// Futility lookup tables (initialized at startup) and their access functions
Value FutilityMargins[16][64]; // [depth][moveNumber]
- int FutilityMoveCounts[32]; // [depth]
+ int FutilityMoveCounts[2][32]; // [improving][depth]
inline Value futility_margin(Depth d, int mn) {
}
// Reduction lookup tables (initialized at startup) and their access function
- int8_t Reductions[2][64][64]; // [pv][depth][moveNumber]
+ int8_t Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber]
- template <bool PvNode> inline Depth reduction(Depth d, int mn) {
+ template <bool PvNode> inline Depth reduction(bool i, Depth d, int mn) {
- return (Depth) Reductions[PvNode][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
+ return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
size_t PVSize, PVIdx;
TimeManager TimeMgr;
- int BestMoveChanges;
+ double BestMoveChanges;
Value DrawValue[COLOR_NB];
HistoryStats History;
GainsStats Gains;
void id_loop(Position& pos);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
- bool check_is_dangerous(const Position& pos, Move move, Value futilityBase, Value beta);
bool allows(const Position& pos, Move first, Move second);
bool refutes(const Position& pos, Move first, Move second);
string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
int mc; // moveCount
// Init reductions array
- for (hd = 1; hd < 64; hd++) for (mc = 1; mc < 64; mc++)
+ for (hd = 1; hd < 64; ++hd) for (mc = 1; mc < 64; ++mc)
{
double pvRed = log(double(hd)) * log(double(mc)) / 3.0;
double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
- Reductions[1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
- Reductions[0][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
+ Reductions[1][1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
+ Reductions[0][1][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
+
+ Reductions[1][0][hd][mc] = Reductions[1][1][hd][mc];
+ Reductions[0][0][hd][mc] = Reductions[0][1][hd][mc];
+
+ if (Reductions[0][0][hd][mc] > 2 * ONE_PLY)
+ Reductions[0][0][hd][mc] += ONE_PLY;
+
+ else if (Reductions[0][0][hd][mc] > 1 * ONE_PLY)
+ Reductions[0][0][hd][mc] += ONE_PLY / 2;
}
// Init futility margins array
- for (d = 1; d < 16; d++) for (mc = 0; mc < 64; mc++)
- FutilityMargins[d][mc] = Value(112 * int(log(double(d * d) / 2) / log(2.0) + 1.001) - 8 * mc + 45);
+ for (d = 1; d < 16; ++d) for (mc = 0; mc < 64; ++mc)
+ FutilityMargins[d][mc] = Value(112 * int(2.9 * log(double(d))) - 8 * mc + 45);
// Init futility move count array
- for (d = 0; d < 32; d++)
- FutilityMoveCounts[d] = int(3.001 + 0.3 * pow(double(d), 1.8));
+ for (d = 0; d < 32; ++d)
+ {
+ FutilityMoveCounts[0][d] = int(3 + 0.3 * pow(double(d ), 1.8)) * 3/4 + (2 < d && d < 5);
+ FutilityMoveCounts[1][d] = int(3 + 0.3 * pow(double(d + 0.98), 1.8));
+ }
}
/// Search::perft() is our utility to verify move generation. All the leaf nodes
/// up to the given depth are generated and counted and the sum returned.
-size_t Search::perft(Position& pos, Depth depth) {
+static size_t perft(Position& pos, Depth depth) {
StateInfo st;
size_t cnt = 0;
for (MoveList<LEGAL> it(pos); *it; ++it)
{
- pos.do_move(*it, st, ci, pos.move_gives_check(*it, ci));
- cnt += leaf ? MoveList<LEGAL>(pos).size() : perft(pos, depth - ONE_PLY);
+ pos.do_move(*it, st, ci, pos.gives_check(*it, ci));
+ cnt += leaf ? MoveList<LEGAL>(pos).size() : ::perft(pos, depth - ONE_PLY);
pos.undo_move(*it);
}
return cnt;
}
+size_t Search::perft(Position& pos, Depth depth) {
+ return depth > ONE_PLY ? ::perft(pos, depth) : MoveList<LEGAL>(pos).size();
+}
/// Search::think() is the external interface to Stockfish's search, and is
/// called by the main thread when the program receives the UCI 'go' command. It
else
DrawValue[WHITE] = DrawValue[BLACK] = VALUE_DRAW;
- if (Options["Use Search Log"])
+ if (Options["Write Search Log"])
{
Log log(Options["Search Log Filename"]);
log << "\nSearching: " << RootPos.fen()
}
// Reset the threads, still sleeping: will be wake up at split time
- for (size_t i = 0; i < Threads.size(); i++)
+ for (size_t i = 0; i < Threads.size(); ++i)
Threads[i]->maxPly = 0;
- Threads.sleepWhileIdle = Options["Use Sleeping Threads"];
+ Threads.sleepWhileIdle = Options["Idle Threads Sleep"];
// Set best timer interval to avoid lagging under time pressure. Timer is
// used to check for remaining available thinking time.
