#include "evaluate.h"
#include "history.h"
#include "misc.h"
+#include "movegen.h"
#include "movepick.h"
+#include "lock.h"
#include "san.h"
#include "search.h"
#include "thread.h"
class RootMoveList {
public:
- RootMoveList(Position &pos, Move searchMoves[]);
+ 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);
const bool UseIIDAtPVNodes = true;
const bool UseIIDAtNonPVNodes = false;
- // Internal iterative deepening margin. At Non-PV moves, when
- // UseIIDAtNonPVNodes is true, we do an internal iterative deepening search
- // when the static evaluation is at most IIDMargin below beta.
+ // Internal iterative deepening margin. At Non-PV moves, when
+ // UseIIDAtNonPVNodes is true, we do an internal iterative deepening
+ // search when the static evaluation is at most IIDMargin below beta.
const Value IIDMargin = Value(0x100);
- // Easy move margin. An easy move candidate must be at least this much
+ // Easy move margin. An easy move candidate must be at least this much
// better than the second best move.
const Value EasyMoveMargin = Value(0x200);
- // Problem margin. If the score of the first move at iteration N+1 has
+ // Problem margin. If the score of the first move at iteration N+1 has
// dropped by more than this since iteration N, the boolean variable
// "Problem" is set to true, which will make the program spend some extra
// time looking for a better move.
const Value ProblemMargin = Value(0x28);
- // No problem margin. If the boolean "Problem" is true, and a new move
+ // No problem margin. If the boolean "Problem" is true, and a new move
// is found at the root which is less than NoProblemMargin worse than the
// 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 approximate
// evaluation of the position is more than NullMoveMargin below beta.
const Value NullMoveMargin = Value(0x300);
- // Pruning criterions. See the code and comments in ok_to_prune() to
+ // Pruning criterions. See the code and comments in ok_to_prune() to
// understand their precise meaning.
- const bool PruneEscapeMoves = false;
+ const bool PruneEscapeMoves = false;
const bool PruneDefendingMoves = false;
- const bool PruneBlockingMoves = false;
+ const bool PruneBlockingMoves = false;
+
+ // Only move margin
+ const Value OnlyMoveMargin = Value(100);
// Margins for futility pruning in the quiescence search, and at frontier
- // and near frontier nodes
+ // and near frontier nodes.
const Value FutilityMarginQS = Value(0x80);
+ // Each move futility margin is decreased
+ const Value IncrementalFutilityMargin = Value(0x8);
+
// 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
const Value RazorApprMargins[6] = { Value(0x520), Value(0x300), Value(0x300), Value(0x300), Value(0x300), Value(0x300) };
- /// Variables initialized from UCI options
+ /// 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 ThreatDepth; // heavy SMP read access
// Last seconds noise filtering (LSN)
- bool UseLSNFiltering;
- bool looseOnTime = false;
- int LSNTime; // In milliseconds
- Value LSNValue;
+ const bool UseLSNFiltering = true;
+ const int LSNTime = 4000; // In milliseconds
+ const Value LSNValue = value_from_centipawns(200);
+ 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
// Time managment variables
int SearchStartTime;
int MaxNodes, MaxDepth;
- int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime;
- Move EasyMove;
+ int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
int RootMoveNumber;
bool InfiniteSearch;
bool PonderSearch;
bool FailHigh;
bool FailLow;
bool Problem;
- bool PonderingEnabled;
- int ExactMaxTime;
// Show current line?
bool ShowCurrentLine;
std::ofstream LogFile;
// MP related variables
+ int ActiveThreads = 1;
Depth MinimumSplitDepth;
int MaxThreadsPerSplitPoint;
Thread Threads[THREAD_MAX];
Lock MPLock;
+ Lock IOLock;
bool AllThreadsShouldExit = false;
const int MaxActiveSplitPoints = 8;
SplitPoint SplitPointStack[THREAD_MAX][MaxActiveSplitPoints];
int NodesSincePoll;
int NodesBetweenPolls = 30000;
+ // History table
+ History H;
+
/// 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 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);
+ 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, Move forbiddenMove = 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);
void init_node(SearchStack ss[], int ply, int threadID);
void update_pv(SearchStack ss[], int ply);
- void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply);
- bool connected_moves(const Position &pos, Move m1, Move m2);
+ void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply);
+ 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);
- bool ok_to_do_nullmove(const Position &pos);
- bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d, const History& H);
+ Depth extension(const Position& pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
+ bool ok_to_do_nullmove(const Position& pos);
+ bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
- bool ok_to_history(const Position &pos, Move m);
- void update_history(const Position& pos, Move m, Depth depth, History& H, Move movesSearched[], int moveCount);
+ void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
bool fail_high_ply_1();
void ponderhit();
void print_current_line(SearchStack ss[], int ply, int threadID);
void wait_for_stop_or_ponderhit();
+ void init_ss_array(SearchStack ss[]);
- void idle_loop(int threadID, SplitPoint *waitSp);
+ void idle_loop(int threadID, SplitPoint* waitSp);
void init_split_point_stack();
void destroy_split_point_stack();
bool thread_should_stop(int threadID);
bool thread_is_available(int slave, int master);
bool idle_thread_exists(int master);
- bool split(const Position &pos, SearchStack *ss, int ply,
- Value *alpha, Value *beta, Value *bestValue, Depth depth, int *moves,
- MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode);
+ 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,
+ MovePicker *mp, int master, bool pvNode);
void wake_sleeping_threads();
#if !defined(_MSC_VER)
////
-//// Global variables
+//// Functions
////
-// The main transposition table
-TranspositionTable TT;
-
-
-// Number of active threads:
-int ActiveThreads = 1;
-
-// Locks. In principle, there is no need for IOLock to be a global variable,
-// but it could turn out to be useful for debugging.
-Lock IOLock;
+/// 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.
-// SearchStack::init() initializes a search stack. Used at the beginning of a
-// new search from the root.
-void SearchStack::init(int ply) {
-
- pv[ply] = pv[ply + 1] = MOVE_NONE;
- currentMove = threatMove = MOVE_NONE;
- reduction = Depth(0);
-}
+int perft(Position& pos, Depth depth)
+{
+ Move move;
+ int sum = 0;
+ MovePicker mp = MovePicker(pos, MOVE_NONE, depth, H);
-void SearchStack::initKillers() {
+ // If we are at the last ply we don't need to do and undo
+ // the moves, just to count them.
