#include <fstream>
#include <iostream>
#include <sstream>
+#include <vector>
#include "book.h"
#include "evaluate.h"
void read_uci_options();
bool available_thread_exists(int master) const;
bool thread_is_available(int slave, int master) const;
- bool thread_should_stop(int threadID) const;
+ bool cutoff_at_splitpoint(int threadID) const;
void wake_sleeping_thread(int threadID);
void idle_loop(int threadID, SplitPoint* sp);
};
- // RootMove struct 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).
+ // RootMove struct is used for moves at the root at the tree. For each root
+ // move, we store two scores, a node count, and a PV (really a refutation
+ // in the case of moves which fail low). Value pv_score is normally set at
+ // -VALUE_INFINITE for all non-pv moves, while non_pv_score is computed
+ // according to the order in which moves are returned by MovePicker.
struct RootMove {
- RootMove() : mp_score(0), nodes(0) {}
+ RootMove();
+ RootMove(const RootMove& rm) { *this = rm; }
+ RootMove& operator=(const RootMove& rm);
// RootMove::operator<() is the comparison function used when
// sorting the moves. A move m1 is considered to be better
- // than a move m2 if it has a higher score, or if the moves
- // have equal score but m1 has the higher beta cut-off count.
+ // than a move m2 if it has an higher pv_score, or if it has
+ // equal pv_score but m1 has the higher non_pv_score. In this
+ // way we are guaranteed that PV moves are always sorted as first.
bool operator<(const RootMove& m) const {
-
- return score != m.score ? score < m.score : mp_score <= m.mp_score;
+ return pv_score != m.pv_score ? pv_score < m.pv_score
+ : non_pv_score < m.non_pv_score;
}
- Move move;
- Value score;
- int mp_score;
+ void extract_pv_from_tt(Position& pos);
+ void insert_pv_in_tt(Position& pos);
+ std::string pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine = 0);
+
int64_t nodes;
+ Value pv_score;
+ Value non_pv_score;
Move pv[PLY_MAX_PLUS_2];
};
- // The RootMoveList class is essentially an array of RootMove objects, with
- // a handful of methods for accessing the data in the individual moves.
+ // RootMoveList struct is essentially a std::vector<> of RootMove objects,
+ // with an handful of methods above the standard ones.
- class RootMoveList {
-
- public:
- RootMoveList(Position& pos, Move searchMoves[]);
+ struct RootMoveList : public std::vector<RootMove> {
- Move move(int moveNum) const { return moves[moveNum].move; }
- Move move_pv(int moveNum, int i) const { return moves[moveNum].pv[i]; }
- int move_count() const { return count; }
- Value move_score(int moveNum) const { return moves[moveNum].score; }
- int64_t move_nodes(int moveNum) const { return moves[moveNum].nodes; }
- void add_move_nodes(int moveNum, int64_t nodes) { moves[moveNum].nodes += nodes; }
- void set_move_score(int moveNum, Value score) { moves[moveNum].score = score; }
+ typedef std::vector<RootMove> Base;
- void set_move_pv(int moveNum, const Move pv[]);
- void score_moves(const Position& pos);
- void sort();
- void sort_multipv(int n);
+ RootMoveList(Position& pos, Move searchMoves[]);
+ void set_non_pv_scores(const Position& pos, Move ttm, SearchStack* ss);
- private:
- RootMove moves[MOVES_MAX];
- int count;
+ void sort() { insertion_sort<RootMove, Base::iterator>(begin(), end()); }
+ void sort_multipv(int n) { insertion_sort<RootMove, Base::iterator>(begin(), begin() + n); }
};
// operator<<() that will use it to properly format castling moves.
enum set960 {};
- std::ostream& operator<< (std::ostream& os, const set960& m) {
+ std::ostream& operator<< (std::ostream& os, const set960& f) {
- os.iword(0) = int(m);
+ os.iword(0) = int(f);
return os;
}
+ // Overload operator << for moves to make it easier to print moves in
+ // coordinate notation compatible with UCI protocol.
+ std::ostream& operator<<(std::ostream& os, Move m) {
+
+ bool chess960 = (os.iword(0) != 0); // See set960()
+ return os << move_to_uci(m, chess960);
+ }
+
+
/// Adjustments
// Step 6. Razoring
// Time managment variables
int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime;
- bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
- bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
+ bool UseTimeManagement, InfiniteSearch, Pondering, StopOnPonderhit;
+ bool FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
TimeManager TimeMgr;
// Log file
// Node counters, used only by thread[0] but try to keep in different cache
// lines (64 bytes each) from the heavy multi-thread read accessed variables.
+ bool SendSearchedNodes;
int NodesSincePoll;
int NodesBetweenPolls = 30000;
/// Local functions
- Value id_loop(Position& pos, Move searchMoves[]);
- Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
+ Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove);
+ Value root_search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, RootMoveList& rml);
template <NodeType PvNode, bool SpNode>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous);
+ bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue);
bool connected_moves(const Position& pos, Move m1, Move m2);
bool value_is_mate(Value value);
Value value_to_tt(Value v, int ply);
bool connected_threat(const Position& pos, Move m, Move threat);
Value refine_eval(const TTEntry* tte, Value defaultEval, int ply);
void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount);
- void update_killers(Move m, SearchStack* ss);
+ void update_killers(Move m, Move killers[]);
void update_gains(const Position& pos, Move move, Value before, Value after);
int current_search_time();
std::string value_to_uci(Value v);
int nps(const Position& pos);
void poll(const Position& pos);
- void ponderhit();
void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack* ss, int size);
- void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value);
- void insert_pv_in_tt(const Position& pos, Move pv[]);
- void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
#if !defined(_MSC_VER)
void* init_thread(void* threadID);
/// 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)
+int64_t perft(Position& pos, Depth depth)
{
MoveStack mlist[MOVES_MAX];
StateInfo st;
Move m;
- int sum = 0;
+ int64_t sum = 0;
// Generate all legal moves
- MoveStack* last = generate_moves(pos, mlist);
+ MoveStack* last = generate<MV_LEGAL>(pos, mlist);
// If we are at the last ply we don't need to do and undo
// the moves, just to count them.
