#include <cassert>
#include <cmath>
#include <cstring>
-#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <vector>
+#include <algorithm>
#include "book.h"
#include "evaluate.h"
const bool FakeSplit = false;
// Different node types, used as template parameter
- enum NodeType { Root, PV, NonPV, SplitPointPV, SplitPointNonPV };
+ 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 pv_score, a node count, and a PV (really a refutation
- // in the case of moves which fail low). Value pv_score is normally set at
+ // 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::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
- bool operator<(const RootMove& m) const { return pv_score < m.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);
int64_t nodes;
- Value pv_score;
+ Value score;
+ Value prevScore;
std::vector<Move> pv;
};
inline Value futility_margin(Depth d, int mn) {
- return d < 7 * ONE_PLY ? FutilityMargins[Max(d, 1)][Min(mn, 63)]
+ return d < 7 * ONE_PLY ? FutilityMargins[std::max(int(d), 1)][std::min(mn, 63)]
: 2 * VALUE_INFINITE;
}
template <bool PvNode> inline Depth reduction(Depth d, int mn) {
- return (Depth) Reductions[PvNode][Min(d / ONE_PLY, 63)][Min(mn, 63)];
+ 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
RootMoveList Rml;
// MultiPV mode
- int MultiPV, UCIMultiPV, MultiPVIteration;
+ int MultiPV, UCIMultiPV, MultiPVIdx;
// Time management variables
bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
TimeManager TimeMgr;
SearchLimits Limits;
- // Log file
- std::ofstream LogFile;
-
// Skill level adjustment
int SkillLevel;
bool SkillLevelEnabled;
// 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;
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 update_gains(const Position& pos, Move move, Value before, Value after);
void do_skill_level(Move* best, Move* ponder);
int current_search_time(int set = 0);
// 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<NodeType> struct MovePickerExt : public MovePicker {
+ 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<SplitPointNonPV> : public MovePicker {
+ 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) {}
MovePicker* mp;
};
- template<> struct MovePickerExt<SplitPointPV> : public MovePickerExt<SplitPointNonPV> {
-
- MovePickerExt(const Position& p, Move ttm, Depth d, const History& h, SearchStack* ss, Value b)
- : MovePickerExt<SplitPointNonPV>(p, ttm, d, h, ss, b) {}
- };
-
// 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) {
if (moveIsCheck && pos.see_sign(m) >= 0)
result += CheckExtension[PvNode];
- if (piece_type(pos.piece_on(move_from(m))) == PAWN)
+ 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)
}
if ( captureOrPromotion
- && piece_type(pos.piece_on(move_to(m))) != PAWN
+ && type_of(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))
+ - PieceValueMidgame[pos.piece_on(move_to(m))] == VALUE_ZERO)
+ && !is_special(m))
{
result += PawnEndgameExtension[PvNode];
*dangerous = true;
}
- return Min(result, ONE_PLY);
+ return std::min(result, ONE_PLY);
}
} // namespace
bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) {
- static Book book;
+ static Book book; // Define static to initialize the PRNG only once
// 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;
// Set best NodesBetweenPolls interval to avoid lagging under time pressure
if (Limits.maxNodes)
- NodesBetweenPolls = Min(Limits.maxNodes, 30000);
+ NodesBetweenPolls = std::min(Limits.maxNodes, 30000);
else if (Limits.time && Limits.time < 1000)
NodesBetweenPolls = 1000;
else if (Limits.time && Limits.time < 5000)
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>());
+ Move bookMove = book.probe(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE)
{
if (Limits.ponder)
read_evaluation_uci_options(pos.side_to_move());
Threads.read_uci_options();
- // If needed allocate pawn and material hash tables and adjust TT size
- Threads.init_hash_tables();
+ // Set a new TT size if changed
TT.set_size(Options["Hash"].value<int>());
if (Options["Clear Hash"].value<bool>())
// 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 ? Max(UCIMultiPV, 4) : UCIMultiPV);
+ MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, 4) : UCIMultiPV);
// Wake up needed threads and reset maxPly counter
for (int i = 0; i < Threads.size(); i++)
// Write to log file and keep it open to be accessed during the search
if (Options["Use Search Log"].value<bool>())
{
- string name = Options["Search Log Filename"].value<string>();
- LogFile.open(name.c_str(), std::ios::out | std::ios::app);
-
- if (LogFile.is_open())
- LogFile << "\nSearching: " << pos.to_fen()
- << "\ninfinite: " << Limits.infinite
- << " ponder: " << Limits.ponder
- << " time: " << Limits.time
- << " increment: " << Limits.increment
- << " moves to go: " << Limits.movesToGo
- << endl;
+ Log log(Options["Search Log Filename"].value<string>());
