void idle_loop(int threadID, SplitPoint* sp);
template <bool Fake>
- void split(const Position& pos, SearchStack* ss, Value* alpha, const Value beta, Value* bestValue,
- Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, int master, bool pvNode);
+ void split(const Position& pos, SearchStack* ss, int ply, Value* alpha, const Value beta, Value* bestValue,
+ Depth depth, bool mateThreat, int* moveCount, MovePicker* mp, bool pvNode);
private:
friend void poll();
const Value EasyMoveMargin = Value(0x200);
// Last seconds noise filtering (LSN)
- const bool UseLSNFiltering = true;
- const int LSNTime = 4000; // In milliseconds
+ const bool UseLSNFiltering = false;
+ const int LSNTime = 100; // In milliseconds
const Value LSNValue = value_from_centipawns(200);
bool loseOnTime = false;
/// 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 threadID);
+ 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 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 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, SearchStack* ss);
void ponderhit();
void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack* ss, int size);
- void print_pv_info(const Position& pos, SearchStack* ss, Value alpha, Value beta, Value value);
+ void print_pv_info(const Position& pos, Move* ss, Value alpha, Value beta, Value value);
#if !defined(_MSC_VER)
void *init_thread(void *threadID);
// Init futility margins array
for (d = 0; d < 16; d++) for (mc = 0; mc < 64; mc++)
- FutilityMarginsMatrix[d][mc] = 112 * int(log(double(d * d) / 2) / log(2.0) + 1) - 8 * mc + 45;
+ 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++)
}
-// SearchStack::init() initializes a search stack. Used at the beginning of a
-// new search from the root.
-void SearchStack::init(int ply) {
+// SearchStack::init() initializes a search stack entry.
+// Called at the beginning of search() when starting to examine a new node.
+void SearchStack::init() {
- pv[ply] = pv[ply + 1] = MOVE_NONE;
- currentMove = threatMove = MOVE_NONE;
+ currentMove = threatMove = bestMove = MOVE_NONE;
reduction = Depth(0);
eval = VALUE_NONE;
}
+// SearchStack::initKillers() initializes killers for a search stack entry
void SearchStack::initKillers() {
mateKiller = MOVE_NONE;
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;
TT.new_search();
H.clear();
init_ss_array(ss, PLY_MAX_PLUS_2);
+ pv[0] = pv[1] = MOVE_NONE;
ValueByIteration[1] = rml.get_move_score(0);
- p.reset_ply();
Iteration = 1;
// Is one move significantly better than others after initial scoring ?
}
// 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->pv);
+ TT.insert_pv(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->pv[0] != EasyMove)
+ if (pv[0] != EasyMove)
EasyMove = MOVE_NONE;
if (UseTimeManagement)
// Stop search early if one move seems to be much better than the others
int64_t nodes = TM.nodes_searched();
if ( Iteration >= 8
- && EasyMove == ss->pv[0]
+ && EasyMove == pv[0]
&& ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
&& current_search_time() > MaxSearchTime / 16)
||( rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100
<< " hashfull " << TT.full() << endl;
// Print the best move and the ponder move to the standard output
- if (ss->pv[0] == MOVE_NONE)
+ if (pv[0] == MOVE_NONE)
{
- ss->pv[0] = rml.get_move(0);
- ss->pv[1] = MOVE_NONE;
+ pv[0] = rml.get_move(0);
+ pv[1] = MOVE_NONE;
}
- assert(ss->pv[0] != MOVE_NONE);
+ assert(pv[0] != MOVE_NONE);
