#include <cmath>
#include <cstring>
#include <fstream>
+#include <iomanip>
#include <iostream>
#include <sstream>
#include <vector>
using std::cout;
using std::endl;
+using std::string;
namespace {
const bool FakeSplit = false;
// Different node types, used as template parameter
- enum NodeType { NonPV, PV };
+ enum NodeType { Root, PV, NonPV, SplitPointRoot, SplitPointPV, SplitPointNonPV };
// RootMove struct is used for moves at the root of 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.
+ // move, we store a score, a node count, and a PV (really a refutation
+ // in the case of moves which fail low). Score is normally set at
+ // -VALUE_INFINITE for all non-pv moves.
struct RootMove {
- 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 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 pv_score != m.pv_score ? pv_score < m.pv_score
- : non_pv_score < m.non_pv_score;
- }
+ // than a move m2 if it has an higher score
+ bool operator<(const RootMove& m) const { return score < m.score; }
void extract_pv_from_tt(Position& pos);
void insert_pv_in_tt(Position& pos);
- std::string pv_info_to_uci(Position& pos, int depth, int selDepth,
- Value alpha, Value beta, int pvIdx);
+
int64_t nodes;
- Value pv_score;
- Value non_pv_score;
- Move pv[PLY_MAX_PLUS_2];
+ Value score;
+ Value prevScore;
+ std::vector<Move> pv;
};
- // RootMoveList struct is just a vector of RootMove objects,
- // with an handful of methods above the standard ones.
+ // RootMoveList struct is mainly a std::vector of RootMove objects
struct RootMoveList : public std::vector<RootMove> {
- typedef std::vector<RootMove> Base;
-
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); }
+ RootMove* find(const Move& m, int startIndex = 0);
int bestMoveChanges;
};
- // MovePickerExt template class extends MovePicker and allows to choose at compile
- // time the proper moves source according to the type of node. In the default case
- // we simply create and use a standard MovePicker object.
- template<bool SpNode, bool Root> struct MovePickerExt : 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
- };
-
- // In case of a SpNode we use split point's shared MovePicker object as moves 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;
- };
-
- // In case of a Root node we use RootMoveList as moves source
- template<> struct MovePickerExt<false, true> : public MovePicker {
-
- MovePickerExt(const Position&, Move, Depth, const History&, SearchStack*, Value);
- Move get_next_move();
-
- RootMoveList::iterator rm;
- bool firstCall;
- };
-
/// Constants
// Reduction lookup tables (initialized at startup) and their access function
int8_t Reductions[2][64][64]; // [pv][depth][moveNumber]
- template <NodeType PV> inline Depth reduction(Depth d, int mn) {
+ template <bool PvNode> inline Depth reduction(Depth d, int mn) {
- return (Depth) Reductions[PV][Min(d / ONE_PLY, 63)][Min(mn, 63)];
+ return (Depth) Reductions[PvNode][Min(d / ONE_PLY, 63)][Min(mn, 63)];
}
// Easy move margin. An easy move candidate must be at least this much
RootMoveList Rml;
// MultiPV mode
- int MultiPV, UCIMultiPV;
+ int MultiPV, UCIMultiPV, MultiPVIteration;
// Time management variables
bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
// 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;
Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove);
- template <NodeType PvNode, bool SpNode, bool Root>
+ template <NodeType NT>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
- template <NodeType PvNode>
+ template <NodeType NT>
Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
- template <NodeType PvNode>
- inline Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
-
- return depth < ONE_PLY ? qsearch<PvNode>(pos, ss, alpha, beta, DEPTH_ZERO)
- : search<PvNode, false, false>(pos, ss, alpha, beta, depth);
- }
-
- template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, 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);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
- bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
+ bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, 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 do_skill_level(Move* best, Move* ponder);
int current_search_time(int set = 0);
- std::string value_to_uci(Value v);
- std::string speed_to_uci(int64_t nodes);
+ string score_to_uci(Value v, Value alpha = -VALUE_INFINITE, Value beta = VALUE_INFINITE);
+ string speed_to_uci(int64_t nodes);
+ string pv_to_uci(const Move pv[], int pvNum, bool chess960);
+ string pretty_pv(Position& pos, int depth, Value score, int time, Move pv[]);
+ string depth_to_uci(Depth depth);
void poll(const Position& pos);
void wait_for_stop_or_ponderhit();
+ // MovePickerExt template class extends MovePicker and allows to choose at compile
+ // time the proper moves source according to the type of node. In the default case
+ // we simply create and use a standard MovePicker object.
+ template<bool SpNode> struct MovePickerExt : public MovePicker {
+
+ MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
+ : MovePicker(p, ttm, d, h, ss, b) {}
+ };
+
+ // In case of a SpNode we use split point's shared MovePicker object as moves source
+ template<> struct MovePickerExt<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), mp(ss->sp->mp) {}
+
+ Move get_next_move() { return mp->get_next_move(); }
+ MovePicker* mp;
+ };
+
// Overload operator<<() to make it easier to print moves in a coordinate
// notation compatible with UCI protocol.
std::ostream& operator<<(std::ostream& os, Move m) {
return os;
}
+ // extension() decides whether a move should be searched with normal depth,
+ // or with extended depth. Certain classes of moves (checking moves, in
+ // particular) are searched with bigger depth than ordinary moves and in
+ // any case are marked as 'dangerous'. Note that also if a move is not
+ // extended, as example because the corresponding UCI option is set to zero,
+ // the move is marked as 'dangerous' so, at least, we avoid to prune it.
