void extract_pv_from_tt(Position& pos);
void insert_pv_in_tt(Position& pos);
- std::string pv_info_to_uci(Position& pos, Value alpha, Value beta, int pvLine = 0);
+ std::string pv_info_to_uci(Position& pos, Depth depth, Value alpha, Value beta, int pvLine = 0);
int64_t nodes;
Value pv_score;
typedef std::vector<RootMove> Base;
- RootMoveList(Position& pos, Move searchMoves[]);
- void set_non_pv_scores(const Position& pos, Move ttm, SearchStack* ss);
-
+ void init(Position& pos, Move searchMoves[]);
void sort() { insertion_sort<RootMove, Base::iterator>(begin(), end()); }
void sort_multipv(int n) { insertion_sort<RootMove, Base::iterator>(begin(), begin() + n); }
+
+ int bestMoveChanges;
};
// Extensions. Configurable UCI options
// Array index 0 is used at non-PV nodes, index 1 at PV nodes.
- Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2];
- Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
+ Depth CheckExtension[2], PawnPushTo7thExtension[2], PassedPawnExtension[2];
+ Depth PawnEndgameExtension[2], MateThreatExtension[2];
// Minimum depth for use of singular extension
const Depth SingularExtensionDepth[2] = { 8 * ONE_PLY /* non-PV */, 6 * ONE_PLY /* PV */};
template <NodeType PV>
inline Depth reduction(Depth d, int mn) { return (Depth) ReductionMatrix[PV][Min(d / 2, 63)][Min(mn, 63)]; }
- // Common adjustments
-
- // Search depth at iteration 1
- const Depth InitialDepth = ONE_PLY;
-
// Easy move margin. An easy move candidate must be at least this much
// better than the second best move.
const Value EasyMoveMargin = Value(0x200);
// Book object
Book OpeningBook;
- // Iteration counter
- int Iteration;
-
- // Scores and number of times the best move changed for each iteration
- Value ValueByIteration[PLY_MAX_PLUS_2];
- int BestMoveChangesByIteration[PLY_MAX_PLUS_2];
-
- // Search window management
- int AspirationDelta;
+ // Root move list
+ RootMoveList Rml;
// MultiPV mode
int MultiPV;
/// Local functions
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>
+ template <NodeType PvNode, bool SpNode, bool Root>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO, ply)
- : search<PvNode, false>(pos, ss, alpha, beta, depth, ply);
+ : search<PvNode, false, false>(pos, ss, alpha, beta, depth, ply);
}
template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous);
+ Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, 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);
void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount);
void update_killers(Move m, Move killers[]);
void update_gains(const Position& pos, Move move, Value before, Value after);
+ void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last);
int current_search_time();
std::string value_to_uci(Value v);
int nps(const Position& pos);
void poll(const Position& pos);
void wait_for_stop_or_ponderhit();
- void init_ss_array(SearchStack* ss, int size);
#if !defined(_MSC_VER)
void* init_thread(void* threadID);
DWORD WINAPI init_thread(LPVOID threadID);
#endif
-}
+
+ // MovePickerExt is an extended MovePicker used to choose at compile time
+ // the proper move source according to the type of node.
+ template<bool SpNode, bool Root> struct MovePickerExt;
+
+ // In Root nodes use RootMoveList Rml as source. Score and sort the root moves
+ // before to search them.
+ template<> struct MovePickerExt<false, true> : public MovePicker {
+
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
+ : MovePicker(p, ttm, d, h, ss, b), firstCall(true) {
+ Move move;
+ Value score = VALUE_ZERO;
+
+ // 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.
