/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include <cassert>
#include <cmath>
#include <cstring>
-#include <iomanip>
#include <iostream>
#include <sstream>
-#include <vector>
#include "book.h"
#include "evaluate.h"
#include "history.h"
-#include "misc.h"
#include "movegen.h"
#include "movepick.h"
+#include "notation.h"
#include "search.h"
#include "timeman.h"
#include "thread.h"
volatile SignalsType Signals;
LimitsType Limits;
- std::vector<Move> SearchMoves;
+ std::vector<RootMove> RootMoves;
Position RootPosition;
+ Time::point SearchTime;
+ StateStackPtr SetupStates;
}
-using std::cout;
-using std::endl;
using std::string;
+using Eval::evaluate;
using namespace Search;
namespace {
// Set to true to force running with one thread. Used for debugging
const bool FakeSplit = false;
+ // This is the minimum interval in msec between two check_time() calls
+ const int TimerResolution = 5;
+
// Different node types, used as template parameter
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 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(Move m) {
- nodes = 0;
- score = prevScore = -VALUE_INFINITE;
- pv.push_back(m);
- pv.push_back(MOVE_NONE);
- }
-
- bool operator<(const RootMove& m) const { return score < m.score; }
- bool operator==(const Move& m) const { return pv[0] == m; }
-
- void extract_pv_from_tt(Position& pos);
- void insert_pv_in_tt(Position& pos);
-
- int64_t nodes;
- Value score;
- Value prevScore;
- std::vector<Move> pv;
- };
-
-
- /// Constants
-
// Lookup table to check if a Piece is a slider and its access function
const bool Slidings[18] = { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1 };
inline bool piece_is_slider(Piece p) { return Slidings[p]; }
- // Maximum depth for razoring
- const Depth RazorDepth = 4 * ONE_PLY;
-
// Dynamic razoring margin based on depth
- inline Value razor_margin(Depth d) { return Value(0x200 + 0x10 * int(d)); }
-
- // Maximum depth for use of dynamic threat detection when null move fails low
- const Depth ThreatDepth = 5 * ONE_PLY;
-
- // Minimum depth for use of internal iterative deepening
- const Depth IIDDepth[] = { 8 * ONE_PLY, 5 * ONE_PLY };
-
- // At Non-PV nodes we do an internal iterative deepening search
- // when the static evaluation is bigger then beta - IIDMargin.
- const Value IIDMargin = Value(0x100);
-
- // Minimum depth for use of singular extension
- const Depth SingularExtensionDepth[] = { 8 * ONE_PLY, 6 * ONE_PLY };
-
- // Futility margin for quiescence search
- const Value FutilityMarginQS = Value(0x80);
+ inline Value razor_margin(Depth d) { return Value(512 + 16 * int(d)); }
// Futility lookup tables (initialized at startup) and their access functions
Value FutilityMargins[16][64]; // [depth][moveNumber]
: 2 * VALUE_INFINITE;
}
- inline int futility_move_count(Depth d) {
-
- return d < 16 * ONE_PLY ? FutilityMoveCounts[d] : MAX_MOVES;
- }
-
// Reduction lookup tables (initialized at startup) and their access function
int8_t Reductions[2][64][64]; // [pv][depth][moveNumber]
return (Depth) Reductions[PvNode][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
- // Easy move margin. An easy move candidate must be at least this much
- // better than the second best move.
- const Value EasyMoveMargin = Value(0x150);
-
-
- /// Namespace variables
-
- std::vector<RootMove> RootMoves;
- size_t MultiPV, UCIMultiPV, MultiPVIdx;
+ size_t MultiPV, UCIMultiPV, PVIdx;
TimeManager TimeMgr;
int BestMoveChanges;
int SkillLevel;
- bool SkillLevelEnabled;
+ bool SkillLevelEnabled, Chess960;
History H;
-
- /// Local functions
-
- Move id_loop(Position& pos, Move* ponderMove);
-
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
template <NodeType NT>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
- bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bValue);
+ void id_loop(Position& pos);
+ bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta);
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 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 elapsed_time(bool reset = false);
- 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);
-
- // MovePickerExt class template 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, Stack* 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, Stack* 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) {
-
- bool chess960 = (os.iword(0) != 0); // See set960()
- return os << move_to_uci(m, chess960);
- }
-
- // When formatting a move for std::cout we must know if we are in Chess960 or
- // not. To keep using the handy operator<<() on the move the trick is to embed
- // this flag in the stream itself. Function-like named enum set960 is used as
- // a custom manipulator and the stream internal general-purpose array, accessed
- // through ios_base::iword(), is used to pass the flag to the move's operator<<
- // that will read it to properly format castling moves.
- enum set960 {};
-
- std::ostream& operator<<(std::ostream& os, const set960& f) {
-
- os.iword(0) = f;
- return os;
- }
-
- // is_dangerous() checks whether a move belongs to some classes of known
- // 'dangerous' moves so that we avoid to prune it.
- FORCE_INLINE bool is_dangerous(const Position& pos, Move m, bool captureOrPromotion) {
-
- // Test for a pawn pushed to 7th or a passed pawn move
- if (type_of(pos.piece_on(move_from(m))) == PAWN)
- {
- Color c = pos.side_to_move();
- if ( relative_rank(c, move_to(m)) == RANK_7
- || pos.pawn_is_passed(c, move_to(m)))
- return true;
- }
-
- // Test for a capture that triggers a pawn endgame
- if ( captureOrPromotion
- && type_of(pos.piece_on(move_to(m))) != PAWN
- && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- - PieceValueMidgame[pos.piece_on(move_to(m))] == VALUE_ZERO)
- && !is_special(m))
- return true;
-
- return false;
- }
+ Value refine_eval(const TTEntry* tte, Value ttValue, Value defaultEval);
+ Move do_skill_level();
+ string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
} // namespace
-/// init_search() is called during startup to initialize various lookup tables
+/// Search::init() is called during startup to initialize various lookup tables
void Search::init() {
}
-/// perft() is our utility to verify move generation. All the leaf nodes up to
-/// the given depth are generated and counted and the sum returned.
-
-int64_t Search::perft(Position& pos, Depth depth) {
-
- StateInfo st;
- int64_t sum = 0;
+/// Search::perft() is our utility to verify move generation. All the leaf nodes
+/// up to the given depth are generated and counted and the sum returned.
- MoveList<MV_LEGAL> ml(pos);
+size_t Search::perft(Position& pos, Depth depth) {
- // At the last ply just return the number of moves (leaf nodes)
- if (depth <= ONE_PLY)
- return ml.size();
+ // At the last ply just return the number of legal moves (leaf nodes)
+ if (depth == ONE_PLY)
+ return MoveList<LEGAL>(pos).size();
+ StateInfo st;
+ size_t cnt = 0;
CheckInfo ci(pos);
- for ( ; !ml.end(); ++ml)
+
+ for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
{
pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci));
- sum += perft(pos, depth - ONE_PLY);
+ cnt += perft(pos, depth - ONE_PLY);
pos.undo_move(ml.move());
}
- return sum;
+
+ return cnt;
}
-/// think() is the external interface to Stockfish's search, and is called by the
-/// main thread when the program receives the UCI 'go' command. It searches from
-/// RootPosition and at the end prints the "bestmove" to output.
+/// Search::think() is the external interface to Stockfish's search, and is
+/// called by the main thread when the program receives the UCI 'go' command. It
+/// searches from RootPosition and at the end prints the "bestmove" to output.
void Search::think() {
- static Book book; // Defined static to initialize the PRNG only once
+ static PolyglotBook book; // Defined static to initialize the PRNG only once
Position& pos = RootPosition;
- elapsed_time(true);
- TimeMgr.init(Limits, pos.startpos_ply_counter());
+ Chess960 = pos.is_chess960();
+ Eval::RootColor = pos.side_to_move();
+ int scaledCF = Eval::ContemptFactor * MaterialTable::game_phase(pos) / PHASE_MIDGAME;
+ Eval::ValueDraw[ Eval::RootColor] = VALUE_DRAW - Value(scaledCF);
+ Eval::ValueDraw[~Eval::RootColor] = VALUE_DRAW + Value(scaledCF);
+ TimeMgr.init(Limits, pos.startpos_ply_counter(), pos.side_to_move());
+ TT.new_search();
+ H.clear();
+
+ if (RootMoves.empty())
+ {
+ sync_cout << "info depth 0 score "
+ << score_to_uci(pos.in_check() ? -VALUE_MATE : VALUE_DRAW) << sync_endl;
- // Set output stream mode: normal or chess960. Castling notation is different
- cout << set960(pos.is_chess960());
+ RootMoves.push_back(MOVE_NONE);
+ goto finalize;
+ }
- if (Options["OwnBook"].value<bool>())
+ if (Options["OwnBook"] && !Limits.infinite)
{
- if (Options["Book File"].value<string>() != book.name())
- book.open(Options["Book File"].value<string>());
+ Move bookMove = book.probe(pos, Options["Book File"], Options["Best Book Move"]);
- Move bookMove = book.probe(pos, Options["Best Book Move"].value<bool>());
- if (bookMove != MOVE_NONE)
+ if (bookMove && std::count(RootMoves.begin(), RootMoves.end(), bookMove))
{
- if (!Signals.stop && (Limits.ponder || Limits.infinite))
- Threads.wait_for_stop_or_ponderhit();
-
- cout << "bestmove " << bookMove << endl;
- return;
+ std::swap(RootMoves[0], *std::find(RootMoves.begin(), RootMoves.end(), bookMove));
+ goto finalize;
}
}
- // Read UCI options: GUI could change UCI parameters during the game
- read_evaluation_uci_options(pos.side_to_move());
- Threads.read_uci_options();
-
- TT.set_size(Options["Hash"].value<int>());
- if (Options["Clear Hash"].value<bool>())
- {
- Options["Clear Hash"].set_value("false");
- TT.clear();
- }
-
- UCIMultiPV = Options["MultiPV"].value<size_t>();
- SkillLevel = Options["Skill Level"].value<int>();
+ UCIMultiPV = Options["MultiPV"];
+ SkillLevel = Options["Skill Level"];
// Do we have to play with skill handicap? In this case enable MultiPV that
// we will use behind the scenes to retrieve a set of possible moves.