- cout << "bestmove " << ss->pv[0];
+ cout << "bestmove " << pv[0];
- if (ss->pv[1] != MOVE_NONE)
- cout << " ponder " << ss->pv[1];
+ if (pv[1] != MOVE_NONE)
+ cout << " ponder " << pv[1];
cout << endl;
LogFile << "\nNodes: " << TM.nodes_searched()
<< "\nNodes/second: " << nps()
- << "\nBest move: " << move_to_san(p, ss->pv[0]);
+ << "\nBest move: " << move_to_san(p, pv[0]);
StateInfo st;
- p.do_move(ss->pv[0], st);
+ p.do_move(pv[0], st);
LogFile << "\nPonder move: "
- << move_to_san(p, ss->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;
// Step 5. Evaluate the position statically
// At root we do this only to get reference value for child nodes
if (!isCheck)
- ss->eval = evaluate(pos, ei, 0);
+ ss->eval = evaluate(pos, ei);
// Step 6. Razoring (omitted at root)
// Step 7. Static null move pruning (omitted at root)
alpha = -VALUE_INFINITE;
// Full depth PV search, done on first move or after a fail high
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 0);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, 1);
}
else
{
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+1, -(alpha+1), -alpha, newDepth-ss->reduction, 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->reduction = Depth(0);
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, 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+1, -beta, -alpha, newDepth, 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->pv, PLY_MAX);
- rml.set_move_pv(i, ss->pv);
+ ss->bestMove = move;
+ TT.extract_pv(pos, move, pv, PLY_MAX);
+ 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);
// Update PV
rml.set_move_score(i, value);
- update_pv(ss, 0);
- TT.extract_pv(pos, ss->pv, PLY_MAX);
- rml.set_move_pv(i, ss->pv);
+ ss->bestMove = move;
+ TT.extract_pv(pos, move, pv, PLY_MAX);
+ 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)
// 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 threadID) {
+ 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(pos.ply() > 0 && pos.ply() < PLY_MAX);
- assert(threadID >= 0 && threadID < TM.active_threads());
+ assert(ply > 0 && ply < PLY_MAX);
+ assert(pos.thread() >= 0 && pos.thread() < TM.active_threads());
Move movesSearched[256];
EvalInfo ei;
bool isCheck, singleEvasion, moveIsCheck, captureOrPromotion, dangerous;
bool mateThreat = false;
int moveCount = 0;
- int ply = pos.ply();
+ int threadID = pos.thread();
refinedValue = bestValue = value = -VALUE_INFINITE;
oldAlpha = alpha;
// Step 1. Initialize node and poll. Polling can abort search
TM.incrementNodeCounter(threadID);
- ss->init(ply);
- (ss + 2)->initKillers();
+ ss->init();
+ (ss+2)->initKillers();
if (threadID == 0 && ++NodesSincePoll > NodesBetweenPolls)
{
ei.kingDanger[pos.side_to_move()] = tte->king_danger();
}
else
- ss->eval = evaluate(pos, ei, threadID);
+ ss->eval = evaluate(pos, ei);
refinedValue = refine_eval(tte, ss->eval, ply); // Enhance accuracy with TT value if possible
update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
&& !value_is_mate(beta)
&& !pos.has_pawn_on_7th(pos.side_to_move()))
{
+ // Pass ss->eval to qsearch() and avoid an evaluate call
+ if (!tte || tte->static_value() == VALUE_NONE)
+ TT.store(posKey, ss->eval, VALUE_TYPE_EXACT, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+
Value rbeta = beta - razor_margin(depth);
- Value v = qsearch<NonPV>(pos, ss, rbeta-1, rbeta, Depth(0), 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.