int movesToGo, int maxDepth, int maxNodes, int maxTime, Move searchMoves[]) {
// Initialize global search variables
- StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false;
+ StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false;
NodesSincePoll = 0;
SearchStartTime = get_system_time();
ExactMaxTime = maxTime;
MaxDepth = maxDepth;
MaxNodes = maxNodes;
InfiniteSearch = infinite;
- PonderSearch = ponder;
+ Pondering = ponder;
UseTimeManagement = !ExactMaxTime && !MaxDepth && !MaxNodes && !InfiniteSearch;
// Look for a book move, only during games, not tests
Move bookMove = OpeningBook.get_move(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE)
{
- if (PonderSearch)
+ if (Pondering)
wait_for_stop_or_ponderhit();
cout << "bestmove " << bookMove << endl;
- return true;
+ return !QuitRequest;
}
}
MultiPV = Options["MultiPV"].value<int>();
UseLogFile = Options["Use Search Log"].value<bool>();
- if (UseLogFile)
- LogFile.open(Options["Search Log Filename"].value<std::string>().c_str(), std::ios::out | std::ios::app);
-
- read_weights(pos.side_to_move());
+ read_evaluation_uci_options(pos.side_to_move());
// Set the number of active threads
ThreadsMgr.read_uci_options();
// Write search information to log file
if (UseLogFile)
- LogFile << "Searching: " << pos.to_fen() << endl
- << "infinite: " << infinite
- << " ponder: " << ponder
- << " time: " << myTime
+ {
+ std::string name = Options["Search Log Filename"].value<std::string>();
+ LogFile.open(name.c_str(), std::ios::out | std::ios::app);
+
+ LogFile << "Searching: " << pos.to_fen()
+ << "\ninfinite: " << infinite
+ << " ponder: " << ponder
+ << " time: " << myTime
<< " increment: " << myIncrement
<< " moves to go: " << movesToGo << endl;
+ }
// We're ready to start thinking. Call the iterative deepening loop function
- id_loop(pos, searchMoves);
+ Move ponderMove = MOVE_NONE;
+ Move bestMove = id_loop(pos, searchMoves, &ponderMove);
+
+ // Print final search statistics
+ cout << "info nodes " << pos.nodes_searched()
+ << " nps " << nps(pos)
+ << " time " << current_search_time() << endl;
if (UseLogFile)
+ {
+ LogFile << "\nNodes: " << pos.nodes_searched()
+ << "\nNodes/second: " << nps(pos)
+ << "\nBest move: " << move_to_san(pos, bestMove);
+
+ StateInfo st;
+ pos.do_move(bestMove, st);
+ LogFile << "\nPonder move: "
+ << move_to_san(pos, ponderMove) // Works also with MOVE_NONE
+ << endl;
+
+ // Return from think() with unchanged position
+ pos.undo_move(bestMove);
+
LogFile.close();
+ }
// This makes all the threads to go to sleep
ThreadsMgr.set_active_threads(1);
- return !Quit;
+ // If we are pondering or in infinite search, we shouldn't print the
+ // best move before we are told to do so.
+ if (!StopRequest && (Pondering || InfiniteSearch))
+ wait_for_stop_or_ponderhit();
+
+ // Could be both MOVE_NONE when searching on a stalemate position
+ cout << "bestmove " << bestMove << " ponder " << ponderMove << endl;
+
+ return !QuitRequest;
}
// been consumed, the user stops the search, or the maximum search depth is
// reached.
- Value id_loop(Position& pos, Move searchMoves[]) {
+ Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) {
SearchStack ss[PLY_MAX_PLUS_2];
- Move pv[PLY_MAX_PLUS_2];
+ Depth depth;
Move EasyMove = MOVE_NONE;
Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
- // Moves to search are verified, copied, scored and sorted
+ // Moves to search are verified, scored and sorted
RootMoveList rml(pos, searchMoves);
// Handle special case of searching on a mate/stale position
- if (rml.move_count() == 0)
+ if (rml.size() == 0)
{
- if (PonderSearch)
- wait_for_stop_or_ponderhit();
+ Value s = (pos.is_check() ? -VALUE_MATE : VALUE_DRAW);
- return pos.is_check() ? -VALUE_MATE : VALUE_DRAW;
- }
+ cout << "info depth " << 1
+ << " score " << value_to_uci(s) << endl;
- // Print RootMoveList startup scoring to the standard output,
- // so to output information also for iteration 1.
- cout << set960(pos.is_chess960()) // Is enough to set once at the beginning
- << "info depth " << 1
- << "\ninfo depth " << 1
- << " score " << value_to_uci(rml.move_score(0))
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv " << rml.move(0) << "\n";
+ return MOVE_NONE;
+ }
// Initialize
TT.new_search();
H.clear();
init_ss_array(ss, PLY_MAX_PLUS_2);
- pv[0] = pv[1] = MOVE_NONE;
- ValueByIteration[1] = rml.move_score(0);
+ ValueByIteration[1] = rml[0].pv_score;
Iteration = 1;
+ // Send initial RootMoveList scoring (iteration 1)
+ cout << set960(pos.is_chess960()) // Is enough to set once at the beginning
+ << "info depth " << Iteration
+ << "\n" << rml[0].pv_info_to_uci(pos, alpha, beta) << endl;
+
// Is one move significantly better than others after initial scoring ?
- if ( rml.move_count() == 1
- || rml.move_score(0) > rml.move_score(1) + EasyMoveMargin)
- EasyMove = rml.move(0);
+ if ( rml.size() == 1
+ || rml[0].pv_score > rml[1].pv_score + EasyMoveMargin)
+ EasyMove = rml[0].pv[0];
// Iterative deepening loop
while (Iteration < PLY_MAX)
beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
}
- // Search to the current depth, rml is updated and sorted, alpha and beta could change
- value = root_search(pos, ss, pv, rml, &alpha, &beta);
+ depth = (Iteration - 2) * ONE_PLY + InitialDepth;
- // Write PV to transposition table, in case the relevant entries have
- // been overwritten during the search.
- insert_pv_in_tt(pos, pv);
+ // Search to the current depth, rml is updated and sorted
+ value = root_search(pos, ss, alpha, beta, depth, rml);
- if (AbortSearch)
+ if (StopRequest)
break; // Value cannot be trusted. Break out immediately!
