, this is not by itself sufficient: If "slave" is the master of
// some active split point, it is only available as a slave to the other
// threads which are busy searching the split point at the top of "slave"'s
// split point stack (the "helpful master concept" in YBWC terminology).
bool thread_is_available(int slave, int master) {
+
assert(slave >= 0 && slave < ActiveThreads);
assert(master >= 0 && master < ActiveThreads);
assert(ActiveThreads > 1);
- if(!Threads[slave].idle || slave == master)
- return false;
+ if (!Threads[slave].idle || slave == master)
+ return false;
- if(Threads[slave].activeSplitPoints == 0)
- // No active split points means that the thread is available as a slave
- // for any other thread.
- return true;
+ // Make a local copy to be sure doesn't change under our feet
+ int localActiveSplitPoints = Threads[slave].activeSplitPoints;
- if(ActiveThreads == 2)
- return true;
+ if (localActiveSplitPoints == 0)
+ // No active split points means that the thread is available as
+ // a slave for any other thread.
+ return true;
- // Apply the "helpful master" concept if possible.
- if(SplitPointStack[slave][Threads[slave].activeSplitPoints-1].slaves[master])
- return true;
+ if (ActiveThreads == 2)
+ return true;
+
+ // Apply the "helpful master" concept if possible. Use localActiveSplitPoints
+ // that is known to be > 0, instead of Threads[slave].activeSplitPoints that
+ // could have been set to 0 by another thread leading to an out of bound access.
+ if (SplitPointStack[slave][localActiveSplitPoints - 1].slaves[master])
+ return true;
return false;
}
// a slave for the thread with threadID "master".
bool idle_thread_exists(int master) {
+
assert(master >= 0 && master < ActiveThreads);
assert(ActiveThreads > 1);
- for(int i = 0; i < ActiveThreads; i++)
- if(thread_is_available(i, master))
- return true;
+ for (int i = 0; i < ActiveThreads; i++)
+ if (thread_is_available(i, master))
+ return true;
+
return false;
}
// split() does the actual work of distributing the work at a node between
- // several threads at PV nodes. If it does not succeed in splitting the
+ // several threads at PV nodes. If it does not succeed in splitting the
// node (because no idle threads are available, or because we have no unused
- // split point objects), the function immediately returns false. If
+ // split point objects), the function immediately returns false. If
// splitting is possible, a SplitPoint object is initialized with all the
// data that must be copied to the helper threads (the current position and
// search stack, alpha, beta, the search depth, etc.), 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_pv(). When all
+ // helper threads that they have been assigned work. This will cause them
+ // to instantly leave their idle loops and call sp_search_pv(). When all
// threads have returned from sp_search_pv (or, equivalently, when
// splitPoint->cpus becomes 0), split() returns true.
bool split(const Position& p, SearchStack* sstck, int ply,
Value* alpha, Value* beta, Value* bestValue, const Value futilityValue,
- const Value approximateEval, Depth depth, int* moves,
- MovePicker* mp, int master, bool pvNode) {
+ Depth depth, int* moves, MovePicker* mp, int master, bool pvNode) {
assert(p.is_ok());
assert(sstck != NULL);
assert(ActiveThreads > 1);
SplitPoint* splitPoint;
- int i;
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(!idle_thread_exists(master) ||
- Threads[master].activeSplitPoints >= MaxActiveSplitPoints) {
- lock_release(&MPLock);
- return false;
+ if ( !idle_thread_exists(master)
+ || Threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX)
+ {
+ lock_release(&MPLock);
+ return false;
}
// Pick the next available split point object from the split point stack
splitPoint->finished = false;
splitPoint->ply = ply;
splitPoint->depth = depth;
- splitPoint->alpha = pvNode? *alpha : (*beta - 1);
+ splitPoint->alpha = pvNode ? *alpha : (*beta - 1);
splitPoint->beta = *beta;
splitPoint->pvNode = pvNode;
splitPoint->bestValue = *bestValue;
splitPoint->futilityValue = futilityValue;
- splitPoint->approximateEval = approximateEval;
splitPoint->master = master;
splitPoint->mp = mp;
splitPoint->moves = *moves;
splitPoint->cpus = 1;
- splitPoint->pos.copy(p);
+ splitPoint->pos = &p;
splitPoint->parentSstack = sstck;
- for(i = 0; i < ActiveThreads; i++)
- splitPoint->slaves[i] = 0;
+ for (int i = 0; i < ActiveThreads; i++)
+ splitPoint->slaves[i] = 0;
- // Copy the current position and the search stack to the master thread
- memcpy(splitPoint->sstack[master], sstck, (ply+1)*sizeof(SearchStack));
+ Threads[master].idle = false;
+ Threads[master].stop = false;
Threads[master].splitPoint = splitPoint;
- // Make copies of the current position and search stack for each thread
- for(i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint;
- i++)
- if(thread_is_available(i, master)) {
- memcpy(splitPoint->sstack[i], sstck, (ply+1)*sizeof(SearchStack));
- Threads[i].splitPoint = splitPoint;
- splitPoint->slaves[i] = 1;
- splitPoint->cpus++;
- }
+ // Allocate available threads setting idle flag to false
+ for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
+ if (thread_is_available(i, master))
+ {
+ Threads[i].idle = false;
+ Threads[i].stop = false;
+ Threads[i].splitPoint = splitPoint;
+ splitPoint->slaves[i] = 1;
+ splitPoint->cpus++;
+ }
- // Tell the threads that they have work to do. This will make them leave
- // their idle loop.