+ log << "\nSearching: " << pos.to_fen()
+ << "\ninfinite: " << Limits.infinite
+ << " ponder: " << Limits.ponder
+ << " time: " << Limits.time
+ << " increment: " << Limits.increment
+ << " moves to go: " << Limits.movesToGo
+ << endl;
}
// We're ready to start thinking. Call the iterative deepening loop function
Move bestMove = id_loop(pos, searchMoves, &ponderMove);
// Write final search statistics and close log file
- if (LogFile.is_open())
+ if (Options["Use Search Log"].value<bool>())
{
int t = current_search_time();
- LogFile << "Nodes: " << pos.nodes_searched()
- << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0)
- << "\nBest move: " << move_to_san(pos, bestMove);
+ Log log(Options["Search Log Filename"].value<string>());
+ log << "Nodes: " << pos.nodes_searched()
+ << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0)
+ << "\nBest move: " << move_to_san(pos, bestMove);
StateInfo st;
pos.do_move(bestMove, st);
- LogFile << "\nPonder move: " << move_to_san(pos, ponderMove) << endl;
+ log << "\nPonder move: " << move_to_san(pos, ponderMove) << endl;
pos.undo_move(bestMove); // Return from think() with unchanged position
- LogFile.close();
}
// This makes all the threads to go to sleep
*ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
depth = aspirationDelta = 0;
value = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
- ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
+ ss->currentMove = MOVE_NULL; // Hack to skip update gains
// Moves to search are verified and copied
Rml.init(pos, searchMoves);
// Iterative deepening loop until requested to stop or target depth reached
while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
{
- // Remember best moves and values from previous iteration
- RootMoveList prevRml = Rml;
+ // Save now last iteration's scores, before Rml moves are reordered
+ for (size_t i = 0; i < Rml.size(); i++)
+ Rml[i].prevScore = Rml[i].score;
Rml.bestMoveChanges = 0;
- // MultiPV iteration loop
- for (MultiPVIteration = 0; MultiPVIteration < Min(MultiPV, (int)Rml.size()); MultiPVIteration++)
+ // MultiPV loop. We perform a full root search for each PV line
+ for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, (int)Rml.size()); MultiPVIdx++)
{
// Calculate dynamic aspiration window based on previous iterations
- if (depth >= 5 && abs(prevRml[MultiPVIteration].pv_score) < VALUE_KNOWN_WIN)
+ if (depth >= 5 && abs(Rml[MultiPVIdx].prevScore) < VALUE_KNOWN_WIN)
{
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 = std::min(std::max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
- alpha = Max(prevRml[MultiPVIteration].pv_score - aspirationDelta, -VALUE_INFINITE);
- beta = Min(prevRml[MultiPVIteration].pv_score + aspirationDelta, VALUE_INFINITE);
+ alpha = std::max(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE);
+ beta = std::min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE);
}
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 {
- // Search starting from ss+1 to allow calling update_gains()
+ // Search starts 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);
+ // Bring to front the best move. It is critical that sorting is
+ // done with a stable algorithm because all the values but the first
+ // and eventually the new best one are set to -VALUE_INFINITE and
+ // 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>(Rml.begin() + MultiPVIdx, Rml.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 && value > alpha && value < beta)
+ sort<RootMove>(Rml.begin(), Rml.begin() + MultiPVIdx);
// Write PV back to transposition table in case the relevant entries
// have been overwritten during the search.
- for (int i = 0; i <= MultiPVIteration; i++)
+ for (int i = 0; i <= MultiPVIdx; i++)
Rml[i].insert_pv_in_tt(pos);
- // Value cannot be trusted. Break out immediately!
+ // 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 (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 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 ((value > alpha && value < beta) || current_search_time() > 2000)
- for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
+ for (int i = 0; i < std::min(UCIMultiPV, (int)Rml.size()); i++)
{
- bool updated = (i <= MultiPVIteration);
+ bool updated = (i <= MultiPVIdx);
if (depth == 1 && !updated)
- continue;
+ continue;
- const RootMoveList& rml = (updated ? Rml : prevRml);
+ Depth d = (updated ? depth : depth - 1) * ONE_PLY;
+ Value s = (updated ? Rml[i].score : Rml[i].prevScore);
cout << "info"
- << depth_to_uci((updated ? depth : depth - 1) * ONE_PLY)
- << (i == MultiPVIteration ? score_to_uci(rml[i].pv_score, alpha, beta)
- : score_to_uci(rml[i].pv_score))
+ << 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(&rml[i].pv[0], i + 1, pos.is_chess960())
+ << 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.