//Save info about search result
ValueByIteration[Iteration] = value;
// Drop the easy move if differs from the new best move
- if (pv[0] != EasyMove)
+ if (rml[0].pv[0] != EasyMove)
EasyMove = MOVE_NONE;
if (UseTimeManagement)
// 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)
+ if (Iteration >= 6 && rml.size() == 1)
stopSearch = true;
// Stop search early when the last two iterations returned a mate score
// Stop search early if one move seems to be much better than the others
if ( Iteration >= 8
- && EasyMove == pv[0]
- && ( ( rml.move_nodes(0) > (pos.nodes_searched() * 85) / 100
+ && EasyMove == rml[0].pv[0]
+ && ( ( rml[0].nodes > (pos.nodes_searched() * 85) / 100
&& current_search_time() > TimeMgr.available_time() / 16)
- ||( rml.move_nodes(0) > (pos.nodes_searched() * 98) / 100
+ ||( rml[0].nodes > (pos.nodes_searched() * 98) / 100
&& current_search_time() > TimeMgr.available_time() / 32)))
stopSearch = true;
if (stopSearch)
{
- if (PonderSearch)
+ if (Pondering)
StopOnPonderhit = true;
else
break;
break;
}
- // If we are pondering or in infinite search, we shouldn't print the
- // best move before we are told to do so.
- if (!AbortSearch && (PonderSearch || InfiniteSearch))
- wait_for_stop_or_ponderhit();
- else
- // Print final search statistics
- cout << "info nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " time " << current_search_time() << endl;
-
- // Print the best move and the ponder move to the standard output
- if (pv[0] == MOVE_NONE || MultiPV > 1)
- {
- pv[0] = rml.move(0);
- pv[1] = MOVE_NONE;
- }
-
- assert(pv[0] != MOVE_NONE);
-
- cout << "bestmove " << pv[0];
-
- if (pv[1] != MOVE_NONE)
- cout << " ponder " << pv[1];
-
- cout << endl;
-
- if (UseLogFile)
- {
- if (dbg_show_mean)
- dbg_print_mean(LogFile);
-
- if (dbg_show_hit_rate)
- dbg_print_hit_rate(LogFile);
-
- LogFile << "\nNodes: " << pos.nodes_searched()
- << "\nNodes/second: " << nps(pos)
- << "\nBest move: " << move_to_san(pos, pv[0]);
-
- StateInfo st;
- pos.do_move(pv[0], st);
- LogFile << "\nPonder move: "
- << move_to_san(pos, pv[1]) // Works also with MOVE_NONE
- << endl;
- }
- return rml.move_score(0);
+ *ponderMove = rml[0].pv[1];
+ return rml[0].pv[0];
}
// 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, prints some information to the standard output and handles
- // the fail low/high loops.
-
- Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
+ // similar to search_pv except that it prints some information to the
+ // standard output and handles the fail low/high loops.
+ Value root_search(Position& pos, SearchStack* ss, Value alpha,
+ Value beta, Depth depth, RootMoveList& rml) {
StateInfo st;
+ Move movesSearched[MOVES_MAX];
CheckInfo ci(pos);
int64_t nodes;
Move move;
- Depth depth, ext, newDepth;
- Value value, alpha, beta;
- bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
- int researchCountFH, researchCountFL;
+ Depth ext, newDepth;
+ Value value, oldAlpha;
+ RootMoveList::iterator rm;
+ bool isCheck, moveIsCheck, captureOrPromotion, dangerous, isPvMove;
+ int moveCount, researchCountFH, researchCountFL;
researchCountFH = researchCountFL = 0;
- alpha = *alphaPtr;
- beta = *betaPtr;
+ oldAlpha = alpha;
isCheck = pos.is_check();
- depth = (Iteration - 2) * ONE_PLY + InitialDepth;
// Step 1. Initialize node (polling is omitted at root)
ss->currentMove = ss->bestMove = MOVE_NONE;
while (1)
{
// Sort the moves before to (re)search
- rml.score_moves(pos);
+ rml.set_non_pv_scores(pos, rml[0].pv[0], ss);
rml.sort();
+ moveCount = 0;
// Step 10. Loop through all moves in the root move list
- for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
+ for (rm = rml.begin(); rm != rml.end() && !StopRequest; ++rm)
{
// This is used by time management
- FirstRootMove = (i == 0);
+ FirstRootMove = (rm == rml.begin());
// Save the current node count before the move is searched
nodes = pos.nodes_searched();
+ // If it's time to send nodes info, do it here where we have the
+ // correct accumulated node counts searched by each thread.
+ if (SendSearchedNodes)
+ {
+ SendSearchedNodes = false;
+ cout << "info nodes " << nodes
+ << " nps " << nps(pos)
+ << " time " << current_search_time() << endl;
+ }
+
// Pick the next root move, and print the move and the move number to
// the standard output.
- move = ss->currentMove = rml.move(i);
+ move = ss->currentMove = rm->pv[0];
+ movesSearched[moveCount++] = move;
+ isPvMove = (moveCount <= MultiPV);
if (current_search_time() >= 1000)
cout << "info currmove " << move
- << " currmovenumber " << i + 1 << endl;
+ << " currmovenumber " << moveCount << endl;
moveIsCheck = pos.move_is_check(move);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Step extra. Fail high loop
// If move fails high, we research with bigger window until we are not failing
// high anymore.
- value = - VALUE_INFINITE;
+ value = -VALUE_INFINITE;
while (1)
{
pos.do_move(move, st, ci, moveIsCheck);
// Step extra. pv search
- // We do pv search for first moves (i < MultiPV)
- // and for fail high research (value > alpha)
- if (i < MultiPV || value > alpha)
+ // We do pv search for PV moves and when failing high
+ if (isPvMove || value > alpha)
{
// Aspiration window is disabled in multi-pv case
if (MultiPV > 1)
&& !captureOrPromotion
&& !move_is_castle(move))
{
- ss->reduction = reduction<PV>(depth, i - MultiPV + 2);
+ ss->reduction = reduction<PV>(depth, moveCount - MultiPV + 1);
if (ss->reduction)
{
assert(newDepth-ss->reduction >= ONE_PLY);
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
doFullDepthSearch = (value > alpha);
}
-
- // The move failed high, but if reduction is very big we could
- // face a false positive, retry with a less aggressive reduction,
- // if the move fails high again then go with full depth search.
- if (doFullDepthSearch && ss->reduction > 2 * ONE_PLY)
- {
- assert(newDepth - ONE_PLY >= ONE_PLY);
-
- ss->reduction = ONE_PLY;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
- doFullDepthSearch = (value > alpha);
- }
ss->reduction = DEPTH_ZERO; // Restore original reduction
}
pos.undo_move(move);
// Can we exit fail high loop ?