SkillLevelEnabled = (SkillLevel < 20);
MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, (size_t)4) : UCIMultiPV);
- if (Options["Use Search Log"].value<bool>())
+ if (Options["Use Search Log"])
{
- Log log(Options["Search Log Filename"].value<string>());
+ Log log(Options["Search Log Filename"]);
log << "\nSearching: " << pos.to_fen()
<< "\ninfinite: " << Limits.infinite
<< " ponder: " << Limits.ponder
- << " time: " << Limits.time
- << " increment: " << Limits.increment
- << " moves to go: " << Limits.movesToGo
- << endl;
+ << " time: " << Limits.time[pos.side_to_move()]
+ << " increment: " << Limits.inc[pos.side_to_move()]
+ << " moves to go: " << Limits.movestogo
+ << std::endl;
}
- // Wake up needed threads and reset maxPly counter
- for (int i = 0; i < Threads.size(); i++)
- {
- Threads[i].maxPly = 0;
- Threads[i].wake_up();
- }
+ Threads.wake_up();
// Set best timer interval to avoid lagging under time pressure. Timer is
// used to check for remaining available thinking time.
- if (TimeMgr.available_time())
- Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 8, 20)));
+ if (Limits.use_time_management())
+ Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution)));
+ else if (Limits.nodes)
+ Threads.set_timer(2 * TimerResolution);
else
Threads.set_timer(100);
- // We're ready to start thinking. Call the iterative deepening loop function
- Move ponderMove = MOVE_NONE;
- Move bestMove = id_loop(pos, &ponderMove);
+ // We're ready to start searching. Call the iterative deepening loop function
+ id_loop(pos);
- // Stop timer and send all the slaves to sleep, if not already sleeping
- Threads.set_timer(0);
- Threads.set_size(1);
+ Threads.set_timer(0); // Stop timer
+ Threads.sleep();
- if (Options["Use Search Log"].value<bool>())
+ if (Options["Use Search Log"])
{
- int e = elapsed_time();
+ Time::point elapsed = Time::now() - SearchTime + 1;
- Log log(Options["Search Log Filename"].value<string>());
+ Log log(Options["Search Log Filename"]);
log << "Nodes: " << pos.nodes_searched()
- << "\nNodes/second: " << (e > 0 ? pos.nodes_searched() * 1000 / e : 0)
- << "\nBest move: " << move_to_san(pos, bestMove);
+ << "\nNodes/second: " << pos.nodes_searched() * 1000 / elapsed
+ << "\nBest move: " << move_to_san(pos, RootMoves[0].pv[0]);
StateInfo st;
- pos.do_move(bestMove, st);
- log << "\nPonder move: " << move_to_san(pos, ponderMove) << endl;
- pos.undo_move(bestMove); // Return from think() with unchanged position
+ pos.do_move(RootMoves[0].pv[0], st);
+ log << "\nPonder move: " << move_to_san(pos, RootMoves[0].pv[1]) << std::endl;
+ pos.undo_move(RootMoves[0].pv[0]);
}
- // When we reach max depth we arrive here even without a StopRequest, but if
- // we are pondering or in infinite search, we shouldn't print the best move
- // before we are told to do so.
- if (!Signals.stop && (Limits.ponder || Limits.infinite))
- Threads.wait_for_stop_or_ponderhit();
+finalize:
- // Could be MOVE_NONE when searching on a stalemate position
- cout << "bestmove " << bestMove;
-
- // UCI protol is not clear on allowing sending an empty ponder move, instead
- // it is clear that ponder move is optional. So skip it if empty.
- if (ponderMove != MOVE_NONE)
- cout << " ponder " << ponderMove;
+ // When we reach max depth we arrive here even without Signals.stop is raised,
+ // but if we are pondering or in infinite search, we shouldn't print the best
+ // move before we are told to do so.
+ if (!Signals.stop && (Limits.ponder || Limits.infinite))
+ pos.this_thread()->wait_for_stop_or_ponderhit();
- cout << endl;
+ // Best move could be MOVE_NONE when searching on a stalemate position
+ sync_cout << "bestmove " << move_to_uci(RootMoves[0].pv[0], Chess960)
+ << " ponder " << move_to_uci(RootMoves[0].pv[1], Chess960) << sync_endl;
}
// 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* ponderMove) {
+ void id_loop(Position& pos) {
- Stack ss[PLY_MAX_PLUS_2];
- Value bestValues[PLY_MAX_PLUS_2];
- int bestMoveChanges[PLY_MAX_PLUS_2];
- int depth, aspirationDelta;
- Value bestValue, alpha, beta;
- Move bestMove, skillBest, skillPonder;
+ Stack ss[MAX_PLY_PLUS_2];
+ int depth, prevBestMoveChanges;
+ Value bestValue, alpha, beta, delta;
bool bestMoveNeverChanged = true;
+ Move skillBest = MOVE_NONE;
memset(ss, 0, 4 * sizeof(Stack));
- TT.new_search();
- H.clear();
- RootMoves.clear();
- *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE;
- depth = aspirationDelta = 0;
- bestValue = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ depth = BestMoveChanges = 0;
+ bestValue = delta = -VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update gains
- for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
- if ( SearchMoves.empty()
- || std::count(SearchMoves.begin(), SearchMoves.end(), ml.move()))
- RootMoves.push_back(RootMove(ml.move()));
-
- // Handle special case of searching on a mate/stalemate position
- if (RootMoves.empty())
- {
- 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 (!Signals.stop && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
+ while (!Signals.stop && ++depth <= MAX_PLY && (!Limits.depth || depth <= Limits.depth))
{
- // Save now last iteration's scores, before Rml moves are reordered
+ // Save last iteration's scores before first PV line is searched and all
+ // the move scores but the (new) PV are set to -VALUE_INFINITE.
for (size_t i = 0; i < RootMoves.size(); i++)
RootMoves[i].prevScore = RootMoves[i].score;
+ prevBestMoveChanges = BestMoveChanges;
BestMoveChanges = 0;
// MultiPV loop. We perform a full root search for each PV line
- for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, RootMoves.size()); MultiPVIdx++)
+ for (PVIdx = 0; PVIdx < std::min(MultiPV, RootMoves.size()); PVIdx++)
{
- // Calculate dynamic aspiration window based on previous iterations
- if (depth >= 5 && abs(RootMoves[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN)
+ // Set aspiration window default width
+ if (depth >= 5 && abs(RootMoves[PVIdx].prevScore) < VALUE_KNOWN_WIN)
{
- int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2];
- int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3];
-
- aspirationDelta = std::min(std::max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
- aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
-
- alpha = std::max(RootMoves[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE);
- beta = std::min(RootMoves[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE);
+ delta = Value(16);
+ alpha = RootMoves[PVIdx].prevScore - delta;
+ beta = RootMoves[PVIdx].prevScore + delta;
}
else
{
// Start with a small aspiration window and, in case of fail high/low,
// research with bigger window until not failing high/low anymore.
- do {
+ while (true)
+ {
// Search starts from ss+1 to allow referencing (ss-1). This is
// needed by update gains and ss copy when splitting at Root.
bestValue = search<Root>(pos, ss+1, alpha, beta, depth * ONE_PLY);
// we want to keep the same order for all the moves but the new
// PV that goes to the front. Note that in case of MultiPV search
// the already searched PV lines are preserved.
- sort<RootMove>(RootMoves.begin() + MultiPVIdx, RootMoves.end());
+ sort<RootMove>(RootMoves.begin() + PVIdx, RootMoves.end());
// In case we have found an exact score and we are going to leave
// the fail high/low loop then reorder the PV moves, otherwise
// leave the last PV move in its position so to be searched again.
// Of course this is needed only in MultiPV search.
- if (MultiPVIdx && bestValue > alpha && bestValue < beta)
- sort<RootMove>(RootMoves.begin(), RootMoves.begin() + MultiPVIdx);
+ if (PVIdx && bestValue > alpha && bestValue < beta)
+ sort<RootMove>(RootMoves.begin(), RootMoves.begin() + PVIdx);
- // Write PV back to transposition table in case the relevant entries
- // have been overwritten during the search.
- for (size_t i = 0; i <= MultiPVIdx; i++)
+ // Write PV back to transposition table in case the relevant
+ // entries have been overwritten during the search.
+ for (size_t i = 0; i <= PVIdx; i++)
RootMoves[i].insert_pv_in_tt(pos);
- // If search has been stopped exit the aspiration window loop,
- // note that sorting and writing PV back to TT is safe becuase
- // Rml is still valid, although refers to the previous iteration.
+ // If search has been stopped exit the aspiration window loop.
+ // Sorting and writing PV back to TT is safe becuase RootMoves
+ // is still valid, although refers to previous iteration.
if (Signals.stop)
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. UCI
- // protocol requires to send all the PV lines also if are still
- // to be searched and so refer to the previous search's score.
- if ((bestValue > alpha && bestValue < beta) || elapsed_time() > 2000)
- for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++)
- {
- bool updated = (i <= MultiPVIdx);
-
- if (depth == 1 && !updated)
- continue;
-
- Depth d = (updated ? depth : depth - 1) * ONE_PLY;
- Value s = (updated ? RootMoves[i].score : RootMoves[i].prevScore);
-
- cout << "info"
- << depth_to_uci(d)
- << (i == MultiPVIdx ? score_to_uci(s, alpha, beta) : score_to_uci(s))
- << speed_to_uci(pos.nodes_searched())
- << pv_to_uci(&RootMoves[i].pv[0], i + 1, pos.is_chess960())
- << endl;
- }
+ // if we have a fail high/low and we are deep in the search.