+ while ((move = MovePicker::get_next_move()) != MOVE_NONE)
+ for (rm = Rml.begin(); rm != Rml.end(); ++rm)
+ if (rm->pv[0] == move)
+ {
+ rm->non_pv_score = score--;
+ break;
+ }
+
+ Rml.sort();
+ rm = Rml.begin();
+ }
+
+ Move get_next_move() {
+
+ if (!firstCall)
+ ++rm;
+ else
+ firstCall = false;
+
+ return rm != Rml.end() ? rm->pv[0] : MOVE_NONE;
+ }
+
+ RootMoveList::iterator rm;
+ bool firstCall;
+ };
+
+ // In SpNodes use split point's shared MovePicker object as move source
+ template<> struct MovePickerExt<true, false> : public MovePicker {
+
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
+ SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b),
+ mp(ss->sp->mp) {}
+
+ Move get_next_move() { return mp->get_next_move(); }
+
+ RootMoveList::iterator rm; // Dummy, needed to compile
+ MovePicker* mp;
+ };
+
+ // Default case, create and use a MovePicker object as source
+ template<> struct MovePickerExt<false, false> : public MovePicker {
+
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h,
+ SearchStack* ss, Value b) : MovePicker(p, ttm, d, h, ss, b) {}
+
+ RootMoveList::iterator rm; // Dummy, needed to compile
+ };
+
+} // namespace
////
/// 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
+/// search-related global variables, and calls id_loop(). It returns false
/// when a quit command is received during the search.
bool think(Position& pos, bool infinite, bool ponder, int time[], int increment[],
CheckExtension[1] = Options["Check Extension (PV nodes)"].value<Depth>();
CheckExtension[0] = Options["Check Extension (non-PV nodes)"].value<Depth>();
- SingleEvasionExtension[1] = Options["Single Evasion Extension (PV nodes)"].value<Depth>();
- SingleEvasionExtension[0] = Options["Single Evasion Extension (non-PV nodes)"].value<Depth>();
PawnPushTo7thExtension[1] = Options["Pawn Push to 7th Extension (PV nodes)"].value<Depth>();
PawnPushTo7thExtension[0] = Options["Pawn Push to 7th Extension (non-PV nodes)"].value<Depth>();
PassedPawnExtension[1] = Options["Passed Pawn Extension (PV nodes)"].value<Depth>();
namespace {
- // 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.
+ // id_loop() is the main iterative deepening loop. It calls search() repeatedly
+ // with increasing depth until the allocated thinking time has been consumed,
+ // user stops the search, or the maximum search depth is reached.
Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) {
SearchStack ss[PLY_MAX_PLUS_2];
+ Value bestValues[PLY_MAX_PLUS_2];
+ int bestMoveChanges[PLY_MAX_PLUS_2];
+ int iteration, researchCountFL, researchCountFH, aspirationDelta;
+ Value value, alpha, beta;
Depth depth;
- Move EasyMove = MOVE_NONE;
- Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ Move bestMove, easyMove;
// Moves to search are verified, scored and sorted
- RootMoveList rml(pos, searchMoves);
+ Rml.init(pos, searchMoves);
+
+ // Initialize FIXME move before Rml.init()
+ TT.new_search();
+ H.clear();
+ memset(ss, 0, PLY_MAX_PLUS_2 * sizeof(SearchStack));
+ alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ *ponderMove = bestMove = easyMove = MOVE_NONE;
+ aspirationDelta = 0;
+ iteration = 1;
+ ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
// Handle special case of searching on a mate/stale position
- if (rml.size() == 0)
+ if (Rml.size() == 0)
{
- Value s = (pos.is_check() ? -VALUE_MATE : VALUE_DRAW);
-
- cout << "info depth " << 1
- << " score " << value_to_uci(s) << endl;
+ cout << "info depth " << iteration << " score "
+ << value_to_uci(pos.is_check() ? -VALUE_MATE : VALUE_DRAW)
+ << endl;
return MOVE_NONE;
}
- // Initialize
- TT.new_search();
- H.clear();
- init_ss_array(ss, PLY_MAX_PLUS_2);
- ValueByIteration[1] = rml[0].pv_score;
- Iteration = 1;
-
- // Send initial RootMoveList scoring (iteration 1)
+ // Send initial 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;
+ << "info depth " << iteration
+ << "\n" << Rml[0].pv_info_to_uci(pos, ONE_PLY, alpha, beta) << endl;
// Is one move significantly better than others after initial scoring ?