- if (AbortSearch || value < beta)
+ if (StopRequest || value < beta)
break;
// We are failing high and going to do a research. It's important to update
// the score before research in case we run out of time while researching.
- rml.set_move_score(i, value);
ss->bestMove = move;
- extract_pv_from_tt(pos, move, pv);
- rml.set_move_pv(i, pv);
+ rm->pv_score = value;
+ rm->extract_pv_from_tt(pos);
+
+ // Update killers and history only for non capture moves that fails high
+ if (!pos.move_is_capture_or_promotion(move))
+ {
+ update_history(pos, move, depth, movesSearched, moveCount);
+ update_killers(move, ss->killers);
+ }
- // Print information to the standard output
- print_pv_info(pos, pv, alpha, beta, value);
+ // Inform GUI that PV has changed
+ cout << rm->pv_info_to_uci(pos, alpha, beta) << endl;
// Prepare for a research after a fail high, each time with a wider window
- *betaPtr = beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
+ beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
researchCountFH++;
} // End of fail high loop
// ran out of time. In this case, the return value of the search cannot
// be trusted, and we break out of the loop without updating the best
// move and/or PV.
- if (AbortSearch)
+ if (StopRequest)
break;
// Remember searched nodes counts for this move
- rml.add_move_nodes(i, pos.nodes_searched() - nodes);
+ rm->nodes += pos.nodes_searched() - nodes;
assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
assert(value < beta);
// Step 17. Check for new best move
- if (value <= alpha && i >= MultiPV)
- rml.set_move_score(i, -VALUE_INFINITE);
+ if (!isPvMove && value <= alpha)
+ rm->pv_score = -VALUE_INFINITE;
else
{
// PV move or new best move!
// Update PV
- rml.set_move_score(i, value);
ss->bestMove = move;
- extract_pv_from_tt(pos, move, pv);
- rml.set_move_pv(i, pv);
+ rm->pv_score = value;
+ rm->extract_pv_from_tt(pos);
- if (MultiPV == 1)
- {
- // We record how often the best move has been changed in each
- // iteration. This information is used for time managment: When
- // the best move changes frequently, we allocate some more time.
- if (i > 0)
- BestMoveChangesByIteration[Iteration]++;
+ // We record how often the best move has been changed in each
+ // iteration. This information is used for time managment: When
+ // the best move changes frequently, we allocate some more time.
+ if (!isPvMove && MultiPV == 1)
+ BestMoveChangesByIteration[Iteration]++;
+
+ // Inform GUI that PV has changed, in case of multi-pv UCI protocol
+ // requires we send all the PV lines properly sorted.
+ rml.sort_multipv(moveCount);
- // Print information to the standard output
- print_pv_info(pos, pv, alpha, beta, value);
+ for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++)
+ cout << rml[j].pv_info_to_uci(pos, alpha, beta, j) << endl;
+ // Update alpha. In multi-pv we don't use aspiration window
+ if (MultiPV == 1)
+ {
// Raise alpha to setup proper non-pv search upper bound
if (value > alpha)
alpha = value;
}
- else // MultiPV > 1
- {
- rml.sort_multipv(i);
- for (int j = 0; j < Min(MultiPV, rml.move_count()); j++)
- {
- cout << "info multipv " << j + 1
- << " score " << value_to_uci(rml.move_score(j))
- << " depth " << (j <= i ? Iteration : Iteration - 1)
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv ";
-
- for (int k = 0; rml.move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++)
- cout << rml.move_pv(j, k) << " ";
-
- cout << endl;
- }
- alpha = rml.move_score(Min(i, MultiPV - 1));
- }
+ else // Set alpha equal to minimum score among the PV lines
+ alpha = rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount?
+
} // PV move or new best move
- assert(alpha >= *alphaPtr);
+ assert(alpha >= oldAlpha);
- AspirationFailLow = (alpha == *alphaPtr);
+ AspirationFailLow = (alpha == oldAlpha);
if (AspirationFailLow && StopOnPonderhit)
StopOnPonderhit = false;
- }
+
+ } // Root moves loop
// Can we exit fail low loop ?
- if (AbortSearch || !AspirationFailLow)
+ if (StopRequest || !AspirationFailLow)
break;
// Prepare for a research after a fail low, each time with a wider window
- *alphaPtr = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
+ oldAlpha = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
researchCountFL++;
} // Fail low loop
// Sort the moves before to return
rml.sort();
+ // Write PV lines to transposition table, in case the relevant entries
+ // have been overwritten during the search.
+ for (int i = 0; i < Min(MultiPV, (int)rml.size()); i++)
+ rml[i].insert_pv_in_tt(pos);
+
return alpha;
}
threatMove = sp->threatMove;
mateThreat = sp->mateThreat;
goto split_point_start;
- } else {} // Hack to fix icc's "statement is unreachable" warning
+ }
+ else {} // Hack to fix icc's "statement is unreachable" warning
// Step 1. Initialize node and poll. Polling can abort search
ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
}
// Step 2. Check for aborted search and immediate draw
- if ( AbortSearch || ThreadsMgr.thread_should_stop(threadID)
- || pos.is_draw() || ply >= PLY_MAX - 1)
+ if ( StopRequest
+ || ThreadsMgr.cutoff_at_splitpoint(threadID)
+ || pos.is_draw()
+ || ply >= PLY_MAX - 1)
return VALUE_DRAW;
// Step 3. Mate distance pruning
threatMove = (ss+1)->bestMove;
if ( depth < ThreatDepth
&& (ss-1)->reduction
+ && threatMove != MOVE_NONE
&& connected_moves(pos, (ss-1)->currentMove, threatMove))
return beta - 1;
}
// Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE
- && !ThreadsMgr.thread_should_stop(threadID))
+ && !ThreadsMgr.cutoff_at_splitpoint(threadID))
{
assert(move_is_ok(move));
continue;
}
- // Prune neg. see moves at low depths
+ // Prune moves with negative SEE at low depths
if ( predictedDepth < 2 * ONE_PLY
&& bestValue > value_mated_in(PLY_MAX)
&& pos.see_sign(move) < 0)
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
- if (!SpNode && PvNode && moveCount == 1)
+ if (PvNode && moveCount == 1)
value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
else
{
&& !captureOrPromotion
&& !dangerous
&& !move_is_castle(move)
- && !(ss->killers[0] == move || ss->killers[1] == move))
+ && ss->killers[0] != move
+ && ss->killers[1] != move)
{
ss->reduction = reduction<PvNode>(depth, moveCount);
+
if (ss->reduction)
{
alpha = SpNode ? sp->alpha : alpha;
doFullDepthSearch = (value > alpha);
}
-
- // The move failed high, but if reduction is very big we could
- // face a false positive, retry with a less aggressive reduction,
- // if the move fails high again then go with full depth search.
