#include "lock.h"
#include "san.h"
#include "search.h"
+#include "timeman.h"
#include "thread.h"
#include "tt.h"
#include "ucioption.h"
/// Types
enum NodeType { NonPV, PV };
+ // Set to true to force running with one thread.
+ // Used for debugging SMP code.
+ const bool FakeSplit = false;
+
// ThreadsManager class is used to handle all the threads related stuff in search,
// init, starting, parking and, the most important, launching a slave thread at a
// split point are what this class does. All the access to shared thread data is
void idle_loop(int threadID, SplitPoint* sp);
template <bool Fake>
- bool split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
- Depth depth, bool mateThreat, int* moves, MovePicker* mp, int master, bool pvNode);
+ void split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
+ Depth depth, Move threatMove, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
private:
friend void poll();
int ActiveThreads;
volatile bool AllThreadsShouldExit, AllThreadsShouldSleep;
Thread threads[MAX_THREADS];
- SplitPoint SplitPointStack[MAX_THREADS][ACTIVE_SPLIT_POINTS_MAX];
Lock MPLock, WaitLock;
// 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 a higher score, or if the moves
- // have equal score but m1 has the higher node count.
+ // have equal score but m1 has the higher beta cut-off count.
bool operator<(const RootMove& m) const {
return score != m.score ? score < m.score : theirBeta <= m.theirBeta;
const Depth IIDDepth[2] = { 8 * OnePly /* non-PV */, 5 * OnePly /* PV */};
// At Non-PV nodes we do an internal iterative deepening search
- // when the static evaluation is at most IIDMargin below beta.
+ // when the static evaluation is bigger then beta - IIDMargin.
const Value IIDMargin = Value(0x100);
// Step 11. Decide the new search depth
Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
// Minimum depth for use of singular extension
- const Depth SingularExtensionDepth[2] = { 8 * OnePly /* non-PV */, 6 * OnePly /* PV */};
+ const Depth SingularExtensionDepth[2] = { 7 * OnePly /* non-PV */, 6 * OnePly /* PV */};
// If the TT move is at least SingularExtensionMargin better then the
// remaining ones we will extend it.
int32_t FutilityMarginsMatrix[16][64]; // [depth][moveNumber]
int FutilityMoveCountArray[32]; // [depth]
- inline Value futility_margin(Depth d, int mn) { return Value(d < 7 * OnePly ? FutilityMarginsMatrix[Max(d, 0)][Min(mn, 63)] : 2 * VALUE_INFINITE); }
+ inline Value futility_margin(Depth d, int mn) { return Value(d < 7 * OnePly ? FutilityMarginsMatrix[Max(d, 1)][Min(mn, 63)] : 2 * VALUE_INFINITE); }
inline int futility_move_count(Depth d) { return d < 16 * OnePly ? FutilityMoveCountArray[d] : 512; }
// Step 14. Reduced search
// better than the second best move.
const Value EasyMoveMargin = Value(0x200);
- // Last seconds noise filtering (LSN)
- const bool UseLSNFiltering = true;
- const int LSNTime = 4000; // In milliseconds
- const Value LSNValue = value_from_centipawns(200);
- bool loseOnTime = false;
-
/// Global variables
int MultiPV;
// Time managment variables
- int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime;
- int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
+ int SearchStartTime, MaxNodes, MaxDepth, ExactMaxTime;
bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
+ TimeManager TimeMgr;
// Log file
bool UseLogFile;
// Multi-threads related variables
Depth MinimumSplitDepth;
int MaxThreadsPerSplitPoint;
- ThreadsManager TM;
+ ThreadsManager ThreadsMgr;
// 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.
/// Local functions
Value id_loop(const Position& pos, Move searchMoves[]);
- Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
+ Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
template <NodeType PvNode>
- Value search(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, bool allowNullmove, int threadID, Move excludedMove = MOVE_NONE);
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID);
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
template <NodeType PvNode>
void sp_search(SplitPoint* sp, int threadID);
template <NodeType PvNode>
Depth extension(const Position& pos, Move m, bool captureOrPromotion, bool moveIsCheck, bool singleEvasion, bool mateThreat, bool* dangerous);
- void init_node(SearchStack ss[], int ply, int threadID);
- void update_pv(SearchStack ss[], int ply);
- void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply);
bool connected_moves(const Position& pos, Move m1, Move m2);
bool value_is_mate(Value value);
- bool move_is_killer(Move m, const SearchStack& ss);
- bool ok_to_do_nullmove(const Position& pos);
- bool ok_to_prune(const Position& pos, Move m, Move threat);
+ Value value_to_tt(Value v, int ply);
+ Value value_from_tt(Value v, int ply);
+ bool move_is_killer(Move m, SearchStack* ss);
bool ok_to_use_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_killers(Move m, SearchStack& ss);
+ void update_killers(Move m, SearchStack* ss);
void update_gains(const Position& pos, Move move, Value before, Value after);
int current_search_time();
+ std::string value_to_uci(Value v);
int nps();
void poll();
void ponderhit();
void wait_for_stop_or_ponderhit();
- void init_ss_array(SearchStack ss[]);
- void print_pv_info(const Position& pos, SearchStack ss[], Value alpha, Value beta, Value value);
+ void init_ss_array(SearchStack* ss, int size);
+ void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value);
+ void insert_pv_in_tt(const Position& pos, Move pv[]);
+ void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
#if !defined(_MSC_VER)
void *init_thread(void *threadID);
/// init_threads(), exit_threads() and nodes_searched() are helpers to
/// give accessibility to some TM methods from outside of current file.
-void init_threads() { TM.init_threads(); }
-void exit_threads() { TM.exit_threads(); }
-int64_t nodes_searched() { return TM.nodes_searched(); }
+void init_threads() { ThreadsMgr.init_threads(); }
+void exit_threads() { ThreadsMgr.exit_threads(); }
+int64_t nodes_searched() { return ThreadsMgr.nodes_searched(); }
+
+
+/// init_search() is called during startup. It initializes various lookup tables
+
+void init_search() {
+
+ int d; // depth (OnePly == 2)
+ int hd; // half depth (OnePly == 1)
+ int mc; // moveCount
+
+ // Init reductions array
+ for (hd = 1; hd < 64; hd++) for (mc = 1; mc < 64; mc++)
+ {
+ double pvRed = 0.33 + log(double(hd)) * log(double(mc)) / 4.5;
+ double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
+ ReductionMatrix[PV][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
+ ReductionMatrix[NonPV][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
+ }
+
+ // Init futility margins array
+ for (d = 1; d < 16; d++) for (mc = 0; mc < 64; mc++)
+ FutilityMarginsMatrix[d][mc] = 112 * int(log(double(d * d) / 2) / log(2.0) + 1.001) - 8 * mc + 45;
+
+ // Init futility move count array
+ for (d = 0; d < 32; d++)
+ FutilityMoveCountArray[d] = 3 + (1 << (3 * d / 8));
+}
/// perft() is our utility to verify move generation is bug free. All the legal
int perft(Position& pos, Depth depth)
{
+ MoveStack mlist[256];
StateInfo st;
- Move move;
+ Move m;
int sum = 0;
- MovePicker mp(pos, MOVE_NONE, depth, H);
+
+ // Generate all legal moves
+ MoveStack* last = generate_moves(pos, mlist);
// If we are at the last ply we don't need to do and undo
// the moves, just to count them.
- if (depth <= OnePly) // Replace with '<' to test also qsearch
- {
- while (mp.get_next_move()) sum++;
- return sum;
- }
+ if (depth <= OnePly)
+ return int(last - mlist);
// Loop through all legal moves
CheckInfo ci(pos);
- while ((move = mp.get_next_move()) != MOVE_NONE)
+ for (MoveStack* cur = mlist; cur != last; cur++)
{
- pos.do_move(move, st, ci, pos.move_is_check(move, ci));
+ m = cur->move;
+ pos.do_move(m, st, ci, pos.move_is_check(m, ci));
sum += perft(pos, depth - OnePly);
- pos.undo_move(move);
+ pos.undo_move(m);
}
return sum;
}
/// search-related global variables, and calls root_search(). It returns false
/// when a quit command is received during the search.
-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[]) {
+bool think(const Position& pos, bool infinite, bool ponder, int time[], int increment[],
+ int movesToGo, int maxDepth, int maxNodes, int maxTime, Move searchMoves[]) {
// Initialize global search variables
StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false;
- MaxSearchTime = AbsoluteMaxSearchTime = ExtraSearchTime = 0;
NodesSincePoll = 0;
- TM.resetNodeCounters();
+ ThreadsMgr.resetNodeCounters();
SearchStartTime = get_system_time();
ExactMaxTime = maxTime;
MaxDepth = maxDepth;
}
}
- // Reset loseOnTime flag at the beginning of a new game
- if (button_was_pressed("New Game"))
- loseOnTime = false;
-
// Read UCI option values
TT.set_size(get_option_value_int("Hash"));
if (button_was_pressed("Clear Hash"))
// Set the number of active threads
int newActiveThreads = get_option_value_int("Threads");
- if (newActiveThreads != TM.active_threads())
+ if (newActiveThreads != ThreadsMgr.active_threads())
{
- TM.set_active_threads(newActiveThreads);
- init_eval(TM.active_threads());
+ ThreadsMgr.set_active_threads(newActiveThreads);
+ init_eval(ThreadsMgr.active_threads());
}
// Wake up sleeping threads
- TM.wake_sleeping_threads();
+ ThreadsMgr.wake_sleeping_threads();
// Set thinking time
- int myTime = time[side_to_move];
- int myIncrement = increment[side_to_move];
+ int myTime = time[pos.side_to_move()];
+ int myIncrement = increment[pos.side_to_move()];
if (UseTimeManagement)
- {
- if (!movesToGo) // Sudden death time control
- {
- if (myIncrement)
- {
- MaxSearchTime = myTime / 30 + myIncrement;
- AbsoluteMaxSearchTime = Max(myTime / 4, myIncrement - 100);
- }
- else // Blitz game without increment
- {
- MaxSearchTime = myTime / 30;
- AbsoluteMaxSearchTime = myTime / 8;
- }
- }
- else // (x moves) / (y minutes)
- {
- if (movesToGo == 1)
- {
- MaxSearchTime = myTime / 2;
- AbsoluteMaxSearchTime = (myTime > 3000)? (myTime - 500) : ((myTime * 3) / 4);
- }
- else
- {
- MaxSearchTime = myTime / Min(movesToGo, 20);
- AbsoluteMaxSearchTime = Min((4 * myTime) / movesToGo, myTime / 3);
- }
- }
-
- if (get_option_value_bool("Ponder"))
- {
- MaxSearchTime += MaxSearchTime / 4;
- MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
- }
- }
+ TimeMgr.init(myTime, myIncrement, movesToGo, pos.startpos_ply_counter());
// Set best NodesBetweenPolls interval to avoid lagging under
// heavy time pressure.
