#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
+ bool operator<(const RootMove&) const; // Used to sort
Move move;
Value score;
- int64_t nodes, cumulativeNodes;
+ int64_t nodes, cumulativeNodes, ourBeta, theirBeta;
Move pv[PLY_MAX_PLUS_2];
- int64_t ourBeta, theirBeta;
};
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_multipv(int n);
/// 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
// If the TT move is at least SingleReplyMargin better then the
// remaining ones we will extend it.
- const Value SingleReplyMargin = Value(0x64);
+ const Value SingleReplyMargin = Value(0x20);
// Margins for futility pruning in the quiescence search, and at frontier
// and near frontier nodes.
// 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
- Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0) };
- // Razoring
- const Depth RazorDepth = 4*OnePly;
+ // Depth limit for 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) };
/// 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
+ int LMRPVMoves, LMRNonPVMoves;
// 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 InfiniteSearch, PonderSearch, StopOnPonderhit;
+ bool AbortSearch, Quit;
+ bool FailHigh, FailLow, Problem;
// Show current line?
bool ShowCurrentLine;
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)
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);
void update_killers(Move m, SearchStack& ss);
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)
{
{
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;
+ Idle = StopOnPonderhit = AbortSearch = Quit = false;
+ FailHigh = FailLow = Problem = false;
SearchStartTime = get_system_time();
+ ExactMaxTime = maxTime;
+ NodesSincePoll = 0;
+ InfiniteSearch = infinite;
+ PonderSearch = ponder;
+
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)"));
{
MaxSearchTime = myTime / 30 + myIncrement;
AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
- } else { // Blitz game without increment
+ }
+ else // Blitz game without increment
+ {
MaxSearchTime = myTime / 30;
AbsoluteMaxSearchTime = myTime / 8;
}
if (movesToGo == 1)
{
MaxSearchTime = myTime / 2;
- AbsoluteMaxSearchTime =
- (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
- } else {
+ AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
+ }
+ else
+ {
MaxSearchTime = myTime / Min(movesToGo, 20);
AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
}
// 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.
}
-/// 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() {
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();
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;
// 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
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;
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);
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
{
+ // 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 ( newDepth >= 3*OnePly
&& i >= MultiPV + LMRPVMoves
&& !dangerous
if (value > alpha)
{
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);
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;
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());
}
// Initialize a MovePicker object for the current position, and prepare
{
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);
// Decide the new search depth
- ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
-
- // We want to extend the TT move if it is much better then remaining ones.
- // To verify this we do a reduced search on all the other moves but the ttMove,
- // if result is lower then TT value minus a margin then we assume ttMove is the
- // only one playable. It is a kind of relaxed single reply extension.
- if ( depth >= 4 * OnePly
- && move == ttMove
+ 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)
if (abs(ttValue) < VALUE_KNOWN_WIN)
{
- Depth d = Max(Min(depth / 2, depth - 4 * OnePly), OnePly);
- Value excValue = search(pos, ss, ttValue - SingleReplyMargin, d, ply, false, threadID, ttMove);
+ Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move);
- // If search result is well below the foreseen score of the ttMove then we
- // assume ttMove is the only one realistically playable and we extend it.
if (excValue < ttValue - SingleReplyMargin)
ext = OnePly;
}
&& 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;
}
Move ttMove, move;
Depth ext, newDepth;
Value approximateEval, nullValue, value, futilityValue, futilityValueScaled;
- bool isCheck, useFutilityPruning, singleReply, moveIsCheck, captureOrPromotion, dangerous;
+ bool isCheck, useFutilityPruning, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
int moveCount = 0;
Value bestValue = -VALUE_INFINITE;
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);
}
// 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 && evaluate(pos, ei, threadID) >= 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
futilityValue = VALUE_NONE;
useFutilityPruning = depth < SelectiveDepth && !isCheck;
+ // Calculate depth dependant futility pruning parameters
+ const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8));
+ const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2);
+
// 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));
+ futilityValue = value_from_tt(tte->value(), ply) + FutilityValueMargin;
// Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
if (move == excludedMove)
continue;
- 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);
// Decide the new search depth
- ext = extension(pos, move, false, captureOrPromotion, moveIsCheck, singleReply, mateThreat, &dangerous);
-
- // We want to extend the TT move if it is much better then remaining ones.
