#include <iostream>
#include <sstream>
#include <vector>
+#include <algorithm>
#include "book.h"
#include "evaluate.h"
using std::cout;
using std::endl;
using std::string;
+using Search::Signals;
+using Search::Limits;
+
+namespace Search {
+
+ volatile SignalsType Signals;
+ LimitsType Limits;
+ std::vector<Move> RootMoves;
+ Position RootPosition;
+}
namespace {
// RootMoveList struct is mainly a std::vector of RootMove objects
struct RootMoveList : public std::vector<RootMove> {
- void init(Position& pos, Move searchMoves[]);
+ void init(Position& pos, Move rootMoves[]);
RootMove* find(const Move& m, int startIndex = 0);
int bestMoveChanges;
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
// better than the second best move.
- const Value EasyMoveMargin = Value(0x200);
+ const Value EasyMoveMargin = Value(0x150);
/// Namespace variables
int MultiPV, UCIMultiPV, MultiPVIdx;
// Time management variables
- bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
TimeManager TimeMgr;
- SearchLimits Limits;
// 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.
- int NodesSincePoll;
- int NodesBetweenPolls = 30000;
-
// History table
History H;
/// Local functions
- Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove);
+ Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove);
template <NodeType NT>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth);
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);
+ int elapsed_search_time(int set = 0);
string score_to_uci(Value v, Value alpha = -VALUE_INFINITE, Value beta = VALUE_INFINITE);
string speed_to_uci(int64_t nodes);
string pv_to_uci(const Move pv[], int pvNum, bool chess960);
string pretty_pv(Position& pos, int depth, Value score, int time, Move pv[]);
string depth_to_uci(Depth depth);
- void poll(const Position& pos);
- void wait_for_stop_or_ponderhit();
// MovePickerExt template class extends MovePicker and allows to choose at compile
// time the proper moves source according to the type of node. In the default case
*dangerous = true;
}
- return Min(result, ONE_PLY);
+ return std::min(result, ONE_PLY);
}
} // namespace
/// init_search() is called during startup to initialize various lookup tables
-void init_search() {
+void Search::init() {
int d; // depth (ONE_PLY == 2)
int hd; // half depth (ONE_PLY == 1)
/// 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 perft(Position& pos, Depth depth) {
+int64_t Search::perft(Position& pos, Depth depth) {
StateInfo st;
int64_t sum = 0;
/// variables, and calls id_loop(). It returns false when a "quit" command is
/// received during the search.
-bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) {
+void Search::think() {
- static Book book; // Define static to initialize the PRNG only once
+ static Book book; // Defined static to initialize the PRNG only once
- // Initialize global search-related variables
- StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = false;
- NodesSincePoll = 0;
- current_search_time(get_system_time());
- Limits = limits;
- TimeMgr.init(Limits, pos.startpos_ply_counter());
+ Position& pos = RootPosition;
- // Set output steram in normal or chess960 mode
- cout << set960(pos.is_chess960());
+ // Save "search start" time and reset elapsed time to zero
+ elapsed_search_time(get_system_time());
- // Set best NodesBetweenPolls interval to avoid lagging under time pressure
- if (Limits.maxNodes)
- NodesBetweenPolls = Min(Limits.maxNodes, 30000);
- else if (Limits.time && Limits.time < 1000)
- NodesBetweenPolls = 1000;
- else if (Limits.time && Limits.time < 5000)
- NodesBetweenPolls = 5000;
- else
- NodesBetweenPolls = 30000;
+ // Set output stream mode: normal or chess960. Castling notation is different
+ cout << set960(pos.is_chess960());
// Look for a book move
if (Options["OwnBook"].value<bool>())
Move bookMove = book.probe(pos, Options["Best Book Move"].value<bool>());
if (bookMove != MOVE_NONE)
{
- if (Limits.ponder)
- wait_for_stop_or_ponderhit();
+ if (!Signals.stop && (Limits.ponder || Limits.infinite))
+ Threads.wait_for_stop_or_ponderhit();
cout << "bestmove " << bookMove << endl;
- return !QuitRequest;
+ return;
}
}
- // Read UCI options
- UCIMultiPV = Options["MultiPV"].value<int>();
- SkillLevel = Options["Skill Level"].value<int>();
-
+ // Read UCI options: GUI could change UCI parameters during the game
read_evaluation_uci_options(pos.side_to_move());
Threads.read_uci_options();
TT.clear();
}
+ UCIMultiPV = Options["MultiPV"].value<int>();
+ SkillLevel = Options["Skill Level"].value<int>();
+
// 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);
-
- // Wake up needed threads and reset maxPly counter
- for (int i = 0; i < Threads.size(); i++)
- {
- Threads[i].wake_up();
- Threads[i].maxPly = 0;
- }
+ MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, 4) : UCIMultiPV);
- // Write to log file and keep it open to be accessed during the search
+ // Write current search header to log file
if (Options["Use Search Log"].value<bool>())
{
Log log(Options["Search Log Filename"].value<string>());
<< 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();
+ }
+
+ // Set best timer interval to avoid lagging under time pressure. Timer is
+ // used to check for remaining available thinking time.