<< " increment: " << myIncrement
<< " moves to go: " << movesToGo << endl;
- // LSN filtering. Used only for developing purposes, disabled by default
- if ( UseLSNFiltering
- && loseOnTime)
- {
- // Step 2. If after last move we decided to lose on time, do it now!
- while (SearchStartTime + myTime + 1000 > get_system_time())
- /* wait here */;
- }
-
// We're ready to start thinking. Call the iterative deepening loop function
- Value v = id_loop(pos, searchMoves);
-
- if (UseLSNFiltering)
- {
- // Step 1. If this is sudden death game and our position is hopeless,
- // decide to lose on time.
- if ( !loseOnTime // If we already lost on time, go to step 3.
- && myTime < LSNTime
- && myIncrement == 0
- && movesToGo == 0
- && v < -LSNValue)
- {
- loseOnTime = true;
- }
- else if (loseOnTime)
- {
- // Step 3. Now after stepping over the time limit, reset flag for next match.
- loseOnTime = false;
- }
- }
+ id_loop(pos, searchMoves);
if (UseLogFile)
LogFile.close();
- TM.put_threads_to_sleep();
+ ThreadsMgr.put_threads_to_sleep();
return !Quit;
}
-/// init_search() is called during startup. It initializes various lookup tables
-
-void init_search() {
-
- // Init our reduction lookup tables
- for (int i = 1; i < 64; i++) // i == depth (OnePly = 1)
- for (int j = 1; j < 64; j++) // j == moveNumber
- {
- double pvRed = log(double(i)) * log(double(j)) / 3.0;
- double nonPVRed = log(double(i)) * log(double(j)) / 1.5;
- ReductionMatrix[PV][i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
- ReductionMatrix[NonPV][i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
- }
-
- // Init futility margins array
- for (int i = 0; i < 16; i++) // i == depth (OnePly = 2)
- for (int j = 0; j < 64; j++) // j == moveNumber
- {
- // FIXME: test using log instead of BSR
- FutilityMarginsMatrix[i][j] = (i < 2 ? 0 : 112 * bitScanReverse32(i * i / 2)) - 8 * j + 45;
- }
-
- // Init futility move count array
- for (int i = 0; i < 32; i++) // i == depth (OnePly = 2)
- FutilityMoveCountArray[i] = 3 + (1 << (3 * i / 8));
-}
-
-
-// SearchStack::init() initializes a search stack. Used at the beginning of a
-// new search from the root.
-void SearchStack::init(int ply) {
-
- pv[ply] = pv[ply + 1] = MOVE_NONE;
- currentMove = threatMove = MOVE_NONE;
- reduction = Depth(0);
- eval = VALUE_NONE;
-}
-
-void SearchStack::initKillers() {
-
- mateKiller = MOVE_NONE;
- for (int i = 0; i < KILLER_MAX; i++)
- killers[i] = MOVE_NONE;
-}
-
namespace {
// id_loop() is the main iterative deepening loop. It calls root_search
Value id_loop(const Position& pos, Move searchMoves[]) {
- Position p(pos);
+ Position p(pos, pos.thread());
SearchStack ss[PLY_MAX_PLUS_2];
+ Move pv[PLY_MAX_PLUS_2];
Move EasyMove = MOVE_NONE;
Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
// so to output information also for iteration 1.
cout << "info depth " << 1
<< "\ninfo depth " << 1
- << " score " << value_to_string(rml.get_move_score(0))
+ << " score " << value_to_uci(rml.get_move_score(0))
<< " time " << current_search_time()
- << " nodes " << TM.nodes_searched()
+ << " nodes " << ThreadsMgr.nodes_searched()
<< " nps " << nps()
<< " pv " << rml.get_move(0) << "\n";
// Initialize
TT.new_search();
H.clear();
- init_ss_array(ss);
+ init_ss_array(ss, PLY_MAX_PLUS_2);
+ pv[0] = pv[1] = MOVE_NONE;
ValueByIteration[1] = rml.get_move_score(0);
Iteration = 1;
}
// Search to the current depth, rml is updated and sorted, alpha and beta could change
- value = root_search(p, ss, rml, &alpha, &beta);
+ value = root_search(p, ss, pv, rml, &alpha, &beta);
// Write PV to transposition table, in case the relevant entries have
// been overwritten during the search.
- TT.insert_pv(p, ss[0].pv);
+ insert_pv_in_tt(p, pv);
if (AbortSearch)
break; // Value cannot be trusted. Break out immediately!
ValueByIteration[Iteration] = value;
// Drop the easy move if differs from the new best move
- if (ss[0].pv[0] != EasyMove)
+ if (pv[0] != EasyMove)
EasyMove = MOVE_NONE;
if (UseTimeManagement)
stopSearch = true;
// Stop search early if one move seems to be much better than the others
- int64_t nodes = TM.nodes_searched();
+ int64_t nodes = ThreadsMgr.nodes_searched();
if ( Iteration >= 8
- && EasyMove == ss[0].pv[0]
+ && EasyMove == pv[0]
&& ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
- && current_search_time() > MaxSearchTime / 16)
+ && current_search_time() > TimeMgr.available_time() / 16)
||( rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100
- && current_search_time() > MaxSearchTime / 32)))
+ && current_search_time() > TimeMgr.available_time() / 32)))
stopSearch = true;
// Add some extra time if the best move has changed during the last two iterations
if (Iteration > 5 && Iteration <= 50)
- ExtraSearchTime = BestMoveChangesByIteration[Iteration] * (MaxSearchTime / 2)
- + BestMoveChangesByIteration[Iteration-1] * (MaxSearchTime / 3);
+ TimeMgr.pv_unstability(BestMoveChangesByIteration[Iteration],
+ BestMoveChangesByIteration[Iteration-1]);
// Stop search if most of MaxSearchTime is consumed at the end of the
// iteration. We probably don't have enough time to search the first
// move at the next iteration anyway.
- if (current_search_time() > ((MaxSearchTime + ExtraSearchTime) * 80) / 128)
+ if (current_search_time() > (TimeMgr.available_time() * 80) / 128)
stopSearch = true;
if (stopSearch)
wait_for_stop_or_ponderhit();
else
// Print final search statistics
- cout << "info nodes " << TM.nodes_searched()
+ cout << "info nodes " << ThreadsMgr.nodes_searched()
<< " nps " << nps()
- << " time " << current_search_time()
- << " hashfull " << TT.full() << endl;
+ << " time " << current_search_time() << endl;
// Print the best move and the ponder move to the standard output
- if (ss[0].pv[0] == MOVE_NONE)
+ if (pv[0] == MOVE_NONE)
{
- ss[0].pv[0] = rml.get_move(0);
- ss[0].pv[1] = MOVE_NONE;
+ pv[0] = rml.get_move(0);
+ pv[1] = MOVE_NONE;
}
- assert(ss[0].pv[0] != MOVE_NONE);
+ assert(pv[0] != MOVE_NONE);
- cout << "bestmove " << ss[0].pv[0];
+ cout << "bestmove " << pv[0];
- if (ss[0].pv[1] != MOVE_NONE)
- cout << " ponder " << ss[0].pv[1];
+ if (pv[1] != MOVE_NONE)
+ cout << " ponder " << pv[1];
cout << endl;
if (dbg_show_hit_rate)
dbg_print_hit_rate(LogFile);
- LogFile << "\nNodes: " << TM.nodes_searched()
+ LogFile << "\nNodes: " << ThreadsMgr.nodes_searched()
<< "\nNodes/second: " << nps()
- << "\nBest move: " << move_to_san(p, ss[0].pv[0]);
+ << "\nBest move: " << move_to_san(p, pv[0]);
StateInfo st;
- p.do_move(ss[0].pv[0], st);
+ p.do_move(pv[0], st);
LogFile << "\nPonder move: "
- << move_to_san(p, ss[0].pv[1]) // Works also with MOVE_NONE
+ << move_to_san(p, pv[1]) // Works also with MOVE_NONE
<< endl;
}
return rml.get_move_score(0);
// scheme, prints some information to the standard output and handles
// the fail low/high loops.
- Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
+ Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
EvalInfo ei;
StateInfo st;
alpha = *alphaPtr;
beta = *betaPtr;
isCheck = pos.is_check();
+ depth = (Iteration - 2) * OnePly + InitialDepth;
+
+ // Step 1. Initialize node (polling is omitted at root)
+ ss->currentMove = ss->bestMove = MOVE_NONE;
- // Step 1. Initialize node and poll (omitted at root, but I can see no good reason for this, FIXME)
- // Step 2. Check for aborted search (omitted at root, because we do not initialize root node)
+ // Step 2. Check for aborted search (omitted at root)
// Step 3. Mate distance pruning (omitted at root)
// Step 4. Transposition table lookup (omitted at root)
// Step 5. Evaluate the position statically
// At root we do this only to get reference value for child nodes
- if (!isCheck)
- ss[0].eval = evaluate(pos, ei, 0);
- else
- ss[0].eval = VALUE_NONE; // HACK because we do not initialize root node
+ ss->eval = isCheck ? VALUE_NONE : evaluate(pos, ei);
// Step 6. Razoring (omitted at root)
// Step 7. Static null move pruning (omitted at root)
FirstRootMove = (i == 0);
// Save the current node count before the move is searched
- nodes = TM.nodes_searched();
+ nodes = ThreadsMgr.nodes_searched();
// Reset beta cut-off counters
- TM.resetBetaCounters();
+ ThreadsMgr.resetBetaCounters();
// Pick the next root move, and print the move and the move number to
// the standard output.
- move = ss[0].currentMove = rml.get_move(i);
+ move = ss->currentMove = rml.get_move(i);
if (current_search_time() >= 1000)
cout << "info currmove " << move
captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Step 11. Decide the new search depth
- depth = (Iteration - 2) * OnePly + InitialDepth;
ext = extension<PV>(pos, move, captureOrPromotion, moveIsCheck, false, false, &dangerous);
newDepth = depth + ext;
alpha = -VALUE_INFINITE;
// Full depth PV search, done on first move or after a fail high
- value = -search<PV>(pos, ss, -beta, -alpha, newDepth, 1, false, 0);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
}
else
{
&& !captureOrPromotion
&& !move_is_castle(move))
{
- ss
[0].reduction = reduction<PV>(depth, i - MultiPV + 2);
- if (ss[0].reduction)
+ ss
->reduction = reduction<PV>(depth, i - MultiPV + 2);
+ if (ss->reduction)
{
+ assert(newDepth-ss->reduction >= OnePly);
+
// Reduced depth non-pv search using alpha as upperbound
- value = -search<NonPV>(pos, ss, -(alpha+1), -alpha, newDepth-ss[0].reduction, 1, true, 0);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
+ doFullDepthSearch = (value > alpha);
+ }
+
+ // The move failed high, but if reduction is very big we could
+ // face a false positive, retry with a less aggressive reduction,
+ // if the move fails high again then go with full depth search.
+ if (doFullDepthSearch && ss->reduction > 2 * OnePly)
+ {
+ assert(newDepth - OnePly >= OnePly);
+
+ ss->reduction = OnePly;
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, 1);
doFullDepthSearch = (value > alpha);
}
+ ss->reduction = Depth(0); // Restore original reduction
}
// Step 15. Full depth search
if (doFullDepthSearch)
{
// Full depth non-pv search using alpha as upperbound
- ss[0].reduction = Depth(0);
- value = -search<NonPV>(pos, ss, -(alpha+1), -alpha, newDepth, 1, true, 0);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, 1);
// If we are above alpha then research at same depth but as PV
// to get a correct score or eventually a fail high above beta.
if (value > alpha)
- value = -search<PV>(pos, ss, -beta, -alpha, newDepth, 1, false, 0);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
}
}
// We are failing high and going to do a research. It's important to update
// the score before research in case we run out of time while researching.
rml.set_move_score(i, value);
- update_pv(ss, 0);
- TT.extract_pv(pos, ss[0].pv, PLY_MAX);
- rml.set_move_pv(i, ss[0].pv);
+ ss->bestMove = move;
+ extract_pv_from_tt(pos, move, pv);
+ rml.set_move_pv(i, pv);
// Print information to the standard output
- print_pv_info(pos, ss, alpha, beta, value);
+ print_pv_info(pos, pv, alpha, beta, value);
// Prepare for a research after a fail high, each time with a wider window
*betaPtr = beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
// Remember beta-cutoff and searched nodes counts for this move. The
// info is used to sort the root moves for the next iteration.
int64_t our, their;
- TM.get_beta_counters(pos.side_to_move(), our, their);
+ ThreadsMgr.get_beta_counters(pos.side_to_move(), our, their);
rml.set_beta_counters(i, our, their);
- rml.set_move_nodes(i, TM.nodes_searched() - nodes);
+ rml.set_move_nodes(i, ThreadsMgr.nodes_searched() - nodes);
assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
assert(value < beta);
// Update PV
rml.set_move_score(i, value);
- update_pv(ss, 0);
- TT.extract_pv(pos, ss[0].pv, PLY_MAX);
- rml.set_move_pv(i, ss[0].pv);
+ ss->bestMove = move;
+ extract_pv_from_tt(pos, move, pv);
+ rml.set_move_pv(i, pv);
if (MultiPV == 1)
{
BestMoveChangesByIteration[Iteration]++;
// Print information to the standard output
- print_pv_info(pos, ss, alpha, beta, value);
+ print_pv_info(pos, pv, alpha, beta, value);
// Raise alpha to setup proper non-pv search upper bound
if (value > alpha)
for (int j = 0; j < Min(MultiPV, rml.move_count()); j++)
{
cout << "info multipv " << j + 1
- << " score " << value_to_string(rml.get_move_score(j))
+ << " score " << value_to_uci(rml.get_move_score(j))
<< " depth " << (j <= i ? Iteration : Iteration - 1)
<< " time " << current_search_time()
- << " nodes " << TM.nodes_searched()
+ << " nodes " << ThreadsMgr.nodes_searched()
<< " nps " << nps()
<< " pv ";
// search<>() is the main search function for both PV and non-PV nodes
template <NodeType PvNode>
- Value search(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth,
- int ply, bool allowNullmove, int threadID, Move excludedMove) {
+ Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta > alpha && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
- assert(ply >= 0 && ply < PLY_MAX);
- assert(threadID >= 0 && threadID < TM.active_threads());
+ assert(ply > 0 && ply < PLY_MAX);
+ assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
Move movesSearched[256];
EvalInfo ei;
StateInfo st;
- const TTEntry* tte;
- Move ttMove, move;
+ const TTEntry *tte, *ttx;
+ Key posKey;
+ Move ttMove, move, excludedMove, threatMove;
Depth ext, newDepth;
Value bestValue, value, oldAlpha;
Value refinedValue, nullValue, futilityValueScaled; // Non-PV specific
- bool isCheck, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
+ bool isCheck, singleEvasion, singularExtensionNode, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
int moveCount = 0;
+ int threadID = pos.thread();
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
- if (depth < OnePly)
- return qsearch<PvNode>(pos, ss, alpha, beta, Depth(0), ply, threadID);
+ // Step 1. Initialize node and poll. Polling can abort search
+ ThreadsMgr.incrementNodeCounter(threadID);
+ ss->currentMove = ss->bestMove = threatMove = MOVE_NONE;
+ (ss+2)->killers[0] = (ss+2)->killers[1] = (ss+2)->mateKiller = MOVE_NONE;
- // Step 1. Initialize node and poll
- // Polling can abort search.
- init_node(ss, ply, threadID);
+ if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
+ {
+ NodesSincePoll = 0;
+ poll();
+ }
// Step 2. Check for aborted search and immediate draw
- if (AbortSearch || TM.thread_should_stop(threadID))
+ if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
return Value(0);
if (pos.is_draw() || ply >= PLY_MAX - 1)
// 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 exists.
- Key posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
+ excludedMove = ss->excludedMove;
+ posKey = excludedMove ? pos.get_exclusion_key() : pos.get_key();
tte = TT.retrieve(posKey);
ttMove = (tte ? tte->move() : MOVE_NONE);
if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
{
// Refresh tte entry to avoid aging
- TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove);
+ TT.store(posKey, tte->value(), tte->type(), tte->depth(), ttMove, tte->static_value(), tte->king_danger());
- ss[ply].currentMove = ttMove; // Can be MOVE_NONE
+ ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
- // Step 5. Evaluate the position statically
- // At PV nodes we do this only to update gain statistics
+ // Step 5. Evaluate the position statically and
+ // update gain statistics of parent move.
isCheck = pos.is_check();
- if (!isCheck)
+ if (isCheck)
+ ss->eval = VALUE_NONE;
+ else if (tte)
{
- if (tte && (tte->type() & VALUE_TYPE_EVAL))
- ss[ply].eval = value_from_tt(tte->value(), ply);
- else
- ss[ply].eval = evaluate(pos, ei, threadID);
+ assert(tte->static_value() != VALUE_NONE);
- refinedValue = refine_eval(tte, ss[ply].eval, ply); // Enhance accuracy with TT value if possible
- update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
+ ss->eval = tte->static_value();
+ ei.kingDanger[pos.side_to_move()] = tte->king_danger();
+ refinedValue = refine_eval(tte, ss->eval, ply);
}
+ else
+ {
+ refinedValue = ss->eval = evaluate(pos, ei);
+ TT.store(posKey, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+ }
+
+ // Save gain for the parent non-capture move
+ update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
// Step 6. Razoring (is omitted in PV nodes)
if ( !PvNode
- && refinedValue < beta - razor_margin(depth)
- && ttMove == MOVE_NONE
- && ss[ply - 1].currentMove != MOVE_NULL
&& depth < RazorDepth
&& !isCheck
+ && refinedValue < beta - razor_margin(depth)
+ && ttMove == MOVE_NONE
+ && (ss-1)->currentMove != MOVE_NULL
&& !value_is_mate(beta)
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value rbeta = beta - razor_margin(depth);
- Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, Depth(0), ply, threadID);
+ Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, Depth(0), ply);
if (v < rbeta)
// Logically we should return (v + razor_margin(depth)), but
// surprisingly this did slightly weaker in tests.