- // To verify this we do a reduced search on all the other moves but the ttMove,
- // if result is lower then TT value minus a margin then we assume ttMove is the
- // only one playable. It is a kind of relaxed single reply extension.
- if ( depth >= 4 * OnePly
- && !excludedMove // do not allow recursive single-reply search
- && move == ttMove
+ 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)
if (abs(ttValue) < VALUE_KNOWN_WIN)
{
- Depth d = Max(Min(depth / 2, depth - 4 * OnePly), OnePly);
- Value excValue = search(pos, ss, ttValue - SingleReplyMargin, d, ply, false, threadID, ttMove);
+ Value excValue = search(pos, ss, ttValue - SingleReplyMargin, depth / 2, ply, false, threadID, move);
- // If search result is well below the foreseen score of the ttMove then we
- // assume ttMove is the only one realistically playable and we extend it.
if (excValue < ttValue - SingleReplyMargin)
- ext = (depth >= 8 * OnePly) ? OnePly : ext + OnePly / 2;
+ ext = OnePly;
}
}
&& !captureOrPromotion
&& move != ttMove)
{
- // History pruning. See ok_to_prune() definition
- if ( moveCount >= MCLimit
- && 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)
- + 64*(2+bitScanReverse32(int(depth) * int(depth)));
+ if (futilityValue == VALUE_NONE)
+ futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
- futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
+ futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
- if (futilityValueScaled < beta)
- {
- if (futilityValueScaled > bestValue)
- bestValue = futilityValueScaled;
- continue;
- }
+ if (futilityValueScaled < beta)
+ {
+ if (futilityValueScaled > bestValue)
+ bestValue = futilityValueScaled;
+ continue;
}
}
value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID);
}
else
- value = beta; // Just to trigger next condition
+ value = beta; // Just to trigger next condition
if (value >= beta) // Go with full depth non-pv search
{
// 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,
depth, &moveCount, &mp, threadID, false))
- break;
+ break;
}
// All legal moves have been searched. A special case: If there were
}
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;
// 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);
bool useFutilityPruning = sp->depth < SelectiveDepth
&& !isCheck;
+ const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8));
+ const int FutilityValueMargin = 112 * bitScanReverse32(int(sp->depth) * int(sp->depth) / 2);
+
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)
+ if (sp->futilityValue == VALUE_NONE)
{
- if (sp->futilityValue == VALUE_NONE)
- {
- EvalInfo ei;
- sp->futilityValue = evaluate(pos, ei, threadID)
- + FutilityMargins[int(sp->depth) - 2];
- }
+ EvalInfo ei;
+ sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
+ }
+
+ Value futilityValueScaled = sp->futilityValue - moveCount * IncrementalFutilityMargin;
- if (sp->futilityValue < sp->beta)
+ if (futilityValueScaled < sp->beta)
+ {
+ if (futilityValueScaled > sp->bestValue) // Less then 1% of cases
{
- 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;
}
}
// 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) {
+ bool RootMove::operator<(const RootMove& m) const {
if (score != m.score)
return (score < m.score);
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();
}
- // 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.
// 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];
// 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;
&& 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 4: 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
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));
{
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]));
+ H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]), depth);
}
}
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;
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;
void init_split_point_stack() {
for(int i = 0; i < THREAD_MAX; i++)
- for(int j = 0; j < MaxActiveSplitPoints; j++) {
+ for(int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++) {
SplitPointStack[i][j].parent = NULL;
lock_init(&(SplitPointStack[i][j].lock), NULL);
}
void destroy_split_point_stack() {
for(int i = 0; i < THREAD_MAX; i++)
- for(int j = 0; j < MaxActiveSplitPoints; j++)
+ for(int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
lock_destroy(&(SplitPointStack[i][j].lock));
}
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);
// 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) {
+ Threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX) {
lock_release(&MPLock);
return false;
}
splitPoint->pvNode = pvNode;
splitPoint->bestValue = *bestValue;
splitPoint->futilityValue = futilityValue;
- splitPoint->approximateEval = approximateEval;
splitPoint->master = master;
splitPoint->mp = mp;
splitPoint->moves = *moves;
projects / stockfish / blobdiff