+ TimeMgr.init(Limits, pos.startpos_ply_counter());
+
+ if (TimeMgr.available_time())
+ Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 8, 20)));
+ 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, searchMoves, &ponderMove);
+ Move bestMove = id_loop(pos, &RootMoves[0], &ponderMove);
+
+ // Stop timer, no need to check for available time any more
+ Threads.set_timer(0);
- // Write final search statistics and close log file
+ // This makes all the slave threads to go to sleep, if not already sleeping
+ Threads.set_size(1);
+
+ // Write current search final statistics to log file
if (Options["Use Search Log"].value<bool>())
{
- int t = current_search_time();
+ int e = elapsed_search_time();
Log log(Options["Search Log Filename"].value<string>());
log << "Nodes: " << pos.nodes_searched()
- << "\nNodes/second: " << (t > 0 ? pos.nodes_searched() * 1000 / t : 0)
+ << "\nNodes/second: " << (e > 0 ? pos.nodes_searched() * 1000 / e : 0)
<< "\nBest move: " << move_to_san(pos, bestMove);
StateInfo st;
pos.undo_move(bestMove); // Return from think() with unchanged position
}
- // This makes all the threads to go to sleep
- Threads.set_size(1);
-
- // If we are pondering or in infinite search, we shouldn't print the
- // best move before we are told to do so.
- if (!StopRequest && (Limits.ponder || Limits.infinite))
- wait_for_stop_or_ponderhit();
+ // 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();
// Could be MOVE_NONE when searching on a stalemate position
cout << "bestmove " << bestMove;
cout << " ponder " << ponderMove;
cout << endl;
-
- return !QuitRequest;
}
// with increasing depth until the allocated thinking time has been consumed,
// user stops the search, or the maximum search depth is reached.
- Move id_loop(Position& pos, Move searchMoves[], Move* ponderMove) {
+ Move id_loop(Position& pos, Move rootMoves[], Move* ponderMove) {
SearchStack ss[PLY_MAX_PLUS_2];
Value bestValues[PLY_MAX_PLUS_2];
int bestMoveChanges[PLY_MAX_PLUS_2];
int depth, aspirationDelta;
- Value value, alpha, beta;
- Move bestMove, easyMove, skillBest, skillPonder;
+ Value bestValue, alpha, beta;
+ Move bestMove, skillBest, skillPonder;
+ bool bestMoveNeverChanged = true;
// Initialize stuff before a new search
memset(ss, 0, 4 * sizeof(SearchStack));
TT.new_search();
H.clear();
- *ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
+ *ponderMove = bestMove = skillBest = skillPonder = MOVE_NONE;
depth = aspirationDelta = 0;
- value = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
- ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
+ bestValue = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ ss->currentMove = MOVE_NULL; // Hack to skip update gains
// Moves to search are verified and copied
- Rml.init(pos, searchMoves);
+ Rml.init(pos, rootMoves);
// Handle special case of searching on a mate/stalemate position
if (!Rml.size())
}
// Iterative deepening loop until requested to stop or target depth reached
- while (!StopRequest && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
+ while (!Signals.stop && ++depth <= PLY_MAX && (!Limits.maxDepth || depth <= Limits.maxDepth))
{
// Save now last iteration's scores, before Rml moves are reordered
for (size_t i = 0; i < Rml.size(); i++)
Rml.bestMoveChanges = 0;
// MultiPV loop. We perform a full root search for each PV line
- for (MultiPVIdx = 0; MultiPVIdx < Min(MultiPV, (int)Rml.size()); MultiPVIdx++)
+ for (MultiPVIdx = 0; MultiPVIdx < std::min(MultiPV, (int)Rml.size()); MultiPVIdx++)
{
// Calculate dynamic aspiration window based on previous iterations
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(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE);
- beta = Min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE);
+ alpha = std::max(Rml[MultiPVIdx].prevScore - aspirationDelta, -VALUE_INFINITE);
+ beta = std::min(Rml[MultiPVIdx].prevScore + aspirationDelta, VALUE_INFINITE);
}
else
{
// research with bigger window until not failing high/low anymore.