Threads.timer->msec = 0; // Stop the timer
Threads.sleepWhileIdle = true; // Send idle threads to sleep
- if (Options["Use Search Log"])
+ if (Options["Write Search Log"])
{
Time::point elapsed = Time::now() - SearchTime + 1;
void id_loop(Position& pos) {
- Stack stack[MAX_PLY_PLUS_2], *ss = stack+1; // To allow referencing (ss-1)
- int depth, prevBestMoveChanges;
+ Stack stack[MAX_PLY_PLUS_6], *ss = stack+2; // To allow referencing (ss-2)
+ int depth;
Value bestValue, alpha, beta, delta;
- memset(ss-1, 0, 4 * sizeof(Stack));
- depth = BestMoveChanges = 0;
- bestValue = delta = -VALUE_INFINITE;
+ std::memset(ss-2, 0, 5 * sizeof(Stack));
(ss-1)->currentMove = MOVE_NULL; // Hack to skip update gains
+
+ depth = 0;
+ BestMoveChanges = 0;
+ bestValue = delta = alpha = -VALUE_INFINITE;
+ beta = VALUE_INFINITE;
+
TT.new_search();
History.clear();
Gains.clear();
// Iterative deepening loop until requested to stop or target depth reached
while (++depth <= MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
{
+ // Age out PV variability metric
+ BestMoveChanges *= 0.8;
+
// Save last iteration's scores before first PV line is searched and all
// the move scores but the (new) PV are set to -VALUE_INFINITE.
- for (size_t i = 0; i < RootMoves.size(); i++)
+ for (size_t i = 0; i < RootMoves.size(); ++i)
RootMoves[i].prevScore = RootMoves[i].score;
- prevBestMoveChanges = BestMoveChanges; // Only sensible when PVSize == 1
- BestMoveChanges = 0;
-
// MultiPV loop. We perform a full root search for each PV line
- for (PVIdx = 0; PVIdx < PVSize; PVIdx++)
+ for (PVIdx = 0; PVIdx < PVSize; ++PVIdx)
{
- // Set aspiration window default width
- if (depth >= 5 && abs(RootMoves[PVIdx].prevScore) < VALUE_KNOWN_WIN)
+ // Reset aspiration window starting size
+ if (depth >= 5)
{
delta = Value(16);
- alpha = RootMoves[PVIdx].prevScore - delta;
- beta = RootMoves[PVIdx].prevScore + delta;
- }
- else
- {
- alpha = -VALUE_INFINITE;
- beta = VALUE_INFINITE;
+ alpha = std::max(RootMoves[PVIdx].prevScore - delta,-VALUE_INFINITE);
+ beta = std::min(RootMoves[PVIdx].prevScore + delta, VALUE_INFINITE);
}
// Start with a small aspiration window and, in case of fail high/low,
// Write PV back to transposition table in case the relevant
// entries have been overwritten during the search.
- for (size_t i = 0; i <= PVIdx; i++)
+ for (size_t i = 0; i <= PVIdx; ++i)
RootMoves[i].insert_pv_in_tt(pos);
// If search has been stopped return immediately. Sorting and
if (Signals.stop)
return;
- // In case of failing high/low increase aspiration window and
- // research, otherwise exit the loop.
- if (bestValue > alpha && bestValue < beta)
- break;
-
- // Give some update (without cluttering the UI) before to research
- if (Time::now() - SearchTime > 3000)
+ // When failing high/low give some update (without cluttering
+ // the UI) before to research.
+ if ( (bestValue <= alpha || bestValue >= beta)
+ && Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
- if (abs(bestValue) >= VALUE_KNOWN_WIN)
+ // In case of failing low/high increase aspiration window and
+ // research, otherwise exit the loop.