+ if (depth <= OnePly) // Replace with '<' to test also qsearch
+ {
+ while (mp.get_next_move()) sum++;
+ return sum;
+ }
- mateKiller = MOVE_NONE;
- for (int i = 0; i < KILLER_MAX; i++)
- killers[i] = MOVE_NONE;
+ // Loop through all legal moves
+ CheckInfo ci(pos);
+ while ((move = mp.get_next_move()) != MOVE_NONE)
+ {
+ StateInfo st;
+ pos.do_move(move, st, ci, pos.move_is_check(move, ci));
+ sum += perft(pos, depth - OnePly);
+ pos.undo_move(move);
+ }
+ return sum;
}
-////
-//// Functions
-////
-
/// think() is the external interface to Stockfish's search, and is called when
/// the program receives the UCI 'go' command. It initializes various
/// search-related global variables, and calls root_search(). It returns false
/// when a quit command is received during the search.
-bool think(const Position &pos, bool infinite, bool ponder, int side_to_move,
+bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
int time[], int increment[], int movesToGo, int maxDepth,
int maxNodes, int maxTime, Move searchMoves[]) {
// Initialize global search variables
Idle = false;
SearchStartTime = get_system_time();
- EasyMove = MOVE_NONE;
for (int i = 0; i < THREAD_MAX; i++)
{
Threads[i].nodes = 0ULL;
// 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
+ }
- PonderingEnabled = get_option_value_bool("Ponder");
+ bool PonderingEnabled = get_option_value_bool("Ponder");
MultiPV = get_option_value_int("MultiPV");
CheckExtension[1] = Depth(get_option_value_int("Check Extension (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;
+ 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");
ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine");
if (UseLogFile)
LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
- UseLSNFiltering = get_option_value_bool("LSN filtering");
- LSNTime = get_option_value_int("LSN Time Margin (sec)") * 1000;
- 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");
read_weights(pos.side_to_move());
+ // Set the number of active threads
int newActiveThreads = get_option_value_int("Threads");
if (newActiveThreads != ActiveThreads)
{
init_eval(ActiveThreads);
}
- // Wake up sleeping threads:
+ // Wake up sleeping threads
wake_sleeping_threads();
for (int i = 1; i < ActiveThreads; i++)
assert(thread_is_available(i, 0));
- // Set thinking time:
+ // Set thinking time
int myTime = time[side_to_move];
int myIncrement = increment[side_to_move];
if (movesToGo == 1)
{
MaxSearchTime = myTime / 2;
- AbsoluteMaxSearchTime = Min(myTime / 2, myTime - 500);
+ AbsoluteMaxSearchTime =
+ (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
} else {
MaxSearchTime = myTime / Min(movesToGo, 20);
AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
NodesBetweenPolls = Min(MaxNodes, 30000);
InfiniteSearch = true; // HACK
}
+ else if (myTime && myTime < 1000)
+ NodesBetweenPolls = 1000;
+ else if (myTime && myTime < 5000)
+ NodesBetweenPolls = 5000;
else
NodesBetweenPolls = 30000;
-
- // Write information to search log file:
+ // Write information to search log file
if (UseLogFile)
LogFile << "Searching: " << pos.to_fen() << std::endl
- << "infinite: " << infinite
- << " ponder: " << ponder
- << " time: " << myTime
+ << "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:
- if (!looseOnTime)
+ // We're ready to start thinking. Call the iterative deepening loop function
+ //
+ // FIXME we really need to cleanup all this LSN ugliness
+ if (!loseOnTime)
{
Value v = id_loop(pos, searchMoves);
- looseOnTime = ( UseLSNFiltering
- && myTime < LSNTime
- && myIncrement == 0
- && v < -LSNValue);
+ loseOnTime = ( UseLSNFiltering
+ && myTime < LSNTime
+ && myIncrement == 0
+ && v < -LSNValue);
}
else
{
- looseOnTime = false; // reset for next match
+ loseOnTime = false; // reset for next match
while (SearchStartTime + myTime + 1000 > get_system_time())
; // wait here
id_loop(pos, searchMoves); // to fail gracefully
for (i = 0; i < THREAD_MAX; i++)
Threads[i].activeSplitPoints = 0;
- // Initialize global locks:
+ // Initialize global locks
lock_init(&MPLock, NULL);
lock_init(&IOLock, NULL);
CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID);
#endif
- // Wait until the thread has finished launching:
+ // Wait until the thread has finished launching
while (!Threads[i].running);
}
}
}
+// SearchStack::init() initializes a search stack. Used at the beginning of a
+// new search from the root.
+void SearchStack::init(int ply) {
+
+ pv[ply] = pv[ply + 1] = MOVE_NONE;
+ currentMove = threatMove = MOVE_NONE;
+ reduction = Depth(0);
+}
+
+void SearchStack::initKillers() {
+
+ mateKiller = MOVE_NONE;
+ for (int i = 0; i < KILLER_MAX; i++)
+ killers[i] = MOVE_NONE;
+}
+
namespace {
// id_loop() is the main iterative deepening loop. It calls root_search
// been consumed, the user stops the search, or the maximum search depth is
// reached.
- Value id_loop(const Position &pos, Move searchMoves[]) {
+ Value id_loop(const Position& pos, Move searchMoves[]) {
Position p(pos);
SearchStack ss[PLY_MAX_PLUS_2];
// searchMoves are verified, copied, scored and sorted
RootMoveList rml(p, searchMoves);
+ // 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";
+
// Initialize
TT.new_search();
- for (int i = 0; i < THREAD_MAX; i++)
- Threads[i].H.clear();
-
- for (int i = 0; i < 3; i++)
- {
- ss[i].init(i);
- ss[i].initKillers();
- }
+ H.clear();
+ init_ss_array(ss);
IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0));
Iteration = 1;
- EasyMove = rml.scan_for_easy_move();
+ Move EasyMove = rml.scan_for_easy_move();
// Iterative deepening loop
while (Iteration < PLY_MAX)
// Calculate dynamic search window based on previous iterations
Value alpha, beta;
- if (MultiPV == 1 && Iteration >= 6)
+ if (MultiPV == 1 && Iteration >= 6 && abs(IterationInfo[Iteration - 1].value) < VALUE_KNOWN_WIN)
{
int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue;
int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue;
// 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
if (Iteration >= 6 && rml.move_count() == 1)
stopSearch = true;
// scheme (perhaps we should try to use this at internal PV nodes, too?)
