/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2009 Marco Costalba
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
// Apart for the first one that has its score, following moves
// normally have score -VALUE_INFINITE, so are ordered according
// to the number of beta cutoffs occurred under their subtree during
- // the last iteration.
+ // the last iteration. The counters are per thread variables to avoid
+ // concurrent accessing under SMP case.
struct BetaCounterType {
void clear();
void add(Color us, Depth d, int threadID);
void read(Color us, int64_t& our, int64_t& their);
-
- int64_t hits[THREAD_MAX][2];
};
bool move_is_killer(Move m, const SearchStack& ss);
Depth extension(const Position &pos, Move m, bool pvNode, bool capture, bool check, bool singleReply, bool mateThreat, bool* dangerous);
bool ok_to_do_nullmove(const Position &pos);
- bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d);
+ bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d, const History& H);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
bool ok_to_history(const Position &pos, Move m);
- void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount);
+ void update_history(const Position& pos, Move m, Depth depth, History& H, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
bool fail_high_ply_1();
// but it could turn out to be useful for debugging.
Lock IOLock;
-History H; // Should be made local?
-
-// The empty search stack
-SearchStack EmptySearchStack;
-
// SearchStack::init() initializes a search stack. Used at the beginning of a
// new search from the root.
////
/// think() is the external interface to Stockfish's search, and is called when
-/// the program receives the UCI 'go' command. It initializes various
-/// search-related global variables, and calls root_search()
+/// the program receives the UCI 'go' command. It initializes various
+/// search-related global variables, and calls root_search(). It returns false
+/// when a quit command is received during the search.
-void think(const Position &pos, bool infinite, bool ponder, int side_to_move,
+bool think(const Position &pos, bool infinite, bool ponder, int side_to_move,
int time[], int increment[], int movesToGo, int maxDepth,
int maxNodes, int maxTime, Move searchMoves[]) {
if (bookMove != MOVE_NONE)
{
std::cout << "bestmove " << bookMove << std::endl;
- return;
+ return true;
}
}
if (UseLogFile)
LogFile.close();
- if (Quit)
- {
- stop_threads();
- quit_eval();
- exit(0);
- }
Idle = true;
+ return !Quit;
}
// Wait until the thread has finished launching:
while (!Threads[i].running);
}
-
- // Init also the empty search stack
- EmptySearchStack.init(0);
- EmptySearchStack.initKillers();
}
// Initialize
TT.new_search();
- H.clear();
+ for (int i = 0; i < THREAD_MAX; i++)
+ Threads[i].H.clear();
+
for (int i = 0; i < 3; i++)
{
ss[i].init(i);
if (i < MultiPV)
{
+ // Aspiration window is disabled in multi-pv case
+ if (MultiPV > 1)
+ alpha = -VALUE_INFINITE;
+
value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
// If the value has dropped a lot compared to the last iteration,
// set the boolean variable Problem to true. This variable is used
// Initialize a MovePicker object for the current position, and prepare
// to search all moves
- MovePicker mp = MovePicker(pos, true, ttMove, ss[ply], depth);
+ MovePicker mp = MovePicker(pos, true, ttMove, depth, Threads[threadID].H, &ss[ply]);
Move move, movesSearched[256];
int moveCount = 0;
Move m = ss[ply].pv[ply];
if (ok_to_history(pos, m)) // Only non capture moves are considered
{
- update_history(pos, m, depth, movesSearched, moveCount);
+ update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount);
update_killers(m, ss[ply]);
}
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
// Initialize a MovePicker object for the current position, and prepare
// to search all moves:
- MovePicker mp = MovePicker(pos, false, ttMove, ss[ply], depth);
+ MovePicker mp = MovePicker(pos, false, ttMove, depth, Threads[threadID].H, &ss[ply]);
Move move, movesSearched[256];
int moveCount = 0;
{
// History pruning. See ok_to_prune() definition
if ( moveCount >= 2 + int(depth)
- && ok_to_prune(pos, move, ss[ply].threatMove, depth))
+ && ok_to_prune(pos, move, ss[ply].threatMove, depth, Threads[threadID].H))
continue;
// Value based pruning
Move m = ss[ply].pv[ply];
if (ok_to_history(pos, m)) // Only non capture moves are considered
{
- update_history(pos, m, depth, movesSearched, moveCount);
+ update_history(pos, m, depth, Threads[threadID].H, movesSearched, moveCount);
update_killers(m, ss[ply]);
}
TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
// 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 == 0) will be generated.