// We're betting that the opponent doesn't have a move that will reduce
// the score by more than futility_margin(depth) if we do a null move.
if ( !PvNode
- && allowNullmove
+ && !ss->skipNullMove
&& depth < RazorDepth
&& !isCheck
+ && refinedValue >= beta + futility_margin(depth, 0)
&& !value_is_mate(beta)
- && ok_to_do_nullmove(pos)
- && refinedValue >= beta + futility_margin(depth, 0))
+ && pos.non_pawn_material(pos.side_to_move()))
return refinedValue - futility_margin(depth, 0);
// Step 8. Null move search with verification search (is omitted in PV nodes)
// at least beta. Otherwise we do a null move if static value is not more than
// NullMoveMargin under beta.
if ( !PvNode
- && allowNullmove
+ && !ss->skipNullMove
&& depth > OnePly
&& !isCheck
+ && refinedValue >= beta - (depth >= 4 * OnePly ? NullMoveMargin : 0)
&& !value_is_mate(beta)
- && ok_to_do_nullmove(pos)
- && refinedValue >= beta - (depth >= 4 * OnePly ? NullMoveMargin : 0))
+ && pos.non_pawn_material(pos.side_to_move()))
{
- ss[ply].currentMove = MOVE_NULL;
+ ss->currentMove = MOVE_NULL;
// Null move dynamic reduction based on depth
int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0);
R++;
pos.do_null_move(st);
+ (ss+1)->skipNullMove = true;
- nullValue = -search<NonPV>(pos, ss, -beta, -alpha, depth-R*OnePly, ply+1, false, threadID);
-
+ nullValue = depth-R*OnePly < OnePly ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, Depth(0), ply+1)
+ : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*OnePly, ply+1);
+ (ss+1)->skipNullMove = false;
pos.undo_null_move();
if (nullValue >= beta)
if (depth < 6 * OnePly)
return nullValue;
- // Do zugzwang verification search
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-5*OnePly, ply, false, threadID);
+ // Do verification search at high depths
+ ss->skipNullMove = true;
+ Value v = search<NonPV>(pos, ss, alpha, beta, depth-R*OnePly, ply);
+ ss->skipNullMove = false;
+
if (v >= beta)
return nullValue;
- } else {
+ }
+ else
+ {
// The null move failed low, which means that we may be faced with
// some kind of threat. If the previous move was reduced, check if
// the move that refuted the null move was somehow connected to the
if (nullValue == value_mated_in(ply + 2))
mateThreat = true;
- ss[ply].threatMove = ss[ply + 1].currentMove;
+ threatMove = (ss+1)->bestMove;
if ( depth < ThreatDepth
- && ss[ply - 1].reduction
- && connected_moves(pos, ss[ply - 1].currentMove, ss[ply].threatMove))
+ && (ss-1)->reduction
+ && connected_moves(pos, (ss-1)->currentMove, threatMove))
return beta - 1;
}
}
// Step 9. Internal iterative deepening
- if ( depth >= IIDDepth[PvNode]
- && ttMove == MOVE_NONE
- && (PvNode || (!isCheck && ss[ply].eval >= beta - IIDMargin)))
+ if ( depth >= IIDDepth[PvNode]
+ && ttMove == MOVE_NONE
+ && (PvNode || (!isCheck && ss->eval >= beta - IIDMargin)))
{
Depth d = (PvNode ? depth - 2 * OnePly : depth / 2);
- search<PvNode>(pos, ss, alpha, beta, d, ply, false, threadID);
- ttMove = ss[ply].pv[ply];
+
+ ss->skipNullMove = true;
+ search<PvNode>(pos, ss, alpha, beta, d, ply);
+ ss->skipNullMove = false;
+
+ ttMove = ss->bestMove;
tte = TT.retrieve(posKey);
}
mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
// Initialize a MovePicker object for the current position
- MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply], (PvNode ? -VALUE_INFINITE : beta));
+ MovePicker mp = MovePicker(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
CheckInfo ci(pos);
+ ss->bestMove = MOVE_NONE;
+ singleEvasion = isCheck && mp.number_of_evasions() == 1;
+ singularExtensionNode = depth >= SingularExtensionDepth[PvNode]
+ && tte
+ && tte->move()
+ && !excludedMove // Do not allow recursive singular extension search
+ && is_lower_bound(tte->type())
+ && tte->depth() >= depth - 3 * OnePly;
// Step 10. Loop through moves
// Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
&& (move = mp.get_next_move()) != MOVE_NONE
- && !TM.thread_should_stop(threadID))
+ && !ThreadsMgr.thread_should_stop(threadID))
{
assert(move_is_ok(move));
if (move == excludedMove)
continue;
- singleEvasion = (isCheck && mp.number_of_evasions() == 1);
moveIsCheck = pos.move_is_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
// Step 11. Decide the new search depth
ext = extension<PvNode>(pos, move, captureOrPromotion, moveIsCheck, singleEvasion, mateThreat, &dangerous);
- // Singular extension search. We extend the TT move if its value is much better than
- // its siblings. To verify this we do a reduced search on all the other moves but the
- // ttMove, if result is lower then ttValue minus a margin then we extend ttMove.
- if ( depth >= SingularExtensionDepth[PvNode]
- && tte
+ // 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 then ttValue minus a margin then we extend ttMove.
+ if ( singularExtensionNode
&& move == tte->move()
- && !excludedMove // Do not allow recursive singular extension search
- && ext < OnePly
- && is_lower_bound(tte->type())
- && tte->depth() >= depth - 3 * OnePly)
+ && ext < OnePly)
{
+ // Avoid to do an expensive singular extension search on nodes where
+ // such search have already been done in the past, so assume the last
+ // singular extension search result is still valid.
+ if ( !PvNode
+ && depth < SingularExtensionDepth[PvNode] + 5 * OnePly
+ && (ttx = TT.retrieve(pos.get_exclusion_key())) != NULL)
+ {
+ if (is_upper_bound(ttx->type()))
+ ext = OnePly;
+
+ singularExtensionNode = false;
+ }
+
Value ttValue = value_from_tt(tte->value(), ply);
- if (abs(ttValue) < VALUE_KNOWN_WIN)
+ if (singularExtensionNode && abs(ttValue) < VALUE_KNOWN_WIN)
{
Value b = ttValue - SingularExtensionMargin;
- Value v = search<NonPV>(pos, ss, b - 1, b, depth / 2, ply, false, threadID, move);
-
- if (v < ttValue - SingularExtensionMargin)
+ ss->excludedMove = move;
+ ss->skipNullMove = true;
+ Value v = search<NonPV>(pos, ss, b - 1, b, depth / 2, ply);
+ ss->skipNullMove = false;
+ ss->excludedMove = MOVE_NONE;
+ ss->bestMove = MOVE_NONE;
+ if (v < b)
ext = OnePly;
}
}
newDepth = depth - OnePly + ext;
// Update current move (this must be done after singular extension search)
- movesSearched[moveCount++] = ss[ply].currentMove = move;
+ movesSearched[moveCount++] = ss->currentMove = move;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
+ && !captureOrPromotion
&& !isCheck
&& !dangerous
- && !captureOrPromotion
- && !move_is_castle(move)
- && move != ttMove)
+ && move != ttMove
+ && !move_is_castle(move))
{
// Move count based pruning
if ( moveCount >= futility_move_count(depth)
- && ok_to_prune(pos, move, ss[ply].threatMove)
+ && !(threatMove && connected_threat(pos, move, threatMove))
&& bestValue > value_mated_in(PLY_MAX))
continue;
// Value based pruning
- Depth predictedDepth = newDepth - reduction<NonPV>(depth, moveCount); // FIXME We illogically ignore reduction condition depth >= 3*OnePly
- futilityValueScaled = ss[ply].eval + futility_margin(predictedDepth, moveCount)
+ // We illogically ignore reduction condition depth >= 3*OnePly for predicted depth,
+ // but fixing this made program slightly weaker.
+ Depth predictedDepth = newDepth - reduction<NonPV>(depth, moveCount);
+ futilityValueScaled = ss->eval + futility_margin(predictedDepth, moveCount)
+ H.gain(pos.piece_on(move_from(move)), move_to(move));
if (futilityValueScaled < beta)
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
if (PvNode && moveCount == 1)
- value = -search<PV>(pos, ss, -beta, -alpha, newDepth, ply+1, false, threadID);
+ value = newDepth < OnePly ? -qsearch<PV>(pos, ss+1, -beta, -alpha, Depth(0), ply+1)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
else
{
- // Step 14. Reduced search
- // if the move fails high will be re-searched at full depth.
+ // Step 14. Reduced depth search
+ // If the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true;
if ( depth >= 3 * OnePly
- && !dangerous
&& !captureOrPromotion
+ && !dangerous
&& !move_is_castle(move)
- && !move_is_killer(move, ss[ply]))
+ && !move_is_killer(move, ss))
{
- ss[ply].reduction = reduction<PvNode>(depth, moveCount);
- if (ss[ply].reduction)
+ ss->reduction = reduction<PvNode>(depth, moveCount);
+ if (ss->reduction)
+ {
+ Depth d = newDepth - ss->reduction;
+ value = d < OnePly ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, Depth(0), ply+1)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, ply+1);
+
+ doFullDepthSearch = (value > alpha);
+ }
+
+ // The move failed high, but if reduction is very big we could
+ // face a false positive, retry with a less aggressive reduction,
+ // if the move fails high again then go with full depth search.