- if ( rml.size() == 1
- || rml[0].pv_score > rml[1].pv_score + EasyMoveMargin)
- EasyMove = rml[0].pv[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)
+ while (++iteration <= PLY_MAX && (!MaxDepth || iteration <= MaxDepth) && !StopRequest)
{
- // Initialize iteration
- Iteration++;
- BestMoveChangesByIteration[Iteration] = 0;
+ cout << "info depth " << iteration << endl;
- cout << "info depth " << Iteration << endl;
+ Rml.bestMoveChanges = researchCountFL = researchCountFH = 0;
+ depth = (iteration - 1) * ONE_PLY;
// Calculate dynamic aspiration window based on previous iterations
- if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN)
+ if (MultiPV == 1 && iteration >= 6 && abs(bestValues[iteration - 1]) < VALUE_KNOWN_WIN)
{
- int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2];
- int prevDelta2 = ValueByIteration[Iteration - 2] - ValueByIteration[Iteration - 3];
+ int prevDelta1 = bestValues[iteration - 1] - bestValues[iteration - 2];
+ int prevDelta2 = bestValues[iteration - 2] - bestValues[iteration - 3];
- AspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
- AspirationDelta = (AspirationDelta + 7) / 8 * 8; // Round to match grainSize
+ aspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16);
+ aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
- alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE);
- beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
+ alpha = Max(bestValues[iteration - 1] - aspirationDelta, -VALUE_INFINITE);
+ beta = Min(bestValues[iteration - 1] + aspirationDelta, VALUE_INFINITE);
}
- depth = (Iteration - 2) * ONE_PLY + InitialDepth;
+ // Start with a small aspiration window and, in case of fail high/low,
+ // research with bigger window until not failing high/low anymore.
+ while (true)
+ {
+ // Search starting from ss+1 to allow calling update_gains()
+ value = search<PV, false, true>(pos, ss+1, alpha, beta, depth, 0);
- // Search to the current depth, rml is updated and sorted
- value = root_search(pos, ss, alpha, beta, depth, rml);
+ // 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);
- if (StopRequest)
- break; // Value cannot be trusted. Break out immediately!
+ // Value cannot be trusted. Break out immediately!
+ if (StopRequest)
+ break;
- //Save info about search result
- ValueByIteration[Iteration] = value;
+ assert(value >= alpha);
+
+ // In case of failing high/low increase aspiration window and research,
+ // otherwise exit the fail high/low loop.
+ if (value >= beta)
+ {
+ beta = Min(beta + aspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
+ researchCountFH++;
+ }
+ else if (value <= alpha)
+ {
+ AspirationFailLow = true;
+ StopOnPonderhit = false;
+
+ alpha = Max(alpha - aspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
+ researchCountFL++;
+ }
+ else
+ break;
+ }
+
+ // Collect info about search result
+ bestMove = Rml[0].pv[0];
+ bestValues[iteration] = value;
+ bestMoveChanges[iteration] = Rml.bestMoveChanges;
// Drop the easy move if differs from the new best move
- if (rml[0].pv[0] != EasyMove)
- EasyMove = MOVE_NONE;
+ if (bestMove != easyMove)
+ easyMove = MOVE_NONE;
- if (UseTimeManagement)
+ if (UseTimeManagement && !StopRequest)
{
// Time to stop?