do {
// 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);
+ // needed by update gains and ss copy when splitting at Root.
+ bestValue = search<Root>(pos, ss+1, alpha, beta, depth * ONE_PLY);
// Bring to front the best move. It is critical that sorting is
// done with a stable algorithm because all the values but the first
// 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)
+ if (MultiPVIdx && bestValue > alpha && bestValue < beta)
sort<RootMove>(Rml.begin(), Rml.begin() + MultiPVIdx);
// Write PV back to transposition table in case the relevant entries
// 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)
+ 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 ((value > alpha && value < beta) || current_search_time() > 2000)
- for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
+ if ((bestValue > alpha && bestValue < beta) || elapsed_search_time() > 2000)
+ for (int i = 0; i < std::min(UCIMultiPV, (int)Rml.size()); i++)
{
bool updated = (i <= MultiPVIdx);
// In case of failing high/low increase aspiration window and
// research, otherwise exit the fail high/low loop.
- if (value >= beta)
+ if (bestValue >= beta)
{
- beta = Min(beta + aspirationDelta, VALUE_INFINITE);
+ beta = std::min(beta + aspirationDelta, VALUE_INFINITE);
aspirationDelta += aspirationDelta / 2;
}
- else if (value <= alpha)
+ else if (bestValue <= alpha)
{
- AspirationFailLow = true;
- StopOnPonderhit = false;
+ Signals.failedLowAtRoot = true;
+ Signals.stopOnPonderhit = false;
- alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
+ alpha = std::max(alpha - aspirationDelta, -VALUE_INFINITE);
aspirationDelta += aspirationDelta / 2;
}
else
break;
- } while (abs(value) < VALUE_KNOWN_WIN);
+ } while (abs(bestValue) < VALUE_KNOWN_WIN);
}
// Collect info about search result
bestMove = Rml[0].pv[0];
*ponderMove = Rml[0].pv[1];
- bestValues[depth] = value;
+ bestValues[depth] = bestValue;
bestMoveChanges[depth] = Rml.bestMoveChanges;
// Skills: Do we need to pick now the best and the ponder moves ?
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;
+ log << pretty_pv(pos, depth, bestValue, elapsed_search_time(), &Rml[0].pv[0]) << endl;
}
- // 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;
+ // Filter out startup noise when monitoring best move stability
+ if (depth > 2 && bestMoveChanges[depth])
+ bestMoveNeverChanged = false;
- // Check for some early stop condition
- if (!StopRequest && Limits.useTimeManagement())
+ // Do we have time for the next iteration? Can we stop searching now?
+ if (!Signals.stop && !Signals.stopOnPonderhit && Limits.useTimeManagement())
{
- // 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
- ||( Rml[0].nodes > (pos.nodes_searched() * 85) / 100
- && current_search_time() > TimeMgr.available_time() / 16)
- ||( Rml[0].nodes > (pos.nodes_searched() * 98) / 100
- && current_search_time() > TimeMgr.available_time() / 32)))
- StopRequest = true;
+ bool stop = false; // Local variable instead of the volatile Signals.stop
// Take in account some extra time if the best move has changed
if (depth > 4 && depth < 50)
// 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 (current_search_time() > (TimeMgr.available_time() * 62) / 100)
- StopRequest = true;
+ if (elapsed_search_time() > (TimeMgr.available_time() * 62) / 100)
+ stop = true;
+
+ // Stop search early if one move seems to be much better than others
+ if ( depth >= 10
+ && !stop
+ && ( bestMoveNeverChanged
+ || elapsed_search_time() > (TimeMgr.available_time() * 40) / 100))
+ {
+ Value rBeta = bestValue - EasyMoveMargin;
+ (ss+1)->excludedMove = bestMove;
+ (ss+1)->skipNullMove = true;
+ Value v = search<NonPV>(pos, ss+1, rBeta - 1, rBeta, (depth * ONE_PLY) / 2);
+ (ss+1)->skipNullMove = false;
+ (ss+1)->excludedMove = MOVE_NONE;
+
+ if (v < rBeta)
+ stop = true;
+ }
- // If we are allowed to ponder do not stop the search now but keep pondering
- if (StopRequest && Limits.ponder)
+ if (stop)
{
- StopRequest = false;
- StopOnPonderhit = true;
+ // If we are allowed to ponder do not stop the search now but
+ // keep pondering until GUI sends "ponderhit" or "stop".