+ // 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);
+ beta = std::min(beta + aspirationDelta, VALUE_INFINITE);
aspirationDelta += aspirationDelta / 2;
}
else if (value <= alpha)
AspirationFailLow = true;
StopOnPonderhit = false;
- alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
+ alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE);
aspirationDelta += aspirationDelta / 2;
}
else
bestValues[depth] = value;
bestMoveChanges[depth] = Rml.bestMoveChanges;
- // Do we need to pick now the best and the ponder moves ?
+ // Skills: Do we need to pick now the best and the ponder moves ?
if (SkillLevelEnabled && depth == 1 + SkillLevel)
do_skill_level(&skillBest, &skillPonder);
- if (LogFile.is_open())
- LogFile << pretty_pv(pos, depth, value, current_search_time(), &Rml[0].pv[0]) << endl;
+ if (Options["Use Search Log"].value<bool>())
+ {
+ Log log(Options["Search Log Filename"].value<string>());
+ log << 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))
+ // Init easyMove at first iteration or drop it if differs from the best move
+ 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 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.
+ // Easy move: 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 search to some depth anyway to get a proper score.
if ( depth >= 7
&& easyMove == bestMove
&& ( Rml.size() == 1
template <NodeType NT>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth) {
- const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV);
- const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV);
- const bool RootNode = (NT == Root);
+ 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);
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;
Thread& thread = Threads[pos.thread()];
// Step 3. Mate distance pruning
if (!RootNode)
{
- alpha = Max(value_mated_in(ss->ply), alpha);
- beta = Min(value_mate_in(ss->ply+1), beta);
+ alpha = std::max(value_mated_in(ss->ply), alpha);
+ beta = std::min(value_mate_in(ss->ply+1), beta);
if (alpha >= beta)
return alpha;
}
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[MultiPVIdx].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. 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
- : ok_to_use_TT(tte, depth, beta, ss->ply)))
+ : can_return_tt(tte, depth, beta, ss->ply)))
{
TT.refresh(tte);
- ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ss->ply);
+ ss->bestMove = move = ttMove; // Can be MOVE_NONE
+ value = value_from_tt(tte->value(), ss->ply);
+
+ if ( value >= beta
+ && move
+ && !pos.is_capture_or_promotion(move)
+ && move != ss->killers[0])
+ {
+ ss->killers[1] = ss->killers[0];
+ ss->killers[0] = move;
+ }
+ return value;
}
// Step 5. Evaluate the position statically and update parent's gain statistics
TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ss->evalMargin);
}
- // Save gain for the parent non-capture move
- update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
+ // 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))
+ {
+ Square to = move_to(move);
+ H.update_gain(pos.piece_on(to), to, -(ss-1)->eval - ss->eval);
+ }
// Step 6. Razoring (is omitted in PV nodes)
if ( !PvNode
if (refinedValue - PawnValueMidgame > beta)
R++;
- pos.do_null_move(st);
+ 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);
(ss+1)->skipNullMove = false;
- pos.undo_null_move();
+ pos.do_null_move<false>(st);
if (nullValue >= beta)
{
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
- MovePickerExt<NT> mp(pos, RootNode ? Rml[MultiPVIteration].pv[0] : 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;
&& (move = mp.get_next_move()) != MOVE_NONE
&& !thread.cutoff_occurred())
{
- assert(move_is_ok(move));
+ assert(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.