+ if (bestValue <= alpha)
{
- alpha = -VALUE_INFINITE;
- beta = VALUE_INFINITE;
+ alpha = std::max(bestValue - delta, -VALUE_INFINITE);
+
+ Signals.failedLowAtRoot = true;
+ Signals.stopOnPonderhit = false;
}
else if (bestValue >= beta)
- {
- beta += delta;
- delta += delta / 2;
- }
+ beta = std::min(bestValue + delta, VALUE_INFINITE);
+
else
- {
- Signals.failedLowAtRoot = true;
- Signals.stopOnPonderhit = false;
+ break;
- alpha -= delta;
- delta += delta / 2;
- }
+ delta += delta / 2;
assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
}
if (skill.enabled() && skill.time_to_pick(depth))
skill.pick_move();
- if (Options["Use Search Log"])
+ if (Options["Write Search Log"])
{
RootMove& rm = RootMoves[0];
if (skill.best != MOVE_NONE)
// Take in account some extra time if the best move has changed
if (depth > 4 && depth < 50 && PVSize == 1)
- TimeMgr.pv_instability(BestMoveChanges, prevBestMoveChanges);
+ TimeMgr.pv_instability(BestMoveChanges);
// Stop search if most of available time is already consumed. We
// probably don't have enough time to search the first move at the
Depth ext, newDepth;
Value bestValue, value, ttValue;
Value eval, nullValue, futilityValue;
- bool inCheck, givesCheck, pvMove, singularExtensionNode;
+ bool inCheck, givesCheck, pvMove, singularExtensionNode, improving;
bool captureOrPromotion, dangerous, doFullDepthSearch;
int moveCount, quietCount;
// Step 1. Initialize node
Thread* thisThread = pos.this_thread();
- moveCount = quietCount = 0;
inCheck = pos.checkers();
if (SpNode)
assert(splitPoint->bestValue > -VALUE_INFINITE && splitPoint->moveCount > 0);
- goto split_point_start;
+ goto moves_loop;
}
+ moveCount = quietCount = 0;
bestValue = -VALUE_INFINITE;
ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
if ( ttValue >= beta
&& ttMove
- && !pos.is_capture_or_promotion(ttMove)
+ && !pos.capture_or_promotion(ttMove)
&& ttMove != ss->killers[0])
{
ss->killers[1] = ss->killers[0];
// Step 5. Evaluate the position statically and update parent's gain statistics
if (inCheck)
+ {
ss->staticEval = ss->evalMargin = eval = VALUE_NONE;
+ goto moves_loop;
+ }
else if (tte)
{
// Can ttValue be used as a better position evaluation?
if (ttValue != VALUE_NONE)
- if ( ((tte->bound() & BOUND_LOWER) && ttValue > eval)
- || ((tte->bound() & BOUND_UPPER) && ttValue < eval))
+ if (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))
eval = ttValue;
}
else
Gains.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
}
- // Step 6. Razoring (is omitted in PV nodes)
+ // Step 6. Razoring (skipped when in check)
if ( !PvNode
&& depth < 4 * ONE_PLY
- && !inCheck
&& eval + razor_margin(depth) < beta
&& ttMove == MOVE_NONE
&& abs(beta) < VALUE_MATE_IN_MAX_PLY
return v;
}
- // Step 7. Static null move pruning (is omitted in PV nodes)
+ // Step 7. Static null move pruning (skipped when in check)
// 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
&& !ss->skipNullMove
&& depth < 4 * ONE_PLY
- && !inCheck
&& eval - futility_margin(depth, (ss-1)->futilityMoveCount) >= beta
&& abs(beta) < VALUE_MATE_IN_MAX_PLY
&& abs(eval) < VALUE_KNOWN_WIN
// Step 8. Null move search with verification search (is omitted in PV nodes)
if ( !PvNode
&& !ss->skipNullMove
- && depth > ONE_PLY
- && !inCheck
+ && depth >= 2 * ONE_PLY
&& eval >= beta
&& abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
}
}
- // Step 9. ProbCut (is omitted in PV nodes)
+ // Step 9. ProbCut (skipped when in check)
// If we have a very good capture (i.e. SEE > seeValues[captured_piece_type])
// and a reduced search returns a value much above beta, we can (almost) safely
// prune the previous move.