- bool stopSearch = false;
-
- // 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.size() == 1)
- stopSearch = true;
+ bool noMoreTime = false;
// Stop search early when the last two iterations returned a mate score
- if ( Iteration >= 6
- && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100
- && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100)
- stopSearch = true;
-
- // Stop search early if one move seems to be much better than the others
- if ( Iteration >= 8
- && EasyMove == rml[0].pv[0]
- && ( ( rml[0].nodes > (pos.nodes_searched() * 85) / 100
+ if ( iteration >= 6
+ && abs(bestValues[iteration]) >= abs(VALUE_MATE) - 100
+ && abs(bestValues[iteration-1]) >= abs(VALUE_MATE) - 100)
+ noMoreTime = true;
+
+ // Stop search early if one move seems to be much better than the
+ // others or if there is only a single legal move. In this latter
+ // case we search up to Iteration 8 anyway to get a proper score.
+ if ( iteration >= 8
+ && easyMove == bestMove
+ && ( Rml.size() == 1
+ ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100
&& current_search_time() > TimeMgr.available_time() / 16)
- ||( rml[0].nodes > (pos.nodes_searched() * 98) / 100
+ ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100
&& current_search_time() > TimeMgr.available_time() / 32)))
- stopSearch = true;
+ noMoreTime = true;
// Add some extra time if the best move has changed during the last two iterations
- if (Iteration > 5 && Iteration <= 50)
- TimeMgr.pv_instability(BestMoveChangesByIteration[Iteration],
- BestMoveChangesByIteration[Iteration-1]);
+ if (iteration > 5 && iteration <= 50)
+ TimeMgr.pv_instability(bestMoveChanges[iteration], bestMoveChanges[iteration-1]);
// Stop search if most of MaxSearchTime is consumed at the end of the
// iteration. We probably don't have enough time to search the first
// move at the next iteration anyway.
if (current_search_time() > (TimeMgr.available_time() * 80) / 128)
- stopSearch = true;
+ noMoreTime = true;
- if (stopSearch)
+ if (noMoreTime)
{
if (Pondering)
StopOnPonderhit = true;
break;
}
}
-
- if (MaxDepth && Iteration >= MaxDepth)
- break;
}
- *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 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 ext, newDepth;
- Value value, oldAlpha;
- RootMoveList::iterator rm;
- bool isCheck, moveIsCheck, captureOrPromotion, dangerous, isPvMove;
- int moveCount, researchCountFH, researchCountFL;
-
- researchCountFH = researchCountFL = 0;
- oldAlpha = alpha;
- isCheck = pos.is_check();
-
- // Step 1. Initialize node (polling is omitted at root)
- ss->currentMove = ss->bestMove = MOVE_NONE;
-
- // Step 2. Check for aborted search (omitted at root)
- // Step 3. Mate distance pruning (omitted at root)
- // Step 4. Transposition table lookup (omitted at root)
-
- // Step 5. Evaluate the position statically
- // At root we do this only to get reference value for child nodes
- ss->evalMargin = VALUE_NONE;
- ss->eval = isCheck ? VALUE_NONE : evaluate(pos, ss->evalMargin);
-
- // Step 6. Razoring (omitted at root)
- // Step 7. Static null move pruning (omitted at root)
- // Step 8. Null move search with verification search (omitted at root)
- // Step 9. Internal iterative deepening (omitted at root)
-
- // Step extra. Fail low loop
- // We start with small aspiration window and in case of fail low, we research
- // with bigger window until we are not failing low anymore.
- while (1)
- {
- // Sort the moves before to (re)search
- 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 (rm = rml.begin(); rm != rml.end() && !StopRequest; ++rm)
- {
- // This is used by time management
- 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 = rm->pv[0];
- movesSearched[moveCount++] = move;
- isPvMove = (moveCount <= MultiPV);
-
- if (current_search_time() >= 1000)
- cout << "info currmove " << move
- << " currmovenumber " << moveCount << endl;
-
- moveIsCheck = pos.move_is_check(move);
- captureOrPromotion = pos.move_is_capture_or_promotion(move);
-
- // Step 11. Decide the new search depth
- ext = extension<PV>(pos, move, captureOrPromotion, moveIsCheck, false, false, &dangerous);
- newDepth = depth + ext;
-
- // Step 12. Futility pruning (omitted at root)
-
- // Step extra. Fail high loop
- // If move fails high, we research with bigger window until we are not failing
- // high anymore.