+ template <bool PvNode>
+ FORCE_INLINE Depth extension(const Position& pos, Move m, bool captureOrPromotion,
+ bool moveIsCheck, bool* dangerous) {
+ assert(m != MOVE_NONE);
+
+ Depth result = DEPTH_ZERO;
+ *dangerous = moveIsCheck;
+
+ if (moveIsCheck && pos.see_sign(m) >= 0)
+ result += CheckExtension[PvNode];
+
+ if (piece_type(pos.piece_on(move_from(m))) == PAWN)
+ {
+ Color c = pos.side_to_move();
+ if (relative_rank(c, move_to(m)) == RANK_7)
+ {
+ result += PawnPushTo7thExtension[PvNode];
+ *dangerous = true;
+ }
+ if (pos.pawn_is_passed(c, move_to(m)))
+ {
+ result += PassedPawnExtension[PvNode];
+ *dangerous = true;
+ }
+ }
+
+ if ( captureOrPromotion
+ && piece_type(pos.piece_on(move_to(m))) != PAWN
+ && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
+ - piece_value_midgame(pos.piece_on(move_to(m))) == VALUE_ZERO)
+ && !move_is_special(m))
+ {
+ result += PawnEndgameExtension[PvNode];
+ *dangerous = true;
+ }
+
+ return Min(result, ONE_PLY);
+ }
+
} // namespace
{
double pvRed = log(double(hd)) * log(double(mc)) / 3.0;
double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
- Reductions[PV][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
- Reductions[NonPV][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
+ Reductions[1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
+ Reductions[0][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
}
// Init futility margins array
int64_t perft(Position& pos, Depth depth) {
- MoveStack mlist[MAX_MOVES];
StateInfo st;
- Move m;
int64_t sum = 0;
// Generate all legal moves
- MoveStack* last = generate<MV_LEGAL>(pos, mlist);
+ MoveList<MV_LEGAL> ml(pos);
// If we are at the last ply we don't need to do and undo
// the moves, just to count them.
if (depth <= ONE_PLY)
- return int(last - mlist);
+ return ml.size();
// Loop through all legal moves
CheckInfo ci(pos);
- for (MoveStack* cur = mlist; cur != last; cur++)
+ for ( ; !ml.end(); ++ml)
{
- m = cur->move;
- pos.do_move(m, st, ci, pos.move_gives_check(m, ci));
+ pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci));
sum += perft(pos, depth - ONE_PLY);
- pos.undo_move(m);
+ pos.undo_move(ml.move());
}
return sum;
}
static Book book;
// Initialize global search-related variables
- StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false;
+ StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = false;
NodesSincePoll = 0;
current_search_time(get_system_time());
Limits = limits;
TimeMgr.init(Limits, pos.startpos_ply_counter());
+ // Set output steram in normal or chess960 mode
+ cout << set960(pos.is_chess960());
+
// Set best NodesBetweenPolls interval to avoid lagging under time pressure
if (Limits.maxNodes)
NodesBetweenPolls = Min(Limits.maxNodes, 30000);
// Look for a book move
if (Options["OwnBook"].value<bool>())
{
- if (Options["Book File"].value<std::string>() != book.name())
- book.open(Options["Book File"].value<std::string>());
+ if (Options["Book File"].value<string>() != book.name())
+ book.open(Options["Book File"].value<string>());
Move bookMove = book.get_move(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE)
// Write to log file and keep it open to be accessed during the search
if (Options["Use Search Log"].value<bool>())
{
- std::string name = Options["Search Log Filename"].value<std::string>();
+ string name = Options["Search Log Filename"].value<string>();
LogFile.open(name.c_str(), std::ios::out | std::ios::app);
if (LogFile.is_open())
Move ponderMove = MOVE_NONE;
Move bestMove = id_loop(pos, searchMoves, &ponderMove);
- cout << "info" << speed_to_uci(pos.nodes_searched()) << endl;
-
// Write final search statistics and close log file
if (LogFile.is_open())
{
SearchStack ss[PLY_MAX_PLUS_2];
Value bestValues[PLY_MAX_PLUS_2];
int bestMoveChanges[PLY_MAX_PLUS_2];
- int depth, selDepth, aspirationDelta;
+ int depth, aspirationDelta;
Value value, alpha, beta;
Move bestMove, easyMove, skillBest, skillPonder;
H.clear();
*ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
depth = aspirationDelta = 0;
- alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ value = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
// Moves to search are verified and copied
Rml.init(pos, searchMoves);
// Handle special case of searching on a mate/stalemate position
- if (Rml.size() == 0)
+ if (!Rml.size())
{
- cout << "info depth 0 score "
- << value_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW)
- << endl;
+ cout << "info" << depth_to_uci(DEPTH_ZERO)
+ << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW, alpha, beta) << endl;
return MOVE_NONE;
}
// Iterative deepening loop until requested to stop or target depth reached
while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
{
+ // Save last iteration's scores, this needs to be done now, because in
+ // the following MultiPV loop Rml moves could be reordered.
+ for (size_t i = 0; i < Rml.size(); i++)
+ Rml[i].prevScore = Rml[i].score;
+
Rml.bestMoveChanges = 0;
- cout << set960(pos.is_chess960()) << "info depth " << depth << endl;
- // Calculate dynamic aspiration window based on previous iterations
- if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN)
+ // MultiPV iteration loop
+ for (MultiPVIteration = 0; MultiPVIteration < Min(MultiPV, (int)Rml.size()); MultiPVIteration++)
{
- int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2];
- int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3];
-
- aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
- aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
-
- alpha = Max(bestValues[depth - 1] - aspirationDelta, -VALUE_INFINITE);
- beta = Min(bestValues[depth - 1] + aspirationDelta, VALUE_INFINITE);
- }
-
- // Start with a small aspiration window and, in case of fail high/low,
- // research with bigger window until not failing high/low anymore.
- do {
- // Search starting from ss+1 to allow calling update_gains()
- value = search<PV, false, true>(pos, ss+1, alpha, beta, depth * ONE_PLY);
-
- // Write PV back 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);
-
- // Value cannot be trusted. Break out immediately!
- if (StopRequest)
- break;
+ // Calculate dynamic aspiration window based on previous iterations
+ if (depth >= 5 && abs(Rml[MultiPVIteration].prevScore) < VALUE_KNOWN_WIN)
+ {
+ int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2];
+ int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3];
- assert(value >= alpha);
+ aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
+ aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
- // 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, VALUE_INFINITE);
- aspirationDelta += aspirationDelta / 2;
+ alpha = Max(Rml[MultiPVIteration].prevScore - aspirationDelta, -VALUE_INFINITE);
+ beta = Min(Rml[MultiPVIteration].prevScore + aspirationDelta, VALUE_INFINITE);
}
- else if (value <= alpha)
+ else
{
- AspirationFailLow = true;
- StopOnPonderhit = false;
-
- alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
- aspirationDelta += aspirationDelta / 2;
+ alpha = -VALUE_INFINITE;
+ beta = VALUE_INFINITE;
}
- else
- break;
- } while (abs(value) < VALUE_KNOWN_WIN);
+ // Start with a small aspiration window and, in case of fail high/low,
+ // research with bigger window until not failing high/low anymore.
+ do {
+ // Search starting from ss+1 to allow referencing (ss-1). This is
+ // needed by update_gains() and ss copy when splitting at Root.