+ if (doFullDepthSearch && ss->reduction > 2 * OnePly)
{
- value = -search<NonPV>(pos, ss, -(alpha+1), -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID);
+ assert(newDepth - OnePly >= OnePly);
+
+ ss->reduction = OnePly;
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, ply+1);
doFullDepthSearch = (value > alpha);
}
+ ss->reduction = Depth(0); // Restore original reduction
}
// Step 15. Full depth search
if (doFullDepthSearch)
{
- ss[ply].reduction = Depth(0);
- value = -search<NonPV>(pos, ss, -(alpha+1), -alpha, newDepth, ply+1, true, threadID);
+ value = newDepth < OnePly ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, Depth(0), ply+1)
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, ply+1);
// 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 && value < beta)
- value = -search<PV>(pos, ss, -beta, -alpha, newDepth, ply+1, false, threadID);
+ value = newDepth < OnePly ? -qsearch<PV>(pos, ss+1, -beta, -alpha, Depth(0), ply+1)
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, ply+1);
}
}
bestValue = value;
if (value > alpha)
{
- if (PvNode && value < beta) // This guarantees that always: alpha < beta
+ if (PvNode && value < beta) // We want always alpha < beta
alpha = value;
- update_pv(ss, ply);
if (value == value_mate_in(ply + 1))
- ss[ply].mateKiller = move;
+ ss->mateKiller = move;
+
+ ss->bestMove = move;
}
}
// Step 18. Check for split
- if ( TM.active_threads() > 1
+ if ( depth >= MinimumSplitDepth
+ && ThreadsMgr.active_threads() > 1
&& bestValue < beta
- && depth >= MinimumSplitDepth
- && Iteration <= 99
- && TM.available_thread_exists(threadID)
+ && ThreadsMgr.available_thread_exists(threadID)
&& !AbortSearch
- && !TM.thread_should_stop(threadID)
- && TM.split<false>(pos, ss, ply, &alpha, beta, &bestValue,
- depth, mateThreat, &moveCount, &mp, threadID, PvNode))
- break;
-
- // Uncomment to debug sp_search() in single thread mode
- if ( bestValue < beta
- && depth >= 4
- && Iteration <= 99
- && !AbortSearch
- && !TM.thread_should_stop(threadID)
- && TM.split<true>(pos, ss, ply, &alpha, beta, &bestValue,
- depth, mateThreat, &moveCount, &mp, threadID, PvNode))
- break;
+ && !ThreadsMgr.thread_should_stop(threadID)
+ && Iteration <= 99)
+ ThreadsMgr.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
+ threatMove, mateThreat, &moveCount, &mp, PvNode);
}
// Step 19. Check for mate and stalemate
// no legal moves, it must be mate or stalemate.
// If one move was excluded return fail low score.
if (!moveCount)
- return excludedMove ? oldAlpha : (isCheck ? value_mated_in(ply) : VALUE_DRAW);
+ return excludedMove ? oldAlpha : isCheck ? value_mated_in(ply) : VALUE_DRAW;
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
// history counters, and killer moves.
- if (AbortSearch || TM.thread_should_stop(threadID))
+ if (AbortSearch || ThreadsMgr.thread_should_stop(threadID))
return bestValue;
- if (bestValue <= oldAlpha)
- TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
+ ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
+ move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove);
+ TT.store(posKey, value_to_tt(bestValue, ply), vt, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
- else if (bestValue >= beta)
+ // Update killers and history only for non capture moves that fails high
+ if (bestValue >= beta)
{
- TM.incrementBetaCounter(pos.side_to_move(), depth, threadID);
- move = ss[ply].pv[ply];
- TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
+ ThreadsMgr.incrementBetaCounter(pos.side_to_move(), depth, threadID);
if (!pos.move_is_capture_or_promotion(move))
{
update_history(pos, move, depth, movesSearched, moveCount);
- update_killers(move, ss[ply]);
+ update_killers(move, ss);
}
}
- else
- TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
// less than OnePly).
template <NodeType PvNode>
- Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta,
- Depth depth, int ply, int threadID) {
+ Value qsearch(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply) {
assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
assert(PvNode || alpha == beta - 1);
assert(depth <= 0);
- assert(ply >= 0 && ply < PLY_MAX);
- assert(threadID >= 0 && threadID < TM.active_threads());
+ assert(ply > 0 && ply < PLY_MAX);
+ assert(pos.thread() >= 0 && pos.thread() < ThreadsMgr.active_threads());
EvalInfo ei;
StateInfo st;
Move ttMove, move;
- Value staticValue, bestValue, value, futilityBase, futilityValue;
- bool isCheck, enoughMaterial, moveIsCheck, evasionPrunable;
- const TTEntry* tte = NULL;
- int moveCount = 0;
+ Value bestValue, value, futilityValue, futilityBase;
+ bool isCheck, deepChecks, enoughMaterial, moveIsCheck, evasionPrunable;
+ const TTEntry* tte;
Value oldAlpha = alpha;
- // Initialize, and make an early exit in case of an aborted search,
- // an instant draw, maximum ply reached, etc.
- init_node(ss, ply, threadID);
-
- // After init_node() that calls poll()
- if (AbortSearch || TM.thread_should_stop(threadID))
- return Value(0);
+ ThreadsMgr.incrementNodeCounter(pos.thread());
+ ss->bestMove = ss->currentMove = MOVE_NONE;
+ // Check for an instant draw or maximum ply reached
if (pos.is_draw() || ply >= PLY_MAX - 1)
return VALUE_DRAW;
if (!PvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
{
- assert(tte->type() != VALUE_TYPE_EVAL);
-
- ss[ply].currentMove = ttMove; // Can be MOVE_NONE
+ ss->bestMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
// Evaluate the position statically
if (isCheck)
- staticValue = -VALUE_INFINITE;
- else if (tte && (tte->type() & VALUE_TYPE_EVAL))
- staticValue = value_from_tt(tte->value(), ply);
- else
- staticValue = evaluate(pos, ei, threadID);
-
- if (!isCheck)
{
- ss[ply].eval = staticValue;
- update_gains(pos, ss[ply - 1].currentMove, ss[ply - 1].eval, ss[ply].eval);
+ bestValue = futilityBase = -VALUE_INFINITE;
+ ss->eval = VALUE_NONE;
+ deepChecks = enoughMaterial = false;
}
+ else
+ {
+ if (tte)
+ {
+ assert(tte->static_value() != VALUE_NONE);
- // Initialize "stand pat score", and return it immediately if it is
- // at least beta.
- bestValue = staticValue;
+ ei.kingDanger[pos.side_to_move()] = tte->king_danger();
+ bestValue = tte->static_value();
+ }
+ else
+ bestValue = evaluate(pos, ei);
- if (bestValue >= beta)
- {
- // Store the score to avoid a future costly evaluation() call
- if (!isCheck && !tte && ei.kingDanger[pos.side_to_move()] == 0)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EV_LO, Depth(-127*OnePly), MOVE_NONE);
+ ss->eval = bestValue;
+ update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
- return bestValue;
- }
+ // 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, ply), VALUE_TYPE_LOWER, DEPTH_NONE, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+
+ return bestValue;
+ }
+
+ if (PvNode && bestValue > alpha)
+ alpha = bestValue;
- if (bestValue > alpha)
- alpha = bestValue;
+ // If we are near beta then try to get a cutoff pushing checks a bit further
+ deepChecks = (depth == -OnePly && bestValue >= beta - PawnValueMidgame / 8);
- // If we are near beta then try to get a cutoff pushing checks a bit further
- bool deepChecks = (depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8);
+ // Futility pruning parameters, not needed when in check
+ futilityBase = bestValue + FutilityMarginQS + ei.kingDanger[pos.side_to_move()];
+ enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
+ }
// Initialize a MovePicker object for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
// and we are near beta) will be generated.
MovePicker mp = MovePicker(pos, ttMove, deepChecks ? Depth(0) : depth, H);
CheckInfo ci(pos);
- enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
- futilityBase = staticValue + FutilityMarginQS + ei.kingDanger[pos.side_to_move()];
// Loop through the moves until no moves remain or a beta cutoff occurs
while ( alpha < beta
moveIsCheck = pos.move_is_check(move, ci);
- // Update current move
- moveCount++;
- ss[ply].currentMove = move;
-
// Futility pruning
if ( !PvNode
- && enoughMaterial
&& !isCheck
&& !moveIsCheck
&& move != ttMove
+ && enoughMaterial
&& !move_is_promotion(move)
&& !pos.move_is_passed_pawn_push(move))
{
&& pos.see_sign(move) < 0)
continue;
+ // Update current move
+ ss->currentMove = move;
+
// Make and search the move
pos.do_move(move, st, ci, moveIsCheck);
- value = -qsearch<PvNode>(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
+ value = -qsearch<PvNode>(pos, ss+1, -beta, -alpha, depth-OnePly, ply+1);
pos.undo_move(move);
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
if (value > alpha)
{
alpha = value;
- update_pv(ss, ply);
+ ss->bestMove = move;
}
}
}
// All legal moves have been searched. A special case: If we're in check
// and no legal moves were found, it is checkmate.
- if (!moveCount && isCheck) // Mate!
+ if (isCheck && bestValue == -VALUE_INFINITE)
return value_mated_in(ply);
// Update transposition table
Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
- if (bestValue <= oldAlpha)
- {
- // If bestValue isn't changed it means it is still the static evaluation
- // of the node, so keep this info to avoid a future evaluation() call.