- value = -VALUE_INFINITE;
-
- while (1)
- {
- // Step 13. Make the move
- pos.do_move(move, st, ci, moveIsCheck);
-
- // Step extra. pv search
- // 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)
- alpha = -VALUE_INFINITE;
-
- // Full depth PV search, done on first move or after a fail high
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
- }
- else
- {
- // Step 14. Reduced search
- // if the move fails high will be re-searched at full depth
- bool doFullDepthSearch = true;
-
- if ( depth >= 3 * ONE_PLY
- && !dangerous
- && !captureOrPromotion
- && !move_is_castle(move))
- {
- ss->reduction = reduction<PV>(depth, moveCount - MultiPV + 1);
- if (ss->reduction)
- {
- assert(newDepth-ss->reduction >= ONE_PLY);
-
- // Reduced depth non-pv search using alpha as upperbound
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
- doFullDepthSearch = (value > alpha);
- }
- ss->reduction = DEPTH_ZERO; // Restore original reduction
- }
-
- // Step 15. Full depth search
- if (doFullDepthSearch)
- {
- // Full depth non-pv search using alpha as upperbound
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, 1);
-
- // If we are above alpha then research at same depth but as PV
- // to get a correct score or eventually a fail high above beta.
- if (value > alpha)
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
- }
- }
-
- // Step 16. Undo move
- pos.undo_move(move);
-
- // Can we exit fail high loop ?
- 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.
- ss->bestMove = move;
- 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);
- }
-
- // 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
- beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
- researchCountFH++;
-
- } // End of fail high loop
-
- // Finished searching the move. If AbortSearch is true, the search
- // was aborted because the user interrupted the search or because we
- // ran out of time. In this case, the return value of the search cannot
- // be trusted, and we break out of the loop without updating the best
- // move and/or PV.
- if (StopRequest)
- break;
-
- // Remember searched nodes counts for this move
- rm->nodes += pos.nodes_searched() - nodes;
-
- assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
- assert(value < beta);
-
- // Step 17. Check for new best move
- if (!isPvMove && value <= alpha)
- rm->pv_score = -VALUE_INFINITE;
- else
- {
- // PV move or new best move!
-
- // Update PV
- ss->bestMove = move;
- rm->pv_score = value;
- rm->extract_pv_from_tt(pos);
-
- // 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);
-
- 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 // 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 >= oldAlpha);
-
- AspirationFailLow = (alpha == oldAlpha);
-
- if (AspirationFailLow && StopOnPonderhit)
- StopOnPonderhit = false;
-
- } // Root moves loop
-
- // Can we exit fail low loop ?
- if (StopRequest || !AspirationFailLow)
- break;
-
- // Prepare for a research after a fail low, each time with a wider window
- 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;
+ *ponderMove = Rml[0].pv[1];
+ return bestMove;
}
// all this work again. We also don't need to store anything to the hash table
// here: This is taken care of after we return from the split point.
- template <NodeType PvNode, bool SpNode>
+ template <NodeType PvNode, bool SpNode, bool Root>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta > alpha && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
- assert(ply > 0 && ply < PLY_MAX);
+ assert((Root || ply > 0) && ply < PLY_MAX);
assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
Move movesSearched[MOVES_MAX];
+ int64_t nodes;
StateInfo st;
const TTEntry *tte;
Key posKey;
ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
- bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
+ bool isPvMove, isCheck, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
- int moveCount = 0;
+ int moveCount = 0, playedMoveCount = 0;
int threadID = pos.thread();
SplitPoint* sp = NULL;
+
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
isCheck = pos.is_check();
mateThreat = sp->mateThreat;
goto split_point_start;
}
- else {} // Hack to fix icc's "statement is unreachable" warning
+ else if (Root)
+ bestValue = alpha;
// 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 ( StopRequest
- || ThreadsMgr.cutoff_at_splitpoint(threadID)
- || pos.is_draw()
- || ply >= PLY_MAX - 1)
+ if (( StopRequest
+ || ThreadsMgr.cutoff_at_splitpoint(threadID)
+ || pos.is_draw()
+ || ply >= PLY_MAX - 1) && !Root)
return VALUE_DRAW;
// Step 3. Mate distance pruning
return alpha;
// Step 4. Transposition table lookup
-
// We don't want the score of a partial search to overwrite a previous full search
// TT value, so we use a different position key in case of an excluded move exists.