- if (RootNode && !Rml.find(move, MultiPVIteration))
+ // 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 && !Rml.find(move, MultiPVIdx))
continue;
// At PV and SpNode nodes we want all moves to be legal since the beginning
// 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;
- }
-
// For long searches send current move info to GUI
- if (current_search_time() > 2000)
+ if (pos.thread() == 0 && current_search_time() > 2000)
cout << "info" << depth_to_uci(depth)
- << " currmove " << move << " currmovenumber " << moveCount + MultiPVIteration << endl;
+ << " currmove " << move
+ << " currmovenumber " << moveCount + MultiPVIdx << endl;
}
// At Root and at first iteration do a PV search on all the moves to score root moves
- isPvMove = (PvNode && moveCount <= ((RootNode && depth <= ONE_PLY) ? MAX_MOVES : 1));
+ isPvMove = (PvNode && moveCount <= (RootNode && depth <= ONE_PLY ? MAX_MOVES : 1));
givesCheck = pos.move_gives_check(move, ci);
- captureOrPromotion = pos.move_is_capture_or_promotion(move);
+ captureOrPromotion = pos.is_capture_or_promotion(move);
// Step 12. Decide the new search depth
ext = extension<PvNode>(pos, move, captureOrPromotion, givesCheck, &dangerous);
&& !inCheck
&& !dangerous
&& move != ttMove
- && !move_is_castle(move))
+ && !is_castle(move))
{
// Move count based pruning
if ( moveCount >= futility_move_count(depth)
// 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);
- futilityValueScaled = futilityBase + futility_margin(predictedDepth, moveCount)
- + H.gain(pos.piece_on(move_from(move)), move_to(move));
+ 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;
}
if ( depth > 3 * ONE_PLY
&& !captureOrPromotion
&& !dangerous
- && !move_is_castle(move)
+ && !is_castle(move)
&& ss->killers[0] != move
&& ss->killers[1] != move
&& (ss->reduction = reduction<PvNode>(depth, moveCount)) != DEPTH_ZERO)
alpha = sp->alpha;
}
- if (value > bestValue)
- {
- bestValue = value;
- ss->bestMove = move;
-
- if ( !RootNode
- && PvNode
- && value > alpha
- && value < beta) // We want always alpha < beta
- alpha = value;
-
- if (SpNode && !thread.cutoff_occurred())
- {
- sp->bestValue = value;
- sp->ss->bestMove = move;
- sp->alpha = alpha;
- sp->is_betaCutoff = (value >= beta);
- }
- }
-
- if (RootNode)
+ // 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
RootMove* rm = Rml.find(move);
rm->nodes += pos.nodes_searched() - nodes;
if (isPvMove || value > alpha)
{
// Update PV
- rm->pv_score = value;
+ rm->score = value;
rm->extract_pv_from_tt(pos);
// We record how often the best move has been changed in each
// the best move changes frequently, we allocate some more time.
if (!isPvMove && MultiPV == 1)
Rml.bestMoveChanges++;
-
- // Update alpha.
- if (value > alpha)
- alpha = value;
}
else
// 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->pv_score = -VALUE_INFINITE;
+ rm->score = -VALUE_INFINITE;
} // RootNode
+ if (value > bestValue)
+ {
+ bestValue = value;
+ ss->bestMove = move;
+
+ if ( PvNode
+ && value > alpha
+ && value < beta) // We want always alpha < beta
+ alpha = value;
+
+ 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 ( !RootNode
- && !SpNode
+ if ( !SpNode
&& depth >= Threads.min_split_depth()
&& bestValue < beta
&& Threads.available_slave_exists(pos.thread())
&& !StopRequest
&& !thread.cutoff_occurred())
- Threads.split<FakeSplit>(pos, ss, &alpha, beta, &bestValue, depth,
- threatMove, moveCount, &mp, PvNode);
+ bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, depth,
+ threatMove, moveCount, &mp, NT);
}
// 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.
+ // 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
+ // 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.
if (!SpNode && !moveCount)
return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
// Update killers and history only for non capture moves that fails high
if ( bestValue >= beta
- && !pos.move_is_capture_or_promotion(move))
+ && !pos.is_capture_or_promotion(move))
{
if (move != ss->killers[0])
{
bool inCheck, enoughMaterial, givesCheck, evasionPrunable;
const TTEntry* tte;
Depth ttDepth;
+ ValueType vt;
Value oldAlpha = alpha;
ss->bestMove = ss->currentMove = MOVE_NONE;
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);
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));
+ assert(is_ok(move));
givesCheck = pos.move_gives_check(move, ci);
&& !givesCheck
&& move != ttMove
&& enoughMaterial
- && !move_is_promotion(move)
- && !pos.move_is_passed_pawn_push(move))
+ && !is_promotion(move)
+ && !pos.is_passed_pawn_push(move))