+ value = search<Root>(pos, ss+1, alpha, beta, depth * ONE_PLY);
+
+ // It is critical that sorting is done with a stable algorithm
+ // because all the values but the first are usually set to
+ // -VALUE_INFINITE and we want to keep the same order for all
+ // the moves but the new PV that goes to head.
+ sort<RootMove>(Rml.begin() + MultiPVIteration, Rml.end());
+
+ // In case we have found an exact score reorder the PV moves
+ // before leaving the fail high/low loop, otherwise leave the
+ // last PV move in its position so to be searched again.
+ if (value > alpha && value < beta)
+ sort<RootMove>(Rml.begin(), Rml.begin() + MultiPVIteration);
+
+ // Write PV back to transposition table in case the relevant entries
+ // have been overwritten during the search.
+ for (int i = 0; i <= MultiPVIteration; i++)
+ Rml[i].insert_pv_in_tt(pos);
+
+ // Value cannot be trusted. Break out immediately!
+ if (StopRequest)
+ break;
+
+ // Send full PV info to GUI if we are going to leave the loop or
+ // if we have a fail high/low and we are deep in the search.
+ if ((value > alpha && value < beta) || current_search_time() > 2000)
+ for (int i = 0; i < Min(UCIMultiPV, MultiPVIteration + 1); i++)
+ cout << "info"
+ << depth_to_uci(depth * ONE_PLY)
+ << (i == MultiPVIteration ? score_to_uci(Rml[i].score, alpha, beta) :
+ score_to_uci(Rml[i].score))
+ << speed_to_uci(pos.nodes_searched())
+ << pv_to_uci(&Rml[i].pv[0], i + 1, pos.is_chess960())
+ << endl;
+
+ // 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, VALUE_INFINITE);
+ aspirationDelta += aspirationDelta / 2;
+ }
+ else if (value <= alpha)
+ {
+ AspirationFailLow = true;
+ StopOnPonderhit = false;
+
+ alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
+ aspirationDelta += aspirationDelta / 2;
+ }
+ else
+ break;
+
+ } while (abs(value) < VALUE_KNOWN_WIN);
+ }
// Collect info about search result
bestMove = Rml[0].pv[0];
if (SkillLevelEnabled && depth == 1 + SkillLevel)
do_skill_level(&skillBest, &skillPonder);
- // Retrieve max searched depth among threads
- selDepth = 0;
- for (int i = 0; i < Threads.size(); i++)
- if (Threads[i].maxPly > selDepth)
- selDepth = Threads[i].maxPly;
-
- // Send PV line to GUI and to log file
- for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
- cout << Rml[i].pv_info_to_uci(pos, depth, selDepth, alpha, beta, i) << endl;
-
if (LogFile.is_open())
- LogFile << pretty_pv(pos, depth, value, current_search_time(), Rml[0].pv) << endl;
+ LogFile << pretty_pv(pos, depth, value, current_search_time(), &Rml[0].pv[0]) << endl;
// Init easyMove after first iteration or drop if differs from the best move
- if (depth == 1 && (Rml.size() == 1 || Rml[0].pv_score > Rml[1].pv_score + EasyMoveMargin))
+ if (depth == 1 && (Rml.size() == 1 || Rml[0].score > Rml[1].score + EasyMoveMargin))
easyMove = bestMove;
else if (bestMove != easyMove)
easyMove = MOVE_NONE;
// Check for some early stop condition
if (!StopRequest && Limits.useTimeManagement())
{
- // Stop search early when the last two iterations returned a mate score
- if ( depth >= 5
- && abs(bestValues[depth]) >= VALUE_MATE_IN_PLY_MAX
- && abs(bestValues[depth - 1]) >= VALUE_MATE_IN_PLY_MAX)
- StopRequest = true;
-
// Stop search early if one move seems to be much better than the
// others or if there is only a single legal move. Also in the latter
// case we search up to some depth anyway to get a proper score.
// 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, bool Root>
+ template <NodeType NT>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
+ const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV || NT == SplitPointRoot);
+ const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot);
+ const bool RootNode = (NT == Root || NT == SplitPointRoot);
+
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta > alpha && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
Depth ext, newDepth;
ValueType vt;
Value bestValue, value, oldAlpha;
- Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific
+ Value refinedValue, nullValue, futilityBase, futilityValue;
bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous;
int moveCount = 0, playedMoveCount = 0;
- int threadID = pos.thread();
+ Thread& thread = Threads[pos.thread()];
SplitPoint* sp = NULL;
refinedValue = bestValue = value = -VALUE_INFINITE;
ss->ply = (ss-1)->ply + 1;
// Used to send selDepth info to GUI
- if (PvNode && Threads[threadID].maxPly < ss->ply)
- Threads[threadID].maxPly = ss->ply;
+ if (PvNode && thread.maxPly < ss->ply)
+ thread.maxPly = ss->ply;
- if (SpNode)
+ // Step 1. Initialize node and poll. Polling can abort search
+ if (!SpNode)
+ {
+ ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE;
+ (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
+ (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
+ }
+ else
{
sp = ss->sp;
tte = NULL;
threatMove = sp->threatMove;
goto split_point_start;
}
- else if (Root)
- bestValue = alpha;
- // Step 1. Initialize node and poll. Polling can abort search
- ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE;
- (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
- (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
-
- if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
+ if (pos.thread() == 0 && ++NodesSincePoll > NodesBetweenPolls)
{
NodesSincePoll = 0;
poll(pos);
// Step 2. Check for aborted search and immediate draw
if (( StopRequest
- || Threads[threadID].cutoff_occurred()
- || pos.is_draw()
- || ss->ply > PLY_MAX) && !Root)
+ || pos.is_draw<false>()
+ || ss->ply > PLY_MAX) && !RootNode)
return VALUE_DRAW;
// Step 3. Mate distance pruning
- alpha = Max(value_mated_in(ss->ply), alpha);
- beta = Min(value_mate_in(ss->ply+1), beta);
- if (alpha >= beta)
- return alpha;
+ if (!RootNode)
+ {
+ alpha = Max(value_mated_in(ss->ply), alpha);
+ beta = Min(value_mate_in(ss->ply+1), beta);
+ if (alpha >= beta)
+ 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.
excludedMove = ss->excludedMove;
posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
-
tte = TT.probe(posKey);
- ttMove = tte ? tte->move() : MOVE_NONE;
+ ttMove = RootNode ? Rml[MultiPVIteration].pv[0] : tte ? tte->move() : MOVE_NONE;
// At PV nodes we check for exact scores, while at non-PV nodes we check for
// a fail high/low. Biggest advantage at probing at PV nodes is to have a
- // smooth experience in analysis mode.
