Depth depth, bool mateThreat, int* moves, MovePicker* mp, int master, bool pvNode);
private:
- friend void poll(SearchStack ss[], int ply);
+ friend void poll();
int ActiveThreads;
volatile bool AllThreadsShouldExit, AllThreadsShouldSleep;
// Step 14. Reduced search
- int ReductionLevel; // 0 = most aggressive reductions, 7 = minimum reductions
-
// Reduction lookup tables (initialized at startup) and their getter functions
- int8_t PVReductionMatrix[8][64][64]; // [depth][moveNumber]
- int8_t NonPVReductionMatrix[8][64][64]; // [depth][moveNumber]
+ int8_t PVReductionMatrix[64][64]; // [depth][moveNumber]
+ int8_t NonPVReductionMatrix[64][64]; // [depth][moveNumber]
- inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[ReductionLevel][Min(d / 2, 63)][Min(mn, 63)]; }
- inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[ReductionLevel][Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
// Common adjustments
int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime;
int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
- bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
-
- // Show current line?
- bool ShowCurrentLine;
+ bool FirstRootMove, AbortSearch, Quit, AspirationFailLow, ZugDetection;
// Log file
bool UseLogFile;
Depth extension(const Position&, Move, bool, bool, bool, bool, bool, bool*);
bool ok_to_do_nullmove(const Position& pos);
bool ok_to_prune(const Position& pos, Move m, Move threat);
- bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
+ bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply, bool allowNullmove);
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);
int current_search_time();
int nps();
- void poll(SearchStack ss[], int ply);
+ void poll();
void ponderhit();
void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack ss[]);
MinimumSplitDepth = get_option_value_int("Minimum Split Depth") * OnePly;
MaxThreadsPerSplitPoint = get_option_value_int("Maximum Number of Threads per Split Point");
- ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine");
MultiPV = get_option_value_int("MultiPV");
Chess960 = get_option_value_bool("UCI_Chess960");
UseLogFile = get_option_value_bool("Use Search Log");
+ ZugDetection = get_option_value_bool("Zugzwang detection"); // To be removed after 1.7.1
if (UseLogFile)
LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
return !Quit;
}
-// init_reduction_tables() is called by init_search() and initializes
-// the tables used by LMR.
-static void init_reduction_tables(int8_t pvTable[64][64], int8_t nonPvTable[64][64], int pvInhib, int nonPvInhib)
-{
- double pvBase = 1.001 - log(3.0) * log(16.0) / pvInhib;
- double nonPvBase = 1.001 - log(3.0) * log(4.0) / nonPvInhib;
+/// 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 = pvBase + log(double(i)) * log(double(j)) / pvInhib;
- double nonPVRed = nonPvBase + log(double(i)) * log(double(j)) / nonPvInhib;
-
- pvTable[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
- nonPvTable[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
+ double pvRed = 0.5 + log(double(i)) * log(double(j)) / 6.0;
+ double nonPVRed = 0.5 + log(double(i)) * log(double(j)) / 3.0;
+ PVReductionMatrix[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
+ NonPVReductionMatrix[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
}
-}
-
-// init_search() is called during startup. It initializes various lookup tables
-void init_search() {
-
- // Init reduction lookup tables
- for (int i = 0; i < 8; i++)
- init_reduction_tables(PVReductionMatrix[i], NonPVReductionMatrix[i], int(4 * pow(1.3, i)), int(2 * pow(1.3, i)));
// Init futility margins array
for (int i = 0; i < 16; i++) // i == depth (OnePly = 2)
beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
}
- // Choose optimum reduction level
- ReductionLevel = 2;
-
- if (UseTimeManagement)
- {
- int level = int(floor(log(float(MaxSearchTime) / current_search_time()) / log(2.0) + 1.0));
- ReductionLevel = Min(Max(level, 0), 7);
- }
- else
- {
- //FIXME
- }
-
// Search to the current depth, rml is updated and sorted, alpha and beta could change
value = root_search(p, ss, rml, &alpha, &beta);
tte = TT.retrieve(posKey);
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (tte && ok_to_use_TT(tte, depth, beta, ply))
+ if (tte && ok_to_use_TT(tte, depth, beta, ply, allowNullmove))
{
ss[ply].currentMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
if (nullValue >= value_mate_in(PLY_MAX))
nullValue = beta;
- if (depth < 6 * OnePly)
- return nullValue;
+ // Do zugzwang verification search for high depths, don't store in TT
+ // if search was stopped.