{
futilityValue = futilityBase
- + piece_value_endgame(pos.piece_on(move_to(move)))
- + (move_is_ep(move) ? PawnValueEndgame : VALUE_ZERO);
+ + PieceValueEndgame[pos.piece_on(move_to(move))]
+ + (is_enpassant(move) ? PawnValueEndgame : VALUE_ZERO);
- if (futilityValue < alpha)
+ if (futilityValue < beta)
{
if (futilityValue > bestValue)
bestValue = futilityValue;
+
continue;
}
evasionPrunable = !PvNode
&& inCheck
&& bestValue > VALUE_MATED_IN_PLY_MAX
- && !pos.move_is_capture(move)
+ && !pos.is_capture(move)
&& !pos.can_castle(pos.side_to_move());
// Don't search moves with negative SEE values
if ( !PvNode
&& (!inCheck || evasionPrunable)
&& move != ttMove
- && !move_is_promotion(move)
+ && !is_promotion(move)
&& pos.see_sign(move) < 0)
continue;
&& !inCheck
&& givesCheck
&& move != ttMove
- && !pos.move_is_capture_or_promotion(move)
+ && !pos.is_capture_or_promotion(move)
&& ss->eval + PawnValueMidgame / 4 < beta
&& !check_is_dangerous(pos, move, futilityBase, beta, &bestValue))
{
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);
from = move_from(move);
to = move_to(move);
- them = opposite_color(pos.side_to_move());
+ them = flip(pos.side_to_move());
ksq = pos.king_square(them);
kingAtt = pos.attacks_from<KING>(ksq);
pc = pos.piece_on(from);
return true;
// Rule 2. Queen contact check is very dangerous
- if ( piece_type(pc) == QUEEN
+ if ( type_of(pc) == QUEEN
&& bit_is_set(kingAtt, to))
return true;
while (b)
{
victimSq = pop_1st_bit(&b);
- futilityValue = futilityBase + piece_value_endgame(pos.piece_on(victimSq));
+ futilityValue = futilityBase + PieceValueEndgame[pos.piece_on(victimSq)];
// Note that here we generate illegal "double move"!
if ( futilityValue >= beta
Piece p1, p2;
Square ksq;
- assert(m1 && move_is_ok(m1));
- assert(m2 && move_is_ok(m2));
+ assert(is_ok(m1));
+ assert(is_ok(m2));
// Case 1: The moving piece is the same in both moves
f2 = move_from(m2);
bool connected_threat(const Position& pos, Move m, Move threat) {
- assert(move_is_ok(m));
- assert(threat && move_is_ok(threat));
- assert(!pos.move_is_capture_or_promotion(m));
- assert(!pos.move_is_passed_pawn_push(m));
+ assert(is_ok(m));
+ assert(is_ok(threat));
+ assert(!pos.is_capture_or_promotion(m));
+ assert(!pos.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)
- && ( piece_value_midgame(pos.piece_on(tfrom)) >= piece_value_midgame(pos.piece_on(tto))
- || piece_type(pos.piece_on(tfrom)) == KING)
+ if ( pos.is_capture(threat)
+ && ( PieceValueMidgame[pos.piece_on(tfrom)] >= PieceValueMidgame[pos.piece_on(tto)]
+ || type_of(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);
return ( tte->depth() >= depth
- || v >= Max(VALUE_MATE_IN_PLY_MAX, beta)
- || v < Min(VALUE_MATED_IN_PLY_MAX, beta))
+ || 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));
}
- // update_gains() updates the gains table of a non-capture move given
- // the static position evaluation before and after the move.
-
- void update_gains(const Position& pos, Move m, Value before, Value after) {
-
- if ( m != MOVE_NULL
- && before != VALUE_NONE
- && after != VALUE_NONE
- && pos.captured_piece_type() == PIECE_TYPE_NONE
- && !move_is_special(m))
- H.update_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
- }
-
-
// current_search_time() returns the number of milliseconds which have passed
// since the beginning of the current search.
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?
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 size = std::min(MultiPV, (int)Rml.size());
+ int max = Rml[0].score;
+ int var = std::min(max - Rml[size - 1].score, int(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 rm;
rm.pv.push_back(ml.move());
rm.pv.push_back(MOVE_NONE);
- rm.pv_score = -VALUE_INFINITE;
+ rm.score = rm.prevScore = -VALUE_INFINITE;
rm.nodes = 0;
push_back(rm);
}
int ply = 1;
Move m = pv[0];
- assert(m != MOVE_NONE && pos.move_is_pl(m));
+ assert(m != MOVE_NONE && pos.is_pseudo_legal(m));
pv.clear();
pv.push_back(m);
while ( (tte = TT.probe(pos.get_key())) != NULL
&& tte->move() != MOVE_NONE
- && pos.move_is_pl(tte->move())
+ && 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))
Value v, m = VALUE_NONE;
int ply = 0;
- assert(pv[0] != MOVE_NONE && pos.move_is_pl(pv[0]));
+ assert(pv[0] != MOVE_NONE && pos.is_pseudo_legal(pv[0]));
do {
k = pos.get_key();
} // namespace
-// ThreadsManager::idle_loop() is where the threads are parked when they have no work
-// to do. The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint
-// object for which the current thread is the master.