- ValueType type = (bestValue == staticValue && !ei.kingDanger[pos.side_to_move()] ? VALUE_TYPE_EV_UP : VALUE_TYPE_UPPER);
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), type, d, MOVE_NONE);
- }
- else if (bestValue >= beta)
- {
- move = ss[ply].pv[ply];
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move);
+ ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), vt, d, ss->bestMove, ss->eval, ei.kingDanger[pos.side_to_move()]);
- // Update killers only for good checking moves
- if (!pos.move_is_capture_or_promotion(move))
- update_killers(move, ss[ply]);
- }
- else
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss[ply].pv[ply]);
+ // Update killers only for checking moves that fails high
+ if ( bestValue >= beta
+ && !pos.move_is_capture_or_promotion(ss->bestMove))
+ update_killers(ss->bestMove, ss);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
template <NodeType PvNode>
void sp_search(SplitPoint* sp, int threadID) {
- assert(threadID >= 0 && threadID < TM.active_threads());
+ assert(threadID >= 0 && threadID < ThreadsMgr.active_threads());
+ assert(ThreadsMgr.active_threads() > 1);
StateInfo st;
Move move;
int moveCount;
value = -VALUE_INFINITE;
- Position pos(*sp->pos);
+ Position pos(*sp->pos, threadID);
CheckInfo ci(pos);
- SearchStack* ss = sp->sstack[threadID];
+ SearchStack* ss = sp->sstack[threadID] + 1;
isCheck = pos.is_check();
// Step 10. Loop through moves
lock_grab(&(sp->lock));
while ( sp->bestValue < sp->beta
- && !TM.thread_should_stop(threadID)
- && (move = sp->mp->get_next_move()) != MOVE_NONE)
+ && (move = sp->mp->get_next_move()) != MOVE_NONE
+ && !ThreadsMgr.thread_should_stop(threadID))
{
- moveCount = ++sp->moves;
+ moveCount = ++sp->moveCount;
lock_release(&(sp->lock));
assert(move_is_ok(move));
newDepth = sp->depth - OnePly + ext;
// Update current move
- ss[sp->ply].currentMove = move;
+ ss->currentMove = move;
// Step 12. Futility pruning (is omitted in PV nodes)
if ( !PvNode
+ && !captureOrPromotion
&& !isCheck
&& !dangerous
- && !captureOrPromotion
&& !move_is_castle(move))
{
// Move count based pruning
if ( moveCount >= futility_move_count(sp->depth)
- && ok_to_prune(pos, move, ss[sp->ply].threatMove)
+ && !(sp->threatMove && connected_threat(pos, move, sp->threatMove))
&& sp->bestValue > value_mated_in(PLY_MAX))
{
lock_grab(&(sp->lock));
// Value based pruning
Depth predictedDepth = newDepth - reduction<NonPV>(sp->depth, moveCount);
- futilityValueScaled = ss[sp->ply].eval + futility_margin(predictedDepth, moveCount)
+ futilityValueScaled = ss->eval + futility_margin(predictedDepth, moveCount)
+ H.gain(pos.piece_on(move_from(move)), move_to(move));
if (futilityValueScaled < sp->beta)
pos.do_move(move, st, ci, moveIsCheck);
// Step 14. Reduced search
- // if the move fails high will be re-searched at full depth.
+ // If the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true;
- if ( !dangerous
- && !captureOrPromotion
+ if ( !captureOrPromotion
+ && !dangerous
&& !move_is_castle(move)
- && !move_is_killer(move, ss[sp->ply]))
+ && !move_is_killer(move, ss))
{
- ss
[sp->ply].reduction = reduction<PvNode>(sp->depth, moveCount);
- if (ss[sp->ply].reduction)
+ ss
->reduction = reduction<PvNode>(sp->depth, moveCount);
+ if (ss->reduction)
{
Value localAlpha = sp->alpha;
- value = -search<NonPV>(pos, ss, -(localAlpha+1), -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
- doFullDepthSearch = (value > localAlpha && !TM.thread_should_stop(threadID));
+ Depth d = newDepth - ss->reduction;
+ value = d < OnePly ? -qsearch<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0), sp->ply+1)
+ : - search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, d, sp->ply+1);
+
+ doFullDepthSearch = (value > localAlpha);
}
+
+ // The move failed high, but if reduction is very big we could
+ // face a false positive, retry with a less aggressive reduction,
+ // if the move fails high again then go with full depth search.
+ if (doFullDepthSearch && ss->reduction > 2 * OnePly)
+ {
+ assert(newDepth - OnePly >= OnePly);
+
+ ss->reduction = OnePly;
+ Value localAlpha = sp->alpha;
+ value = -search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth-ss->reduction, sp->ply+1);
+ doFullDepthSearch = (value > localAlpha);
+ }
+ ss->reduction = Depth(0); // Restore original reduction
}
// Step 15. Full depth search
if (doFullDepthSearch)
{
- ss[sp->ply].reduction = Depth(0);
Value localAlpha = sp->alpha;
- value = -search<NonPV>(pos, ss, -(localAlpha+1), -localAlpha, newDepth, sp->ply+1, true, threadID);
-
- if (PvNode && value > localAlpha && value < sp->beta && !TM.thread_should_stop(threadID))
- value = -search<PV>(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, false, threadID);
+ value = newDepth < OnePly ? -qsearch<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0), sp->ply+1)
+ : - search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth, sp->ply+1);
+
+ // 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 > localAlpha && value < sp->beta)
+ value = newDepth < OnePly ? -qsearch<PV>(pos, ss+1, -sp->beta, -sp->alpha, Depth(0), sp->ply+1)
+ : - search<PV>(pos, ss+1, -sp->beta, -sp->alpha, newDepth, sp->ply+1);
}
// Step 16. Undo move
// Step 17. Check for new best move
lock_grab(&(sp->lock));
- if (value > sp->bestValue && !TM.thread_should_stop(threadID))
+ if (value > sp->bestValue && !ThreadsMgr.thread_should_stop(threadID))
{
sp->bestValue = value;
if (PvNode && value < sp->beta) // This guarantees that always: sp->alpha < sp->beta
sp->alpha = value;
- sp_update_pv(sp->parentSstack, ss, sp->ply);
-
- if (PvNode && value == value_mate_in(sp->ply + 1))
- ss[sp->ply].mateKiller = move;
+ sp->parentSstack->bestMove = ss->bestMove = move;
}
}
}
/* Here we have the lock still grabbed */
sp->slaves[threadID] = 0;
- sp->cpus--;
lock_release(&(sp->lock));
}
- // init_node() is called at the beginning of all the search functions
- // (search() qsearch(), and so on) and initializes the
- // search stack object corresponding to the current node. Once every
- // NodesBetweenPolls nodes, init_node() also calls poll(), which polls
- // for user input and checks whether it is time to stop the search.
-
- void init_node(SearchStack ss[], int ply, int threadID) {
-
- assert(ply >= 0 && ply < PLY_MAX);
- assert(threadID >= 0 && threadID < TM.active_threads());
-
- TM.incrementNodeCounter(threadID);
-
- if (threadID == 0)
- {
- NodesSincePoll++;
- if (NodesSincePoll >= NodesBetweenPolls)
- {
- poll();
- NodesSincePoll = 0;
- }
- }
- ss[ply].init(ply);
- ss[ply + 2].initKillers();
-
-
- }
-
- // update_pv() is called whenever a search returns a value > alpha.
- // It updates the PV in the SearchStack object corresponding to the
- // current node.
-
- void update_pv(SearchStack ss[], int ply) {
-
- assert(ply >= 0 && ply < PLY_MAX);
-
- int p;
-
- ss[ply].pv[ply] = ss[ply].currentMove;
-
- for (p = ply + 1; ss[ply + 1].pv[p] != MOVE_NONE; p++)
- ss[ply].pv[p] = ss[ply + 1].pv[p];
-
- ss[ply].pv[p] = MOVE_NONE;
- }
-
-
- // sp_update_pv() is a variant of update_pv for use at split points. The
- // difference between the two functions is that sp_update_pv also updates
- // the PV at the parent node.
-
- void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply) {
-
- assert(ply >= 0 && ply < PLY_MAX);
-
- int p;
-
- ss[ply].pv[ply] = pss[ply].pv[ply] = ss[ply].currentMove;
-
- for (p = ply + 1; ss[ply + 1].pv[p] != MOVE_NONE; p++)
- ss[ply].pv[p] = pss[ply].pv[p] = ss[ply + 1].pv[p];
-
- ss[ply].pv[p] = pss[ply].pv[p] = MOVE_NONE;
- }
-
// connected_moves() tests whether two moves are 'connected' in the sense
// that the first move somehow made the second move possible (for instance
}
- // value_is_mate() checks if the given value is a mate one
- // eventually compensated for the ply.
+ // value_is_mate() checks if the given value is a mate one eventually
+ // compensated for the ply.
bool value_is_mate(Value value) {
}
- // move_is_killer() checks if the given move is among the
- // killer moves of that ply.
+ // 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.
+ // 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))
+ return v + ply;
+
+ if (v <= value_mated_in(PLY_MAX))
+ 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 value_from_tt(Value v, int ply) {
+
+ if (v >= value_mate_in(PLY_MAX))
+ return v - ply;
- bool move_is_killer(Move m, const SearchStack& ss) {
+ if (v <= value_mated_in(PLY_MAX))
+ return v + ply;
+
+ return v;
+ }
- const Move* k = ss.killers;
- for (int i = 0; i < KILLER_MAX; i++, k++)
- if (*k == m)
- return true;
+
+ // move_is_killer() checks if the given move is among the killer moves
+
+ bool move_is_killer(Move m, SearchStack* ss) {
+
+ if (ss->killers[0] == m || ss->killers[1] == m)
+ return true;
return false;
}
if (*dangerous)
{
- if (moveIsCheck)
+ if (moveIsCheck && pos.see_sign(m) >= 0)
result += CheckExtension[PvNode];
if (singleEvasion)
}
- // ok_to_do_nullmove() looks at the current position and decides whether
- // doing a 'null move' should be allowed. In order to avoid zugzwang
- // problems, null moves are not allowed when the side to move has very
- // little material left. Currently, the test is a bit too simple: Null
- // moves are avoided only when the side to move has only pawns left.