- for(i = 0; i < ActiveThreads; i++)
- if(i == master || splitPoint->slaves[i]) {
- Threads[i].workIsWaiting = true;
- Threads[i].idle = false;
- Threads[i].stop = false;
- }
+ assert(splitPoint->cpus > 1);
+ // We can release the lock because master and slave threads are already booked
lock_release(&MPLock);
- // Everything is set up. The master thread enters the idle loop, from
+ // 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 (int i = 0; i < ActiveThreads; i++)
+ if (i == master || splitPoint->slaves[i])
+ {
+ memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack));
+ Threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop()
+ }
+
+ // Everything is set up. The master thread enters the idle loop, from
// which it will instantly launch a search, because its workIsWaiting
// slot is 'true'. We send the split point as a second parameter to the
// idle loop, which means that the main thread will return from the idle
// loop when all threads have finished their work at this split point
- // (i.e. when // splitPoint->cpus == 0).
+ // (i.e. when splitPoint->cpus == 0).
idle_loop(master, splitPoint);
// We have returned from the idle loop, which means that all threads are
- // finished. Update alpha, beta and bestvalue, and return.
+ // finished. Update alpha, beta and bestValue, and return.
lock_grab(&MPLock);
- if(pvNode) *alpha = splitPoint->alpha;
+
+ if (pvNode)
+ *alpha = splitPoint->alpha;
+
*beta = splitPoint->beta;
*bestValue = splitPoint->bestValue;
Threads[master].stop = false;
Threads[master].idle = false;
Threads[master].activeSplitPoints--;
Threads[master].splitPoint = splitPoint->parent;
- lock_release(&MPLock);
+ lock_release(&MPLock);
return true;
}
// to start a new search from the root.
void wake_sleeping_threads() {
- if(ActiveThreads > 1) {
- for(int i = 1; i < ActiveThreads; i++) {
- Threads[i].idle = true;
- Threads[i].workIsWaiting = false;
- }
+
+ if (ActiveThreads > 1)
+ {
+ for (int i = 1; i < ActiveThreads; i++)
+ {
+ Threads[i].idle = true;
+ Threads[i].workIsWaiting = false;
+ }
+
#if !defined(_MSC_VER)
pthread_mutex_lock(&WaitLock);
pthread_cond_broadcast(&WaitCond);
pthread_mutex_unlock(&WaitLock);
#else
- for(int i = 1; i < THREAD_MAX; i++)
- SetEvent(SitIdleEvent[i]);
+ for (int i = 1; i < THREAD_MAX; i++)
+ SetEvent(SitIdleEvent[i]);
#endif
}
}
// init_thread() is the function which is called when a new thread is
- // launched. It simply calls the idle_loop() function with the supplied
- // threadID. There are two versions of this function; one for POSIX threads
- // and one for Windows threads.
+ // launched. It simply calls the idle_loop() function with the supplied
+ // threadID. There are two versions of this function; one for POSIX
+ // threads and one for Windows threads.
#if !defined(_MSC_VER)
- void *init_thread(void *threadID) {
- idle_loop(*(int *)threadID, NULL);
+ void* init_thread(void *threadID) {
+
+ idle_loop(*(int*)threadID, NULL);
return NULL;
}
#else
DWORD WINAPI init_thread(LPVOID threadID) {
- idle_loop(*(int *)threadID, NULL);
+
+ idle_loop(*(int*)threadID, NULL);
return NULL;
}
projects / stockfish / blobdiff