// 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;
- Bitboard dcCandidates = pos.discovered_check_candidates(pos.side_to_move());
+ CheckInfo ci(pos);
// Loop through all the moves in the root move list
for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
<< " currmovenumber " << i + 1 << std::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;
- ext = extension(pos, move, true, pos.move_is_capture(move), pos.move_is_check(move), false, false, &dangerous);
+ ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
// Make the move, and search it
- pos.do_move(move, st, dcCandidates);
+ pos.do_move(move, st, ci, moveIsCheck);
if (i < MultiPV)
{
}
else
{
- value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
+ if ( newDepth >= 3*OnePly
+ && i >= MultiPV + LMRPVMoves
+ && !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
+
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);
+ 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);
+ }
}
}
// Update PV
rml.set_move_score(i, value);
update_pv(ss, 0);
+ TT.extract_pv(pos, ss[0].pv, PLY_MAX);
rml.set_move_pv(i, ss[0].pv);
if (MultiPV == 1)
if (i > 0)
BestMoveChangesByIteration[Iteration]++;
- // Print search information to the standard output:
+ // 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()
std::cout << std::endl;
if (UseLogFile)
- LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, ss[0].pv)
+ 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;
if (value > alpha)
// search_pv() is the main search function for PV nodes.
- Value search_pv(Position &pos, SearchStack ss[], Value alpha, Value beta,
+ Value search_pv(Position& pos, SearchStack ss[], Value alpha, Value beta,
Depth depth, int ply, int threadID) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(ply >= 0 && ply < PLY_MAX);
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;
+ int moveCount = 0;
+ Value bestValue = -VALUE_INFINITE;
+
if (depth < OnePly)
return qsearch(pos, ss, alpha, beta, Depth(0), ply, threadID);
if (pos.is_draw())
return VALUE_DRAW;
- EvalInfo ei;
-
if (ply >= PLY_MAX - 1)
- return evaluate(pos, ei, threadID);
+ return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID);
// Mate distance pruning
- Value oldAlpha = alpha;
+ oldAlpha = alpha;
alpha = Max(value_mated_in(ply), alpha);
beta = Min(value_mate_in(ply+1), beta);
if (alpha >= beta)
// 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.get_key());
- Move ttMove = (tte ? tte->move() : MOVE_NONE);
+ 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)
// Initialize a MovePicker object for the current position, and prepare
// to search all moves
- MovePicker mp = MovePicker(pos, true, ttMove, depth, Threads[threadID].H, &ss[ply]);
-
- Move move, movesSearched[256];
- int moveCount = 0;
- Value value, bestValue = -VALUE_INFINITE;
- Bitboard dcCandidates = mp.discovered_check_candidates();
- Color us = pos.side_to_move();
- bool isCheck = pos.is_check();
- bool mateThreat = pos.has_mate_threat(opposite_color(us));
+ 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]);
// Loop through all legal moves until no moves remain or a beta cutoff
// occurs.
{
assert(move_is_ok(move));
- bool singleReply = (isCheck && mp.number_of_moves() == 1);
- bool moveIsCheck = pos.move_is_check(move, dcCandidates);
- bool moveIsCapture = pos.move_is_capture(move);
+ singleReply = (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
- bool dangerous;
- Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
- Depth newDepth = depth - OnePly + ext;
+ ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
+
+ // Only move extension
+ if ( moveCount == 1
+ && ext < OnePly
+ && depth >= 8 * OnePly
+ && tte
+ && (tte->type() & VALUE_TYPE_LOWER)
+ && tte->move() != MOVE_NONE
+ && 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 - OnlyMoveMargin, depth / 2, ply, false, threadID, tte->move());
+ if (excValue < ttValue - OnlyMoveMargin)
+ ext = OnePly;
+ }
+ }
+
+ newDepth = depth - OnePly + ext;
// Make and search the move
- StateInfo st;
- pos.do_move(move, st, dcCandidates);
+ pos.do_move(move, st, ci, moveIsCheck);
if (moveCount == 1) // The first move in list is the PV
value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
{
// 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.
- if ( depth >= 2*OnePly
+ if ( depth >= 3*OnePly
&& moveCount >= LMRPVMoves
&& !dangerous
- && !moveIsCapture
- && !move_promotion(move)
+ && !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
{
}
// 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:
+ // (from the computer's point of view) since the previous iteration.