- if ( !Root
- && tte
- && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT
- : ok_to_use_TT(tte, depth, beta, ss->ply)))
+ // smooth experience in analysis mode. We don't probe at Root nodes otherwise
+ // we should also update RootMoveList to avoid bogus output.
+ if (!RootNode && tte && (PvNode ? tte->depth() >= depth && tte->type() == VALUE_TYPE_EXACT
+ : can_return_tt(tte, depth, beta, ss->ply)))
{
TT.refresh(tte);
ss->bestMove = ttMove; // Can be MOVE_NONE
pos.do_null_move(st);
(ss+1)->skipNullMove = true;
- nullValue = -search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY);
+ nullValue = depth-R*ONE_PLY < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*ONE_PLY);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
}
}
- // Step 9. Internal iterative deepening
+ // Step 9. ProbCut (is omitted in PV nodes)
+ // If we have a very good capture (i.e. SEE > seeValues[captured_piece_type])
+ // and a reduced search returns a value much above beta, we can (almost) safely
+ // prune the previous move.
+ if ( !PvNode
+ && depth >= RazorDepth + ONE_PLY
+ && !inCheck
+ && !ss->skipNullMove
+ && excludedMove == MOVE_NONE
+ && abs(beta) < VALUE_MATE_IN_PLY_MAX)
+ {
+ Value rbeta = beta + 200;
+ Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY;
+
+ assert(rdepth >= ONE_PLY);
+
+ MovePicker mp(pos, ttMove, H, pos.captured_piece_type());
+ CheckInfo ci(pos);
+
+ while ((move = mp.get_next_move()) != MOVE_NONE)
+ if (pos.pl_move_is_legal(move, ci.pinned))
+ {
+ pos.do_move(move, st, ci, pos.move_gives_check(move, ci));
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth);
+ pos.undo_move(move);
+ if (value >= rbeta)
+ return value;
+ }
+ }
+
+ // Step 10. Internal iterative deepening
if ( depth >= IIDDepth[PvNode]
&& ttMove == MOVE_NONE
&& (PvNode || (!inCheck && ss->eval + IIDMargin >= beta)))
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
ss->skipNullMove = true;
- search<PvNode>(pos, ss, alpha, beta, d);
+ search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d);
ss->skipNullMove = false;
tte = TT.probe(posKey);
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
- MovePickerExt<SpNode, Root> mp(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
+ MovePickerExt<SpNode> mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
futilityBase = ss->eval + ss->evalMargin;
- singularExtensionNode = !Root
+ singularExtensionNode = !RootNode
&& !SpNode
&& depth >= SingularExtensionDepth[PvNode]
&& ttMove != MOVE_NONE
bestValue = sp->bestValue;
}
- // Step 10. Loop through moves
- // Loop through all legal moves until no moves remain or a beta cutoff occurs
+ // Step 11. Loop through moves
+ // Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE
- && !Threads[threadID].cutoff_occurred())
+ && !thread.cutoff_occurred())
{
assert(move_is_ok(move));
+ if (move == excludedMove)
+ continue;
+
+ // At root obey the "searchmoves" option and skip moves not listed in Root Move List.
+ // Also in MultiPV mode we skip moves which already have got an exact score
+ // in previous MultiPV Iteration. Finally any illegal move is skipped here.
+ if (RootNode && !Rml.find(move, MultiPVIteration))
+ continue;
+
+ // At PV and SpNode nodes we want all moves to be legal since the beginning
+ if ((PvNode || SpNode) && !pos.pl_move_is_legal(move, ci.pinned))
+ continue;
+
if (SpNode)
{
moveCount = ++sp->moveCount;
lock_release(&(sp->lock));
}
- else if (move == excludedMove)
- continue;
else
moveCount++;
- if (Root)
+ if (RootNode)
{
// 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" << speed_to_uci(pos.nodes_searched()) << endl;
- }
-
- if (current_search_time() > 2000)
- cout << "info currmove " << move
- << " currmovenumber " << moveCount << endl;
+ // For long searches send current move info to GUI
+ if (pos.thread() == 0 && current_search_time() > 2000)
+ cout << "info" << depth_to_uci(depth)
+ << " currmove " << move
+ << " currmovenumber " << moveCount + MultiPVIteration << endl;
}
// At Root and at first iteration do a PV search on all the moves to score root moves
- isPvMove = (PvNode && moveCount <= (Root ? depth <= ONE_PLY ? 1000 : MultiPV : 1));
+ isPvMove = (PvNode && moveCount <= (RootNode && depth <= ONE_PLY ? MAX_MOVES : 1));
givesCheck = pos.move_gives_check(move, ci);
- captureOrPromotion = pos.move_is_capture(move) || move_is_promotion(move);
+ captureOrPromotion = pos.move_is_capture_or_promotion(move);
- // Step 11. Decide the new search depth
+ // Step 12. Decide the new search depth
ext = extension<PvNode>(pos, move, captureOrPromotion, givesCheck, &dangerous);
// Singular extension search. If all moves but one fail low on a search of
// a margin then we extend ttMove.