+ if ((bestValue > alpha && bestValue < beta) || Time::now() - SearchTime > 2000)
+ sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
// In case of failing high/low increase aspiration window and
// research, otherwise exit the fail high/low loop.
if (bestValue >= beta)
{
- beta = std::min(beta + aspirationDelta, VALUE_INFINITE);
- aspirationDelta += aspirationDelta / 2;
+ beta += delta;
+ delta += delta / 2;
}
else if (bestValue <= alpha)
{
Signals.failedLowAtRoot = true;
Signals.stopOnPonderhit = false;
- alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE);
- aspirationDelta += aspirationDelta / 2;
+ alpha -= delta;
+ delta += delta / 2;
}
else
break;
- } while (abs(bestValue) < VALUE_KNOWN_WIN);
- }
+ // Search with full window in case we have a win/mate score
+ if (abs(bestValue) >= VALUE_KNOWN_WIN)
+ {
+ alpha = -VALUE_INFINITE;
+ beta = VALUE_INFINITE;
+ }
- bestMove = RootMoves[0].pv[0];
- *ponderMove = RootMoves[0].pv[1];
- bestValues[depth] = bestValue;
- bestMoveChanges[depth] = BestMoveChanges;
+ assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
+ }
+ }
- // Skills: Do we need to pick now the best and the ponder moves ?
+ // Skills: Do we need to pick now the best move ?
if (SkillLevelEnabled && depth == 1 + SkillLevel)
- do_skill_level(&skillBest, &skillPonder);
+ skillBest = do_skill_level();
- if (Options["Use Search Log"].value<bool>())
+ if (!Signals.stop && Options["Use Search Log"])
{
- Log log(Options["Search Log Filename"].value<string>());
- log << pretty_pv(pos, depth, bestValue, elapsed_time(), &RootMoves[0].pv[0]) << endl;
+ Log log(Options["Search Log Filename"]);
+ log << pretty_pv(pos, depth, bestValue, Time::now() - SearchTime, &RootMoves[0].pv[0])
+ << std::endl;
}
// Filter out startup noise when monitoring best move stability
- if (depth > 2 && bestMoveChanges[depth])
+ if (depth > 2 && BestMoveChanges)
bestMoveNeverChanged = false;
// Do we have time for the next iteration? Can we stop searching now?
- if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement())
+ if (!Signals.stop && !Signals.stopOnPonderhit && Limits.use_time_management())
{
- bool stop = false; // Local variable instead of the volatile Signals.stop
+ bool stop = false; // Local variable, not the volatile Signals.stop
// Take in account some extra time if the best move has changed
if (depth > 4 && depth < 50)
- TimeMgr.pv_instability(bestMoveChanges[depth], bestMoveChanges[depth - 1]);
+ TimeMgr.pv_instability(BestMoveChanges, prevBestMoveChanges);
- // Stop search if most of available time is already consumed. We probably don't
- // have enough time to search the first move at the next iteration anyway.
- if (elapsed_time() > (TimeMgr.available_time() * 62) / 100)
+ // Stop search if most of available time is already consumed. We
+ // probably don't have enough time to search the first move at the
+ // next iteration anyway.
+ if (Time::now() - SearchTime > (TimeMgr.available_time() * 62) / 100)
stop = true;
// Stop search early if one move seems to be much better than others
- if ( depth >= 10
+ if ( depth >= 12
&& !stop
- && ( bestMoveNeverChanged
- || elapsed_time() > (TimeMgr.available_time() * 40) / 100))
+ && ( (bestMoveNeverChanged && pos.captured_piece_type())
+ || Time::now() - SearchTime > (TimeMgr.available_time() * 40) / 100))
{
- Value rBeta = bestValue - EasyMoveMargin;
- (ss+1)->excludedMove = bestMove;
+ Value rBeta = bestValue - 2 * PawnValueMg;
+ (ss+1)->excludedMove = RootMoves[0].pv[0];
(ss+1)->skipNullMove = true;
- Value v = search<NonPV>(pos, ss+1, rBeta - 1, rBeta, (depth * ONE_PLY) / 2);
+ Value v = search<NonPV>(pos, ss+1, rBeta - 1, rBeta, (depth - 3) * ONE_PLY);
(ss+1)->skipNullMove = false;
(ss+1)->excludedMove = MOVE_NONE;
}
}
- // When using skills overwrite best and ponder moves with the sub-optimal ones
+ // When using skills swap best PV line with the sub-optimal one
if (SkillLevelEnabled)
{
if (skillBest == MOVE_NONE) // Still unassigned ?
- do_skill_level(&skillBest, &skillPonder);
+ skillBest = do_skill_level();
- bestMove = skillBest;
- *ponderMove = skillPonder;
+ std::swap(RootMoves[0], *std::find(RootMoves.begin(), RootMoves.end(), skillBest));
}
-
- return bestMove;
}
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);
- assert(pos.thread() >= 0 && pos.thread() < Threads.size());
+ assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
+ assert(PvNode || (alpha == beta - 1));
+ assert(depth > DEPTH_ZERO);
- Move movesSearched[MAX_MOVES];
- int64_t nodes;
+ Move movesSearched[64];
StateInfo st;
const TTEntry *tte;
+ SplitPoint* sp;
Key posKey;
- Move ttMove, move, excludedMove, threatMove;
+ Move ttMove, move, excludedMove, bestMove, threatMove;
Depth ext, newDepth;
- ValueType vt;
- Value bestValue, value, oldAlpha;
- Value refinedValue, nullValue, futilityBase, futilityValue;
- bool isPvMove, inCheck, singularExtensionNode, givesCheck;
+ Value bestValue, value, ttValue;
+ Value refinedValue, nullValue, futilityValue;
+ bool inCheck, givesCheck, pvMove, singularExtensionNode;
bool captureOrPromotion, dangerous, doFullDepthSearch;
- int moveCount = 0, playedMoveCount = 0;
- Thread& thread = Threads[pos.thread()];
- SplitPoint* sp = NULL;
+ int moveCount, playedMoveCount;
- refinedValue = bestValue = value = -VALUE_INFINITE;
- oldAlpha = alpha;
+ // Step 1. Initialize node
+ Thread* thisThread = pos.this_thread();
+ moveCount = playedMoveCount = 0;
inCheck = pos.in_check();
- ss->ply = (ss-1)->ply + 1;
-
- // Used to send selDepth info to GUI
- if (PvNode && thread.maxPly < ss->ply)
- thread.maxPly = ss->ply;
- // Step 1. Initialize node
- 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
+ if (SpNode)
{
sp = ss->sp;
+ bestMove = sp->bestMove;
+ threatMove = sp->threatMove;
+ bestValue = sp->bestValue;
tte = NULL;
ttMove = excludedMove = MOVE_NONE;
- threatMove = sp->threatMove;
+ ttValue = VALUE_NONE;
+
+ assert(sp->bestValue > -VALUE_INFINITE && sp->moveCount > 0);
+
goto split_point_start;
}
- // Step 2. Check for aborted search and immediate draw
- if (( Signals.stop
- || pos.is_draw<false>()
- || ss->ply > PLY_MAX) && !RootNode)
- return VALUE_DRAW;
+ bestValue = -VALUE_INFINITE;
+ ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
+ ss->ply = (ss-1)->ply + 1;
+ (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
+ (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
+
+ // Used to send selDepth info to GUI
+ if (PvNode && thisThread->maxPly < ss->ply)
+ thisThread->maxPly = ss->ply;
- // Step 3. Mate distance pruning
if (!RootNode)
{
- alpha = std::max(value_mated_in(ss->ply), alpha);
- beta = std::min(value_mate_in(ss->ply+1), beta);
+ // Step 2. Check for aborted search and immediate draw
+ if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)
+ return Eval::ValueDraw[pos.side_to_move()];
+
+ // Step 3. Mate distance pruning. Even if we mate at the next move our score
+ // would be at best mate_in(ss->ply+1), but if alpha is already bigger because
+ // a shorter mate was found upward in the tree then there is no need to search
+ // further, we will never beat current alpha. Same logic but with reversed signs
+ // applies also in the opposite condition of being mated instead of giving mate,
+ // in this case return a fail-high score.
+ alpha = std::max(mated_in(ss->ply), alpha);
+ beta = std::min(mate_in(ss->ply+1), beta);
if (alpha >= beta)
return alpha;
}
// 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();
+ posKey = excludedMove ? pos.exclusion_key() : pos.key();
tte = TT.probe(posKey);
- ttMove = RootNode ? RootMoves[MultiPVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
+ ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
+ ttValue = tte ? value_from_tt(tte->value(), ss->ply) : VALUE_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. 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)))
+ if ( !RootNode
+ && tte && tte->depth() >= depth
+ && ( PvNode ? tte->type() == BOUND_EXACT
+ : ttValue >= beta ? (tte->type() & BOUND_LOWER)
+ : (tte->type() & BOUND_UPPER)))
{
TT.refresh(tte);
- ss->bestMove = move = ttMove; // Can be MOVE_NONE
- value = value_from_tt(tte->value(), ss->ply);
+ ss->currentMove = ttMove; // Can be MOVE_NONE
- if ( value >= beta
- && move
- && !pos.is_capture_or_promotion(move)
- && move != ss->killers[0])
+ if ( ttValue >= beta
+ && ttMove
+ && !pos.is_capture_or_promotion(ttMove)
+ && ttMove != ss->killers[0])
{
ss->killers[1] = ss->killers[0];
- ss->killers[0] = move;
+ ss->killers[0] = ttMove;
}
- return value;
+ return ttValue;
}
// Step 5. Evaluate the position statically and update parent's gain statistics
if (inCheck)
- ss->eval = ss->evalMargin = VALUE_NONE;
+ ss->eval = ss->evalMargin = refinedValue = VALUE_NONE;
else if (tte)
{
assert(tte->static_value() != VALUE_NONE);
ss->eval = tte->static_value();
ss->evalMargin = tte->static_value_margin();
- refinedValue = refine_eval(tte, ss->eval, ss->ply);
+ refinedValue = refine_eval(tte, ttValue, ss->eval);
}
else
{
refinedValue = ss->eval = evaluate(pos, ss->evalMargin);
- TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ss->evalMargin);
+ TT.store(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ss->evalMargin);
}
// Update gain for the parent non-capture move given the static position
// evaluation before and after the move.