- if (doFullDepthSearch && ss->reduction > 2 * ONE_PLY)
- {
- assert(newDepth - ONE_PLY >= ONE_PLY);
-
- ss->reduction = ONE_PLY;
- alpha = SpNode ? sp->alpha : alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, ply+1);
- doFullDepthSearch = (value > alpha);
- }
ss->reduction = DEPTH_ZERO; // Restore original reduction
}
alpha = sp->alpha;
}
- if (value > bestValue && !(SpNode && ThreadsMgr.thread_should_stop(threadID)))
+ if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID)))
{
bestValue = value;
if (value > alpha)
{
- if (SpNode && (!PvNode || value >= beta))
- sp->stopRequest = true;
-
if (PvNode && value < beta) // We want always alpha < beta
{
alpha = value;
+
if (SpNode)
sp->alpha = value;
}
+ else if (SpNode)
+ sp->betaCutoff = true;
if (value == value_mate_in(ply + 1))
ss->mateKiller = move;
&& ThreadsMgr.active_threads() > 1
&& bestValue < beta
&& ThreadsMgr.available_thread_exists(threadID)
- && !AbortSearch
- && !ThreadsMgr.thread_should_stop(threadID)
+ && !StopRequest
+ && !ThreadsMgr.cutoff_at_splitpoint(threadID)
&& Iteration <= 99)
ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
threatMove, mateThreat, moveCount, &mp, PvNode);
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (!SpNode && !AbortSearch && !ThreadsMgr.thread_should_stop(threadID))
+ if (!SpNode && !StopRequest && !ThreadsMgr.cutoff_at_splitpoint(threadID))
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
&& !pos.move_is_capture_or_promotion(move))
{
update_history(pos, move, depth, movesSearched, moveCount);
- update_killers(move, ss);
+ update_killers(move, ss->killers);
}
}
return bestValue;
}
- Bitboard attacks(const Piece P, const Square sq, const Bitboard occ)
- {
- switch(P)
- {
- case WP:
- case BP:
- case WN:
- case BN:
- case WK:
- case BK:
- return StepAttackBB[P][sq];
- case WB:
- case BB:
- return bishop_attacks_bb(sq, occ);
- case WR:
- case BR:
- return rook_attacks_bb(sq, occ);
- case WQ:
- case BQ:
- return bishop_attacks_bb(sq, occ) | rook_attacks_bb(sq, occ);
- default:
- assert(false);
- return 0ULL;
- }
- }
-
- bool check_is_useless(Position &pos, Move move, Value eval, Value futilityBase, Value beta, Value *bValue)
- {
- Value bestValue = *bValue;
-
- /// Rule 1. Using checks to reposition pieces when close to beta
- if (eval + PawnValueMidgame / 4 < beta)
- {
- if (eval + PawnValueMidgame / 4 > bestValue)
- bestValue = eval + PawnValueMidgame / 4;
- }
- else
- return false;
-
- Square from = move_from(move);
- Square to = move_to(move);
- Color oppColor = opposite_color(pos.side_to_move());
- Square oppKing = pos.king_square(oppColor);
-
- Bitboard occ = pos.occupied_squares() & ~(1ULL << from) & ~(1ULL <<oppKing);
- Bitboard oppOcc = pos.pieces_of_color(oppColor) & ~(1ULL <<oppKing);
- Bitboard oldAtt = attacks(pos.piece_on(from), from, occ);
- Bitboard newAtt = attacks(pos.piece_on(from), to, occ);
-
- // Rule 2. Checks which give opponent's king at most one escape square are dangerous
- Bitboard escapeBB = attacks(WK, oppKing, 0) & ~oppOcc & ~newAtt & ~(1ULL << to);
-
- if (!escapeBB)
- return false;
-
- if (!(escapeBB & (escapeBB - 1)))
- return false;
-
- /// Rule 3. Queen contact check is very dangerous
- if ( pos.type_of_piece_on(from) == QUEEN
- && bit_is_set(attacks(WK, oppKing, 0), to))
- return false;
-
- /// Rule 4. Creating new double threats with checks
- Bitboard newVictims = oppOcc & ~oldAtt & newAtt;
-
- while(newVictims)
- {
- Square victimSq = pop_1st_bit(&newVictims);
-
- Value futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq);
-
- // Note that here we generate illegal "double move"!
- if (futilityValue >= beta && pos.see_sign(make_move(from, victimSq)) >= 0)
- return false;
-
- if (futilityValue > bestValue)
- bestValue = futilityValue;
- }
-
- *bValue = bestValue;
- return true;
- }
-
// qsearch() is the quiescence search function, which is called by the main
// search function when the remaining depth is zero (or, to be more precise,
// less than ONE_PLY).
Value bestValue, value, evalMargin, futilityValue, futilityBase;
bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
const TTEntry* tte;
+ Depth ttDepth;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
- // Decide whether or not to include checks
+ // Decide whether or not to include checks, this fixes also the type of
+ // TT entry depth that we are going to use. Note that in qsearch we use
+ // only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
isCheck = pos.is_check();
-
- Depth d;
- if (isCheck || depth >= -ONE_PLY)
- d = DEPTH_ZERO;
- else
- d = DEPTH_ZERO - ONE_PLY;
+ ttDepth = (isCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS);
// Transposition table lookup. At PV nodes, we don't use the TT for
// pruning, but only for move ordering.
tte = TT.retrieve(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (!PvNode && tte && ok_to_use_TT(tte, d, beta, ply))
+ if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ply))
{
ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
// Initialize a MovePicker object for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
- // queen promotions and checks (only if depth == 0 or depth == -ONE_PLY
- // and we are near beta) will be generated.
- MovePicker mp = MovePicker(pos, ttMove, d, H);
+ // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
+ // be generated.