if ( singularExtensionNode
&& move == ttMove
+ && pos.pl_move_is_legal(move, ci.pinned)
&& ext < ONE_PLY)
{
Value ttValue = value_from_tt(tte->value(), ss->ply);
}
// Update current move (this must be done after singular extension search)
- ss->currentMove = move;
newDepth = depth - ONE_PLY + ext;
- // Step 12. Futility pruning (is omitted in PV nodes)
+ // Step 13. Futility pruning (is omitted in PV nodes)
if ( !PvNode
&& !captureOrPromotion
&& !inCheck
// Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
- Depth predictedDepth = newDepth - reduction<NonPV>(depth, moveCount);
- futilityValueScaled = futilityBase + futility_margin(predictedDepth, moveCount)
- + H.gain(pos.piece_on(move_from(move)), move_to(move));
+ Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
+ futilityValue = futilityBase + futility_margin(predictedDepth, moveCount)
+ + H.gain(pos.piece_on(move_from(move)), move_to(move));
- if (futilityValueScaled < beta)
+ if (futilityValue < beta)
{
if (SpNode)
{
lock_grab(&(sp->lock));
- if (futilityValueScaled > sp->bestValue)
- sp->bestValue = bestValue = futilityValueScaled;
+ if (futilityValue > sp->bestValue)
+ sp->bestValue = bestValue = futilityValue;
}
- else if (futilityValueScaled > bestValue)
- bestValue = futilityValueScaled;
+ else if (futilityValue > bestValue)
+ bestValue = futilityValue;
continue;
}
}
}
- // Step 13. Make the move
- pos.do_move(move, st, ci, givesCheck);
+ // Check for legality only before to do the move
+ if (!pos.pl_move_is_legal(move, ci.pinned))
+ {
+ moveCount--;
+ continue;
+ }
+ ss->currentMove = move;
if (!SpNode && !captureOrPromotion)
movesSearched[playedMoveCount++] = move;
+ // Step 14. Make the move
+ pos.do_move(move, st, ci, givesCheck);
+
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
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);
- }
+ value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
else
{
- // Step 14. Reduced depth search
+ // Step 15. Reduced depth search
// If the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true;
- alpha = SpNode ? sp->alpha : alpha;
- if ( depth >= 3 * ONE_PLY
+ if ( depth > 3 * ONE_PLY
&& !captureOrPromotion
&& !dangerous
&& !move_is_castle(move)
&& ss->killers[0] != move
- && ss->killers[1] != move)
+ && ss->killers[1] != move
+ && (ss->reduction = reduction<PvNode>(depth, moveCount)) != DEPTH_ZERO)
{
- ss->reduction = reduction<PvNode>(depth, moveCount);
- if (ss->reduction)
- {
- Depth d = newDepth - ss->reduction;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
+ Depth d = newDepth - ss->reduction;
+ alpha = SpNode ? sp->alpha : alpha;
- doFullDepthSearch = (value > alpha);
- }
- ss->reduction = DEPTH_ZERO; // Restore original reduction
- }
+ value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
- // Probcut search for bad captures. If a reduced search returns a value
- // very below beta then we can (almost) safely prune the bad capture.
- if ( depth >= 3 * ONE_PLY
- && depth < 8 * ONE_PLY
- && mp.isBadCapture()
- && move != ttMove
- && !dangerous
- && !move_is_promotion(move)
- && abs(alpha) < VALUE_MATE_IN_PLY_MAX)
- {
- ss->reduction = 3 * ONE_PLY;
- Value rAlpha = alpha - 300;
- Depth d = newDepth - ss->reduction;
- value = -search<NonPV>(pos, ss+1, -(rAlpha+1), -rAlpha, d);
- doFullDepthSearch = (value > rAlpha);
- ss->reduction = DEPTH_ZERO; // Restore original reduction
+ ss->reduction = DEPTH_ZERO;
+ doFullDepthSearch = (value > alpha);
}
- // Step 15. Full depth search
+ // Step 16. Full depth search
if (doFullDepthSearch)
{
alpha = SpNode ? sp->alpha : alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth);
+ value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth);
// 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 && (Root || value < beta))
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth);
+ if (PvNode && value > alpha && (RootNode || value < beta))
+ value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
}
}
- // Step 16. Undo move
+ // Step 17. Undo move
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
- // Step 17. Check for new best move
+ // Step 18. Check for new best move
if (SpNode)
{
lock_grab(&(sp->lock));
alpha = sp->alpha;
}
- if (value > bestValue && !(SpNode && Threads[threadID].cutoff_occurred()))
- {
- bestValue = value;
-
- if (SpNode)
- sp->bestValue = value;
-
- if (!Root && value > alpha)
- {
- if (PvNode && value < beta) // We want always alpha < beta
- {
- alpha = value;
-
- if (SpNode)
- sp->alpha = value;
- }
- else if (SpNode)
- sp->is_betaCutoff = true;
-
- if (value == value_mate_in(ss->ply + 1))
- ss->mateKiller = move;
-
- ss->bestMove = move;
-
- if (SpNode)
- sp->ss->bestMove = move;
- }
- }
-
- if (Root)
+ // 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 don't update the best move and/or PV.
+ if (RootNode && !StopRequest)
{
- // 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;
+ RootMove* rm = Rml.find(move);
+ rm->nodes += pos.nodes_searched() - nodes;
// PV move or new best move ?
if (isPvMove || value > alpha)
{
// Update PV
- ss->bestMove = move;
- mp.rm->pv_score = value;
- mp.rm->extract_pv_from_tt(pos);
+ rm->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 management: When
// the best move changes frequently, we allocate some more time.
if (!isPvMove && MultiPV == 1)
Rml.bestMoveChanges++;
-
- Rml.sort_multipv(moveCount);
-
- // 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;
}
else
- mp.rm->pv_score = -VALUE_INFINITE;
+ // All other moves but the PV are set to the lowest value, this
+ // is not a problem when sorting becuase sort is stable and move
+ // position in the list is preserved, just the PV is pushed up.
+ rm->score = -VALUE_INFINITE;
+
+ } // RootNode
+
+ if (value > bestValue)
+ {
+ bestValue = value;
+ ss->bestMove = move;
- } // Root
+ if ( PvNode
+ && value > alpha
+ && value < beta) // We want always alpha < beta
+ alpha = value;
- // Step 18. Check for split
- if ( !Root
- && !SpNode
+ if (SpNode && !thread.cutoff_occurred())
+ {
+ sp->bestValue = value;
+ sp->ss->bestMove = move;
+ sp->alpha = alpha;
+ sp->is_betaCutoff = (value >= beta);
+ }
+ }
+
+ // Step 19. Check for split
+ if ( !SpNode
&& depth >= Threads.min_split_depth()
&& bestValue < beta
- && Threads.available_slave_exists(threadID)
+ && Threads.available_slave_exists(pos.thread())
&& !StopRequest
- && !Threads[threadID].cutoff_occurred())
- Threads.split<FakeSplit>(pos, ss, &alpha, beta, &bestValue, depth,
- threatMove, moveCount, &mp, PvNode);
+ && !thread.cutoff_occurred())
+ bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, depth,
+ threatMove, moveCount, &mp, NT);
}
- // Step 19. Check for mate and stalemate
+ // Step 20. Check for mate and stalemate
// All legal moves have been searched and if there are
// no legal moves, it must be mate or stalemate.