- if ( (move = (ss-1)->currentMove) != MOVE_NULL
- && (ss-1)->eval != VALUE_NONE
- && ss->eval != VALUE_NONE
- && pos.captured_piece_type() == PIECE_TYPE_NONE
- && !is_special(move))
+ if ( (move = (ss-1)->currentMove) != MOVE_NULL
+ && (ss-1)->eval != VALUE_NONE
+ && ss->eval != VALUE_NONE
+ && !pos.captured_piece_type()
+ && type_of(move) == NORMAL)
{
- Square to = move_to(move);
+ Square to = to_sq(move);
H.update_gain(pos.piece_on(to), to, -(ss-1)->eval - ss->eval);
}
// Step 6. Razoring (is omitted in PV nodes)
if ( !PvNode
- && depth < RazorDepth
+ && depth < 4 * ONE_PLY
&& !inCheck
&& refinedValue + razor_margin(depth) < beta
&& ttMove == MOVE_NONE
- && abs(beta) < VALUE_MATE_IN_PLY_MAX
- && !pos.has_pawn_on_7th(pos.side_to_move()))
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY
+ && !pos.pawn_on_7th(pos.side_to_move()))
{
Value rbeta = beta - razor_margin(depth);
Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO);
// the score by more than futility_margin(depth) if we do a null move.
if ( !PvNode
&& !ss->skipNullMove
- && depth < RazorDepth
+ && depth < 4 * ONE_PLY
&& !inCheck
- && refinedValue - futility_margin(depth, 0) >= beta
- && abs(beta) < VALUE_MATE_IN_PLY_MAX
+ && refinedValue - FutilityMargins[depth][0] >= beta
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
- return refinedValue - futility_margin(depth, 0);
+ return refinedValue - FutilityMargins[depth][0];
// Step 8. Null move search with verification search (is omitted in PV nodes)
if ( !PvNode
&& depth > ONE_PLY
&& !inCheck
&& refinedValue >= beta
- && abs(beta) < VALUE_MATE_IN_PLY_MAX
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
{
ss->currentMove = MOVE_NULL;
// Null move dynamic reduction based on depth
- int R = 3 + (depth >= 5 * ONE_PLY ? depth / 8 : 0);
+ Depth R = 3 * ONE_PLY + depth / 4;
// Null move dynamic reduction based on value
- if (refinedValue - PawnValueMidgame > beta)
- R++;
+ if (refinedValue - PawnValueMg > beta)
+ R += ONE_PLY;
pos.do_null_move<true>(st);
(ss+1)->skipNullMove = true;
- 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);
+ nullValue = depth-R < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R);
(ss+1)->skipNullMove = false;
pos.do_null_move<false>(st);
if (nullValue >= beta)
{
// Do not return unproven mate scores
- if (nullValue >= VALUE_MATE_IN_PLY_MAX)
+ if (nullValue >= VALUE_MATE_IN_MAX_PLY)
nullValue = beta;
if (depth < 6 * ONE_PLY)
// Do verification search at high depths
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*ONE_PLY);
+ Value v = search<NonPV>(pos, ss, alpha, beta, depth-R);
ss->skipNullMove = false;
if (v >= beta)
// move which was reduced. If a connection is found, return a fail
// low score (which will cause the reduced move to fail high in the
// parent node, which will trigger a re-search with full depth).
- threatMove = (ss+1)->bestMove;
+ threatMove = (ss+1)->currentMove;
- if ( depth < ThreatDepth
+ if ( depth < 5 * ONE_PLY
&& (ss-1)->reduction
&& threatMove != MOVE_NONE
&& connected_moves(pos, (ss-1)->currentMove, threatMove))
// and a reduced search returns a value much above beta, we can (almost) safely
// prune the previous move.
if ( !PvNode
- && depth >= RazorDepth + ONE_PLY
+ && depth >= 5 * ONE_PLY
&& !inCheck
&& !ss->skipNullMove
&& excludedMove == MOVE_NONE
- && abs(beta) < VALUE_MATE_IN_PLY_MAX)
+ && abs(beta) < VALUE_MATE_IN_MAX_PLY)
{
Value rbeta = beta + 200;
Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY;
assert(rdepth >= ONE_PLY);
+ assert((ss-1)->currentMove != MOVE_NONE);
+ assert((ss-1)->currentMove != MOVE_NULL);
MovePicker mp(pos, ttMove, H, pos.captured_piece_type());
CheckInfo ci(pos);
- while ((move = mp.get_next_move()) != MOVE_NONE)
+ while ((move = mp.next_move<false>()) != MOVE_NONE)
if (pos.pl_move_is_legal(move, ci.pinned))
{
+ ss->currentMove = move;
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);
}
// Step 10. Internal iterative deepening
- if ( depth >= IIDDepth[PvNode]
+ if ( depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
&& ttMove == MOVE_NONE
- && (PvNode || (!inCheck && ss->eval + IIDMargin >= beta)))
+ && (PvNode || (!inCheck && ss->eval + Value(256) >= beta)))
{
Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
split_point_start: // At split points actual search starts from here
- MovePickerExt<SpNode> mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
+ MovePicker mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
- ss->bestMove = MOVE_NONE;
- futilityBase = ss->eval + ss->evalMargin;
+ value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
singularExtensionNode = !RootNode
&& !SpNode
- && depth >= SingularExtensionDepth[PvNode]
- && ttMove != MOVE_NONE
+ && depth >= (PvNode ? 6 * ONE_PLY : 8 * ONE_PLY)
+ && ttMove != MOVE_NONE
&& !excludedMove // Recursive singular search is not allowed
- && (tte->type() & VALUE_TYPE_LOWER)
- && tte->depth() >= depth - 3 * ONE_PLY;
- if (SpNode)
- {
- lock_grab(&(sp->lock));
- bestValue = sp->bestValue;
- moveCount = sp->moveCount;
-
- assert(bestValue > -VALUE_INFINITE && moveCount > 0);
- }
+ && (tte->type() & BOUND_LOWER)
+ && tte->depth() >= depth - 3 * ONE_PLY;
// 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
- && !thread.cutoff_occurred())
+ while ((move = mp.next_move<SpNode>()) != MOVE_NONE)
{
assert(is_ok(move));
// At root obey the "searchmoves" option and skip moves not listed in Root
// Move List, as a consequence any illegal move is also skipped. In MultiPV
// mode we also skip PV moves which have been already searched.
- if (RootNode && !std::count(RootMoves.begin() + MultiPVIdx, RootMoves.end(), move))
- 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))
+ if (RootNode && !std::count(RootMoves.begin() + PVIdx, RootMoves.end(), move))
continue;
if (SpNode)
{
+ // Shared counter cannot be decremented later if move turns out to be illegal
+ if (!pos.pl_move_is_legal(move, ci.pinned))
+ continue;
+
moveCount = ++sp->moveCount;
- lock_release(&(sp->lock));
+ sp->mutex.unlock();
}
else
moveCount++;
if (RootNode)
{
- // This is used by time management
Signals.firstRootMove = (moveCount == 1);
- nodes = pos.nodes_searched();
-
- if (pos.thread() == 0 && elapsed_time() > 2000)
- cout << "info" << depth_to_uci(depth)
- << " currmove " << move
- << " currmovenumber " << moveCount + MultiPVIdx << endl;
+ if (thisThread == Threads.main_thread() && Time::now() - SearchTime > 2000)
+ sync_cout << "info depth " << depth / ONE_PLY
+ << " currmove " << move_to_uci(move, Chess960)
+ << " currmovenumber " << moveCount + PVIdx << sync_endl;
}
- isPvMove = (PvNode && moveCount <= 1);
+ ext = DEPTH_ZERO;
captureOrPromotion = pos.is_capture_or_promotion(move);
givesCheck = pos.move_gives_check(move, ci);
- dangerous = givesCheck || is_dangerous(pos, move, captureOrPromotion);
- ext = DEPTH_ZERO;
+ dangerous = givesCheck
+ || pos.is_passed_pawn_push(move)
+ || type_of(move) == CASTLE
+ || ( captureOrPromotion // Entering a pawn endgame?
+ && type_of(pos.piece_on(to_sq(move))) != PAWN
+ && type_of(move) == NORMAL
+ && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
+ - PieceValue[Mg][pos.piece_on(to_sq(move))] == VALUE_ZERO));
// Step 12. Extend checks and, in PV nodes, also dangerous moves
if (PvNode && dangerous)
ext = ONE_PLY;
else if (givesCheck && pos.see_sign(move) >= 0)
- ext = PvNode ? ONE_PLY : ONE_PLY / 2;
+ ext = ONE_PLY / 2;
// 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. To verify this we do a reduced search
// on all the other moves but the ttMove, if result is lower than ttValue minus
// a margin then we extend ttMove.