if ( ply == 1
&& Iteration >= 2
&& -value <= IterationInfo[Iteration-1].value - ProblemMargin)
&& idle_thread_exists(threadID)
&& !AbortSearch
&& !thread_should_stop(threadID)
- && split(pos, ss, ply, &alpha, &beta, &bestValue, depth,
- &moveCount, &mp, dcCandidates, threadID, true))
+ && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE, VALUE_NONE,
+ depth, &moveCount, &mp, threadID, true))
break;
}
// 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 (isCheck ? value_mated_in(ply) : VALUE_DRAW);
else if (bestValue >= beta)
{
BetaCounter.add(pos.side_to_move(), depth, threadID);
- Move m = ss[ply].pv[ply];
- if (ok_to_history(pos, m)) // Only non capture moves are considered
+ move = ss[ply].pv[ply];
+ if (!pos.move_is_capture_or_promotion(move))
{
- update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount);
- update_killers(m, ss[ply]);
+ 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, m);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
}
else
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]);
// 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) {
+ Value search(Position& pos, SearchStack ss[], Value beta, Depth depth,
+ int ply, bool allowNullmove, int threadID, Move forbiddenMove) {
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
+ Move movesSearched[256];
+ EvalInfo ei;
+ StateInfo st;
+ const TTEntry* tte;
+ Move ttMove, move;
+ Depth ext, newDepth;
+ Value approximateEval, nullValue, value, futilityValue, futilityValueScaled;
+ bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous;
+ bool mateThreat = false;
+ int moveCount = 0;
+ Value bestValue = -VALUE_INFINITE;
+
if (depth < OnePly)
return qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
if (pos.is_draw())
return VALUE_DRAW;
- EvalInfo ei;
-
if (ply >= PLY_MAX - 1)
- return evaluate(pos, ei, threadID);
+ return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID);
// Mate distance pruning
if (value_mated_in(ply) >= beta)
if (value_mate_in(ply + 1) < beta)
return beta - 1;
+ // Position key calculation
+ Key posKey = pos.get_key();
+
+ if (forbiddenMove != MOVE_NONE)
+ posKey ^= Position::zobExclusion;
+
// Transposition table lookup
- const TTEntry* tte = TT.retrieve(pos.get_key());
- Move ttMove = (tte ? tte->move() : MOVE_NONE);
+ tte = TT.retrieve(posKey);
+ ttMove = (tte ? tte->move() : MOVE_NONE);
if (tte && ok_to_use_TT(tte, depth, beta, ply))
{
return value_from_tt(tte->value(), ply);
}
- Value approximateEval = quick_evaluate(pos);
- bool mateThreat = false;
- bool isCheck = pos.is_check();
+ approximateEval = quick_evaluate(pos);
+ isCheck = pos.is_check();
// Null move search
if ( allowNullmove
{
ss[ply].currentMove = MOVE_NULL;
- StateInfo st;
pos.do_null_move(st);
- int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
- Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
+ // Null move dynamic reduction based on depth
+ int R = (depth >= 5 * OnePly ? 4 : 3);
+
+ // Null move dynamic reduction based on value
+ if (approximateEval - beta > PawnValueMidgame)
+ R++;
+
+ nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move();
- if (value_is_mate(nullValue))
- {
- /* Do not return unproven mates */
- }
- else if (nullValue >= beta)
+ if (nullValue >= beta)
{
if (depth < 6 * OnePly)
return beta;
&& ttMove == MOVE_NONE
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
- Value v = qsearch(pos, ss, beta-1, beta, Depth(0), ply, threadID);
- if (v < beta - RazorMargins[int(depth) - 2])
+ Value rbeta = beta - RazorMargins[int(depth) - 2];
+ Value v = qsearch(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID);
+ if (v < rbeta)
return v;
}
}
// Initialize a MovePicker object for the current position, and prepare
- // to search all moves:
- MovePicker mp = MovePicker(pos, false, ttMove, depth, Threads[threadID].H, &ss[ply]);
+ // to search all moves.
+ MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
+ CheckInfo ci(pos);
+ futilityValue = VALUE_NONE;
+ useFutilityPruning = depth < SelectiveDepth && !isCheck;
- Move move, movesSearched[256];
- int moveCount = 0;
- Value value, bestValue = -VALUE_INFINITE;
- Bitboard dcCandidates = mp.discovered_check_candidates();
- Value futilityValue = VALUE_NONE;
- bool 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];
+
+ // Move count pruning limit
+ const int MCLimit = 3 + (1 << (3*int(depth)/8));
// Loop through all legal moves until no moves remain or a beta cutoff
// occurs.
{
assert(move_is_ok(move));
- bool singleReply = (isCheck && mp.number_of_moves() == 1);
- bool moveIsCheck = pos.move_is_check(move, dcCandidates);
- bool moveIsCapture = pos.move_is_capture(move);
+ if (move == forbiddenMove)
+ continue;
+
+ singleReply = (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
- bool dangerous;
- Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, singleReply, mateThreat, &dangerous);
- Depth newDepth = depth - OnePly + ext;
+ ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
+
+ // Only move extension
+ if ( forbiddenMove == MOVE_NONE
+ && moveCount == 1
+ && ext < OnePly
+ && depth >= 8 * OnePly
+ && tte
+ && (tte->type() & VALUE_TYPE_LOWER)
+ && tte->move() != MOVE_NONE
+ && 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 - OnlyMoveMargin, depth / 2, ply, false, threadID, tte->move());
+ if (excValue < ttValue - OnlyMoveMargin)
+ ext = OnePly;
+ }
+ }
+
+ newDepth = depth - OnePly + ext;
// Futility pruning
if ( useFutilityPruning
&& !dangerous
- && !moveIsCapture
- && !move_promotion(move))
+ && !captureOrPromotion
+ && move != ttMove)
{
+ //std::cout << std::endl;
+ //for (int d = 2; d < 14; d++)
+ // std::cout << d << ", " << 64*(1+bitScanReverse32(d*d)) << std::endl;
+
+ //std::cout << std::endl;
+/*
+ 64*(1+bitScanReverse32(d*d))
+
+ 2 -> 256 - 256
+ 3 -> 288 - 320
+ 4 -> 512 - 384
+ 5 -> 544 - 384
+ 6 -> 592 - 448
+ 7 -> 624 - 448
+ 8 -> 672 - 512
+ 9 -> 704 - 512
+ 10 -> 832 - 512
+ 11 -> 864 - 512
+ 12 -> 928 - 576
+ 13 -> 960 - 576
+
+ 300 + 2*(1 << (3*d/4))
+
+ 2 -> 256 - 304
+ 3 -> 288 - 308
+ 4 -> 512 - 316
+ 5 -> 544 - 316
+ 6 -> 592 - 332
+ 7 -> 624 - 364
+ 8 -> 672 - 428
+ 9 -> 704 - 428
+ 10 -> 832 - 556
+ 11 -> 864 - 812
+ 12 -> 928 - 1324
+ 13 -> 960 - 1324
+
+
+ 3 + (1 << (3*int(depth)/8))
+
+ 1 * onePly - > moveCount >= 4
+ 2 * onePly - > moveCount >= 5
+ 3 * onePly - > moveCount >= 7
+ 4 * onePly - > moveCount >= 11
+ 5 * onePly - > moveCount >= 11
+ 6 * onePly - > moveCount >= 19
+ 7 * onePly - > moveCount >= 35
+*/
// History pruning. See ok_to_prune() definition
- if ( moveCount >= 2 + int(depth)
- && ok_to_prune(pos, move, ss[ply].threatMove, depth, Threads[threadID].H))
+ if ( moveCount >= MCLimit
+ && ok_to_prune(pos, move, ss[ply].threatMove, depth)
+ && bestValue > value_mated_in(PLY_MAX))
continue;
// Value based pruning
{
if (futilityValue == VALUE_NONE)
futilityValue = evaluate(pos, ei, threadID)
- + FutilityMargins[int(depth) - 2];
+ + 64*(2+bitScanReverse32(int(depth) * int(depth)));
+
+ futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
- if (futilityValue < beta)
+ if (futilityValueScaled < beta)
{
- if (futilityValue > bestValue)
- bestValue = futilityValue;
+ if (futilityValueScaled > bestValue)
+ bestValue = futilityValueScaled;
continue;
}
}
}
// Make and search the move
- StateInfo st;
- pos.do_move(move, st, dcCandidates);
+ 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.