// If one move was excluded return fail low score.
if (!SpNode && !moveCount)
return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
- // Step 20. Update tables
+ // Step 21. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (!SpNode && !StopRequest && !Threads[threadID].cutoff_occurred())
+ if (!SpNode && !StopRequest && !thread.cutoff_occurred())
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
// Update killers and history only for non capture moves that fails high
if ( bestValue >= beta
- && !pos.move_is_capture(move)
- && !move_is_promotion(move))
+ && !pos.move_is_capture_or_promotion(move))
{
if (move != ss->killers[0])
{
if (SpNode)
{
// Here we have the lock still grabbed
- sp->is_slave[threadID] = false;
+ sp->is_slave[pos.thread()] = false;
sp->nodes += pos.nodes_searched();
lock_release(&(sp->lock));
}
// search function when the remaining depth is zero (or, to be more precise,
// less than ONE_PLY).
- template <NodeType PvNode>
+ template <NodeType NT>
Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
+ const bool PvNode = (NT == PV);
+
+ assert(NT == PV || NT == NonPV);
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
bool inCheck, enoughMaterial, givesCheck, evasionPrunable;
const TTEntry* tte;
Depth ttDepth;
+ ValueType vt;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (ss->ply > PLY_MAX || pos.is_draw())
+ if (pos.is_draw<true>() || ss->ply > PLY_MAX)
return VALUE_DRAW;
// Decide whether or not to include checks, this fixes also the type of
tte = TT.probe(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (!PvNode && tte && ok_to_use_TT(tte, ttDepth, beta, ss->ply))
+ if (!PvNode && tte && can_return_tt(tte, ttDepth, beta, ss->ply))
{
ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ss->ply);
else
ss->eval = bestValue = evaluate(pos, evalMargin);
- update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
-
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta)
{
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
- MovePicker mp(pos, ttMove, depth, H);
+ MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
- while ( alpha < beta
+ while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE)
{
assert(move_is_ok(move));
&& !pos.move_is_passed_pawn_push(move))
{
futilityValue = futilityBase
- + pos.endgame_value_of_piece_on(move_to(move))
+ + piece_value_endgame(pos.piece_on(move_to(move)))
+ (move_is_ep(move) ? PawnValueEndgame : VALUE_ZERO);
- if (futilityValue < alpha)
+ if (futilityValue < beta)
{
if (futilityValue > bestValue)
bestValue = futilityValue;
+
continue;
}
}
// Detect non-capture evasions that are candidate to be pruned
- evasionPrunable = inCheck
+ evasionPrunable = !PvNode
+ && inCheck
&& bestValue > VALUE_MATED_IN_PLY_MAX
&& !pos.move_is_capture(move)
&& !pos.can_castle(pos.side_to_move());
&& !inCheck
&& givesCheck
&& move != ttMove
- && !pos.move_is_capture(move)
- && !move_is_promotion(move)
+ && !pos.move_is_capture_or_promotion(move)
&& ss->eval + PawnValueMidgame / 4 < beta
&& !check_is_dangerous(pos, move, futilityBase, beta, &bestValue))
{
continue;
}
+ // Check for legality only before to do the move
+ if (!pos.pl_move_is_legal(move, ci.pinned))
+ continue;
+
// Update current move
ss->currentMove = move;
// Make and search the move
pos.do_move(move, st, ci, givesCheck);
- value = -qsearch<PvNode>(pos, ss+1, -beta, -alpha, depth-ONE_PLY);
+ value = -qsearch<NT>(pos, ss+1, -beta, -alpha, depth-ONE_PLY);
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
if (value > bestValue)
{
bestValue = value;
- if (value > alpha)
- {
+ ss->bestMove = move;
+
+ if ( PvNode
+ && value > alpha
+ && value < beta) // We want always alpha < beta
alpha = value;
- ss->bestMove = move;
- }
}
}
return value_mated_in(ss->ply);
// 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, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin);
+ move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
+ vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
+ : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
+
+ TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
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);
+ b = kingAtt & ~pos.pieces(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
+ if ( piece_type(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);
+ b = pos.pieces(them) & newAtt & ~oldAtt & ~(1ULL << ksq);
while (b)
{
victimSq = pop_1st_bit(&b);
- futilityValue = futilityBase + pos.endgame_value_of_piece_on(victimSq);
+ futilityValue = futilityBase + piece_value_endgame(pos.piece_on(victimSq));
// Note that here we generate illegal "double move"!
if ( futilityValue >= beta
bool connected_moves(const Position& pos, Move m1, Move m2) {
Square f1, t1, f2, t2;
- Piece p;
+ Piece p1, p2;
+ Square ksq;
assert(m1 && move_is_ok(m1));
assert(m2 && move_is_ok(m2));
return true;
// Case 3: Moving through the vacated square
- if ( piece_is_slider(pos.piece_on(f2))
+ p2 = pos.piece_on(f2);
+ if ( piece_is_slider(p2)
&& bit_is_set(squares_between(f2, t2), f1))
return true;
// Case 4: The destination square for m2 is defended by the moving piece in m1
- p = pos.piece_on(t1);
- if (bit_is_set(pos.attacks_from(p, t1), t2))
+ p1 = pos.piece_on(t1);
+ if (bit_is_set(pos.attacks_from(p1, t1), t2))
return true;
// Case 5: Discovered check, checking piece is the piece moved in m1
- if ( piece_is_slider(p)
- && bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), f2)
- && !bit_is_set(squares_between(t1, pos.king_square(pos.side_to_move())), t2))
+ ksq = pos.king_square(pos.side_to_move());
+ if ( piece_is_slider(p1)
+ && bit_is_set(squares_between(t1, ksq), f2))
{
- // discovered_check_candidates() works also if the Position's side to
- // move is the opposite of the checking piece.
- Color them = opposite_color(pos.side_to_move());
- Bitboard dcCandidates = pos.discovered_check_candidates(them);
-
- if (bit_is_set(dcCandidates, f2))
+ Bitboard occ = pos.occupied_squares();
+ clear_bit(&occ, f2);
+ if (bit_is_set(pos.attacks_from(p1, t1, occ), ksq))
return true;
}
return false;
}
- // extension() decides whether a move should be searched with normal depth,
- // or with extended depth. Certain classes of moves (checking moves, in
- // particular) are searched with bigger depth than ordinary moves and in
- // any case are marked as 'dangerous'. Note that also if a move is not
- // extended, as example because the corresponding UCI option is set to zero,
- // the move is marked as 'dangerous' so, at least, we avoid to prune it.