- if ( singularExtensionNode
+ if ( singularExtensionNode
&& !ext
- && move == ttMove
- && pos.pl_move_is_legal(move, ci.pinned))
+ && move == ttMove
+ && pos.pl_move_is_legal(move, ci.pinned)
+ && abs(ttValue) < VALUE_KNOWN_WIN)
{
- Value ttValue = value_from_tt(tte->value(), ss->ply);
-
- if (abs(ttValue) < VALUE_KNOWN_WIN)
- {
- Value rBeta = ttValue - int(depth);
- ss->excludedMove = move;
- ss->skipNullMove = true;
- value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
- ss->skipNullMove = false;
- ss->excludedMove = MOVE_NONE;
- ss->bestMove = MOVE_NONE;
- if (value < rBeta)
- ext = ONE_PLY;
- }
+ Value rBeta = ttValue - int(depth);
+ ss->excludedMove = move;
+ ss->skipNullMove = true;
+ value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
+ ss->skipNullMove = false;
+ ss->excludedMove = MOVE_NONE;
+
+ if (value < rBeta)
+ ext = rBeta >= beta ? ONE_PLY + ONE_PLY / 2 : ONE_PLY;
}
// Update current move (this must be done after singular extension search)
&& !inCheck
&& !dangerous
&& move != ttMove
- && !is_castle(move)
- && (bestValue > VALUE_MATED_IN_PLY_MAX || bestValue == -VALUE_INFINITE))
+ && (bestValue > VALUE_MATED_IN_MAX_PLY || ( bestValue == -VALUE_INFINITE
+ && alpha > VALUE_MATED_IN_MAX_PLY)))
{
// Move count based pruning
- if ( moveCount >= futility_move_count(depth)
+ if ( depth < 16 * ONE_PLY
+ && moveCount >= FutilityMoveCounts[depth]
&& (!threatMove || !connected_threat(pos, move, threatMove)))
{
if (SpNode)
- lock_grab(&(sp->lock));
+ sp->mutex.lock();
continue;
}
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
- futilityValue = futilityBase + futility_margin(predictedDepth, moveCount)
- + H.gain(pos.piece_on(move_from(move)), move_to(move));
+ futilityValue = ss->eval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
+ + H.gain(pos.piece_moved(move), to_sq(move));
if (futilityValue < beta)
{
if (SpNode)
- lock_grab(&(sp->lock));
+ sp->mutex.lock();
continue;
}
&& pos.see_sign(move) < 0)
{
if (SpNode)
- lock_grab(&(sp->lock));
+ sp->mutex.lock();
continue;
}
continue;
}
+ pvMove = PvNode ? moveCount == 1 : false;
ss->currentMove = move;
- if (!SpNode && !captureOrPromotion)
+ if (!SpNode && !captureOrPromotion && playedMoveCount < 64)
movesSearched[playedMoveCount++] = move;
// Step 14. Make the move
// Step 15. Reduced depth search (LMR). If the move fails high will be
// re-searched at full depth.
- if ( depth > 3 * ONE_PLY
- && !isPvMove
+ if ( depth > 3 * ONE_PLY
+ && !pvMove
&& !captureOrPromotion
&& !dangerous
- && !is_castle(move)
&& ss->killers[0] != move
&& ss->killers[1] != move)
{
ss->reduction = reduction<PvNode>(depth, moveCount);
- Depth d = newDepth - ss->reduction;
+ Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
alpha = SpNode ? sp->alpha : alpha;
- value = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO);
ss->reduction = DEPTH_ZERO;
}
else
- doFullDepthSearch = !isPvMove;
+ doFullDepthSearch = !pvMove;
// Step 16. Full depth search, when LMR is skipped or fails high
if (doFullDepthSearch)
// Only for PV nodes do a full PV search on the first move or after a fail
// high, in the latter case search only if value < beta, otherwise let the
// parent node to fail low with value <= alpha and to try another move.
- if (PvNode && (isPvMove || (value > alpha && (RootNode || value < beta))))
+ if (PvNode && (pvMove || (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 18. Check for new best move
if (SpNode)
{
- lock_grab(&(sp->lock));
+ sp->mutex.lock();
bestValue = sp->bestValue;
alpha = sp->alpha;
}
- // Finished searching the move. If StopRequest is true, the search
+ // Finished searching the move. If Signals.stop 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 && !Signals.stop)
+ if (Signals.stop || thisThread->cutoff_occurred())
+ return bestValue;
+
+ if (RootNode)
{
RootMove& rm = *std::find(RootMoves.begin(), RootMoves.end(), move);
- rm.nodes += pos.nodes_searched() - nodes;
// PV move or new best move ?
- if (isPvMove || value > alpha)
+ if (pvMove || value > alpha)
{
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)
+ if (!pvMove && MultiPV == 1)
BestMoveChanges++;
}
else
// 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;
-
}
if (value > bestValue)
{
bestValue = value;
- ss->bestMove = move;
-
- if ( PvNode
- && value > alpha
- && value < beta) // We want always alpha < beta
- alpha = value;
+ if (SpNode) sp->bestValue = value;
- if (SpNode && !thread.cutoff_occurred())
+ if (value > alpha)
{
- sp->bestValue = value;
- sp->ss->bestMove = move;
- sp->alpha = alpha;
- sp->is_betaCutoff = (value >= beta);
+ bestMove = move;
+ if (SpNode) sp->bestMove = move;
+
+ if (PvNode && value < beta)
+ {
+ alpha = value; // Update alpha here! Always alpha < beta
+ if (SpNode) sp->alpha = value;
+ }
+ else // Fail high
+ {
+ if (SpNode) sp->cutoff = true;
+ break;
+ }
}
}
- // Step 19. Check for split
+ // Step 19. Check for splitting the search
if ( !SpNode
- && depth >= Threads.min_split_depth()
- && bestValue < beta
- && Threads.available_slave_exists(pos.thread())
- && !Signals.stop
- && !thread.cutoff_occurred())
- bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, depth,
- threatMove, moveCount, &mp, NT);
+ && depth >= Threads.min_split_depth()
+ && bestValue < beta
+ && Threads.available_slave_exists(thisThread))
+ {
+ bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, &bestMove,
+ depth, threatMove, moveCount, mp, NT);
+ break;
+ }
}
+ if (SpNode)
+ return bestValue;
+
// 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. Note that we can have a false positive in
- // case of StopRequest or thread.cutoff_occurred() are set, but this is
+ // case of Signals.stop or thread.cutoff_occurred() are set, but this is
// harmless because return value is discarded anyhow in the parent nodes.
// If we are in a singular extension search then return a fail low score.
+ // A split node has at least one move, the one tried before to be splitted.
if (!moveCount)
- return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
+ return excludedMove ? alpha : inCheck ? mated_in(ss->ply) : VALUE_DRAW;
// If we have pruned all the moves without searching return a fail-low score
if (bestValue == -VALUE_INFINITE)
bestValue = alpha;
}
- // Step 21. Update tables
- // Update transposition table entry, history and killers
- if (!SpNode && !Signals.stop && !thread.cutoff_occurred())
+ if (bestValue >= beta) // Failed high
{
- move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
- vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
- : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT;
-
- TT.store(posKey, value_to_tt(bestValue, ss->ply), vt, depth, move, ss->eval, ss->evalMargin);
+ TT.store(posKey, value_to_tt(bestValue, ss->ply), BOUND_LOWER, depth,
+ bestMove, ss->eval, ss->evalMargin);
- // Update killers and history only for non capture moves that fails high
- if ( bestValue >= beta
- && !pos.is_capture_or_promotion(move))
+ if (!pos.is_capture_or_promotion(bestMove) && !inCheck)
{
- if (move != ss->killers[0])
+ if (bestMove != ss->killers[0])
{
ss->killers[1] = ss->killers[0];
- ss->killers[0] = move;
+ ss->killers[0] = bestMove;
}
- update_history(pos, move, depth, movesSearched, playedMoveCount);
- }
- }
- if (SpNode)
- {
- // Here we have the lock still grabbed
- sp->is_slave[pos.thread()] = false;
- sp->nodes += pos.nodes_searched();
- lock_release(&(sp->lock));
+ // Increase history value of the cut-off move
+ Value bonus = Value(int(depth) * int(depth));
+ H.add(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
+
+ // Decrease history of all the other played non-capture moves
+ for (int i = 0; i < playedMoveCount - 1; i++)
+ {
+ Move m = movesSearched[i];
+ H.add(pos.piece_moved(m), to_sq(m), -bonus);
+ }
+ }
}
+ else // Failed low or PV search
+ TT.store(posKey, value_to_tt(bestValue, ss->ply),
+ PvNode && bestMove != MOVE_NONE ? BOUND_EXACT : BOUND_UPPER,
+ depth, bestMove, ss->eval, ss->evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
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);
- assert(depth <= 0);
- assert(pos.thread() >= 0 && pos.thread() < Threads.size());
+ assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
+ assert(PvNode || (alpha == beta - 1));
+ assert(depth <= DEPTH_ZERO);
StateInfo st;
- Move ttMove, move;
- Value bestValue, value, evalMargin, futilityValue, futilityBase;
- bool inCheck, enoughMaterial, givesCheck, evasionPrunable;
const TTEntry* tte;
+ Key posKey;
+ Move ttMove, move, bestMove;
+ Value bestValue, value, ttValue, futilityValue, futilityBase;
+ bool inCheck, givesCheck, enoughMaterial, evasionPrunable;
Depth ttDepth;
- ValueType vt;
- Value oldAlpha = alpha;
- ss->bestMove = ss->currentMove = MOVE_NONE;
+ inCheck = pos.in_check();
+ ss->currentMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (pos.is_draw<true>() || ss->ply > PLY_MAX)
- return VALUE_DRAW;
+ if (pos.is_draw<true>() || ss->ply > MAX_PLY)
+ return Eval::ValueDraw[pos.side_to_move()];
+
+ // Transposition table lookup. At PV nodes, we don't use the TT for
+ // pruning, but only for move ordering.
+ posKey = pos.key();
+ tte = TT.probe(posKey);
+ ttMove = tte ? tte->move() : MOVE_NONE;
+ ttValue = tte ? value_from_tt(tte->value(),ss->ply) : VALUE_NONE;
// Decide whether or not to include checks, this fixes also the type of
// TT entry depth that we are going to use. Note that in qsearch we use
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
- inCheck = pos.in_check();
- ttDepth = (inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS);
+ ttDepth = inCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS : DEPTH_QS_NO_CHECKS;
- // Transposition table lookup. At PV nodes, we don't use the TT for
- // pruning, but only for move ordering.