excludedMove = ss->excludedMove;
}
// Step 9. Internal iterative deepening
- if ( depth >= IIDDepth[PvNode]
- && ttMove == MOVE_NONE
+ if ( depth >= IIDDepth[PvNode]
+ && ttMove == MOVE_NONE
&& (PvNode || (!isCheck && ss->eval >= beta - IIDMargin)))
{
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
- // FIXME currently MovePicker() c'tor is needless called also in SplitPoint
- MovePicker mpBase(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
- MovePicker& mp = SpNode ? *sp->mp : mpBase;
+ MovePickerExt<SpNode, Root> mp(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
- singleEvasion = !SpNode && isCheck && mp.number_of_evasions() == 1;
futilityBase = ss->eval + ss->evalMargin;
- singularExtensionNode = !SpNode
+ singularExtensionNode = !Root
+ && !SpNode
&& depth >= SingularExtensionDepth[PvNode]
&& tte
&& tte->move()
else if (move == excludedMove)
continue;
else
- movesSearched[moveCount++] = move;
+ moveCount++;
+
+ if (Root)
+ {
+ // This is used by time management
+ FirstRootMove = (moveCount == 1);
+ // 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;
+ }
+
+ if (current_search_time() >= 1000)
+ cout << "info currmove " << move
+ << " currmovenumber " << moveCount << endl;
+ }
+
+ isPvMove = (PvNode && moveCount <= (Root ? MultiPV : 1));
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Step 11. Decide the new search depth
- ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous);
+ ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, mateThreat, &dangerous);
// Singular extension search. If all moves but one fail low on a search of (alpha-s, beta-s),
// and just one fails high on (alpha, beta), then that move is singular and should be extended.
// Update current move (this must be done after singular extension search)
ss->currentMove = move;
- newDepth = depth - ONE_PLY + ext;
+ newDepth = depth - (!Root ? ONE_PLY : DEPTH_ZERO) + ext;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
// Step 13. Make the move
pos.do_move(move, st, ci, moveIsCheck);
+ if (!SpNode && !captureOrPromotion)
+ movesSearched[playedMoveCount++] = move;
+
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
- if (PvNode && moveCount == 1)
+ if (isPvMove)
+ {
+ // Aspiration window is disabled in multi-pv case
+ if (Root && MultiPV > 1)
+ alpha = -VALUE_INFINITE;
+
value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
+ }
else
{
// Step 14. Reduced depth search
&& ss->killers[0] != move
&& ss->killers[1] != move)
{
- ss->reduction = reduction<PvNode>(depth, moveCount);
-
+ ss->reduction = Root ? reduction<PvNode>(depth, moveCount - MultiPV + 1)
+ : reduction<PvNode>(depth, moveCount);
if (ss->reduction)
{
alpha = SpNode ? sp->alpha : alpha;
// Step extra. pv search (only in PV nodes)
// Search only for possible new PV nodes, if instead value >= beta then
// parent node fails low with value <= alpha and tries another move.