- if ( depth >= 2*OnePly
+ if ( depth >= 3*OnePly
&& moveCount >= LMRNonPVMoves
&& !dangerous
- && !moveIsCapture
- && !move_promotion(move)
+ && !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
{
&& idle_thread_exists(threadID)
&& !AbortSearch
&& !thread_should_stop(threadID)
- && split(pos, ss, ply, &beta, &beta, &bestValue, depth, &moveCount,
- &mp, dcCandidates, threadID, false))
+ && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval,
+ depth, &moveCount, &mp, threadID, false))
break;
}
// 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 (forbiddenMove == MOVE_NONE ? (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW) : beta - 1);
// 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 m = ss[ply].pv[ply];
- if (ok_to_history(pos, m)) // Only non capture moves are considered
+ move = ss[ply].pv[ply];
+ if (!pos.move_is_capture_or_promotion(move))
{
- update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount);
- update_killers(m, ss[ply]);
+ 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, m);
+ TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
}
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
// search function when the remaining depth is zero (or, to be more precise,
// less than OnePly).
- Value qsearch(Position &pos, SearchStack ss[], Value alpha, Value beta,
+ Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta,
Depth depth, int ply, int threadID) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
+ EvalInfo ei;
+ StateInfo st;
+ Move ttMove, move;
+ Value staticValue, bestValue, value, futilityValue;
+ bool isCheck, enoughMaterial, moveIsCheck;
+ const TTEntry* tte = NULL;
+ int moveCount = 0;
+ bool pvNode = (beta - alpha != 1);
+
// Initialize, and make an early exit in case of an aborted search,
// an instant draw, maximum ply reached, etc.
init_node(ss, ply, threadID);
return VALUE_DRAW;
// Transposition table lookup, only when not in PV
- TTEntry* tte = NULL;
- bool pvNode = (beta - alpha != 1);
if (!pvNode)
{
tte = TT.retrieve(pos.get_key());
return value_from_tt(tte->value(), ply);
}
}
- Move ttMove = (tte ? tte->move() : MOVE_NONE);
+ ttMove = (tte ? tte->move() : MOVE_NONE);
// Evaluate the position statically
- EvalInfo ei;
- Value staticValue;
- bool isCheck = pos.is_check();
+ isCheck = pos.is_check();
ei.futilityMargin = Value(0); // Manually initialize futilityMargin
if (isCheck)
staticValue = -VALUE_INFINITE;
- else if (tte && tte->type() == VALUE_TYPE_EVAL)
+ else if (tte && (tte->type() & VALUE_TYPE_EVAL))
{
// Use the cached evaluation score if possible
- assert(tte->value() == evaluate(pos, ei, threadID));
assert(ei.futilityMargin == Value(0));
staticValue = tte->value();
else
staticValue = evaluate(pos, ei, threadID);
- if (ply == PLY_MAX - 1)
- return evaluate(pos, ei, threadID);
+ if (ply >= PLY_MAX - 1)
+ return pos.is_check() ? quick_evaluate(pos) : evaluate(pos, ei, threadID);
// Initialize "stand pat score", and return it immediately if it is
// at least beta.
- Value bestValue = staticValue;
+ bestValue = staticValue;
if (bestValue >= beta)
{
// Store the score to avoid a future costly evaluation() call
if (!isCheck && !tte && ei.futilityMargin == 0)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EV_LO, Depth(-127*OnePly), MOVE_NONE);
return bestValue;
}
// 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, pvNode, ttMove, depth, Threads[threadID].H);
- Move move;
- int moveCount = 0;
- Bitboard dcCandidates = mp.discovered_check_candidates();
- Color us = pos.side_to_move();
- bool enoughMaterial = pos.non_pawn_material(us) > RookValueMidgame;
+ MovePicker mp = MovePicker(pos, ttMove, depth, H);
+ CheckInfo ci(pos);
+ enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
// Loop through the moves until no moves remain or a beta cutoff
// occurs.
moveCount++;
ss[ply].currentMove = move;
+ moveIsCheck = pos.move_is_check(move, ci);
+
// Futility pruning
if ( enoughMaterial
&& !isCheck
&& !pvNode
- && !move_promotion(move)
- && !pos.move_is_check(move, dcCandidates)
+ && !moveIsCheck
+ && move != ttMove
+ && !move_is_promotion(move)
&& !pos.move_is_passed_pawn_push(move))
{
- Value 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 = 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;
if (futilityValue < alpha)
{
// Don't search captures and checks with negative SEE values
if ( !isCheck
- && !move_promotion(move)
- && (pos.midgame_value_of_piece_on(move_from(move)) >
- pos.midgame_value_of_piece_on(move_to(move)))
- && pos.see(move) < 0)
+ && move != ttMove
+ && !move_is_promotion(move)
+ && pos.see_sign(move) < 0)
continue;
- // Make and search the move.
- StateInfo st;
- pos.do_move(move, st, dcCandidates);
- Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
+ // Make and search the move
+ pos.do_move(move, st, ci, moveIsCheck);
+ value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
}
// All legal moves have been searched. A special case: If we're in check
- // and no legal moves were found, it is checkmate:
- if (pos.is_check() && moveCount == 0) // Mate!
+ // 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 m = ss[ply].pv[ply];
+ move = ss[ply].pv[ply];
if (!pvNode)
{
+ // 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.