- tte = TT.probe(pos.get_key());
- ttMove = (tte ? tte->move() : MOVE_NONE);
-
- if (!PvNode && tte && can_return_tt(tte, ttDepth, beta, ss->ply))
+ if ( tte && tte->depth() >= ttDepth
+ && ( PvNode ? tte->type() == BOUND_EXACT
+ : ttValue >= beta ? (tte->type() & BOUND_LOWER)
+ : (tte->type() & BOUND_UPPER)))
{
- ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ss->ply);
+ ss->currentMove = ttMove; // Can be MOVE_NONE
+ return ttValue;
}
// Evaluate the position statically
if (inCheck)
{
+ ss->eval = ss->evalMargin = VALUE_NONE;
bestValue = futilityBase = -VALUE_INFINITE;
- ss->eval = evalMargin = VALUE_NONE;
enoughMaterial = false;
}
else
{
assert(tte->static_value() != VALUE_NONE);
- evalMargin = tte->static_value_margin();
ss->eval = bestValue = tte->static_value();
+ ss->evalMargin = tte->static_value_margin();
}
else
- ss->eval = bestValue = evaluate(pos, evalMargin);
+ ss->eval = bestValue = evaluate(pos, ss->evalMargin);
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta)
{
if (!tte)
- TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, evalMargin);
+ TT.store(pos.key(), value_to_tt(bestValue, ss->ply), BOUND_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, ss->evalMargin);
return bestValue;
}
if (PvNode && bestValue > alpha)
alpha = bestValue;
- futilityBase = ss->eval + evalMargin + FutilityMarginQS;
- enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
+ futilityBase = ss->eval + ss->evalMargin + Value(128);
+ enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMg;
}
// Initialize a MovePicker object for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
- MovePicker mp(pos, ttMove, depth, H, move_to((ss-1)->currentMove));
+ MovePicker mp(pos, ttMove, depth, H, to_sq((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
- while ( bestValue < beta
- && (move = mp.get_next_move()) != MOVE_NONE)
+ while ((move = mp.next_move<false>()) != MOVE_NONE)
{
assert(is_ok(move));
&& !givesCheck
&& move != ttMove
&& enoughMaterial
- && !is_promotion(move)
+ && type_of(move) != PROMOTION
&& !pos.is_passed_pawn_push(move))
{
futilityValue = futilityBase
- + PieceValueEndgame[pos.piece_on(move_to(move))]
- + (is_enpassant(move) ? PawnValueEndgame : VALUE_ZERO);
+ + PieceValue[Eg][pos.piece_on(to_sq(move))]
+ + (type_of(move) == ENPASSANT ? PawnValueEg : VALUE_ZERO);
if (futilityValue < beta)
{
// Detect non-capture evasions that are candidate to be pruned
evasionPrunable = !PvNode
- && inCheck
- && bestValue > VALUE_MATED_IN_PLY_MAX
+ && inCheck
+ && bestValue > VALUE_MATED_IN_MAX_PLY
&& !pos.is_capture(move)
&& !pos.can_castle(pos.side_to_move());
if ( !PvNode
&& (!inCheck || evasionPrunable)
&& move != ttMove
- && !is_promotion(move)
+ && type_of(move) != PROMOTION
&& pos.see_sign(move) < 0)
continue;
&& givesCheck
&& move != ttMove
&& !pos.is_capture_or_promotion(move)
- && ss->eval + PawnValueMidgame / 4 < beta
- && !check_is_dangerous(pos, move, futilityBase, beta, &bestValue))
- {
- if (ss->eval + PawnValueMidgame / 4 > bestValue)
- bestValue = ss->eval + PawnValueMidgame / 4;
-
+ && ss->eval + PawnValueMg / 4 < beta
+ && !check_is_dangerous(pos, move, futilityBase, beta))
continue;
- }
// Check for legality only before to do the move
if (!pos.pl_move_is_legal(move, ci.pinned))
// Make and search the move
pos.do_move(move, st, ci, givesCheck);
- value = -qsearch<NT>(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);
- // New best move?
+ // Check for new best move
if (value > bestValue)
{
bestValue = value;
- ss->bestMove = move;
- if ( PvNode
- && value > alpha
- && value < beta) // We want always alpha < beta
- alpha = value;
+ if (value > alpha)
+ {
+ if (PvNode && value < beta) // Update alpha here! Always alpha < beta
+ {
+ alpha = value;
+ bestMove = move;
+ }
+ else // Fail high
+ {
+ TT.store(posKey, value_to_tt(value, ss->ply), BOUND_LOWER,
+ ttDepth, move, ss->eval, ss->evalMargin);
+
+ return value;
+ }
+ }
}
}
// All legal moves have been searched. A special case: If we're in check
// and no legal moves were found, it is checkmate.
if (inCheck && bestValue == -VALUE_INFINITE)
- return value_mated_in(ss->ply);
+ return mated_in(ss->ply); // Plies to mate from the root
- // Update transposition table
- 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);
+ TT.store(posKey, value_to_tt(bestValue, ss->ply),
+ PvNode && bestMove != MOVE_NONE ? BOUND_EXACT : BOUND_UPPER,
+ ttDepth, bestMove, ss->eval, ss->evalMargin);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
// bestValue is updated only when returning false because in that case move
// will be pruned.
- bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta, Value *bestValue)
+ bool check_is_dangerous(Position &pos, Move move, Value futilityBase, Value beta)
{
Bitboard b, occ, oldAtt, newAtt, kingAtt;
- Square from, to, ksq, victimSq;
+ Square from, to, ksq;
Piece pc;
Color them;
- Value futilityValue, bv = *bestValue;
- from = move_from(move);
- to = move_to(move);
- them = flip(pos.side_to_move());
+ from = from_sq(move);
+ to = to_sq(move);
+ them = ~pos.side_to_move();
ksq = pos.king_square(them);
kingAtt = pos.attacks_from<KING>(ksq);
- pc = pos.piece_on(from);
+ pc = pos.piece_moved(move);
- occ = pos.occupied_squares() & ~(1ULL << from) & ~(1ULL << ksq);
+ occ = pos.pieces() ^ from ^ ksq;
oldAtt = pos.attacks_from(pc, from, occ);
newAtt = pos.attacks_from(pc, to, occ);
// Rule 1. Checks which give opponent's king at most one escape square are dangerous
b = kingAtt & ~pos.pieces(them) & ~newAtt & ~(1ULL << to);
- if (!(b && (b & (b - 1))))
+ if (!more_than_one(b))
return true;
// Rule 2. Queen contact check is very dangerous
- if ( type_of(pc) == QUEEN
- && bit_is_set(kingAtt, to))
+ if (type_of(pc) == QUEEN && (kingAtt & to))
return true;
// Rule 3. Creating new double threats with checks
b = pos.pieces(them) & newAtt & ~oldAtt & ~(1ULL << ksq);
-
while (b)
{
- victimSq = pop_1st_bit(&b);
- futilityValue = futilityBase + PieceValueEndgame[pos.piece_on(victimSq)];
-
// Note that here we generate illegal "double move"!
- if ( futilityValue >= beta
- && pos.see_sign(make_move(from, victimSq)) >= 0)
+ if (futilityBase + PieceValue[Eg][pos.piece_on(pop_lsb(&b))] >= beta)
return true;
-
- if (futilityValue > bv)
- bv = futilityValue;
}
- // Update bestValue only if check is not dangerous (because we will prune the move)
- *bestValue = bv;
return false;
}
assert(is_ok(m2));
// Case 1: The moving piece is the same in both moves
- f2 = move_from(m2);
- t1 = move_to(m1);
+ f2 = from_sq(m2);
+ t1 = to_sq(m1);
if (f2 == t1)
return true;
// Case 2: The destination square for m2 was vacated by m1
- t2 = move_to(m2);
- f1 = move_from(m1);
+ t2 = to_sq(m2);
+ f1 = from_sq(m1);
if (t2 == f1)
return true;
// Case 3: Moving through the vacated square
p2 = pos.piece_on(f2);
- if ( piece_is_slider(p2)
- && bit_is_set(squares_between(f2, t2), f1))
+ if (piece_is_slider(p2) && (between_bb(f2, t2) & f1))
return true;
// Case 4: The destination square for m2 is defended by the moving piece in m1
p1 = pos.piece_on(t1);
- if (bit_is_set(pos.attacks_from(p1, t1), t2))
+ if (pos.attacks_from(p1, t1) & t2)
return true;
// Case 5: Discovered check, checking piece is the piece moved in m1
ksq = pos.king_square(pos.side_to_move());
if ( piece_is_slider(p1)
- && bit_is_set(squares_between(t1, ksq), f2))
- {
- Bitboard occ = pos.occupied_squares();
- clear_bit(&occ, f2);
- if (bit_is_set(pos.attacks_from(p1, t1, occ), ksq))
- return true;
- }
+ && (between_bb(t1, ksq) & f2)
+ && (pos.attacks_from(p1, t1, pos.pieces() ^ f2) & ksq))
+ return true;
+
return false;
}
// value_to_tt() adjusts a mate score from "plies to mate from the root" to
- // "plies to mate from the current ply". Non-mate scores are unchanged.
+ // "plies to mate from the current position". Non-mate scores are unchanged.
// The function is called before storing a value to the transposition table.
Value value_to_tt(Value v, int ply) {
- if (v >= VALUE_MATE_IN_PLY_MAX)
+ if (v >= VALUE_MATE_IN_MAX_PLY)
return v + ply;
- if (v <= VALUE_MATED_IN_PLY_MAX)
+ if (v <= VALUE_MATED_IN_MAX_PLY)
return v - ply;
return v;
}
- // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score from
- // the transposition table to a mate score corrected for the current ply.
+ // value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score
+ // from the transposition table (where refers to the plies to mate/be mated
+ // from current position) to "plies to mate/be mated from the root".