if ( !PvNode
&& depth >= 5 * ONE_PLY
- && !inCheck
&& !ss->skipNullMove
&& abs(beta) < VALUE_MATE_IN_MAX_PLY)
{
CheckInfo ci(pos);
while ((move = mp.next_move<false>()) != MOVE_NONE)
- if (pos.pl_move_is_legal(move, ci.pinned))
+ if (pos.legal(move, ci.pinned))
{
ss->currentMove = move;
- pos.do_move(move, st, ci, pos.move_gives_check(move, ci));
+ pos.do_move(move, st, ci, pos.gives_check(move, ci));
value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
pos.undo_move(move);
if (value >= rbeta)
}
}
- // Step 10. Internal iterative deepening
+ // Step 10. Internal iterative deepening (skipped when in check)
if ( depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
&& ttMove == MOVE_NONE
- && (PvNode || (!inCheck && ss->staticEval + Value(256) >= beta)))
+ && (PvNode || ss->staticEval + Value(256) >= beta))
{
Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
ttMove = tte ? tte->move() : MOVE_NONE;
}
-split_point_start: // At split points actual search starts from here
+moves_loop: // When in check and at SpNode search starts from here
Square prevMoveSq = to_sq((ss-1)->currentMove);
Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
- MovePicker mp(pos, ttMove, depth, History, countermoves, ss, PvNode ? -VALUE_INFINITE : beta);
+ MovePicker mp(pos, ttMove, depth, History, countermoves, ss);
CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
+ improving = ss->staticEval >= (ss-2)->staticEval
+ || ss->staticEval == VALUE_NONE
+ ||(ss-2)->staticEval == VALUE_NONE;
+
singularExtensionNode = !RootNode
&& !SpNode
- && depth >= (PvNode ? 6 * ONE_PLY : 8 * ONE_PLY)
+ && depth >= 8 * ONE_PLY
&& ttMove != MOVE_NONE
&& !excludedMove // Recursive singular search is not allowed
&& (tte->bound() & BOUND_LOWER)
if (SpNode)
{
// Shared counter cannot be decremented later if move turns out to be illegal
- if (!pos.pl_move_is_legal(move, ci.pinned))
+ if (!pos.legal(move, ci.pinned))
continue;
moveCount = ++splitPoint->moveCount;
splitPoint->mutex.unlock();
}
else
- moveCount++;
+ ++moveCount;
if (RootNode)
{
Signals.firstRootMove = (moveCount == 1);
- if (thisThread == Threads.main_thread() && Time::now() - SearchTime > 3000)
+ if (thisThread == Threads.main() && Time::now() - SearchTime > 3000)
sync_cout << "info depth " << depth / ONE_PLY
<< " currmove " << move_to_uci(move, pos.is_chess960())
<< " currmovenumber " << moveCount + PVIdx << sync_endl;
}
ext = DEPTH_ZERO;
- captureOrPromotion = pos.is_capture_or_promotion(move);
- givesCheck = pos.move_gives_check(move, ci);
+ captureOrPromotion = pos.capture_or_promotion(move);
+ givesCheck = pos.gives_check(move, ci);
dangerous = givesCheck
- || pos.is_passed_pawn_push(move)
- || type_of(move) == CASTLE
- || ( captureOrPromotion // Entering a pawn endgame?
- && type_of(pos.piece_on(to_sq(move))) != PAWN
- && type_of(move) == NORMAL
- && ( pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK)
- - PieceValue[MG][pos.piece_on(to_sq(move))] == VALUE_ZERO));
-
- // Step 12. Extend checks and, in PV nodes, also dangerous moves
- if (PvNode && dangerous)
- ext = ONE_PLY;
+ || pos.passed_pawn_push(move)
+ || type_of(move) == CASTLE;
- else if (givesCheck && pos.see_sign(move) >= 0)
- ext = ONE_PLY / 2;
+ // Step 12. Extend checks
+ if (givesCheck && pos.see_sign(move) >= 0)
+ ext = ONE_PLY;
// 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
if ( singularExtensionNode
&& move == ttMove
&& !ext
- && pos.pl_move_is_legal(move, ci.pinned)
+ && pos.legal(move, ci.pinned)
&& abs(ttValue) < VALUE_KNOWN_WIN)
{
assert(ttValue != VALUE_NONE);
{
// Move count based pruning
if ( depth < 16 * ONE_PLY
- && moveCount >= FutilityMoveCounts[depth]
+ && moveCount >= FutilityMoveCounts[improving][depth]
&& (!threatMove || !refutes(pos, move, threatMove)))
{
if (SpNode)
// Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
- Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
+ Depth predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
futilityValue = ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
- + Gains[pos.piece_moved(move)][to_sq(move)];
+ + Gains[pos.moved_piece(move)][to_sq(move)];
if (futilityValue < beta)
{
ss->futilityMoveCount = 0;
// Check for legality only before to do the move
- if (!RootNode && !SpNode && !pos.pl_move_is_legal(move, ci.pinned))
+ if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
{
- moveCount--;
+ --moveCount;
continue;
}
// Step 15. Reduced depth search (LMR). If the move fails high will be
// re-searched at full depth.