+ ValueType type = (bestValue == staticValue && !ei.futilityMargin ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
+
if (bestValue < beta)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE);
+ 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, m);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
}
// Update killers only for good check moves
- if (alpha >= beta && ok_to_history(pos, m)) // Only non capture moves are considered
- update_killers(m, ss[ply]);
+ if (alpha >= beta && !pos.move_is_capture_or_promotion(move))
+ update_killers(move, ss[ply]);
return bestValue;
}
// also don't need to store anything to the hash table here: This is taken
// care of after we return from the split point.
- void sp_search(SplitPoint *sp, int threadID) {
+ void sp_search(SplitPoint* sp, int threadID) {
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
Position pos = Position(sp->pos);
- SearchStack *ss = sp->sstack[threadID];
+ CheckInfo ci(pos);
+ SearchStack* ss = sp->sstack[threadID];
Value value;
Move move;
bool isCheck = pos.is_check();
{
assert(move_is_ok(move));
- bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
- bool moveIsCapture = pos.move_is_capture(move);
+ bool moveIsCheck = pos.move_is_check(move, ci);
+ bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
lock_grab(&(sp->lock));
int moveCount = ++sp->moves;
// Decide the new search depth.
bool dangerous;
- Depth ext = extension(pos, move, false, moveIsCapture, moveIsCheck, false, false, &dangerous);
+ Depth ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Prune?
if ( useFutilityPruning
&& !dangerous
- && !moveIsCapture
- && !move_promotion(move)
- && moveCount >= 2 + int(sp->depth)
- && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth, Threads[threadID].H))
- continue;
+ && !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)
+ && sp->bestValue > value_mated_in(PLY_MAX))
+ continue;
+
+ // Value based pruning
+ if (sp->approximateEval < sp->beta)
+ {
+ if (sp->futilityValue == VALUE_NONE)
+ {
+ 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;
+ }
+ }
+ }
// Make and search the move.
StateInfo st;
- pos.do_move(move, st, sp->dcCandidates);
+ 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.
if ( !dangerous
&& moveCount >= LMRNonPVMoves
- && !moveIsCapture
- && !move_promotion(move)
+ && !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
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 (sp->bestValue >= sp->beta)
+ lock_grab(&(sp->lock));
+ if (value > sp->bestValue && !thread_should_stop(threadID))
{
- sp_update_pv(sp->parentSstack, ss, sp->ply);
- for (int i = 0; i < ActiveThreads; i++)
- if (i != threadID && (i == sp->master || sp->slaves[i]))
- Threads[i].stop = true;
+ sp->bestValue = value;
+ if (sp->bestValue >= sp->beta)
+ {
+ sp_update_pv(sp->parentSstack, ss, sp->ply);
+ 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;
+ }
+ }
+ lock_release(&(sp->lock));
}
- lock_release(&(sp->lock));
}
lock_grab(&(sp->lock));
// If this is the master thread and we have been asked to stop because of
- // a beta cutoff higher up in the tree, stop all slave threads:
+ // a beta cutoff higher up in the tree, stop all slave threads.
if (sp->master == threadID && thread_should_stop(threadID))
for (int i = 0; i < ActiveThreads; i++)
if (sp->slaves[i])
// the normal search_pv() function, but simpler. Because we have already
// probed the hash table and searched the first move before splitting, we
// don't have to repeat all this work in sp_search_pv(). We also don't
- // need to store anything to the hash table here: This is taken care of
+ // need to store anything to the hash table here: This is taken care of
// after we return from the split point.
- void sp_search_pv(SplitPoint *sp, int threadID) {
+ void sp_search_pv(SplitPoint* sp, int threadID) {
assert(threadID >= 0 && threadID < ActiveThreads);
assert(ActiveThreads > 1);
Position pos = Position(sp->pos);
- SearchStack *ss = sp->sstack[threadID];
+ CheckInfo ci(pos);
+ SearchStack* ss = sp->sstack[threadID];
Value value;
Move move;
&& !thread_should_stop(threadID)
&& (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
{
- bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
- bool moveIsCapture = pos.move_is_capture(move);
+ bool moveIsCheck = pos.move_is_check(move, ci);
+ bool captureOrPromotion = pos.move_is_capture_or_promotion(move);
assert(move_is_ok(move));
// Decide the new search depth.
bool dangerous;
- Depth ext = extension(pos, move, true, moveIsCapture, moveIsCheck, false, false, &dangerous);
+ Depth ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Make and search the move.
StateInfo st;
- pos.do_move(move, st, sp->dcCandidates);
+ 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.
if ( !dangerous
&& moveCount >= LMRPVMoves
- && !moveIsCapture
- && !move_promotion(move)
+ && !captureOrPromotion
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
{
// When the search fails high at ply 1 while searching the first
// move at the root, set the flag failHighPly1. This is used for
- // time managment: We don't want to stop the search early in
+ // 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)
if (value == value_mate_in(sp->ply + 1))
ss[sp->ply].mateKiller = move;
- if(value >= sp->beta)
+ if (value >= sp->beta)
{
- for(int i = 0; i < ActiveThreads; i++)
- if(i != threadID && (i == sp->master || sp->slaves[i]))
+ for (int i = 0; i < ActiveThreads; i++)
+ if (i != threadID && (i == sp->master || sp->slaves[i]))
Threads[i].stop = true;
sp->finished = true;
bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
// Generate all legal moves
- int lm_count = generate_legal_moves(pos, mlist);
+ MoveStack* last = generate_moves(pos, mlist);
// Add each move to the moves[] array
- for (int i = 0; i < lm_count; i++)
+ for (MoveStack* cur = mlist; cur != last; cur++)
{
bool includeMove = includeAllMoves;
for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
- includeMove = (searchMoves[k] == mlist[i].move);
+ includeMove = (searchMoves[k] == cur->move);
if (!includeMove)
continue;
// Find a quick score for the move
StateInfo st;
SearchStack ss[PLY_MAX_PLUS_2];
+ init_ss_array(ss);
- moves[count].move = mlist[i].move;
+ moves[count].move = cur->move;
pos.do_move(moves[count].move, st);
moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
pos.undo_move(moves[count].move);
// for user input and checks whether it is time to stop the search.