Value value_from_tt(Value v, int ply) {
- if (v >= VALUE_MATE_IN_PLY_MAX)
+ if (v >= VALUE_MATE_IN_MAX_PLY)
return v - ply;
- if (v <= VALUE_MATED_IN_PLY_MAX)
+ if (v <= VALUE_MATED_IN_MAX_PLY)
return v + ply;
return v;
Square mfrom, mto, tfrom, tto;
- mfrom = move_from(m);
- mto = move_to(m);
- tfrom = move_from(threat);
- tto = move_to(threat);
+ mfrom = from_sq(m);
+ mto = to_sq(m);
+ tfrom = from_sq(threat);
+ tto = to_sq(threat);
// Case 1: Don't prune moves which move the threatened piece
if (mfrom == 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.is_capture(threat)
- && ( PieceValueMidgame[pos.piece_on(tfrom)] >= PieceValueMidgame[pos.piece_on(tto)]
+ && ( PieceValue[Mg][pos.piece_on(tfrom)] >= PieceValue[Mg][pos.piece_on(tto)]
|| type_of(pos.piece_on(tfrom)) == KING)
&& pos.move_attacks_square(m, tto))
return true;
// Case 3: If the moving piece in the threatened move is a slider, don't
// prune safe moves which block its ray.
- if ( piece_is_slider(pos.piece_on(tfrom))
- && bit_is_set(squares_between(tfrom, tto), mto)
- && pos.see_sign(m) >= 0)
+ if ( piece_is_slider(pos.piece_on(tfrom))
+ && (between_bb(tfrom, tto) & mto)
+ && pos.see_sign(m) >= 0)
return true;
return false;
}
- // can_return_tt() returns true if a transposition table score can be used to
- // cut-off at a given point in search.
-
- bool can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply) {
-
- Value v = value_from_tt(tte->value(), ply);
-
- return ( tte->depth() >= depth
- || v >= std::max(VALUE_MATE_IN_PLY_MAX, beta)
- || v < std::min(VALUE_MATED_IN_PLY_MAX, beta))
-
- && ( ((tte->type() & VALUE_TYPE_LOWER) && v >= beta)
- || ((tte->type() & VALUE_TYPE_UPPER) && v < beta));
- }
-
-
// refine_eval() returns the transposition table score if possible, otherwise
// falls back on static position evaluation.
- Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) {
+ Value refine_eval(const TTEntry* tte, Value v, Value defaultEval) {
assert(tte);
- Value v = value_from_tt(tte->value(), ply);
-
- if ( ((tte->type() & VALUE_TYPE_LOWER) && v >= defaultEval)
- || ((tte->type() & VALUE_TYPE_UPPER) && v < defaultEval))
+ if ( ((tte->type() & BOUND_LOWER) && v >= defaultEval)
+ || ((tte->type() & BOUND_UPPER) && v < defaultEval))
return v;
return defaultEval;
}
- // update_history() registers a good move that produced a beta-cutoff in
- // history and marks as failures all the other moves of that ply.
-
- void update_history(const Position& pos, Move move, Depth depth,
- Move movesSearched[], int moveCount) {
- Move m;
- Value bonus = Value(int(depth) * int(depth));
-
- H.update(pos.piece_on(move_from(move)), move_to(move), bonus);
-
- for (int i = 0; i < moveCount - 1; i++)
- {
- m = movesSearched[i];
-
- assert(m != move);
-
- H.update(pos.piece_on(move_from(m)), move_to(m), -bonus);
- }
- }
-
-
- // current_search_time() returns the number of milliseconds which have passed
- // since the beginning of the current search.
-
- int elapsed_time(bool reset) {
-
- static int searchStartTime;
-
- if (reset)
- searchStartTime = get_system_time();
-
- return get_system_time() - searchStartTime;
- }
-
-
- // 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.
-
- string score_to_uci(Value v, Value alpha, Value beta) {
-
- std::stringstream s;
-
- if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << " score cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
- else
- 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.
-
- string speed_to_uci(int64_t nodes) {
-
- std::stringstream s;
- int t = elapsed_time();
-
- s << " nodes " << nodes
- << " 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;
- int selDepth = 0;
-
- // Retrieve max searched depth among threads
- 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();
- }
-
-
- // 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"). It uses the two below helper to
- // pretty format time and score respectively.
-
- 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();
- }
-
- string pretty_pv(Position& pos, int depth, Value value, int time, Move pv[]) {
-
- const int64_t K = 1000;
- const int64_t M = 1000000;
-
- StateInfo state[PLY_MAX_PLUS_2], *st = state;
- Move* m = pv;
- string san, padding;
- size_t length;
- std::stringstream s;
-
- 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 ";
-
- padding = string(s.str().length(), ' ');
- length = padding.length();
-
- while (*m != MOVE_NONE)
- {
- san = move_to_san(pos, *m);
-
- if (length + san.length() > 80)
- {
- s << "\n" + padding;
- length = padding.length();
- }
-
- s << san << ' ';
- length += san.length() + 1;
-
- pos.do_move(*m++, *st++);
- }
-
- // Restore original position before to leave
- while (m != pv)
- pos.undo_move(*--m);
-
- return s.str();
- }
-
-
// When playing with strength handicap choose best move among the MultiPV set
// using a statistical rule dependent on SkillLevel. Idea by Heinz van Saanen.
- void do_skill_level(Move* best, Move* ponder) {
+ Move do_skill_level() {
assert(MultiPV > 1);
static RKISS rk;
// PRNG sequence should be not deterministic
- for (int i = abs(get_system_time() % 50); i > 0; i--)
+ for (int i = Time::now() % 50; i > 0; i--)
rk.rand<unsigned>();
- // Rml list is already sorted by score in descending order
+ // RootMoves are already sorted by score in descending order
size_t size = std::min(MultiPV, RootMoves.size());
- int variance = std::min(RootMoves[0].score - RootMoves[size - 1].score, PawnValueMidgame);
+ int variance = std::min(RootMoves[0].score - RootMoves[size - 1].score, PawnValueMg);
int weakness = 120 - 2 * SkillLevel;
int max_s = -VALUE_INFINITE;
+ Move best = MOVE_NONE;
// Choose best move. For each move score we add two terms both dependent on
// weakness, one deterministic and bigger for weaker moves, and one random,
int s = RootMoves[i].score;
// Don't allow crazy blunders even at very low skills
- if (i > 0 && RootMoves[i-1].score > s + EasyMoveMargin)
+ if (i > 0 && RootMoves[i-1].score > s + 2 * PawnValueMg)
break;
// This is our magic formula
if (s > max_s)
{
max_s = s;
- *best = RootMoves[i].pv[0];
- *ponder = RootMoves[i].pv[1];
+ best = RootMoves[i].pv[0];
}
}
+ return best;
}
- // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
- // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
- // allow to always have a ponder move even when we fail high at root and also a
- // long PV to print that is important for position analysis.
+ // uci_pv() formats PV information according to UCI protocol. UCI requires
+ // to send all the PV lines also if are still to be searched and so refer to
+ // the previous search score.
- void RootMove::extract_pv_from_tt(Position& pos) {
+ string uci_pv(const Position& pos, int depth, Value alpha, Value beta) {
- StateInfo state[PLY_MAX_PLUS_2], *st = state;
- TTEntry* tte;
- int ply = 1;
- Move m = pv[0];
-
- assert(m != MOVE_NONE && pos.is_pseudo_legal(m));
+ std::stringstream s;
+ Time::point elaspsed = Time::now() - SearchTime + 1;
+ int selDepth = 0;
- pv.clear();
- pv.push_back(m);
- pos.do_move(m, *st++);
+ for (size_t i = 0; i < Threads.size(); i++)
+ if (Threads[i].maxPly > selDepth)
+ selDepth = Threads[i].maxPly;
- while ( (tte = TT.probe(pos.get_key())) != NULL
- && tte->move() != MOVE_NONE
- && pos.is_pseudo_legal(tte->move())
- && pos.pl_move_is_legal(tte->move(), pos.pinned_pieces())
- && ply < PLY_MAX
- && (!pos.is_draw<false>() || ply < 2))
+ for (size_t i = 0; i < std::min(UCIMultiPV, RootMoves.size()); i++)
{
- pv.push_back(tte->move());
- pos.do_move(tte->move(), *st++);
- ply++;
+ bool updated = (i <= PVIdx);
+
+ if (depth == 1 && !updated)
+ continue;
+
+ int d = (updated ? depth : depth - 1);
+ Value v = (updated ? RootMoves[i].score : RootMoves[i].prevScore);
+
+ if (s.rdbuf()->in_avail())
+ s << "\n";
+
+ s << "info depth " << d
+ << " seldepth " << selDepth
+ << " score " << (i == PVIdx ? score_to_uci(v, alpha, beta) : score_to_uci(v))
+ << " nodes " << pos.nodes_searched()
+ << " nps " << pos.nodes_searched() * 1000 / elaspsed
+ << " time " << elaspsed
+ << " multipv " << i + 1
+ << " pv";
+
+ for (size_t j = 0; RootMoves[i].pv[j] != MOVE_NONE; j++)
+ s << " " << move_to_uci(RootMoves[i].pv[j], Chess960);
}
- pv.push_back(MOVE_NONE);
- do pos.undo_move(pv[--ply]); while (ply);
+ return s.str();
}
+} // namespace
- // insert_pv_in_tt() is called at the end of a search iteration, and inserts
- // the PV back into the TT. This makes sure the old PV moves are searched
- // first, even if the old TT entries have been overwritten.
-
- void RootMove::insert_pv_in_tt(Position& pos) {
- StateInfo state[PLY_MAX_PLUS_2], *st = state;
- TTEntry* tte;
- Key k;
- Value v, m = VALUE_NONE;
- int ply = 0;
+/// RootMove::extract_pv_from_tt() builds a PV by adding moves from the TT table.