- if ( depth > 3 * ONE_PLY
+ if ( depth >= 3 * ONE_PLY
&& !pvMove
&& !captureOrPromotion
- && !dangerous
&& move != ttMove
&& move != ss->killers[0]
&& move != ss->killers[1])
{
- ss->reduction = reduction<PvNode>(depth, moveCount);
+ ss->reduction = reduction<PvNode>(improving, depth, moveCount);
if (!PvNode && cutNode)
ss->reduction += ONE_PLY;
+ else if (History[pos.piece_on(to_sq(move))][to_sq(move)] < 0)
+ ss->reduction += ONE_PLY / 2;
+
if (move == countermoves[0] || move == countermoves[1])
- ss->reduction = std::max(DEPTH_ZERO, ss->reduction-ONE_PLY);
+ ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY);
Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
if (SpNode)
// iteration. This information is used for time management: When
// the best move changes frequently, we allocate some more time.
if (!pvMove)
- BestMoveChanges++;
+ ++BestMoveChanges;
}
else
// All other moves but the PV are set to the lowest value, this
// Quiet best move: update killers, history and countermoves
if ( bestValue >= beta
- && !pos.is_capture_or_promotion(bestMove)
+ && !pos.capture_or_promotion(bestMove)
&& !inCheck)
{
if (ss->killers[0] != bestMove)
// Increase history value of the cut-off move and decrease all the other
// played non-capture moves.
Value bonus = Value(int(depth) * int(depth));
- History.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
- for (int i = 0; i < quietCount - 1; i++)
+ History.update(pos.moved_piece(bestMove), to_sq(bestMove), bonus);
+ for (int i = 0; i < quietCount - 1; ++i)
{
Move m = quietsSearched[i];
- History.update(pos.piece_moved(m), to_sq(m), -bonus);
+ History.update(pos.moved_piece(m), to_sq(m), -bonus);
}
if (is_ok((ss-1)->currentMove))
Key posKey;
Move ttMove, move, bestMove;
Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha;
- bool givesCheck, enoughMaterial, evasionPrunable;
+ bool givesCheck, evasionPrunable;
Depth ttDepth;
// To flag BOUND_EXACT a node with eval above alpha and no available moves
ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
: DEPTH_QS_NO_CHECKS;
- // Transposition table lookup. At PV nodes, we don't use the TT for
- // pruning, but only for move ordering.
+ // Transposition table lookup
posKey = pos.key();
tte = TT.probe(posKey);
ttMove = tte ? tte->move() : MOVE_NONE;
{
ss->staticEval = ss->evalMargin = VALUE_NONE;
bestValue = futilityBase = -VALUE_INFINITE;
- enoughMaterial = false;
}
else
{
if ( (ss->staticEval = bestValue = tte->eval_value()) == VALUE_NONE
||(ss->evalMargin = tte->eval_margin()) == VALUE_NONE)
ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
+
+ // Can ttValue be used as a better position evaluation?