- // It's probably a good idea to avoid null moves in at least some more
- // complicated endgames, e.g. KQ vs KR. FIXME
+ // connected_threat() tests whether it is safe to forward prune a move or if
+ // is somehow coonected to the threat move returned by null search.
- bool ok_to_do_nullmove(const Position& pos) {
-
- return pos.non_pawn_material(pos.side_to_move()) != Value(0);
- }
-
-
- // ok_to_prune() tests whether it is safe to forward prune a move. Only
- // 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) {
+ bool connected_threat(const Position& pos, Move m, Move threat) {
assert(move_is_ok(m));
- assert(threat == MOVE_NONE || move_is_ok(threat));
+ assert(threat && move_is_ok(threat));
assert(!pos.move_is_check(m));
assert(!pos.move_is_capture_or_promotion(m));
assert(!pos.move_is_passed_pawn_push(m));
Square mfrom, mto, tfrom, tto;
- // Prune if there isn't any threat move
- if (threat == MOVE_NONE)
- return true;
-
mfrom = move_from(m);
mto = move_to(m);
tfrom = move_from(threat);
// Case 1: Don't prune moves which move the threatened piece
if (mfrom == tto)
- return false;
+ return true;
// Case 2: If the threatened piece has value less than or equal to the
// value of the threatening piece, don't prune move which defend it.
&& ( pos.midgame_value_of_piece_on(tfrom) >= pos.midgame_value_of_piece_on(tto)
|| pos.type_of_piece_on(tfrom) == KING)
&& pos.move_attacks_square(m, tto))
- return false;
+ 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)
- return false;
+ return true;
- return true;
+ return false;
}
Value refine_eval(const TTEntry* tte, Value defaultEval, int ply) {
- if (!tte)
- return defaultEval;
+ assert(tte);
Value v = value_from_tt(tte->value(), ply);
// update_killers() add a good move that produced a beta-cutoff
// among the killer moves of that ply.
- void update_killers(Move m, SearchStack& ss) {
+ void update_killers(Move m, SearchStack* ss) {
- if (m == ss.killers[0])
+ if (m == ss->killers[0])
return;
- for (int i = KILLER_MAX - 1; i > 0; i--)
- ss.killers[i] = ss.killers[i - 1];
-
- ss.killers[0] = m;
+ ss->killers[1] = ss->killers[0];
+ ss->killers[0] = m;
}
&& before != VALUE_NONE
&& after != VALUE_NONE
&& pos.captured_piece() == NO_PIECE_TYPE
- && !move_is_castle(m)
- && !move_is_promotion(m))
+ && !move_is_special(m))
H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after));
}
}
+ // value_to_uci() converts a value to a string suitable for use with the UCI protocol
+
+ std::string value_to_uci(Value v) {
+
+ std::stringstream s;
+
+ if (abs(v) < VALUE_MATE - PLY_MAX * OnePly)
+ s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to pawn = 100
+ else
+ s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2 );
+
+ return s.str();
+ }
+
// nps() computes the current nodes/second count.
int nps() {
int t = current_search_time();
- return (t > 0 ? int((TM.nodes_searched() * 1000) / t) : 0);
+ return (t > 0 ? int((ThreadsMgr.nodes_searched() * 1000) / t) : 0);
}
if (dbg_show_hit_rate)
dbg_print_hit_rate();
- cout << "info nodes " << TM.nodes_searched() << " nps " << nps()
- << " time " << t << " hashfull " << TT.full() << endl;
+ cout << "info nodes " << ThreadsMgr.nodes_searched() << " nps " << nps()
+ << " time " << t << endl;
}
// Should we stop the search?
bool stillAtFirstMove = FirstRootMove
&& !AspirationFailLow
- && t > MaxSearchTime + ExtraSearchTime;
+ && t > TimeMgr.available_time();
- bool noMoreTime = t > AbsoluteMaxSearchTime
+ bool noMoreTime = t > TimeMgr.maximum_time()
|| stillAtFirstMove;
if ( (Iteration >= 3 && UseTimeManagement && noMoreTime)
|| (ExactMaxTime && t >= ExactMaxTime)
- || (Iteration >= 3 && MaxNodes && TM.nodes_searched() >= MaxNodes))
+ || (Iteration >= 3 && MaxNodes && ThreadsMgr.nodes_searched() >= MaxNodes))
AbortSearch = true;
}
bool stillAtFirstMove = FirstRootMove
&& !AspirationFailLow
- && t > MaxSearchTime + ExtraSearchTime;
+ && t > TimeMgr.available_time();
- bool noMoreTime = t > AbsoluteMaxSearchTime
+ bool noMoreTime = t > TimeMgr.maximum_time()
|| stillAtFirstMove;
if (Iteration >= 3 && UseTimeManagement && (noMoreTime || StopOnPonderhit))
}
- // init_ss_array() does a fast reset of the first entries of a SearchStack array
+ // init_ss_array() does a fast reset of the first entries of a SearchStack
+ // array and of all the excludedMove and skipNullMove entries.
- void init_ss_array(SearchStack ss[]) {
+ void init_ss_array(SearchStack* ss, int size) {
- for (int i = 0; i < 3; i++)
+ for (int i = 0; i < size; i++, ss++)
{
- ss[i].init(i);
- ss[i].initKillers();
+ ss->excludedMove = MOVE_NONE;
+ ss->skipNullMove = false;
+ ss->reduction = Depth(0);
+
+ if (i < 3)
+ ss->killers[0] = ss->killers[1] = ss->mateKiller = MOVE_NONE;
}
}
// print_pv_info() prints to standard output and eventually to log file information on
// the current PV line. It is called at each iteration or after a new pv is found.
- void print_pv_info(const Position& pos, SearchStack ss[], Value alpha, Value beta, Value value) {
+ void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value) {
cout << "info depth " << Iteration
- << " score " << value_to_string(value)
- << ((value >= beta) ? " lowerbound" :
- ((value <= alpha)? " upperbound" : ""))
+ << " score " << value_to_uci(value)
+ << (value >= beta ? " lowerbound" : value <= alpha ? " upperbound" : "")
<< " time " << current_search_time()
- << " nodes " << TM.nodes_searched()
+ << " nodes " << ThreadsMgr.nodes_searched()
<< " nps " << nps()
<< " pv ";
- for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++)
- cout << ss[0].pv[j] << " ";
+ for (Move* m = pv; *m != MOVE_NONE; m++)
+ cout << *m << " ";
cout << endl;
if (UseLogFile)
{
- ValueType type = (value >= beta ? VALUE_TYPE_LOWER
- : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
+ ValueType t = value >= beta ? VALUE_TYPE_LOWER :
+ value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
LogFile << pretty_pv(pos, current_search_time(), Iteration,
- TM.nodes_searched(), value, type, ss[0].pv) << endl;
+ ThreadsMgr.nodes_searched(), value, t, pv) << endl;
}
}
+ // 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 insert_pv_in_tt(const Position& pos, Move pv[]) {
+
+ StateInfo st;
+ TTEntry* tte;
+ Position p(pos, pos.thread());
+ EvalInfo ei;
+ Value v;
+
+ for (int i = 0; pv[i] != MOVE_NONE; i++)
+ {
+ tte = TT.retrieve(p.get_key());
+ if (!tte || tte->move() != pv[i])
+ {
+ v = (p.is_check() ? VALUE_NONE : evaluate(p, ei));
+ TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, ei.kingDanger[pos.side_to_move()]);
+ }
+ p.do_move(pv[i], st);
+ }
+ }
+
+
+ // 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.
+
+ void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) {
+
+ StateInfo st;
+ TTEntry* tte;
+ Position p(pos, pos.thread());
+ int ply = 0;
+
+ assert(bestMove != MOVE_NONE);
+
+ pv[ply] = bestMove;
+ p.do_move(pv[ply++], st);
+
+ while ( (tte = TT.retrieve(p.get_key())) != NULL
+ && tte->move() != MOVE_NONE
+ && move_is_legal(p, tte->move())
+ && ply < PLY_MAX
+ && (!p.is_draw() || ply < 2))
+ {
+ pv[ply] = tte->move();
+ p.do_move(pv[ply++], st);
+ }
+ pv[ply] = MOVE_NONE;
+ }
+
+
// init_thread() is the function which is called when a new thread is
// launched. It simply calls the idle_loop() function with the supplied
// threadID. There are two versions of this function; one for POSIX
void* init_thread(void *threadID) {
- TM.idle_loop(*(int*)threadID, NULL);
+ ThreadsMgr.idle_loop(*(int*)threadID, NULL);
return NULL;
}
DWORD WINAPI init_thread(LPVOID threadID) {
- TM.idle_loop(*(int*)threadID, NULL);
+ ThreadsMgr.idle_loop(*(int*)threadID, NULL);
return 0;
}
threads[threadID].state = THREAD_AVAILABLE;
}
- // If this thread is the master of a split point and all threads have
+ // 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 && sp->cpus == 0)
+ int i = 0;
+ for ( ; sp && i < ActiveThreads && !sp->slaves[i]; i++) {}
+
+ if (i == ActiveThreads)
{
- // Because sp->cpus is decremented under lock protection,
- // be sure sp->lock has been released before to proceed.