+ MovePicker mp(pos, ttMove, depth, H);
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
// Don't search useless checks
if ( !PvNode
&& !isCheck
- && move != ttMove
- && !move_is_promotion(move)
- && !pos.move_is_capture(move)
- && moveIsCheck
- && check_is_useless(pos, move, ss->eval, futilityBase, beta, &bestValue))
+ && moveIsCheck
+ && move != ttMove
+ && !pos.move_is_capture_or_promotion(move)
+ && ss->eval + PawnValueMidgame / 4 < beta
+ && !check_is_dangerous(pos, move, futilityBase, beta, &bestValue))
+ {
+ if (ss->eval + PawnValueMidgame / 4 > bestValue)
+ bestValue = ss->eval + PawnValueMidgame / 4;
+
continue;
+ }
// Update current move
ss->currentMove = move;
// Update transposition table
ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, d, ss->bestMove, ss->eval, evalMargin);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
}
+ // check_is_dangerous() tests if a checking move can be pruned in qsearch().
+ // bestValue is updated only when returning false because in that case move
+ // will be pruned.
+
+ bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bestValue)
+ {
+ Bitboard b, occ, oldAtt, newAtt, kingAtt;
+ Square from, to, ksq, victimSq;
+ Piece pc;
+ Color them;
+ Value futilityValue, bv = *bestValue;
+
+ from = move_from(move);
+ to = move_to(move);
+ them = opposite_color(pos.side_to_move());
+ ksq = pos.king_square(them);
+ kingAtt = pos.attacks_from<KING>(ksq);
+ pc = pos.piece_on(from);
+
+ occ = pos.occupied_squares() & ~(1ULL << from) & ~(1ULL << ksq);
+ oldAtt = pos.attacks_from(pc, from, occ);
+ newAtt = pos.attacks_from(pc, to, occ);
+
+ // Rule 1. Checks which give opponent's king at most one escape square are dangerous
+ b = kingAtt & ~pos.pieces_of_color(them) & ~newAtt & ~(1ULL << to);
+
+ if (!(b && (b & (b - 1))))
+ return true;
+
+ // Rule 2. Queen contact check is very dangerous
+ if ( type_of_piece(pc) == QUEEN
+ && bit_is_set(kingAtt, to))
+ return true;
+
+ // Rule 3. Creating new double threats with checks
+ b = pos.pieces_of_color(them) & newAtt & ~oldAtt & ~(1ULL << ksq);
+
+ while (b)
+ {
+ victimSq = pop_1st_bit(&b);
+ futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq);
+
+ // Note that here we generate illegal "double move"!
+ if ( futilityValue >= beta
+ && pos.see_sign(make_move(from, victimSq)) >= 0)
+ return true;
+
+ if (futilityValue > bv)
+ bv = futilityValue;
+ }
+
+ // Update bestValue only if check is not dangerous (because we will prune the move)
+ *bestValue = bv;
+ return false;
+ }
+
+
// connected_moves() tests whether two moves are 'connected' in the sense
// that the first move somehow made the second move possible (for instance
// if the moving piece is the same in both moves). The first move is assumed
Square f1, t1, f2, t2;
Piece p;
- assert(move_is_ok(m1));
- assert(move_is_ok(m2));
-
- if (m2 == MOVE_NONE)
- return false;
+ assert(m1 && move_is_ok(m1));
+ assert(m2 && move_is_ok(m2));
// Case 1: The moving piece is the same in both moves
f2 = move_from(m2);
// update_killers() add a good move that produced a beta-cutoff
// among the killer moves of that ply.
- void update_killers(Move m, SearchStack* ss) {
+ void update_killers(Move m, Move killers[]) {
- if (m == ss->killers[0])
+ if (m == killers[0])
return;
- ss->killers[1] = ss->killers[0];
- ss->killers[0] = m;
+ killers[1] = killers[0];
+ killers[0] = m;
}
}
- // current_search_time() returns the number of milliseconds which have passed
- // since the beginning of the current search.
+ // init_ss_array() does a fast reset of the first entries of a SearchStack
+ // array and of all the excludedMove and skipNullMove entries.
- int current_search_time() {
+ void init_ss_array(SearchStack* ss, int size) {
- return get_system_time() - SearchStartTime;
+ for (int i = 0; i < size; i++, ss++)
+ {
+ ss->excludedMove = MOVE_NONE;
+ ss->skipNullMove = false;
+ ss->reduction = DEPTH_ZERO;
+ ss->sp = NULL;
+
+ if (i < 3)
+ ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE;
+ }
}
- // value_to_uci() converts a value to a string suitable for use with the UCI protocol
+ // value_to_uci() converts a value to a string suitable for use with the UCI
+ // protocol specifications:
+ //
+ // cp <x> The score from the engine's point of view in centipawns.
+ // mate <y> Mate in y moves, not plies. If the engine is getting mated
+ // use negative values for y.
std::string value_to_uci(Value v) {
std::stringstream s;
if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to pawn = 100
+ s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
else
s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2 );
return s.str();
}
- // nps() computes the current nodes/second count.
+
+ // current_search_time() returns the number of milliseconds which have passed
+ // since the beginning of the current search.
+
+ int current_search_time() {
+
+ return get_system_time() - SearchStartTime;
+ }
+
+
+ // nps() computes the current nodes/second count
int nps(const Position& pos) {
int t = current_search_time();
// Poll for input
- if (data_available())
+ if (input_available())
{
// We are line oriented, don't read single chars
std::string command;
if (command == "quit")
{
- AbortSearch = true;
- PonderSearch = false;
- Quit = true;
+ // Quit the program as soon as possible
+ Pondering = false;
+ QuitRequest = StopRequest = true;
return;
}
else if (command == "stop")
{
- AbortSearch = true;
- PonderSearch = false;
+ // Stop calculating as soon as possible, but still send the "bestmove"
+ // and possibly the "ponder" token when finishing the search.
+ Pondering = false;
+ StopRequest = true;
}
else if (command == "ponderhit")
- ponderhit();
+ {
+ // The opponent has played the expected move. GUI sends "ponderhit" if
+ // we were told to ponder on the same move the opponent has played. We
+ // should continue searching but switching from pondering to normal search.
+ Pondering = false;
+
+ if (StopOnPonderhit)
+ StopRequest = true;
+ }
}
// Print search information
if (dbg_show_hit_rate)
dbg_print_hit_rate();
- cout << "info nodes " << pos.nodes_searched() << " nps " << nps(pos)
- << " time " << t << endl;
+ // Send info on searched nodes as soon as we return to root
+ SendSearchedNodes = true;
}
// Should we stop the search?