void init_node(SearchStack ss[], int ply, int threadID) {
+
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
Threads[threadID].nodes++;
- if(threadID == 0) {
- NodesSincePoll++;
- if(NodesSincePoll >= NodesBetweenPolls) {
- poll();
- NodesSincePoll = 0;
- }
+ if (threadID == 0)
+ {
+ NodesSincePoll++;
+ if (NodesSincePoll >= NodesBetweenPolls)
+ {
+ poll();
+ NodesSincePoll = 0;
+ }
}
-
ss[ply].init(ply);
ss[ply+2].initKillers();
- if(Threads[threadID].printCurrentLine)
- print_current_line(ss, ply, threadID);
+ if (Threads[threadID].printCurrentLine)
+ print_current_line(ss, ply, threadID);
}
// 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) {
+ 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;
// 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) {
+ bool connected_moves(const Position& pos, Move m1, Move m2) {
+
Square f1, t1, f2, t2;
+ Piece p;
assert(move_is_ok(m1));
assert(move_is_ok(m2));
- if(m2 == MOVE_NONE)
- return false;
+ if (m2 == MOVE_NONE)
+ return false;
- // Case 1: The moving piece is the same in both moves.
+ // Case 1: The moving piece is the same in both moves
f2 = move_from(m2);
t1 = move_to(m1);
- if(f2 == t1)
- return true;
+ if (f2 == t1)
+ return true;
- // Case 2: The destination square for m2 was vacated by m1.
+ // Case 2: The destination square for m2 was vacated by m1
t2 = move_to(m2);
f1 = move_from(m1);
- if(t2 == f1)
- return true;
+ if (t2 == f1)
+ return true;
- // Case 3: Moving through the vacated square:
- if(piece_is_slider(pos.piece_on(f2)) &&
- bit_is_set(squares_between(f2, t2), f1))
+ // Case 3: Moving through the vacated square
+ if ( piece_is_slider(pos.piece_on(f2))
+ && 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:
- if(pos.piece_attacks_square(pos.piece_on(t1), t1, t2))
- return true;
+ // Case 4: The destination square for m2 is attacked 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(pos.piece_on(t1)) &&
- bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())),
- f2) &&
- !bit_is_set(squares_between(t2, 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(pos.type_of_piece_on(t1) == BISHOP) {
- if(bit_is_set(bishop_attacks_bb(ksq, occ), t1))
- return true;
- }
- else if(pos.type_of_piece_on(t1) == ROOK) {
- if(bit_is_set(rook_attacks_bb(ksq, occ), t1))
- return true;
- }
- else {
- assert(pos.type_of_piece_on(t1) == QUEEN);
- if(bit_is_set(queen_attacks_bb(ksq, occ), t1))
- return true;
- }
+ // Case 5: Discovered check, checking piece is the piece moved in m1
+ if ( piece_is_slider(p)
+ && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
+ && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2))
+ {
+ 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;
+ }
}
-
return false;
}
// 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 capture, bool check,
- bool singleReply, bool mateThreat, bool* dangerous) {
+ Depth extension(const Position& pos, Move m, bool pvNode, bool captureOrPromotion,
+ bool check, bool singleReply, bool mateThreat, bool* dangerous) {
assert(m != MOVE_NONE);
Depth result = Depth(0);
- *dangerous = check || singleReply || mateThreat;
+ *dangerous = check | singleReply | mateThreat;
- if (check)
- result += CheckExtension[pvNode];
+ if (*dangerous)
+ {
+ if (check)
+ result += CheckExtension[pvNode];
- if (singleReply)
- result += SingleReplyExtension[pvNode];
+ if (singleReply)
+ result += SingleReplyExtension[pvNode];
- if (mateThreat)
- result += MateThreatExtension[pvNode];
+ if (mateThreat)
+ result += MateThreatExtension[pvNode];
+ }
if (pos.type_of_piece_on(move_from(m)) == PAWN)
{
- if (pos.move_is_pawn_push_to_7th(m))
+ Color c = pos.side_to_move();
+ if (relative_rank(c, move_to(m)) == RANK_7)
{
result += PawnPushTo7thExtension[pvNode];
*dangerous = true;
}
- if (pos.move_is_passed_pawn_push(m))
+ if (pos.pawn_is_passed(c, move_to(m)))
{
result += PassedPawnExtension[pvNode];
*dangerous = true;
}
}
- if ( capture
+ if ( captureOrPromotion
&& pos.type_of_piece_on(move_to(m)) != PAWN
&& ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- pos.midgame_value_of_piece_on(move_to(m)) == Value(0))
- && !move_promotion(m)
+ && !move_is_promotion(m)
&& !move_is_ep(m))
{
result += PawnEndgameExtension[pvNode];
}
if ( pvNode
- && capture
+ && captureOrPromotion
&& pos.type_of_piece_on(move_to(m)) != PAWN
- && pos.see(m) >= 0)
+ && pos.see_sign(m) >= 0)
{
result += OnePly/2;
*dangerous = true;
// 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) {
- if(pos.non_pawn_material(pos.side_to_move()) == Value(0))
- return false;
- return true;
+ bool ok_to_do_nullmove(const Position& pos) {
+
+ return pos.non_pawn_material(pos.side_to_move()) != Value(0);
}
// 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, const History& H) {
- Square mfrom, mto, tfrom, tto;
+ bool ok_to_prune(const Position& pos, Move m, Move threat, Depth d) {
assert(move_is_ok(m));
assert(threat == MOVE_NONE || move_is_ok(threat));
- assert(!move_promotion(m));
assert(!pos.move_is_check(m));
- assert(!pos.move_is_capture(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;
+
mfrom = move_from(m);
mto = move_to(m);
tfrom = move_from(threat);
tto = move_to(threat);
- // Case 1: Castling moves are never pruned.
+ // Case 1: Castling moves are never pruned
if (move_is_castle(m))
return false;
&& ( 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;
+ return false;
- // Case 4: Don't prune moves with good history.