+ if (Limits.ponder) // FIXME racing
+ Signals.stopOnPonderhit = true;
+ else
+ Signals.stop = true;
}
}
}
ValueType vt;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityBase, futilityValue;
- bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous;
+ bool isPvMove, inCheck, singularExtensionNode, givesCheck;
+ bool captureOrPromotion, dangerous, doFullDepthSearch;
int moveCount = 0, playedMoveCount = 0;
Thread& thread = Threads[pos.thread()];
SplitPoint* sp = NULL;
if (PvNode && thread.maxPly < ss->ply)
thread.maxPly = ss->ply;
- // Step 1. Initialize node and poll. Polling can abort search
+ // Step 1. Initialize node
if (!SpNode)
{
ss->currentMove = ss->bestMove = threatMove = (ss+1)->excludedMove = MOVE_NONE;
goto split_point_start;
}
- if (pos.thread() == 0 && ++NodesSincePoll > NodesBetweenPolls)
- {
- NodesSincePoll = 0;
- poll(pos);
- }
-
// Step 2. Check for aborted search and immediate draw
- if (( StopRequest
+ if (( Signals.stop
|| pos.is_draw<false>()
|| ss->ply > PLY_MAX) && !RootNode)
return VALUE_DRAW;
// 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;
}
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 (RootNode)
{
// This is used by time management
- FirstRootMove = (moveCount == 1);
+ Signals.firstRootMove = (moveCount == 1);
// Save the current node count before the move is searched
nodes = pos.nodes_searched();
// For long searches send current move info to GUI
- if (pos.thread() == 0 && current_search_time() > 2000)
+ if (pos.thread() == 0 && elapsed_search_time() > 2000)
cout << "info" << depth_to_uci(depth)
<< " 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 <= 1);
givesCheck = pos.move_gives_check(move, ci);
captureOrPromotion = pos.is_capture_or_promotion(move);
Value rBeta = ttValue - int(depth);
ss->excludedMove = move;
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
+ value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2);
ss->skipNullMove = false;
ss->excludedMove = MOVE_NONE;
ss->bestMove = MOVE_NONE;
- if (v < rBeta)
+ if (value < rBeta)
ext = ONE_PLY;
}
}
// Step 14. Make the move
pos.do_move(move, st, ci, givesCheck);
- // Step extra. pv search (only in PV nodes)
- // The first move in list is the expected PV
- if (isPvMove)
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
- else
+ // Step 15. Reduced depth search (LMR). If the move fails high will be
+ // re-searched at full depth.
+ if ( depth > 3 * ONE_PLY
+ && !isPvMove
+ && !captureOrPromotion
+ && !dangerous
+ && !is_castle(move)
+ && ss->killers[0] != move
+ && ss->killers[1] != move)
{
- // Step 15. Reduced depth search
- // If the move fails high will be re-searched at full depth.
- bool doFullDepthSearch = true;
-
- if ( depth > 3 * ONE_PLY
- && !captureOrPromotion
- && !dangerous
- && !is_castle(move)
- && ss->killers[0] != move
- && ss->killers[1] != move
- && (ss->reduction = reduction<PvNode>(depth, moveCount)) != DEPTH_ZERO)
- {
- Depth d = newDepth - ss->reduction;
- alpha = SpNode ? sp->alpha : alpha;
+ ss->reduction = reduction<PvNode>(depth, moveCount);
+ Depth d = newDepth - ss->reduction;
+ 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 = d < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
- ss->reduction = DEPTH_ZERO;
- doFullDepthSearch = (value > alpha);
- }
+ doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO);
+ ss->reduction = DEPTH_ZERO;
+ }
+ else
+ doFullDepthSearch = !isPvMove;
- // Step 16. Full depth search
- if (doFullDepthSearch)
- {
- alpha = SpNode ? sp->alpha : alpha;
- value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth);
-
- // Step extra. pv search (only in PV nodes)
- // Search only for possible new PV nodes, if instead value >= beta then
- // parent node fails low with value <= alpha and tries another move.