+ // Because sp->slaves[] is reset under lock protection,
+ // be sure sp->lock has been released before to return.
lock_grab(&(sp->lock));
lock_release(&(sp->lock));
#endif
// Initialize global locks
- lock_init(&MPLock, NULL);
- lock_init(&WaitLock, NULL);
+ lock_init(&MPLock);
+ lock_init(&WaitLock);
#if !defined(_MSC_VER)
pthread_cond_init(&WaitCond, NULL);
SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
#endif
- // Initialize SplitPointStack locks
+ // Initialize splitPoints[] locks
for (i = 0; i < MAX_THREADS; i++)
- for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
- {
- SplitPointStack[i][j].parent = NULL;
- lock_init(&(SplitPointStack[i][j].lock), NULL);
- }
+ for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
+ lock_init(&(threads[i].splitPoints[j].lock));
// Will be set just before program exits to properly end the threads
AllThreadsShouldExit = false;
// Wait for thread termination
for (int i = 1; i < MAX_THREADS; i++)
- while (threads[i].state != THREAD_TERMINATED);
+ while (threads[i].state != THREAD_TERMINATED) {}
// Now we can safely destroy the locks
for (int i = 0; i < MAX_THREADS; i++)
- for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
- lock_destroy(&(SplitPointStack[i][j].lock));
+ for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
+ lock_destroy(&(threads[i].splitPoints[j].lock));
lock_destroy(&WaitLock);
lock_destroy(&MPLock);
// Apply the "helpful master" concept if possible. Use localActiveSplitPoints
// that is known to be > 0, instead of threads[slave].activeSplitPoints that
// could have been set to 0 by another thread leading to an out of bound access.
- if (SplitPointStack[slave][localActiveSplitPoints - 1].slaves[master])
+ if (threads[slave].splitPoints[localActiveSplitPoints - 1].slaves[master])
return true;
return false;
// split() does the actual work of distributing the work at a node between
- // several threads at PV nodes. If it does not succeed in splitting the
+ // several available threads. If it does not succeed in splitting the
// node (because no idle threads are available, or because we have no unused
- // split point objects), the function immediately returns false. If
- // splitting is possible, a SplitPoint object is initialized with all the
- // data that must be copied to the helper threads (the current position and
- // search stack, alpha, beta, the search depth, etc.), and we tell our
- // helper threads that they have been assigned work. This will cause them
- // to instantly leave their idle loops and call sp_search_pv(). When all
- // threads have returned from sp_search_pv (or, equivalently, when
- // splitPoint->cpus becomes 0), split() returns true.
+ // split point objects), the function immediately returns. If splitting is
+ // possible, a SplitPoint object is initialized with all the data that must be
+ // copied to the helper threads and we tell our helper threads that they have
+ // been assigned work. This will cause them to instantly leave their idle loops
+ // and call sp_search(). When all threads have returned from sp_search() then
+ // split() returns.
template <bool Fake>
- bool ThreadsManager::split(const Position& p, SearchStack* sstck, int ply,
- Value* alpha, const Value beta, Value* bestValue,
- Depth depth, bool mateThreat, int* moves, MovePicker* mp, int master, bool pvNode) {
-
+ void ThreadsManager::split(const Position& p, SearchStack* ss, int ply, Value* alpha,
+ const Value beta, Value* bestValue, Depth depth, Move threatMove,
+ bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode) {
assert(p.is_ok());
- assert(sstck != NULL);
- assert(ply >= 0 && ply < PLY_MAX);
+ assert(ply > 0 && ply < PLY_MAX);
assert(*bestValue >= -VALUE_INFINITE);
assert(*bestValue <= *alpha);
assert(*alpha < beta);
assert(beta <= VALUE_INFINITE);
assert(depth > Depth(0));
- assert(master >= 0 && master < ActiveThreads);
- assert(Fake || ActiveThreads > 1);
+ assert(p.thread() >= 0 && p.thread() < ActiveThreads);
+ assert(ActiveThreads > 1);
- SplitPoint* splitPoint;
+ int i, master = p.thread();
+ Thread& masterThread = threads[master];
lock_grab(&MPLock);
// If no other thread is available to help us, or if we have too many
// active split points, don't split.
- if ( (!Fake && !available_thread_exists(master))
- || threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX)
+ if ( !available_thread_exists(master)
+ || masterThread.activeSplitPoints >= MAX_ACTIVE_SPLIT_POINTS)
{
lock_release(&MPLock);
- return false;
+ return;
}
// Pick the next available split point object from the split point stack
- splitPoint = &SplitPointStack[master][threads[master].activeSplitPoints];
+ SplitPoint& splitPoint = masterThread.splitPoints[masterThread.activeSplitPoints++];
// Initialize the split point object
- splitPoint->parent = threads[master].splitPoint;
- splitPoint->stopRequest = false;
- splitPoint->ply = ply;
- splitPoint->depth = depth;
- splitPoint->mateThreat = mateThreat;
- splitPoint->alpha = *alpha;
- splitPoint->beta = beta;
- splitPoint->pvNode = pvNode;
- splitPoint->bestValue = *bestValue;
- splitPoint->master = master;
- splitPoint->mp = mp;
- splitPoint->moves = *moves;
- splitPoint->cpus = 1;
- splitPoint->pos = &p;
- splitPoint->parentSstack = sstck;
- for (int i = 0; i < ActiveThreads; i++)
- splitPoint->slaves[i] = 0;
-
- threads[master].splitPoint = splitPoint;
- threads[master].activeSplitPoints++;
+ splitPoint.parent = masterThread.splitPoint;
+ splitPoint.stopRequest = false;
+ splitPoint.ply = ply;
+ splitPoint.depth = depth;
+ splitPoint.threatMove = threatMove;
+ splitPoint.mateThreat = mateThreat;
+ splitPoint.alpha = *alpha;
+ splitPoint.beta = beta;
+ splitPoint.pvNode = pvNode;
+ splitPoint.bestValue = *bestValue;
+ splitPoint.mp = mp;
+ splitPoint.moveCount = *moveCount;
+ splitPoint.pos = &p;
+ splitPoint.parentSstack = ss;
+ for (i = 0; i < ActiveThreads; i++)
+ splitPoint.slaves[i] = 0;
+
+ masterThread.splitPoint = &splitPoint;
// If we are here it means we are not available
- assert(threads[master].state != THREAD_AVAILABLE);
+ assert(masterThread.state != THREAD_AVAILABLE);
+
+ int workersCnt = 1; // At least the master is included
// Allocate available threads setting state to THREAD_BOOKED
- for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
- if (!Fake && thread_is_available(i, master))
+ for (i = 0; !Fake && i < ActiveThreads && workersCnt < MaxThreadsPerSplitPoint; i++)
+ if (thread_is_available(i, master))
{
threads[i].state = THREAD_BOOKED;
- threads[i].splitPoint = splitPoint;
- splitPoint->slaves[i] = 1;
- splitPoint->cpus++;
+ threads[i].splitPoint = &splitPoint;
+ splitPoint.slaves[i] = 1;
+ workersCnt++;
}
- assert(Fake || splitPoint->cpus > 1);
+ assert(Fake || workersCnt > 1);
// We can release the lock because slave threads are already booked and master is not available
lock_release(&MPLock);
// Tell the threads that they have work to do. This will make them leave
// their idle loop. But before copy search stack tail for each thread.
- for (int i = 0; i < ActiveThreads; i++)
- if (i == master || splitPoint->slaves[i])
+ for (i = 0; i < ActiveThreads; i++)
+ if (i == master || splitPoint.slaves[i])
{
- memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 4 * sizeof(SearchStack));
+ memcpy(splitPoint.sstack[i], ss - 1, 4 * sizeof(SearchStack));
assert(i == master || threads[i].state == THREAD_BOOKED);
// which it will instantly launch a search, because its state is
// THREAD_WORKISWAITING. We send the split point as a second parameter to the
// idle loop, which means that the main thread will return from the idle
- // loop when all threads have finished their work at this split point
- // (i.e. when splitPoint->cpus == 0).
- idle_loop(master, splitPoint);
+ // loop when all threads have finished their work at this split point.
+ idle_loop(master, &splitPoint);
// We have returned from the idle loop, which means that all threads are
// finished. Update alpha and bestValue, and return.
lock_grab(&MPLock);
- *alpha = splitPoint->alpha;
- *bestValue = splitPoint->bestValue;
- threads[master].activeSplitPoints--;
- threads[master].splitPoint = splitPoint->parent;
+ *alpha = splitPoint.alpha;
+ *bestValue = splitPoint.bestValue;
+ masterThread.activeSplitPoints--;
+ masterThread.splitPoint = splitPoint.parent;
lock_release(&MPLock);
- return true;
}
StateInfo st;
bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
+ // Initialize search stack
+ init_ss_array(ss, PLY_MAX_PLUS_2);
+ ss[0].currentMove = ss[0].bestMove = MOVE_NONE;
+ ss[0].eval = VALUE_NONE;
+
// Generate all legal moves
MoveStack* last = generate_moves(pos, mlist);
continue;
// Find a quick score for the move
- init_ss_array(ss);
pos.do_move(cur->move, st);
+ ss[0].currentMove = cur->move;
moves[count].move = cur->move;
- moves[count].score = -qsearch<PV>(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
+ moves[count].score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1);
moves[count].pv[0] = cur->move;
moves[count].pv[1] = MOVE_NONE;
pos.undo_move(cur->move);
projects / stockfish / blobdiff