- MovePicker mp = MovePicker(pos, pvNode, ttMove, EmptySearchStack, depth);
+ MovePicker mp = MovePicker(pos, pvNode, ttMove, depth, Threads[threadID].H);
Move move;
int moveCount = 0;
Bitboard dcCandidates = mp.discovered_check_candidates();
&& !moveIsCapture
&& !move_promotion(move)
&& moveCount >= 2 + int(sp->depth)
- && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth))
+ && ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth, Threads[threadID].H))
continue;
// Make and search the move.
void BetaCounterType::clear() {
for (int i = 0; i < THREAD_MAX; i++)
- hits[i][WHITE] = hits[i][BLACK] = 0ULL;
+ Threads[i].betaCutOffs[WHITE] = Threads[i].betaCutOffs[BLACK] = 0ULL;
}
void BetaCounterType::add(Color us, Depth d, int threadID) {
// Weighted count based on depth
- hits[threadID][us] += int(d);
+ Threads[threadID].betaCutOffs[us] += unsigned(d);
}
void BetaCounterType::read(Color us, int64_t& our, int64_t& their) {
our = their = 0UL;
for (int i = 0; i < THREAD_MAX; i++)
{
- our += hits[i][us];
- their += hits[i][opposite_color(us)];
+ our += Threads[i].betaCutOffs[us];
+ their += Threads[i].betaCutOffs[opposite_color(us)];
}
}
// non-tactical moves late in the move list close to the leaves are
// candidates for pruning.
- bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d) {
+ bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d, const History& H) {
Square mfrom, mto, tfrom, tto;
assert(move_is_ok(m));
return false;
// Case 4: Don't prune moves with good history.
- if (!H.ok_to_prune(pos.piece_on(move_from(m)), m, d))
+ if (!H.ok_to_prune(pos.piece_on(mfrom), mto, d))
return false;
// Case 5: If the moving piece in the threatened move is a slider, don't
// 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 m, Depth depth,
+ void update_history(const Position& pos, Move m, Depth depth, History& H,
Move movesSearched[], int moveCount) {
- H.success(pos.piece_on(move_from(m)), m, depth);
+ H.success(pos.piece_on(move_from(m)), move_to(m), depth);
for (int i = 0; i < moveCount - 1; i++)
{
assert(m != movesSearched[i]);
if (ok_to_history(pos, movesSearched[i]))
- H.failure(pos.piece_on(move_from(movesSearched[i])), movesSearched[i]);
+ H.failure(pos.piece_on(move_from(movesSearched[i])), move_to(movesSearched[i]));
}
}
AbortSearch = true;
PonderSearch = false;
Quit = true;
+ return;
}
else if(command == "stop")
{
// after which the bestmove and pondermove will be printed (in id_loop()).
void wait_for_stop_or_ponderhit() {
+
std::string command;
- while(true) {
- if(!std::getline(std::cin, command))
- command = "quit";
+ while (true)
+ {
+ if (!std::getline(std::cin, command))
+ command = "quit";
- if(command == "quit") {
- stop_threads();
- quit_eval();
- exit(0);
- }
- else if(command == "ponderhit" || command == "stop")
- break;
+ if (command == "quit")
+ {
+ Quit = true;
+ break;
+ }
+ else if(command == "ponderhit" || command == "stop")
+ break;
}
}