- template <NodeType PvNode>
- Depth extension(const Position& pos, Move m, bool captureOrPromotion,
- bool moveIsCheck, bool* dangerous) {
-
- assert(m != MOVE_NONE);
-
- Depth result = DEPTH_ZERO;
- *dangerous = moveIsCheck;
-
- if (moveIsCheck && pos.see_sign(m) >= 0)
- result += CheckExtension[PvNode];
-
- if (pos.type_of_piece_on(move_from(m)) == PAWN)
- {
- Color c = pos.side_to_move();
- if (relative_rank(c, move_to(m)) == RANK_7)
- {
- result += PawnPushTo7thExtension[PvNode];
- *dangerous = true;
- }
- if (pos.pawn_is_passed(c, move_to(m)))
- {
- result += PassedPawnExtension[PvNode];
- *dangerous = true;
- }
- }
-
- if ( captureOrPromotion
- && pos.type_of_piece_on(move_to(m)) != PAWN
- && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- - pos.midgame_value_of_piece_on(move_to(m)) == VALUE_ZERO)
- && !move_is_special(m))
- {
- result += PawnEndgameExtension[PvNode];
- *dangerous = true;
- }
-
- return Min(result, ONE_PLY);
- }
-
-
// connected_threat() tests whether it is safe to forward prune a move or if
// is somehow connected to the threat move returned by null search.
assert(move_is_ok(m));
assert(threat && move_is_ok(threat));
- assert(!pos.move_gives_check(m));
- assert(!pos.move_is_capture(m) && !move_is_promotion(m));
+ assert(!pos.move_is_capture_or_promotion(m));
assert(!pos.move_is_passed_pawn_push(m));
Square mfrom, mto, tfrom, tto;
// Case 2: If the threatened piece has value less than or equal to the
// value of the threatening piece, don't prune moves which defend it.
if ( pos.move_is_capture(threat)
- && ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto)
- || pos.type_of_piece_on(tfrom) == KING)
+ && ( piece_value_midgame(pos.piece_on(tfrom)) >= piece_value_midgame(pos.piece_on(tto))
+ || piece_type(pos.piece_on(tfrom)) == KING)
&& pos.move_attacks_square(m, tto))
return true;
}
- // ok_to_use_TT() returns true if a transposition table score
- // can be used at a given point in search.
+ // can_return_tt() returns true if a transposition table score
+ // can be used to cut-off at a given point in search.
- bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply) {
+ bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply) {
Value v = value_from_tt(tte->value(), ply);
}
- // value_to_uci() converts a value to a string suitable for use with the UCI
+ // score_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) {
+ string score_to_uci(Value v, Value alpha, Value beta) {
std::stringstream s;
if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
+ s << " score cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
else
- s << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
+ s << " score mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
+
+ s << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
return s.str();
}
// speed_to_uci() returns a string with time stats of current search suitable
// to be sent to UCI gui.
- std::string speed_to_uci(int64_t nodes) {
+ string speed_to_uci(int64_t nodes) {
std::stringstream s;
int t = current_search_time();
s << " nodes " << nodes
- << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0)
+ << " nps " << (t > 0 ? int(nodes * 1000 / t) : 0)
<< " time " << t;
return s.str();
}
+ // pv_to_uci() returns a string with information on the current PV line
+ // formatted according to UCI specification.
+
+ string pv_to_uci(const Move pv[], int pvNum, bool chess960) {
+
+ std::stringstream s;
+
+ s << " multipv " << pvNum << " pv " << set960(chess960);
+
+ for ( ; *pv != MOVE_NONE; pv++)
+ s << *pv << " ";
+
+ return s.str();
+ }
+
+ // depth_to_uci() returns a string with information on the current depth and
+ // seldepth formatted according to UCI specification.
+
+ string depth_to_uci(Depth depth) {
+
+ std::stringstream s;
+
+ // Retrieve max searched depth among threads
+ int selDepth = 0;
+ for (int i = 0; i < Threads.size(); i++)
+ if (Threads[i].maxPly > selDepth)
+ selDepth = Threads[i].maxPly;
+
+ s << " depth " << depth / ONE_PLY << " seldepth " << selDepth;
+
+ return s.str();
+ }
+
+ string time_to_string(int millisecs) {
+
+ const int MSecMinute = 1000 * 60;
+ const int MSecHour = 1000 * 60 * 60;
+
+ int hours = millisecs / MSecHour;
+ int minutes = (millisecs % MSecHour) / MSecMinute;
+ int seconds = ((millisecs % MSecHour) % MSecMinute) / 1000;
+
+ std::stringstream s;
+
+ if (hours)
+ s << hours << ':';
+
+ s << std::setfill('0') << std::setw(2) << minutes << ':' << std::setw(2) << seconds;
+ return s.str();
+ }
+
+ string score_to_string(Value v) {
+
+ std::stringstream s;
+
+ if (v >= VALUE_MATE_IN_PLY_MAX)
+ s << "#" << (VALUE_MATE - v + 1) / 2;
+ else if (v <= VALUE_MATED_IN_PLY_MAX)
+ s << "-#" << (VALUE_MATE + v) / 2;
+ else
+ s << std::setprecision(2) << std::fixed << std::showpos << float(v) / PawnValueMidgame;
+
+ return s.str();
+ }
+
+ // pretty_pv() creates a human-readable string from a position and a PV.
+ // It is used to write search information to the log file (which is created
+ // when the UCI parameter "Use Search Log" is "true").
+
+ string pretty_pv(Position& pos, int depth, Value value, int time, Move pv[]) {
+
+ const int64_t K = 1000;
+ const int64_t M = 1000000;
+ const int startColumn = 28;
+ const size_t maxLength = 80 - startColumn;
+
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ Move* m = pv;
+ string san;
+ std::stringstream s;
+ size_t length = 0;
+
+ // First print depth, score, time and searched nodes...