- if (PvNode && value > alpha && (RootNode || value < beta))
- value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
- }
+ // Step 16. Full depth search, when LMR is skipped or fails high
+ if (doFullDepthSearch)
+ {
+ alpha = SpNode ? sp->alpha : alpha;
+ value = newDepth < ONE_PLY ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth);
}
+ // 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))))
+ value = newDepth < ONE_PLY ? -qsearch<PV>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth);
+
// Step 17. Undo move
pos.undo_move(move);
// 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)
+ if (RootNode && !Signals.stop)
{
// Remember searched nodes counts for this move
RootMove* rm = Rml.find(move);
&& depth >= Threads.min_split_depth()
&& bestValue < beta
&& Threads.available_slave_exists(pos.thread())
- && !StopRequest
+ && !Signals.stop
&& !thread.cutoff_occurred())
bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, depth,
threatMove, moveCount, &mp, NT);
// Step 21. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (!SpNode && !StopRequest && !thread.cutoff_occurred())
+ if (!SpNode && !Signals.stop && !thread.cutoff_occurred())
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER
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
- && !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.
- int current_search_time(int set) {
+ int elapsed_search_time(int set) {
static int searchStartTime;
string speed_to_uci(int64_t nodes) {
std::stringstream s;
- int t = current_search_time();
+ int t = elapsed_search_time();
s << " nodes " << nodes
<< " nps " << (t > 0 ? int(nodes * 1000 / t) : 0)
return s.str();
}
+
// pv_to_uci() returns a string with information on the current PV line
// formatted according to UCI specification.
return s.str();
}
+
// depth_to_uci() returns a string with information on the current depth and
// seldepth formatted according to UCI specification.
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").
return s.str();
}
- // poll() performs two different functions: It polls for user input, and it
- // looks at the time consumed so far and decides if it's time to abort the
- // search.
-
- void poll(const Position& pos) {
-
- static int lastInfoTime;
- int t = current_search_time();
-
- // Poll for input
- if (input_available())
- {
- // We are line oriented, don't read single chars
- string command;
-
- if (!std::getline(std::cin, command) || command == "quit")
- {
- // Quit the program as soon as possible
- Limits.ponder = false;
- QuitRequest = StopRequest = true;
- return;
- }
- else if (command == "stop")
- {
- // Stop calculating as soon as possible, but still send the "bestmove"
- // and possibly the "ponder" token when finishing the search.
- Limits.ponder = false;
- StopRequest = true;
- }
- else if (command == "ponderhit")
- {
- // The opponent has played the expected move. GUI sends "ponderhit" if
- // we were told to ponder on the same move the opponent has played. We
- // should continue searching but switching from pondering to normal search.
- Limits.ponder = false;
-
- if (StopOnPonderhit)
- StopRequest = true;
- }
- }
-
- // Print search information
- if (t < 1000)
- lastInfoTime = 0;
-
- else if (lastInfoTime > t)
- // HACK: Must be a new search where we searched less than
- // NodesBetweenPolls nodes during the first second of search.
- lastInfoTime = 0;
-
- else if (t - lastInfoTime >= 1000)
- {
- lastInfoTime = t;
-
- dbg_print_mean();
- dbg_print_hit_rate();
- }
-
- // Should we stop the search?
- if (Limits.ponder)
- return;
-
- bool stillAtFirstMove = FirstRootMove
- && !AspirationFailLow
- && t > TimeMgr.available_time();
-
- bool noMoreTime = t > TimeMgr.maximum_time()
- || stillAtFirstMove;
-
- if ( (Limits.useTimeManagement() && noMoreTime)
- || (Limits.maxTime && t >= Limits.maxTime)
- || (Limits.maxNodes && pos.nodes_searched() >= Limits.maxNodes)) // FIXME
- StopRequest = true;
- }
-
-
- // wait_for_stop_or_ponderhit() is called when the maximum depth is reached
- // while the program is pondering. The point is to work around a wrinkle in
- // the UCI protocol: When pondering, the engine is not allowed to give a
- // "bestmove" before the GUI sends it a "stop" or "ponderhit" command.