+ if ( ( depth < 6 * OnePly
+ || search(pos, ss, beta, depth-5*OnePly, ply, false, threadID) >= beta)
+ && !AbortSearch
+ && !TM.thread_should_stop(threadID))
+ {
+ assert(value_to_tt(nullValue, ply) == nullValue);
- // Do zugzwang verification search
- Value v = search(pos, ss, beta, depth-5*OnePly, ply, false, threadID);
- if (v >= beta)
+ TT.store(posKey, nullValue, VALUE_TYPE_NS_LO, depth, MOVE_NONE);
return nullValue;
+ }
} 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
tte = TT.retrieve(pos.get_key());
ttMove = (tte ? tte->move() : MOVE_NONE);
- if (!pvNode && tte && ok_to_use_TT(tte, depth, beta, ply))
+ if (!pvNode && tte && ok_to_use_TT(tte, depth, beta, ply, true))
{
assert(tte->type() != VALUE_TYPE_EVAL);
alpha = bestValue;
// If we are near beta then try to get a cutoff pushing checks a bit further
- bool deepChecks = depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8;
+ bool deepChecks = (depth == -OnePly && staticValue >= beta - PawnValueMidgame / 8);
// Initialize a MovePicker object for the current position, and prepare
// to search the moves. Because the depth is <= 0 here, only captures,
// Detect blocking evasions that are candidate to be pruned
evasionPrunable = isCheck
- && bestValue != -VALUE_INFINITE
+ && bestValue > value_mated_in(PLY_MAX)
&& !pos.move_is_capture(move)
&& pos.type_of_piece_on(move_from(move)) != KING
&& !pos.can_castle(pos.side_to_move());
NodesSincePoll++;
if (NodesSincePoll >= NodesBetweenPolls)
{
- poll(ss, ply);
+ poll();
NodesSincePoll = 0;
}
}
}
- // ok_to_use_TT() returns true if a transposition table score
- // can be used at a given point in search.
+ // ok_to_use_TT() returns true if a transposition table score can be used at a
+ // given point in search. To avoid zugzwang issues TT cutoffs at the root node
+ // of a null move verification search are not allowed if the TT value was found
+ // by a null search, this is implemented testing allowNullmove and TT entry type.
- bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply) {
+ bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply, bool allowNullmove) {
Value v = value_from_tt(tte->value(), ply);
- return ( tte->depth() >= depth
+ return (allowNullmove || !(tte->type() & VALUE_TYPE_NULL) || !ZugDetection)
+
+ && ( tte->depth() >= depth
|| v >= Max(value_mate_in(PLY_MAX), beta)
|| v < Min(value_mated_in(PLY_MAX), beta))
// looks at the time consumed so far and decides if it's time to abort the
// search.
- void poll(SearchStack ss[], int ply) {
+ void poll() {
static int lastInfoTime;
int t = current_search_time();
cout << "info nodes " << TM.nodes_searched() << " nps " << nps()
<< " time " << t << " hashfull " << TT.full() << endl;
-
- // We only support current line printing in single thread mode
- if (ShowCurrentLine && TM.active_threads() == 1)
- {
- cout << "info currline";
- for (int p = 0; p < ply; p++)
- cout << " " << ss[p].currentMove;
-
- cout << endl;
- }
}
// Should we stop the search?
}
// Wait until the thread has finished launching and is gone to sleep
- while (threads[i].state != THREAD_SLEEPING);
+ while (threads[i].state != THREAD_SLEEPING) {}
}
}
SplitPoint* sp;
- for (sp = threads[threadID].splitPoint; sp && !sp->stopRequest; sp = sp->parent);
+ for (sp = threads[threadID].splitPoint; sp && !sp->stopRequest; sp = sp->parent) {}
return sp != NULL;
}
projects / stockfish / blobdiff