+ // Case 4: Don't prune moves with good history
if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d))
return false;
&& threat != MOVE_NONE
&& piece_is_slider(pos.piece_on(tfrom))
&& bit_is_set(squares_between(tfrom, tto), mto)
- && pos.see(m) >= 0)
- return false;
+ && pos.see_sign(m) >= 0)
+ return false;
return true;
}
}
- // ok_to_history() returns true if a move m can be stored
- // in history. Should be a non capturing move nor a promotion.
-
- bool ok_to_history(const Position& pos, Move m) {
-
- return !pos.move_is_capture(m) && !move_promotion(m);
- }
-
-
// 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, History& H,
+ void update_history(const Position& pos, Move m, Depth depth,
Move movesSearched[], int moveCount) {
H.success(pos.piece_on(move_from(m)), move_to(m), depth);
for (int i = 0; i < moveCount - 1; i++)
{
assert(m != movesSearched[i]);
- if (ok_to_history(pos, movesSearched[i]))
+ if (!pos.move_is_capture_or_promotion(movesSearched[i]))
H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
}
}
ss.killers[0] = m;
}
+
// 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.
bool fail_high_ply_1() {
+
for(int i = 0; i < ActiveThreads; i++)
- if(Threads[i].failHighPly1)
- return true;
+ if (Threads[i].failHighPly1)
+ return true;
+
return false;
}
Quit = true;
return;
}
- else if(command == "stop")
+ else if (command == "stop")
{
AbortSearch = true;
PonderSearch = false;
}
- else if(command == "ponderhit")
+ else if (command == "ponderhit")
ponderhit();
}
// Print search information
// it correctly predicted the opponent's move.
void ponderhit() {
+
int t = current_search_time();
PonderSearch = false;
- if(Iteration >= 3 &&
+ if (Iteration >= 3 &&
(!InfiniteSearch && (StopOnPonderhit ||
t > AbsoluteMaxSearchTime ||
(RootMoveNumber == 1 &&
// thread. Called when the UCI option UCI_ShowCurrLine is 'true'.
void print_current_line(SearchStack ss[], int ply, int threadID) {
+
assert(ply >= 0 && ply < PLY_MAX);
assert(threadID >= 0 && threadID < ActiveThreads);
- if(!Threads[threadID].idle) {
- lock_grab(&IOLock);
- std::cout << "info currline " << (threadID + 1);
- for(int p = 0; p < ply; p++)
- std::cout << " " << ss[p].currentMove;
- std::cout << std::endl;
- lock_release(&IOLock);
+ if (!Threads[threadID].idle)
+ {
+ lock_grab(&IOLock);
+ std::cout << "info currline " << (threadID + 1);
+ for (int p = 0; p < ply; p++)
+ std::cout << " " << ss[p].currentMove;
+
+ std::cout << std::endl;
+ lock_release(&IOLock);
}
Threads[threadID].printCurrentLine = false;
- if(threadID + 1 < ActiveThreads)
- Threads[threadID + 1].printCurrentLine = true;
+ if (threadID + 1 < ActiveThreads)
+ Threads[threadID + 1].printCurrentLine = true;
+ }
+
+
+ // init_ss_array() does a fast reset of the first entries of a SearchStack array
+
+ void init_ss_array(SearchStack ss[]) {
+
+ for (int i = 0; i < 3; i++)
+ {
+ ss[i].init(i);
+ ss[i].initKillers();
+ }
}
Quit = true;
break;
}
- else if(command == "ponderhit" || command == "stop")
+ else if (command == "ponderhit" || command == "stop")
break;
}
}
// The parameter "waitSp", if non-NULL, is a pointer to an active SplitPoint
// object for which the current thread is the master.
- void idle_loop(int threadID, SplitPoint *waitSp) {
+ void idle_loop(int threadID, SplitPoint* waitSp) {
assert(threadID >= 0 && threadID < THREAD_MAX);
Threads[threadID].running = true;
#endif
}
- // If this thread has been assigned work, launch a search:
+ // If this thread has been assigned work, launch a search
if(Threads[threadID].workIsWaiting) {
Threads[threadID].workIsWaiting = false;
if(Threads[threadID].splitPoint->pvNode)
}
// 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:
+ // finished their work at this split point, return from the idle loop.
if(waitSp != NULL && waitSp->cpus == 0)
return;
}
bool thread_should_stop(int threadID) {
assert(threadID >= 0 && threadID < ActiveThreads);
- SplitPoint *sp;
+ SplitPoint* sp;
if(Threads[threadID].stop)
return true;
// 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, Depth depth, int *moves,
- MovePicker *mp, Bitboard dcCandidates, int master, bool pvNode) {
+ 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) {
assert(p.is_ok());
assert(sstck != NULL);
assert(master >= 0 && master < ActiveThreads);
assert(ActiveThreads > 1);
- SplitPoint *splitPoint;
+ 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:
+ // active split points, don't split.
if(!idle_thread_exists(master) ||
Threads[master].activeSplitPoints >= MaxActiveSplitPoints) {
lock_release(&MPLock);
return false;
}
- // Pick the next available split point object from the split point stack:
+ // Pick the next available split point object from the split point stack
splitPoint = SplitPointStack[master] + Threads[master].activeSplitPoints;
Threads[master].activeSplitPoints++;
- // Initialize the split point object:
+ // Initialize the split point object
splitPoint->parent = Threads[master].splitPoint;
splitPoint->finished = false;
splitPoint->ply = ply;
splitPoint->alpha = pvNode? *alpha : (*beta - 1);
splitPoint->beta = *beta;
splitPoint->pvNode = pvNode;
- splitPoint->dcCandidates = dcCandidates;
splitPoint->bestValue = *bestValue;
+ splitPoint->futilityValue = futilityValue;
+ splitPoint->approximateEval = approximateEval;
splitPoint->master = master;
splitPoint->mp = mp;
splitPoint->moves = *moves;
for(i = 0; i < ActiveThreads; i++)
splitPoint->slaves[i] = 0;
- // Copy the current position and the search stack to the master thread:
+ // Copy the current position and the search stack to the master thread
memcpy(splitPoint->sstack[master], sstck, (ply+1)*sizeof(SearchStack));
Threads[master].splitPoint = splitPoint;
- // Make copies of the current position and search stack for each thread:
+ // 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)) {
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;
*beta = splitPoint->beta;
projects / stockfish / blobdiff