- if (PvNode && value > alpha && value < beta)
+ if (PvNode && value > alpha && (Root || value < beta))
value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
}
}
alpha = sp->alpha;
}
- if (value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID)))
+ if (!Root && value > bestValue && !(SpNode && ThreadsMgr.cutoff_at_splitpoint(threadID)))
{
bestValue = value;
}
}
+ if (Root)
+ {
+ // To avoid to exit with bestValue == -VALUE_INFINITE
+ if (value > bestValue)
+ bestValue = value;
+
+ // Finished searching the move. If StopRequest is true, the search
+ // was aborted because the user interrupted the search or because we
+ // ran out of time. In this case, the return value of the search cannot
+ // be trusted, and we break out of the loop without updating the best
+ // move and/or PV.
+ if (StopRequest)
+ break;
+
+ // Remember searched nodes counts for this move
+ mp.rm->nodes += pos.nodes_searched() - nodes;
+
+ // Step 17. Check for new best move
+ if (!isPvMove && value <= alpha)
+ mp.rm->pv_score = -VALUE_INFINITE;
+ else
+ {
+ // PV move or new best move!
+
+ // Update PV
+ ss->bestMove = move;
+ mp.rm->pv_score = value;
+ mp.rm->extract_pv_from_tt(pos);
+
+ // 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)
+ Rml.bestMoveChanges++;
+
+ // 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);
+
+ for (int j = 0; j < Min(MultiPV, (int)Rml.size()); j++)
+ cout << Rml[j].pv_info_to_uci(pos, depth, alpha, beta, j) << endl;
+
+ // Update alpha. In multi-pv we don't use aspiration window, so
+ // set alpha equal to minimum score among the PV lines.
+ if (MultiPV > 1)
+ alpha = Rml[Min(moveCount, MultiPV) - 1].pv_score; // FIXME why moveCount?
+ else if (value > alpha)
+ alpha = value;
+
+ } // PV move or new best move
+ }
+
// Step 18. Check for split
- if ( !SpNode
+ if ( !Root
+ && !SpNode
&& depth >= ThreadsMgr.min_split_depth()
&& ThreadsMgr.active_threads() > 1
&& bestValue < beta
&& ThreadsMgr.available_thread_exists(threadID)
&& !StopRequest
- && !ThreadsMgr.cutoff_at_splitpoint(threadID)
- && Iteration <= 99)
+ && !ThreadsMgr.cutoff_at_splitpoint(threadID))
ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
threatMove, mateThreat, moveCount, &mp, PvNode);
}
if ( bestValue >= beta
&& !pos.move_is_capture_or_promotion(move))
{
- update_history(pos, move, depth, movesSearched, moveCount);
+ update_history(pos, move, depth, movesSearched, playedMoveCount);
update_killers(move, ss->killers);
}
}
}
+ // qsearch_scoring() scores each move of a list using a qsearch() evaluation,
+ // it is used in RootMoveList to get an initial scoring.
+ void qsearch_scoring(Position& pos, MoveStack* mlist, MoveStack* last) {
+
+ SearchStack ss[PLY_MAX_PLUS_2];
+ StateInfo st;
+
+ memset(ss, 0, 4 * sizeof(SearchStack));
+ ss[0].eval = ss[0].evalMargin = VALUE_NONE;
+
+ for (MoveStack* cur = mlist; cur != last; cur++)
+ {
+ ss[0].currentMove = cur->move;
+ pos.do_move(cur->move, st);
+ cur->score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
+ pos.undo_move(cur->move);
+ }
+ }
+
+
// 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.
// 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.