- // We simply wait here until one of these commands is sent, and return,
- // after which the bestmove and pondermove will be printed.
-
- void wait_for_stop_or_ponderhit() {
-
- string command;
-
- // Wait for a command from stdin
- while ( std::getline(std::cin, command)
- && command != "ponderhit" && command != "stop" && command != "quit") {};
-
- if (command != "ponderhit" && command != "stop")
- QuitRequest = true; // Must be "quit" or getline() returned false
- }
-
// 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) {
assert(MultiPV > 1);
// 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 size = std::min(MultiPV, (int)Rml.size());
int max = Rml[0].score;
- int var = Min(max - Rml[size - 1].score, PawnValueMidgame);
+ int var = std::min(max - Rml[size - 1].score, int(PawnValueMidgame));
int wk = 120 - 2 * SkillLevel;
// PRNG sequence should be non deterministic
/// RootMove and RootMoveList method's definitions
- void RootMoveList::init(Position& pos, Move searchMoves[]) {
+ void RootMoveList::init(Position& pos, Move rootMoves[]) {
Move* sm;
bestMoveChanges = 0;
// Generate all legal moves and add them to RootMoveList
for (MoveList<MV_LEGAL> ml(pos); !ml.end(); ++ml)
{
- // If we have a searchMoves[] list then verify the move
+ // If we have a rootMoves[] list then verify the move
// is in the list before to add it.
- for (sm = searchMoves; *sm && *sm != ml.move(); sm++) {}
+ for (sm = rootMoves; *sm && *sm != ml.move(); sm++) {}
- if (sm != searchMoves && *sm != ml.move())
+ if (sm != rootMoves && *sm != ml.move())
continue;
RootMove rm;
return NULL;
}
+
// extract_pv_from_tt() builds a PV by adding moves from the transposition table.
// We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
// allow to always have a ponder move even when we fail high at root and also a
do pos.undo_move(pv[--ply]); while (ply);
}
+
// insert_pv_in_tt() is called at the end of a search iteration, and inserts
// the PV back into the TT. This makes sure the old PV moves are searched
// first, even if the old TT entries have been overwritten.
do pos.undo_move(pv[--ply]); while (ply);
}
-} // namespace
-
-
-// Little helper used by idle_loop() to check that all the slave threads of a
-// split point have finished searching.
-
-static bool all_slaves_finished(SplitPoint* sp) {
-
- for (int i = 0; i < Threads.size(); i++)
- if (sp->is_slave[i])
- return false;
- return true;
-}
+} // namespace
// Thread::idle_loop() is where the thread is parked when it has no work to do.
lock_grab(&sleepLock);
// If we are master and all slaves have finished don't go to sleep
- if (sp && all_slaves_finished(sp))
+ if (sp && Threads.split_point_finished(sp))
{
lock_release(&sleepLock);
break;
// 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 && all_slaves_finished(sp))
+ 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.
}
}
}
+
+
+// do_timer_event() is called by the timer thread when the timer triggers
+
+void do_timer_event() {
+
+ static int lastInfoTime;
+ int e = elapsed_search_time();
+
+ // Print debug information every one second
+ if (!lastInfoTime || get_system_time() - lastInfoTime >= 1000)
+ {
+ lastInfoTime = get_system_time();
+
+ dbg_print_mean();
+ dbg_print_hit_rate();
+ }
+
+ // Should we stop the search?
+ if (Limits.ponder)
+ return;
+
+ bool stillAtFirstMove = Signals.firstRootMove
+ && !Signals.failedLowAtRoot
+ && e > TimeMgr.available_time();
+
+ bool noMoreTime = e > TimeMgr.maximum_time()
+ || stillAtFirstMove;
+
+ if ( (Limits.useTimeManagement() && noMoreTime)
+ || (Limits.maxTime && e >= Limits.maxTime)
+ /* missing nodes limit */ ) // FIXME
+ Signals.stop = true;
+}
projects / stockfish / blobdiff