+// Little helper used by idle_loop() to check that all the slave threads of a
+// split point have finished searching.
-void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) {
+static bool all_slaves_finished(SplitPoint* sp) {
- assert(threadID >= 0 && threadID < MAX_THREADS);
+ for (int i = 0; i < Threads.size(); i++)
+ if (sp->is_slave[i])
+ return false;
+
+ return true;
+}
- int i;
- bool allFinished;
+
+// 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.
+
+void Thread::idle_loop(SplitPoint* sp) {
while (true)
{
- // Slave threads can exit as soon as AllThreadsShouldExit raises,
- // master should exit as last one.
- if (allThreadsShouldExit)
- {
- assert(!sp);
- threads[threadID].state = Thread::TERMINATED;
- return;
- }
-
- // If we are not thinking, wait for a condition to be signaled
+ // If we are not searching, wait for a condition to be signaled
// instead of wasting CPU time polling for work.
- while ( threadID >= activeThreads
- || threads[threadID].state == Thread::INITIALIZING
- || (useSleepingThreads && threads[threadID].state == Thread::AVAILABLE))
+ while ( do_sleep
+ || do_terminate
+ || (Threads.use_sleeping_threads() && !is_searching))
{
- assert(!sp || useSleepingThreads);
- assert(threadID != 0 || useSleepingThreads);
+ assert((!sp && threadID) || Threads.use_sleeping_threads());
- if (threads[threadID].state == Thread::INITIALIZING)
- threads[threadID].state = Thread::AVAILABLE;
+ // Slave thread should exit as soon as do_terminate flag raises
+ if (do_terminate)
+ {
+ assert(!sp);
+ return;
+ }
// Grab the lock to avoid races with Thread::wake_up()
- lock_grab(&threads[threadID].sleepLock);
-
- // If we are master and all slaves have finished do not go to sleep
- for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {}
- allFinished = (i == activeThreads);
+ lock_grab(&sleepLock);
- if (allFinished || allThreadsShouldExit)
+ // If we are master and all slaves have finished don't go to sleep
+ if (sp && all_slaves_finished(sp))
{
- lock_release(&threads[threadID].sleepLock);
+ lock_release(&sleepLock);
break;
}
- // Do sleep here after retesting sleep conditions
- if (threadID >= activeThreads || threads[threadID].state == Thread::AVAILABLE)
- cond_wait(&threads[threadID].sleepCond, &threads[threadID].sleepLock);
+ // Do sleep after retesting sleep conditions under lock protection, in
+ // particular we need to avoid a deadlock in case a master thread has,
+ // 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);
- lock_release(&threads[threadID].sleepLock);
+ lock_release(&sleepLock);
}
// If this thread has been assigned work, launch a search
- if (threads[threadID].state == Thread::WORKISWAITING)
+ if (is_searching)
{
- assert(!allThreadsShouldExit);
-
- threads[threadID].state = Thread::SEARCHING;
+ assert(!do_terminate);
// Copy split point position and search stack and call search()
- // with SplitPoint template parameter set to true.
SearchStack ss[PLY_MAX_PLUS_2];
- SplitPoint* tsp = threads[threadID].splitPoint;
+ SplitPoint* tsp = splitPoint;
Position pos(*tsp->pos, threadID);
memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack));
(ss+1)->sp = tsp;
- if (tsp->pvNode)
+ 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
+ else if (tsp->nodeType == NonPV)
search<SplitPointNonPV>(pos, ss+1, tsp->alpha, tsp->beta, tsp->depth);
+ else
+ assert(false);
- assert(threads[threadID].state == Thread::SEARCHING);
+ assert(is_searching);
- threads[threadID].state = Thread::AVAILABLE;
+ is_searching = false;
// 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 ( useSleepingThreads
+ if ( Threads.use_sleeping_threads()
&& threadID != tsp->master
- && threads[tsp->master].state == Thread::AVAILABLE)
- threads[tsp->master].wake_up();
+ && !Threads[tsp->master].is_searching)
+ Threads[tsp->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.
- for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {}
- allFinished = (i == activeThreads);
-
- if (allFinished)
+ if (sp && all_slaves_finished(sp))
{
- // Because sp->slaves[] is reset under lock protection,
+ // 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));
-
- // 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;
}
}