+ s << set960(pos.is_chess960())
+ << std::setw(2) << depth
+ << std::setw(8) << score_to_string(value)
+ << std::setw(8) << time_to_string(time);
+
+ if (pos.nodes_searched() < M)
+ s << std::setw(8) << pos.nodes_searched() / 1 << " ";
+ else if (pos.nodes_searched() < K * M)
+ s << std::setw(7) << pos.nodes_searched() / K << "K ";
+ else
+ s << std::setw(7) << pos.nodes_searched() / M << "M ";
+
+ // ...then print the full PV line in short algebraic notation
+ while (*m != MOVE_NONE)
+ {
+ san = move_to_san(pos, *m);
+ length += san.length() + 1;
+
+ if (length > maxLength)
+ {
+ length = san.length() + 1;
+ s << "\n" + string(startColumn, ' ');
+ }
+ s << san << ' ';
+
+ pos.do_move(*m++, *st++);
+ }
+
+ // Restore original position before to leave
+ while (m != pv) pos.undo_move(*--m);
+
+ return s.str();
+ }
// poll() performs two different functions: It polls for user input, and it
// looks at the time consumed so far and decides if it's time to abort the
if (input_available())
{
// We are line oriented, don't read single chars
- std::string command;
+ string command;
if (!std::getline(std::cin, command) || command == "quit")
{
dbg_print_mean();
dbg_print_hit_rate();
-
- // Send info on searched nodes as soon as we return to root
- SendSearchedNodes = true;
}
// Should we stop the search?
void wait_for_stop_or_ponderhit() {
- std::string command;
+ string command;
// Wait for a command from stdin
while ( std::getline(std::cin, command)
static RKISS rk;
- // Rml list is already sorted by pv_score in descending order
+ // Rml list is already sorted by score in descending order
int s;
int max_s = -VALUE_INFINITE;
int size = Min(MultiPV, (int)Rml.size());
- int max = Rml[0].pv_score;
- int var = Min(max - Rml[size - 1].pv_score, PawnValueMidgame);
+ int max = Rml[0].score;
+ int var = Min(max - Rml[size - 1].score, PawnValueMidgame);
int wk = 120 - 2 * SkillLevel;
// PRNG sequence should be non deterministic
// then we choose the move with the resulting highest score.
for (int i = 0; i < size; i++)
{
- s = Rml[i].pv_score;
+ s = Rml[i].score;
// Don't allow crazy blunders even at very low skills
- if (i > 0 && Rml[i-1].pv_score > s + EasyMoveMargin)
+ if (i > 0 && Rml[i-1].score > s + EasyMoveMargin)
break;
// This is our magical formula
/// 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;
- }
-
void RootMoveList::init(Position& pos, Move searchMoves[]) {
- MoveStack mlist[MAX_MOVES];
Move* sm;
-
- clear();
bestMoveChanges = 0;
+ clear();
// Generate all legal moves and add them to RootMoveList
- MoveStack* last = generate<MV_LEGAL>(pos, mlist);
- for (MoveStack* cur = mlist; cur != last; cur++)
+ for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
{
- // If we have a searchMoves[] list then verify cur->move
+ // If we have a searchMoves[] list then verify the move
// is in the list before to add it.
- for (sm = searchMoves; *sm && *sm != cur->move; sm++) {}
+ for (sm = searchMoves; *sm && *sm != ml.move(); sm++) {}
- if (searchMoves[0] && *sm != cur->move)
+ if (sm != searchMoves && *sm != ml.move())
continue;
RootMove rm;
- rm.pv[0] = cur->move;
- rm.pv[1] = MOVE_NONE;
- rm.pv_score = -VALUE_INFINITE;
+ rm.pv.push_back(ml.move());
+ rm.pv.push_back(MOVE_NONE);
+ rm.score = rm.prevScore = -VALUE_INFINITE;
+ rm.nodes = 0;
push_back(rm);
}
}
+ RootMove* RootMoveList::find(const Move& m, int startIndex) {
+
+ for (size_t i = startIndex; i < size(); i++)
+ if ((*this)[i].pv[0] == m)
+ return &(*this)[i];
+
+ return NULL;
+ }
+
// 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
StateInfo state[PLY_MAX_PLUS_2], *st = state;
TTEntry* tte;
int ply = 1;
+ Move m = pv[0];
- assert(pv[0] != MOVE_NONE && pos.move_is_pl(pv[0]));
+ assert(m != MOVE_NONE && pos.move_is_pl(m));
- pos.do_move(pv[0], *st++);
-
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+ pv.clear();
+ pv.push_back(m);
+ pos.do_move(m, *st++);
while ( (tte = TT.probe(pos.get_key())) != NULL
&& tte->move() != MOVE_NONE
&& pos.move_is_pl(tte->move())
- && pos.pl_move_is_legal(tte->move(), pinned)
+ && pos.pl_move_is_legal(tte->move(), pos.pinned_pieces())
&& ply < PLY_MAX
- && (!pos.is_draw() || ply < 2))
+ && (!pos.is_draw<false>() || ply < 2))
{
- pv[ply] = tte->move();
- pos.do_move(pv[ply++], *st++);
+ pv.push_back(tte->move());
+ pos.do_move(tte->move(), *st++);
+ ply++;
}
- pv[ply] = MOVE_NONE;
+ pv.push_back(MOVE_NONE);
do pos.undo_move(pv[--ply]); while (ply);
}
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.
-
- std::string RootMove::pv_info_to_uci(Position& pos, int depth, int selDepth, Value alpha,
- Value beta, int pvIdx) {
- std::stringstream s;
-
- s << "info depth " << depth
- << " seldepth " << selDepth
- << " multipv " << pvIdx + 1
- << " score " << value_to_uci(pv_score)
- << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "")
- << speed_to_uci(pos.nodes_searched())
- << " pv ";
-
- for (Move* m = pv; *m != MOVE_NONE; m++)
- s << *m << " ";
-
- return s.str();
- }
-
- // Specializations for MovePickerExt in case of Root node
- MovePickerExt<false, true>::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 standard ordering used in main search, the moves
- // are scored according to the order in which they are returned by MovePicker.
- // This is the second order score that is used to compare the moves when
- // the first orders pv_score 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 MovePickerExt<false, true>::get_next_move() {
-
- if (!firstCall)
- ++rm;
- else
- firstCall = false;
-
- return rm != Rml.end() ? rm->pv[0] : MOVE_NONE;
- }
-
} // namespace
memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack));
(ss+1)->sp = tsp;
- if (tsp->pvNode)
- search<PV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
+ if (tsp->nodeType == Root)
+ search<SplitPointRoot>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
+ else if (tsp->nodeType == PV)
+ search<SplitPointPV>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
+ else if (tsp->nodeType == NonPV)
+ search<SplitPointNonPV>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
else
- search<NonPV, true, false>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
+ assert(false);
assert(threads[threadID].state == Thread::SEARCHING);
// In helpful master concept a master can help only a sub-tree, and
// because here is all finished is not possible master is booked.
assert(threads[threadID].state == Thread::AVAILABLE);
-
- threads[threadID].state = Thread::SEARCHING;
return;
}
}
projects / stockfish / blobdiff