- if (PonderSearch)
+ if (Pondering)
return;
bool stillAtFirstMove = FirstRootMove
bool noMoreTime = t > TimeMgr.maximum_time()
|| stillAtFirstMove;
- if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
+ if ( (UseTimeManagement && noMoreTime)
|| (ExactMaxTime && t >= ExactMaxTime)
- || (Iteration >= 3 && MaxNodes && pos.nodes_searched() >= MaxNodes))
- AbortSearch = true;
- }
-
-
- // ponderhit() is called when the program is pondering (i.e. thinking while
- // it's the opponent's turn to move) in order to let the engine know that
- // it correctly predicted the opponent's move.
-
- void ponderhit() {
-
- int t = current_search_time();
- PonderSearch = false;
-
- bool stillAtFirstMove = FirstRootMove
- && !AspirationFailLow
- && t > TimeMgr.available_time();
-
- bool noMoreTime = t > TimeMgr.maximum_time()
- || stillAtFirstMove;
-
- if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
- AbortSearch = true;
- }
-
-
- // init_ss_array() does a fast reset of the first entries of a SearchStack
- // array and of all the excludedMove and skipNullMove entries.
-
- void init_ss_array(SearchStack* ss, int size) {
-
- for (int i = 0; i < size; i++, ss++)
- {
- ss->excludedMove = MOVE_NONE;
- ss->skipNullMove = false;
- ss->reduction = DEPTH_ZERO;
- ss->sp = NULL;
-
- if (i < 3)
- ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE;
- }
+ || (MaxNodes && pos.nodes_searched() >= MaxNodes)) // FIXME
+ StopRequest = true;
}
// the UCI protocol: When pondering, the engine is not allowed to give a
// "bestmove" before the GUI sends it a "stop" or "ponderhit" command.
// We simply wait here until one of these commands is sent, and return,
- // after which the bestmove and pondermove will be printed (in id_loop()).
+ // after which the bestmove and pondermove will be printed.
void wait_for_stop_or_ponderhit() {
while (true)
{
+ // Wait for a command from stdin
if (!std::getline(std::cin, command))
command = "quit";
if (command == "quit")
{
- Quit = true;
+ QuitRequest = true;
break;
}
else if (command == "ponderhit" || command == "stop")
}
- // print_pv_info() prints to standard output and eventually to log file information on
- // the current PV line. It is called at each iteration or after a new pv is found.
-
- void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value) {
-
- cout << "info depth " << Iteration
- << " score " << value_to_uci(value)
- << (value >= beta ? " lowerbound" : value <= alpha ? " upperbound" : "")
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv ";
-
- for (Move* m = pv; *m != MOVE_NONE; m++)
- cout << *m << " ";
-
- cout << endl;
-
- if (UseLogFile)
- {
- ValueType t = value >= beta ? VALUE_TYPE_LOWER :
- value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
-
- LogFile << pretty_pv(pos, current_search_time(), Iteration, value, t, pv) << endl;
- }
- }
-
-
- // insert_pv_in_tt() is called at the end of a search iteration, and inserts
- // the PV back into the TT. This makes sure the old PV moves are searched
- // first, even if the old TT entries have been overwritten.
-
- void insert_pv_in_tt(const Position& pos, Move pv[]) {
-
- StateInfo st;
- TTEntry* tte;
- Position p(pos, pos.thread());
- Value v, m = VALUE_NONE;
-
- for (int i = 0; pv[i] != MOVE_NONE; i++)
- {
- tte = TT.retrieve(p.get_key());
- if (!tte || tte->move() != pv[i])
- {
- v = (p.is_check() ? VALUE_NONE : evaluate(p, m));
- TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, m);
- }
- p.do_move(pv[i], st);
- }
- }
-
-
- // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
- // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
- // allow to always have a ponder move even when we fail high at root and also a
- // long PV to print that is important for position analysis.
-
- void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) {
-
- StateInfo st;
- TTEntry* tte;
- Position p(pos, pos.thread());
- int ply = 0;
-
- assert(bestMove != MOVE_NONE);
-
- pv[ply] = bestMove;
- p.do_move(pv[ply++], st);
-
- while ( (tte = TT.retrieve(p.get_key())) != NULL
- && tte->move() != MOVE_NONE
- && move_is_legal(p, tte->move())
- && ply < PLY_MAX
- && (!p.is_draw() || ply < 2))
- {
- pv[ply] = tte->move();
- p.do_move(pv[ply++], st);
- }
- pv[ply] = MOVE_NONE;
- }
-
-
// init_thread() is the function which is called when a new thread is
// launched. It simply calls the idle_loop() function with the supplied
// threadID. There are two versions of this function; one for POSIX
}
- // thread_should_stop() checks whether the thread should stop its search.
- // This can happen if a beta cutoff has occurred in the thread's currently
- // active split point, or in some ancestor of the current split point.
+ // cutoff_at_splitpoint() checks whether a beta cutoff has occurred in
+ // the thread's currently active split point, or in some ancestor of
+ // the current split point.
- bool ThreadsManager::thread_should_stop(int threadID) const {
+ bool ThreadsManager::cutoff_at_splitpoint(int threadID) const {
assert(threadID >= 0 && threadID < activeThreads);
SplitPoint* sp = threads[threadID].splitPoint;
- for ( ; sp && !sp->stopRequest; sp = sp->parent) {}
+ for ( ; sp && !sp->betaCutoff; sp = sp->parent) {}
return sp != NULL;
}
// Initialize the split point object
splitPoint.parent = masterThread.splitPoint;
splitPoint.master = master;
- splitPoint.stopRequest = false;
+ splitPoint.betaCutoff = false;
splitPoint.ply = ply;
splitPoint.depth = depth;
splitPoint.threatMove = threatMove;
}
- /// The RootMoveList class
+ /// RootMove and RootMoveList method's definitions
+
+ RootMove::RootMove() {
+
+ nodes = 0;
+ pv_score = non_pv_score = -VALUE_INFINITE;
+ pv[0] = MOVE_NONE;
+ }
+
+ RootMove& RootMove::operator=(const RootMove& rm) {
+
+ const Move* src = rm.pv;
+ Move* dst = pv;
+
+ // Avoid a costly full rm.pv[] copy
+ do *dst++ = *src; while (*src++ != MOVE_NONE);
+
+ nodes = rm.nodes;
+ pv_score = rm.pv_score;
+ non_pv_score = rm.non_pv_score;
+ return *this;
+ }
+
+ // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
+ // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
+ // allow to always have a ponder move even when we fail high at root and also a
+ // long PV to print that is important for position analysis.
