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 = 2; // 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
const Value EasyMoveMargin = Value(0x200);
// Last seconds noise filtering (LSN)
- const bool UseLSNFiltering = true;
+ const bool UseLSNFiltering = false;
const int LSNTime = 4000; // In milliseconds
const Value LSNValue = value_from_centipawns(200);
bool loseOnTime = false;
bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
- // Show current line?
- bool ShowCurrentLine;
-
// Log file
bool UseLogFile;
std::ofstream LogFile;
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");
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(pos.get_key());
}
- // Step 10. Loop through moves
- // Loop through all legal moves until no moves remain or a beta cutoff occurs
-
// Initialize a MovePicker object for the current position
mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
CheckInfo ci(pos);
+ // Step 10. Loop through moves
+ // Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( alpha < beta
&& (move = mp.get_next_move()) != MOVE_NONE
&& !TM.thread_should_stop(threadID))
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);
}
// Step 6. Razoring
- if ( !value_is_mate(beta)
+ if ( refinedValue < beta - razor_margin(depth)
+ && ttMove == MOVE_NONE
+ && ss[ply - 1].currentMove != MOVE_NULL
+ && depth < RazorDepth
&& !isCheck
- && depth < RazorDepth
- && refinedValue < beta - razor_margin(depth)
- && ss[ply - 1].currentMove != MOVE_NULL
- && ttMove == MOVE_NONE
+ && !value_is_mate(beta)
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
Value rbeta = beta - razor_margin(depth);
// Step 7. Static null move pruning
// We're betting that the opponent doesn't have a move that will reduce
- // the score by more than fuility_margin(depth) if we do a null move.
- if ( !isCheck
- && allowNullmove
- && depth < RazorDepth
- && refinedValue - futility_margin(depth, 0) >= beta)
+ // the score by more than futility_margin(depth) if we do a null move.
+ if ( allowNullmove
+ && depth < RazorDepth
+ && !isCheck
+ && !value_is_mate(beta)
+ && ok_to_do_nullmove(pos)
+ && refinedValue >= beta + futility_margin(depth, 0))
return refinedValue - futility_margin(depth, 0);
// Step 8. Null move search with verification search
{
ss[ply].currentMove = MOVE_NULL;
- pos.do_null_move(st);
-
// Null move dynamic reduction based on depth
int R = 3 + (depth >= 5 * OnePly ? depth / 8 : 0);
if (refinedValue - beta > PawnValueMidgame)
R++;
+ pos.do_null_move(st);
+
nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
pos.undo_null_move();
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)
+ // Special flag null values that are not zugzwang checked
+ ValueType vt = (depth < 6 * OnePly ? VALUE_TYPE_NS_LO : VALUE_TYPE_LOWER);
+ TT.store(posKey, nullValue, vt, 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(posKey);
}
- // Step 10. Loop through moves
- // Loop through all legal moves until no moves remain or a beta cutoff occurs
-
// Initialize a MovePicker object for the current position
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply], beta);
CheckInfo ci(pos);
+ // 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))
if ( depth >= SingularExtensionDepthAtNonPVNodes
&& tte
&& move == tte->move()
- && !excludedMove // Do not allow recursive single-reply search
+ && !excludedMove // Do not allow recursive singular extension search
&& ext < OnePly
&& is_lower_bound(tte->type())
&& tte->depth() >= depth - 3 * OnePly)
// Step 13. Make the move
pos.do_move(move, st, ci, moveIsCheck);
- // Step 14. Reduced search
- // if the move fails high will be re-searched at full depth.
+ // Step 14. Reduced search, if the move fails high
+ // will be re-searched at full depth.
bool doFullDepthSearch = true;
if ( depth >= 3*OnePly
}
// Step 19. Check for mate and stalemate
- // All legal moves have been searched and if there were
+ // All legal moves have been searched and if there are
// no legal moves, it must be mate or stalemate.
- // If one move was excluded return fail low.
+ // If one move was excluded return fail low score.
if (!moveCount)
- return excludedMove ? beta - 1 : (pos.is_check() ? value_mated_in(ply) : VALUE_DRAW);
+ return excludedMove ? beta - 1 : (isCheck ? value_mated_in(ply) : VALUE_DRAW);
// Step 20. Update tables
// If the search is not aborted, update the transposition table,
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,
enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMidgame;
futilityBase = staticValue + FutilityMarginQS + ei.futilityMargin[pos.side_to_move()];
- // Loop through the moves until no moves remain or a beta cutoff
- // occurs.
+ // Loop through the moves until no moves remain or a beta cutoff occurs
while ( alpha < beta
&& (move = mp.get_next_move()) != MOVE_NONE)
{
// 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 && pos.is_check()) // Mate!
+ if (!moveCount && isCheck) // Mate!
return value_mated_in(ply);
// Update transposition table
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))
+
+ && ( 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?
projects / stockfish / blobdiff