/// Namespace variables
- // Root move list
RootMoveList Rml;
-
- // MultiPV mode
size_t MultiPV, UCIMultiPV, MultiPVIdx;
-
- // Time management variables
TimeManager TimeMgr;
-
- // Skill level adjustment
int SkillLevel;
bool SkillLevelEnabled;
-
- // History table
History H;
StateInfo st;
int64_t sum = 0;
- // Generate all legal moves
MoveList<MV_LEGAL> ml(pos);
- // If we are at the last ply we don't need to do and undo
- // the moves, just to count them.
+ // At the last ply just return the number of moves (leaf nodes)
if (depth <= ONE_PLY)
return ml.size();
- // Loop through all legal moves
CheckInfo ci(pos);
for ( ; !ml.end(); ++ml)
{
static Book book; // Defined static to initialize the PRNG only once
Position& pos = RootPosition;
-
- // Reset elapsed search time
elapsed_time(true);
+ TimeMgr.init(Limits, pos.startpos_ply_counter());
// 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>())
{
if (Options["Book File"].value<string>() != book.name())
read_evaluation_uci_options(pos.side_to_move());
Threads.read_uci_options();
- // Set a new TT size if changed
TT.set_size(Options["Hash"].value<int>());
-
if (Options["Clear Hash"].value<bool>())
{
Options["Clear Hash"].set_value("false");
SkillLevelEnabled = (SkillLevel < 20);
MultiPV = (SkillLevelEnabled ? std::max(UCIMultiPV, (size_t)4) : UCIMultiPV);
- // Write current search header to log file
if (Options["Use Search Log"].value<bool>())
{
Log log(Options["Search Log Filename"].value<string>());
// 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
Move ponderMove = MOVE_NONE;
Move bestMove = id_loop(pos, &RootMoves[0], &ponderMove);
- // Stop timer, no need to check for available time any more
+ // Stop timer and send all the slaves to sleep, if not already sleeping
Threads.set_timer(0);
-
- // 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 e = elapsed_time();
Move bestMove, skillBest, skillPonder;
bool bestMoveNeverChanged = true;
- // Initialize stuff before a new search
memset(ss, 0, 4 * sizeof(Stack));
TT.new_search();
H.clear();
depth = aspirationDelta = 0;
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, rootMoves);
// Handle special case of searching on a mate/stalemate position
} while (abs(bestValue) < VALUE_KNOWN_WIN);
}
- // Collect info about search result
bestMove = Rml[0].pv[0];
*ponderMove = Rml[0].pv[1];
bestValues[depth] = bestValue;
split_point_start: // At split points actual search starts from here
- // Initialize a MovePicker object for the current position
MovePickerExt<SpNode> mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
&& !SpNode
&& depth >= SingularExtensionDepth[PvNode]
&& ttMove != MOVE_NONE
- && !excludedMove // Do not allow recursive singular extension search
+ && !excludedMove // Recursive singular search is not allowed
&& (tte->type() & VALUE_TYPE_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;
if (SpNode)
// This is used by time management
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 && elapsed_time() > 2000)
cout << "info" << depth_to_uci(depth)
<< " currmove " << move
// be trusted, and we don't update the best move and/or PV.
if (RootNode && !Signals.stop)
{
- // Remember searched nodes counts for this move
RootMove* rm = Rml.find(move);
rm->nodes += pos.nodes_searched() - nodes;
// PV move or new best move ?
if (isPvMove || value > alpha)
{
- // Update PV
rm->score = value;
rm->extract_pv_from_tt(pos);
// position in the list is preserved, just the PV is pushed up.
rm->score = -VALUE_INFINITE;
- } // RootNode
+ }
if (value > bestValue)
{
if (!moveCount)
return excludedMove ? oldAlpha : inCheck ? value_mated_in(ss->ply) : VALUE_DRAW;
- // We have pruned all the moves, so return a fail-low score
+ // If we have pruned all the moves without searching return a fail-low score
if (bestValue == -VALUE_INFINITE)
{
assert(!playedMoveCount);
}
// Step 21. Update tables
- // If the search is not aborted, update the transposition table,
- // history counters, and killer moves.
+ // Update transposition table entry, history and killers
if (!SpNode && !Signals.stop && !thread.cutoff_occurred())
{
move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove;
return bestValue;
}
+
// qsearch() is the quiescence search function, which is called by the main
// search function when the remaining depth is zero (or, to be more precise,
// less than ONE_PLY).
if (PvNode && bestValue > alpha)
alpha = bestValue;
- // Futility pruning parameters, not needed when in check
futilityBase = ss->eval + evalMargin + FutilityMarginQS;
enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
}
if (!pos.pl_move_is_legal(move, ci.pinned))
continue;
- // Update current move
ss->currentMove = move;
// Make and search the move
}
- // can_return_tt() returns true if a transposition table score
- // can be used to cut-off 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 can_return_tt(const TTEntry* tte, Depth depth, Value beta, int ply) {
}
- // refine_eval() returns the transposition table score if
- // possible otherwise falls back on static position evaluation.
+ // 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) {
}
- // update_history() registers a good move that produced a beta-cutoff
- // in history and marks as failures all the other moves of that ply.
+ // 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) {
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 helpers
+ // time_to_string() and score_to_string() to format time and score respectively.
+
string time_to_string(int millisecs) {
const int MSecMinute = 1000 * 60;
return s.str();
}
-
- // pretty_pv() creates a human-readable string from a position and a PV.
- // It is used to write search information to the log file (which is created
- // when the UCI parameter "Use Search Log" is "true").
-
string pretty_pv(Position& pos, int depth, Value value, int time, Move pv[]) {
const int64_t K = 1000;
}
- /// RootMove and RootMoveList method's definitions
+ // RootMove and RootMoveList method's definitions
void RootMoveList::init(Position& pos, Move rootMoves[]) {
} // namespace
-// 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.
+/// 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) {
{
assert((!sp && threadID) || Threads.use_sleeping_threads());
- // Slave thread should exit as soon as do_terminate flag raises
if (do_terminate)
{
assert(!sp);
}
-// do_timer_event() is called by the timer thread when the timer triggers
+/// 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
+/// available time and so stop the search.
void do_timer_event() {
static int lastInfoTime;
int e = elapsed_time();
- // Print debug information every one second
- if (!lastInfoTime || get_system_time() - lastInfoTime >= 1000)
+ if (get_system_time() - lastInfoTime >= 1000 || !lastInfoTime)
{
lastInfoTime = get_system_time();
dbg_print_hit_rate();
}
- // Should we stop the search?
if (Limits.ponder)
return;
projects / stockfish / blobdiff