+
+ void RootMove::extract_pv_from_tt(Position& pos) {
+
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ TTEntry* tte;
+ int ply = 1;
+
+ assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+
+ pos.do_move(pv[0], *st++);
+
+ while ( (tte = TT.retrieve(pos.get_key())) != NULL
+ && tte->move() != MOVE_NONE
+ && move_is_legal(pos, tte->move())
+ && ply < PLY_MAX
+ && (!pos.is_draw() || ply < 2))
+ {
+ pv[ply] = tte->move();
+ pos.do_move(pv[ply++], *st++);
+ }
+ pv[ply] = MOVE_NONE;
+
+ do pos.undo_move(pv[--ply]); while (ply);
+ }
+
+ // insert_pv_in_tt() is called at the end of a search iteration, and inserts
+ // the PV back into the TT. This makes sure the old PV moves are searched
+ // first, even if the old TT entries have been overwritten.
+
+ void RootMove::insert_pv_in_tt(Position& pos) {
+
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ TTEntry* tte;
+ Key k;
+ Value v, m = VALUE_NONE;
+ int ply = 0;
+
+ assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+
+ do {
+ k = pos.get_key();
+ tte = TT.retrieve(k);
+
+ // Don't overwrite exsisting correct entries
+ if (!tte || tte->move() != pv[ply])
+ {
+ v = (pos.is_check() ? VALUE_NONE : evaluate(pos, m));
+ TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m);
+ }
+ pos.do_move(pv[ply], *st++);
+
+ } while (pv[++ply] != MOVE_NONE);
+
+ do pos.undo_move(pv[--ply]); while (ply);
+ }
+
+ // pv_info_to_uci() returns a string with information on the current PV line
+ // formatted according to UCI specification and eventually writes the info
+ // to a log file. It is called at each iteration or after a new pv is found.
+
+ std::string RootMove::pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine) {
+
+ std::stringstream s, l;
+ Move* m = pv;
+
+ while (*m != MOVE_NONE)
+ l << *m++ << " ";
+
+ s << "info depth " << Iteration // FIXME
+ << " seldepth " << int(m - pv)
+ << " multipv " << pvLine + 1
+ << " score " << value_to_uci(pv_score)
+ << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "")
+ << " time " << current_search_time()
+ << " nodes " << pos.nodes_searched()
+ << " nps " << nps(pos)
+ << " pv " << l.str();
+
+ if (UseLogFile && pvLine == 0)
+ {
+ ValueType t = pv_score >= beta ? VALUE_TYPE_LOWER :
+ pv_score <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
+
+ LogFile << pretty_pv(pos, current_search_time(), Iteration, pv_score, t, pv) << endl;
+ }
+ return s.str();
+ }
- // RootMoveList c'tor
RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) {
SearchStack ss[PLY_MAX_PLUS_2];
MoveStack mlist[MOVES_MAX];
StateInfo st;
- bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
+ Move* sm;
// Initialize search stack
init_ss_array(ss, PLY_MAX_PLUS_2);
ss[0].eval = ss[0].evalMargin = VALUE_NONE;
- count = 0;
// Generate all legal moves
- MoveStack* last = generate_moves(pos, mlist);
+ MoveStack* last = generate<MV_LEGAL>(pos, mlist);
- // Add each move to the moves[] array
+ // Add each move to the RootMoveList's vector
for (MoveStack* cur = mlist; cur != last; cur++)
{
- bool includeMove = includeAllMoves;
-
- for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
- includeMove = (searchMoves[k] == cur->move);
+ // If we have a searchMoves[] list then verify cur->move
+ // is in the list before to add it.
+ for (sm = searchMoves; *sm && *sm != cur->move; sm++) {}
- if (!includeMove)
+ if (searchMoves[0] && *sm != cur->move)
continue;
- // Find a quick score for the move
- moves[count].move = ss[0].currentMove = moves[count].pv[0] = cur->move;
- moves[count].pv[1] = MOVE_NONE;
+ // Find a quick score for the move and add to the list
pos.do_move(cur->move, st);
- moves[count].score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
+
+ RootMove rm;
+ rm.pv[0] = ss[0].currentMove = cur->move;
+ rm.pv[1] = MOVE_NONE;
+ rm.pv_score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
+ push_back(rm);
+
pos.undo_move(cur->move);
- count++;
}
sort();
}
// Score root moves using the standard way used in main search, the moves
// are scored according to the order in which are returned by MovePicker.
+ // This is the second order score that is used to compare the moves when
+ // the first order pv scores of both moves are equal.
- void RootMoveList::score_moves(const Position& pos)
+ void RootMoveList::set_non_pv_scores(const Position& pos, Move ttm, SearchStack* ss)
{
Move move;
- int score = 1000;
- MovePicker mp = MovePicker(pos, MOVE_NONE, ONE_PLY, H);
+ Value score = VALUE_ZERO;
+ MovePicker mp(pos, ttm, ONE_PLY, H, ss);
while ((move = mp.get_next_move()) != MOVE_NONE)
- for (int i = 0; i < count; i++)
- if (moves[i].move == move)
+ for (Base::iterator it = begin(); it != end(); ++it)
+ if (it->pv[0] == move)
{
- moves[i].mp_score = score--;
+ it->non_pv_score = score--;
break;
}
}
- // RootMoveList simple methods definitions
-
- void RootMoveList::set_move_pv(int moveNum, const Move pv[]) {
-
- int j;
-
- for (j = 0; pv[j] != MOVE_NONE; j++)
- moves[moveNum].pv[j] = pv[j];
-
- moves[moveNum].pv[j] = MOVE_NONE;
- }
-
-
- // RootMoveList::sort() sorts the root move list at the beginning of a new
- // iteration.
-
- void RootMoveList::sort() {
-
- sort_multipv(count - 1); // Sort all items
- }
-
-
- // RootMoveList::sort_multipv() sorts the first few moves in the root move
- // list by their scores and depths. It is used to order the different PVs
- // correctly in MultiPV mode.
-
- void RootMoveList::sort_multipv(int n) {
-
- int i,j;
-
- for (i = 1; i <= n; i++)
- {
- RootMove rm = moves[i];
- for (j = i; j > 0 && moves[j - 1] < rm; j--)
- moves[j] = moves[j - 1];
-
- moves[j] = rm;
- }
- }
-
} // namespace