template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck,
- bool singleEvasion, bool mateThreat, bool* dangerous) {
+ Depth extension(const Position& pos, Move m, bool captureOrPromotion,
+ bool moveIsCheck, bool mateThreat, bool* dangerous) {
assert(m != MOVE_NONE);
Depth result = DEPTH_ZERO;
- *dangerous = moveIsCheck | singleEvasion | mateThreat;
+ *dangerous = moveIsCheck | mateThreat;
if (*dangerous)
{
if (moveIsCheck && pos.see_sign(m) >= 0)
result += CheckExtension[PvNode];
- if (singleEvasion)
- result += SingleEvasionExtension[PvNode];
-
if (mateThreat)
result += MateThreatExtension[PvNode];
}
void update_history(const Position& pos, Move move, Depth depth,
Move movesSearched[], int moveCount) {
Move m;
+ Value bonus = Value(int(depth) * int(depth));
- H.success(pos.piece_on(move_from(move)), move_to(move), depth);
+ H.update(pos.piece_on(move_from(move)), move_to(move), bonus);
for (int i = 0; i < moveCount - 1; i++)
{
assert(m != move);
- if (!pos.move_is_capture_or_promotion(m))
- H.failure(pos.piece_on(move_from(m)), move_to(m), depth);
+ H.update(pos.piece_on(move_from(m)), move_to(m), -bonus);
}
}
void update_killers(Move m, Move killers[]) {
- if (m == killers[0])
- return;
-
- killers[1] = killers[0];
- killers[0] = m;
+ if (m != killers[0])
+ {
+ killers[1] = killers[0];
+ killers[0] = m;
+ }
}
&& after != VALUE_NONE
&& pos.captured_piece_type() == PIECE_TYPE_NONE
&& !move_is_special(m))
- H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
- }
-
-
- // 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;
- }
+ H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
}
ss->sp = tsp;
if (tsp->pvNode)
- search<PV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ search<PV, true, false>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
else
- search<NonPV, true>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
+ search<NonPV, true, false>(pos, ss, tsp->alpha, tsp->beta, tsp->depth, tsp->ply);
assert(threads[threadID].state == THREAD_SEARCHING);
// 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(Position& pos, Value alpha, Value beta, int pvLine) {
+ std::string RootMove::pv_info_to_uci(Position& pos, Depth depth, Value alpha, Value beta, int pvLine) {
std::stringstream s, l;
Move* m = pv;
while (*m != MOVE_NONE)
l << *m++ << " ";
- s << "info depth " << Iteration // FIXME
+ s << "info depth " << depth / ONE_PLY
<< " seldepth " << int(m - pv)
<< " multipv " << pvLine + 1
<< " score " << value_to_uci(pv_score)
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;
+ LogFile << pretty_pv(pos, current_search_time(), depth / ONE_PLY, pv_score, t, pv) << endl;
}
return s.str();
}
- RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) {
+ void RootMoveList::init(Position& pos, Move searchMoves[]) {
- SearchStack ss[PLY_MAX_PLUS_2];
MoveStack mlist[MOVES_MAX];
- StateInfo st;
Move* sm;
- // Initialize search stack
- init_ss_array(ss, PLY_MAX_PLUS_2);
- ss[0].eval = ss[0].evalMargin = VALUE_NONE;
+ clear();
+ bestMoveChanges = 0;
- // Generate all legal moves
+ // Generate all legal moves and score them
MoveStack* last = generate<MV_LEGAL>(pos, mlist);
+ qsearch_scoring(pos, mlist, last);
// Add each move to the RootMoveList's vector
for (MoveStack* cur = mlist; cur != last; cur++)
if (searchMoves[0] && *sm != cur->move)
continue;
- // Find a quick score for the move and add to the list
- pos.do_move(cur->move, st);
-
RootMove rm;
- rm.pv[0] = ss[0].currentMove = cur->move;
+ rm.pv[0] = cur->move;
rm.pv[1] = MOVE_NONE;
- rm.pv_score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
+ rm.pv_score = Value(cur->score);
push_back(rm);
-
- pos.undo_move(cur->move);
}
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::set_non_pv_scores(const Position& pos, Move ttm, SearchStack* ss)
- {
- Move move;
- Value score = VALUE_ZERO;
- MovePicker mp(pos, ttm, ONE_PLY, H, ss);
-
- while ((move = mp.get_next_move()) != MOVE_NONE)
- for (Base::iterator it = begin(); it != end(); ++it)
- if (it->pv[0] == move)
- {
- it->non_pv_score = score--;
- break;
- }
- }
-
} // namespace
projects / stockfish / blobdiff