R++;
pos.do_null_move(st);
-
(ss+1)->skipNullMove = true;
- nullValue = depth-R*OnePly < OnePly ? -qsearch<NonPV>(pos, ss+1, -beta, -alpha, Depth(0), threadID)
- : - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R*OnePly, 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)
return nullValue;
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-5*OnePly, threadID);
+ Value v = search<NonPV>(pos, ss, alpha, beta, depth-5*OnePly, ply);
ss->skipNullMove = false;
- if (v >= beta)
+ if (v >= beta)
return nullValue;
}
else
// Step 9. Internal iterative deepening
if ( depth >= IIDDepth[PvNode]
- && (ttMove == MOVE_NONE || (PvNode && tte->depth() <= depth - 4 * OnePly))
+ && ttMove == MOVE_NONE
&& (PvNode || (!isCheck && ss->eval >= beta - IIDMargin)))
{
Depth d = (PvNode ? depth - 2 * OnePly : depth / 2);
ss->skipNullMove = true;
- search<PvNode>(pos, ss, alpha, beta, d, threadID);
+ search<PvNode>(pos, ss, alpha, beta, d, ply);
ss->skipNullMove = false;
- ttMove = ss->pv[ply];
+ ttMove = ss->bestMove;
tte = TT.retrieve(posKey);
}
Value b = ttValue - SingularExtensionMargin;
ss->excludedMove = move;
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, b - 1, b, depth / 2, threadID);
+ Value v = search<NonPV>(pos, ss, b - 1, b, depth / 2, ply);
ss->skipNullMove = false;
ss->excludedMove = MOVE_NONE;
-
if (v < ttValue - SingularExtensionMargin)
ext = OnePly;
}
// Step extra. pv search (only in PV nodes)
// The first move in list is the expected PV
if (PvNode && moveCount == 1)
- value = newDepth < OnePly ? -qsearch<PV>(pos, ss+1, -beta, -alpha, Depth(0), threadID)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, 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 depth search
if (ss->reduction)
{
Depth d = newDepth - ss->reduction;
- value = d < OnePly ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, Depth(0), threadID)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, threadID);
+ 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);
}
assert(newDepth - OnePly >= OnePly);
ss->reduction = OnePly;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, threadID);
+ 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)
{
- value = newDepth < OnePly ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, Depth(0), threadID)
- : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, 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 = newDepth < OnePly ? -qsearch<PV>(pos, ss+1, -beta, -alpha, Depth(0), threadID)
- : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, 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);
}
}
if (PvNode && value < beta) // This guarantees that always: alpha < beta
alpha = value;
- update_pv(ss, ply);
-
if (value == value_mate_in(ply + 1))
ss->mateKiller = move;
+
+ ss->bestMove = move;
}
}
&& !AbortSearch
&& !TM.thread_should_stop(threadID)
&& Iteration <= 99)
- TM.split<FakeSplit>(pos, ss, &alpha, beta, &bestValue, depth,
- mateThreat, &moveCount, &mp, threadID, PvNode);
+ TM.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
+ mateThreat, &moveCount, &mp, PvNode);
}
// Step 19. Check for mate and stalemate
if (AbortSearch || TM.thread_should_stop(threadID))
return bestValue;
- if (bestValue <= oldAlpha)
- TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+ ValueType f = (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), f, 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->pv[ply];
- TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
if (!pos.move_is_capture_or_promotion(move))
{
update_history(pos, move, depth, movesSearched, moveCount);
update_killers(move, ss);
}
}
- else
- TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss->pv[ply], ss->eval, ei.kingDanger[pos.side_to_move()]);
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 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(pos.ply() > 0 && pos.ply() < PLY_MAX);
- assert(threadID >= 0 && threadID < TM.active_threads());
+ assert(ply > 0 && ply < PLY_MAX);
+ assert(pos.thread() >= 0 && pos.thread() < TM.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;
- int ply = pos.ply();
+ Value bestValue, value, futilityValue, futilityBase;
+ bool isCheck, deepChecks, enoughMaterial, moveIsCheck, evasionPrunable;
+ const TTEntry* tte;
Value oldAlpha = alpha;
- TM.incrementNodeCounter(threadID);
- ss->init(ply);
+ TM.incrementNodeCounter(pos.thread());
+ ss->bestMove = ss->currentMove = MOVE_NONE;
+ ss->eval = VALUE_NONE;
// Check for an instant draw or maximum ply reached
if (pos.is_draw() || ply >= PLY_MAX - 1)
// Evaluate the position statically
if (isCheck)
- staticValue = -VALUE_INFINITE;
- else if (tte && tte->static_value() != VALUE_NONE)
{
- staticValue = tte->static_value();
- ei.kingDanger[pos.side_to_move()] = tte->king_danger();
+ bestValue = futilityBase = -VALUE_INFINITE;
+ deepChecks = enoughMaterial = false;
}
else
- staticValue = evaluate(pos, ei, threadID);
-
- if (!isCheck)
{
- ss->eval = staticValue;
+ if (tte && tte->static_value() != VALUE_NONE)
+ {
+ ei.kingDanger[pos.side_to_move()] = tte->king_danger();
+ bestValue = tte->static_value();
+ }
+ else
+ bestValue = evaluate(pos, ei);
+
+ ss->eval = bestValue;
update_gains(pos, (ss-1)->currentMove, (ss-1)->eval, ss->eval);
- }
- // Initialize "stand pat score", and return it immediately if it is
- // at least beta.