+/// We consider also failing high nodes and not only BOUND_EXACT nodes so to
+/// allow to always have a ponder move even when we fail high at root, and a
+/// long PV to print that is important for position analysis.
- assert(pv[0] != MOVE_NONE && pos.is_pseudo_legal(pv[0]));
+void RootMove::extract_pv_from_tt(Position& pos) {
- do {
- k = pos.get_key();
- tte = TT.probe(k);
+ StateInfo state[MAX_PLY_PLUS_2], *st = state;
+ TTEntry* tte;
+ int ply = 1;
+ Move m = pv[0];
- // Don't overwrite existing correct entries
- if (!tte || tte->move() != pv[ply])
- {
- v = (pos.in_check() ? VALUE_NONE : evaluate(pos, m));
- TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m);
- }
- pos.do_move(pv[ply], *st++);
+ assert(m != MOVE_NONE && pos.is_pseudo_legal(m));
- } while (pv[++ply] != MOVE_NONE);
+ pv.clear();
+ pv.push_back(m);
+ pos.do_move(m, *st++);
- do pos.undo_move(pv[--ply]); while (ply);
+ while ( (tte = TT.probe(pos.key())) != NULL
+ && (m = tte->move()) != MOVE_NONE // Local copy, TT entry could change
+ && pos.is_pseudo_legal(m)
+ && pos.pl_move_is_legal(m, pos.pinned_pieces())
+ && ply < MAX_PLY
+ && (!pos.is_draw<false>() || ply < 2))
+ {
+ pv.push_back(m);
+ pos.do_move(m, *st++);
+ ply++;
}
+ pv.push_back(MOVE_NONE);
-} // namespace
+ do pos.undo_move(pv[--ply]); while (ply);
+}
+
+
+/// RootMove::insert_pv_in_tt() is called at the end of a search iteration, and
+/// inserts the PV back into the TT. This makes sure the old PV moves are searched
+/// first, even if the old TT entries have been overwritten.
+void RootMove::insert_pv_in_tt(Position& pos) {
-/// Thread::idle_loop() is where the thread is parked when it has no work to do.
-/// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object
-/// for which the thread is the master.
+ StateInfo state[MAX_PLY_PLUS_2], *st = state;
+ TTEntry* tte;
+ Key k;
+ Value v, m = VALUE_NONE;
+ int ply = 0;
-void Thread::idle_loop(SplitPoint* sp) {
+ assert(pv[ply] != MOVE_NONE && pos.is_pseudo_legal(pv[ply]));
- while (true)
+ do {
+ k = pos.key();
+ tte = TT.probe(k);
+
+ // Don't overwrite existing correct entries
+ if (!tte || tte->move() != pv[ply])
+ {
+ v = (pos.in_check() ? VALUE_NONE : evaluate(pos, m));
+ TT.store(k, VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[ply], v, m);
+ }
+ pos.do_move(pv[ply], *st++);
+
+ } while (pv[++ply] != MOVE_NONE);
+
+ do pos.undo_move(pv[--ply]); while (ply);
+}
+
+
+/// Thread::idle_loop() is where the thread is parked when it has no work to do
+
+void Thread::idle_loop() {
+
+ // Pointer 'sp_master', if non-NULL, points to the active SplitPoint
+ // object for which the thread is the master.
+ const SplitPoint* sp_master = splitPointsCnt ? curSplitPoint : NULL;
+
+ assert(!sp_master || (sp_master->master == this && is_searching));
+
+ // If this thread is the master of a split point and all slaves have
+ // finished their work at this split point, return from the idle loop.
+ while (!sp_master || sp_master->slavesMask)
{
// If we are not searching, wait for a condition to be signaled
// instead of wasting CPU time polling for work.
while ( do_sleep
- || do_terminate
- || (Threads.use_sleeping_threads() && !is_searching))
+ || do_exit
+ || (!is_searching && Threads.use_sleeping_threads()))
{
- assert((!sp && threadID) || Threads.use_sleeping_threads());
-
- if (do_terminate)
+ if (do_exit)
{
- assert(!sp);
+ assert(!sp_master);
return;
}
// Grab the lock to avoid races with Thread::wake_up()
- lock_grab(&sleepLock);
+ mutex.lock();
// If we are master and all slaves have finished don't go to sleep
- if (sp && Threads.split_point_finished(sp))
+ if (sp_master && !sp_master->slavesMask)
{
- lock_release(&sleepLock);
+ mutex.unlock();
break;
}
// in the meanwhile, allocated us and sent the wake_up() call before we
// had the chance to grab the lock.
if (do_sleep || !is_searching)
- cond_wait(&sleepCond, &sleepLock);
+ sleepCondition.wait(mutex);
- lock_release(&sleepLock);
+ mutex.unlock();
}
// If this thread has been assigned work, launch a search
if (is_searching)
{
- assert(!do_terminate);
-
- // Copy split point position and search stack and call search()
- Stack ss[PLY_MAX_PLUS_2];
- SplitPoint* tsp = splitPoint;
- Position pos(*tsp->pos, threadID);
-
- memcpy(ss, tsp->ss - 1, 4 * sizeof(Stack));
- (ss+1)->sp = tsp;
-
- 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);
+ assert(!do_sleep && !do_exit);
+
+ Threads.mutex.lock();
+
+ assert(is_searching);
+ SplitPoint* sp = curSplitPoint;
+
+ Threads.mutex.unlock();
+
+ Stack ss[MAX_PLY_PLUS_2];
+ Position pos(*sp->pos, this);
+
+ memcpy(ss, sp->ss - 1, 4 * sizeof(Stack));
+ (ss+1)->sp = sp;
+
+ sp->mutex.lock();
+
+ assert(sp->activePositions[idx] == NULL);
+
+ sp->activePositions[idx] = &pos;
+
+ if (sp->nodeType == Root)
+ search<SplitPointRoot>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
+ else if (sp->nodeType == PV)
+ search<SplitPointPV>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
+ else if (sp->nodeType == NonPV)
+ search<SplitPointNonPV>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
else
assert(false);
assert(is_searching);
is_searching = false;
+ sp->activePositions[idx] = NULL;
+ sp->slavesMask &= ~(1ULL << idx);
+ sp->nodes += pos.nodes_searched();
// Wake up master thread so to allow it to return from the idle loop in
// case we are the last slave of the split point.
- if ( Threads.use_sleeping_threads()
- && threadID != tsp->master
- && !Threads[tsp->master].is_searching)
- Threads[tsp->master].wake_up();
- }
+ if ( Threads.use_sleeping_threads()
+ && this != sp->master
+ && !sp->slavesMask)
+ {
+ assert(!sp->master->is_searching);
+ sp->master->wake_up();
+ }
- // If this thread is the master of a split point and all slaves have
- // finished their work at this split point, return from the idle loop.
- if (sp && Threads.split_point_finished(sp))
- {
- // Because sp->is_slave[] is reset under lock protection,
- // be sure sp->lock has been released before to return.
- lock_grab(&(sp->lock));
- lock_release(&(sp->lock));
- return;
+ // After releasing the lock we cannot access anymore any SplitPoint
+ // related data in a safe way becuase it could have been released under
+ // our feet by the sp master. Also accessing other Thread objects is
+ // unsafe because if we are exiting there is a chance are already freed.
+ sp->mutex.unlock();
}
}
}
-/// do_timer_event() is called by the timer thread when the timer triggers. It
-/// is used to print debug info and, more important, to detect when we are out of
+/// check_time() is called by the timer thread when the timer triggers. It is
+/// used to print debug info and, more important, to detect when we are out of
/// available time and so stop the search.
-void do_timer_event() {
+void check_time() {
- static int lastInfoTime;
- int e = elapsed_time();
+ static Time::point lastInfoTime = Time::now();
+ int64_t nodes = 0; // Workaround silly 'uninitialized' gcc warning
- if (get_system_time() - lastInfoTime >= 1000 || !lastInfoTime)
+ if (Time::now() - lastInfoTime >= 1000)
{
- lastInfoTime = get_system_time();
-
- dbg_print_mean();
- dbg_print_hit_rate();
+ lastInfoTime = Time::now();
+ dbg_print();
}
if (Limits.ponder)
return;
+ if (Limits.nodes)
+ {
+ Threads.mutex.lock();
+
+ nodes = RootPosition.nodes_searched();
+
+ // Loop across all split points and sum accumulated SplitPoint nodes plus
+ // all the currently active slaves positions.
+ for (size_t i = 0; i < Threads.size(); i++)
+ for (int j = 0; j < Threads[i].splitPointsCnt; j++)
+ {
+ SplitPoint& sp = Threads[i].splitPoints[j];
+
+ sp.mutex.lock();
+
+ nodes += sp.nodes;
+ Bitboard sm = sp.slavesMask;
+ while (sm)
+ {
+ Position* pos = sp.activePositions[pop_lsb(&sm)];
+ nodes += pos ? pos->nodes_searched() : 0;
+ }
+
+ sp.mutex.unlock();
+ }
+
+ Threads.mutex.unlock();
+ }
+
+ Time::point elapsed = Time::now() - SearchTime;
bool stillAtFirstMove = Signals.firstRootMove
&& !Signals.failedLowAtRoot
- && e > TimeMgr.available_time();
+ && elapsed > TimeMgr.available_time();
- bool noMoreTime = e > TimeMgr.maximum_time()
+ bool noMoreTime = elapsed > TimeMgr.maximum_time() - 2 * TimerResolution
|| stillAtFirstMove;
- if ( (Limits.useTimeManagement() && noMoreTime)
- || (Limits.maxTime && e >= Limits.maxTime)
- /* missing nodes limit */ ) // FIXME
+ if ( (Limits.use_time_management() && noMoreTime)
+ || (Limits.movetime && elapsed >= Limits.movetime)
+ || (Limits.nodes && nodes >= Limits.nodes))
Signals.stop = true;
}
projects / stockfish / blobdiff