- bestValue = staticValue;
+ // 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(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
- if (bestValue >= beta)
- {
- // Store the score to avoid a future costly evaluation() call
- if (!isCheck && !tte)
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, Depth(-127*OnePly), MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+ return bestValue;
+ }
- 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->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+1, -beta, -alpha, depth-OnePly, 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.
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
- }
- else if (bestValue >= beta)
- {
- move = ss->pv[ply];
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
+ ValueType f = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
+ TT.store(pos.get_key(), value_to_tt(bestValue, ply), f, 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);
- }
- else
- TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss->pv[ply], ss->eval, ei.kingDanger[pos.side_to_move()]);
+ // 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);
Position pos(*sp->pos, threadID);
CheckInfo ci(pos);
- int ply = pos.ply();
SearchStack* ss = sp->sstack[threadID] + 1;
isCheck = pos.is_check();
{
Value localAlpha = sp->alpha;
Depth d = newDepth - ss->reduction;
- value = d < OnePly ? -qsearch<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0), threadID)
- : - search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, d, threadID);
+ 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);
}
ss->reduction = OnePly;
Value localAlpha = sp->alpha;
- value = -search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth-ss->reduction, threadID);
+ 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
if (doFullDepthSearch)
{
Value localAlpha = sp->alpha;
- value = newDepth < OnePly ? -qsearch<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, Depth(0), threadID)
- : - search<NonPV>(pos, ss+1, -(localAlpha+1), -localAlpha, newDepth, 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), threadID)
- : - search<PV>(pos, ss+1, -sp->beta, -sp->alpha, newDepth, threadID);
+ 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
if (PvNode && value < sp->beta) // This guarantees that always: sp->alpha < sp->beta
sp->alpha = value;
- sp_update_pv(sp->parentSstack, ss, ply);
+ sp->parentSstack->bestMove = ss->bestMove = move;
}
}
}
lock_release(&(sp->lock));
}
- // 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->pv[ply] = ss->currentMove;
-
- for (p = ply + 1; (ss+1)->pv[p] != MOVE_NONE; p++)
- ss->pv[p] = (ss+1)->pv[p];
-
- ss->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->pv[ply] = pss->pv[ply] = ss->currentMove;
-
- for (p = ply + 1; (ss+1)->pv[p] != MOVE_NONE; p++)
- ss->pv[p] = pss->pv[p] = (ss+1)->pv[p];
-
- ss->pv[p] = pss->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
if (*dangerous)
{
- if (moveIsCheck)
+ if (moveIsCheck && pos.see_sign(m) >= 0)
result += CheckExtension[PvNode];
if (singleEvasion)
if (i < 3)
{
- ss->init(i);
+ ss->init();
ss->initKillers();
}
}
// 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)
<< " nps " << nps()
<< " pv ";
- for (int j = 0; ss->pv[j] != MOVE_NONE && j < PLY_MAX; j++)
- cout << ss->pv[j] << " ";
+ for (int j = 0; pv[j] != MOVE_NONE && j < PLY_MAX; j++)
+ cout << pv[j] << " ";
cout << endl;
: (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
LogFile << pretty_pv(pos, current_search_time(), Iteration,
- TM.nodes_searched(), value, type, ss->pv) << endl;
+ TM.nodes_searched(), value, type, pv) << endl;
}
}
// split() returns.
template <bool Fake>
- void ThreadsManager::split(const Position& p, SearchStack* ss, Value* alpha, const Value beta,
- Value* bestValue, Depth depth, bool mateThreat, int* moveCount,
- 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, bool mateThreat,
+ int* moveCount, MovePicker* mp, bool pvNode) {
assert(p.is_ok());
+ 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(p.thread() >= 0 && p.thread() < ActiveThreads);
assert(ActiveThreads > 1);
+ int master = p.thread();
+
lock_grab(&MPLock);
// If no other thread is available to help us, or if we have too many
// 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;
init_ss_array(ss, PLY_MAX_PLUS_2);
pos.do_move(cur->move, st);
moves[count].move = cur->move;
- moves[count].score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 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