+ if (ttValue != VALUE_NONE)
+ if (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))
+ bestValue = ttValue;
}
else
ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
if (PvNode && bestValue > alpha)
alpha = bestValue;
- futilityBase = ss->staticEval + ss->evalMargin + Value(128);
- enoughMaterial = pos.non_pawn_material(pos.side_to_move()) > RookValueMg;
+ futilityBase = bestValue + ss->evalMargin + Value(128);
}
// Initialize a MovePicker object for the current position, and prepare
{
assert(is_ok(move));
- givesCheck = pos.move_gives_check(move, ci);
+ givesCheck = pos.gives_check(move, ci);
// Futility pruning
if ( !PvNode
&& !InCheck
&& !givesCheck
&& move != ttMove
- && enoughMaterial
&& type_of(move) != PROMOTION
- && !pos.is_passed_pawn_push(move))
+ && futilityBase > -VALUE_KNOWN_WIN
+ && !pos.passed_pawn_push(move))
{
futilityValue = futilityBase
+ PieceValue[EG][pos.piece_on(to_sq(move))]
}
// Detect non-capture evasions that are candidate to be pruned
- evasionPrunable = !PvNode
- && InCheck
+ evasionPrunable = InCheck
&& bestValue > VALUE_MATED_IN_MAX_PLY
- && !pos.is_capture(move)
+ && !pos.capture(move)
&& !pos.can_castle(pos.side_to_move());
// Don't search moves with negative SEE values
&& pos.see_sign(move) < 0)
continue;
- // Don't search useless checks
- if ( !PvNode
- && !InCheck
- && givesCheck
- && move != ttMove
- && !pos.is_capture_or_promotion(move)
- && ss->staticEval + PawnValueMg / 4 < beta
- && !check_is_dangerous(pos, move, futilityBase, beta))
- continue;
-
// Check for legality only before to do the move
- if (!pos.pl_move_is_legal(move, ci.pinned))
+ if (!pos.legal(move, ci.pinned))
continue;
ss->currentMove = move;
}
- // check_is_dangerous() tests if a checking move can be pruned in qsearch()
-
- bool check_is_dangerous(const Position& pos, Move move, Value futilityBase, Value beta)
- {
- Piece pc = pos.piece_moved(move);
- Square from = from_sq(move);
- Square to = to_sq(move);
- Color them = ~pos.side_to_move();
- Square ksq = pos.king_square(them);
- Bitboard enemies = pos.pieces(them);
- Bitboard kingAtt = pos.attacks_from<KING>(ksq);
- Bitboard occ = pos.pieces() ^ from ^ ksq;
- Bitboard oldAtt = pos.attacks_from(pc, from, occ);
- Bitboard newAtt = pos.attacks_from(pc, to, occ);
-
- // Checks which give opponent's king at most one escape square are dangerous
- if (!more_than_one(kingAtt & ~(enemies | newAtt | to)))
- return true;
-
- // Queen contact check is very dangerous
- if (type_of(pc) == QUEEN && (kingAtt & to))
- return true;
-
- // Creating new double threats with checks is dangerous
- Bitboard b = (enemies ^ ksq) & newAtt & ~oldAtt;
- while (b)
- {
- // Note that here we generate illegal "double move"!
- if (futilityBase + PieceValue[EG][pos.piece_on(pop_lsb(&b))] >= beta)
- return true;
- }
-
- return false;
- }
-
-
// allows() tests whether the 'first' move at previous ply somehow makes the
// 'second' move possible, for instance if the moving piece is the same in
// both moves. Normally the second move is the threat (the best move returned
assert(is_ok(first));
assert(is_ok(second));
assert(color_of(pos.piece_on(from_sq(second))) == ~pos.side_to_move());
- assert(color_of(pos.piece_on(to_sq(first))) == ~pos.side_to_move());
+ assert(type_of(first) == CASTLE || color_of(pos.piece_on(to_sq(first))) == ~pos.side_to_move());
Square m1from = from_sq(first);
Square m2from = from_sq(second);
Square m2to = to_sq(second);
// The piece is the same or second's destination was vacated by the first move
- if (m1to == m2from || m2to == m1from)
+ // We exclude the trivial case where a sliding piece does in two moves what
+ // it could do in one move: eg. Ra1a2, Ra2a3.
+ if ( m2to == m1from
+ || (m1to == m2from && !squares_aligned(m1from, m2from, m2to)))
return true;
// Second one moves through the square vacated by first one
// If the threatened piece has value less than or equal to the value of the
// threat piece, don't prune moves which defend it.
- if ( pos.is_capture(second)
+ if ( pos.capture(second)
&& ( PieceValue[MG][pos.piece_on(m2from)] >= PieceValue[MG][pos.piece_on(m2to)]
|| type_of(pos.piece_on(m2from)) == KING))
{
| (attacks_bb<BISHOP>(m2to, occ) & pos.pieces(color_of(pc), QUEEN, BISHOP));
// Verify attackers are triggered by our move and not already existing
- if (xray && (xray ^ (xray & pos.attacks_from<QUEEN>(m2to))))
+ if (unlikely(xray) && (xray & ~pos.attacks_from<QUEEN>(m2to)))
return true;
}
static RKISS rk;
// PRNG sequence should be not deterministic
- for (int i = Time::now() % 50; i > 0; i--)
+ for (int i = Time::now() % 50; i > 0; --i)
rk.rand<unsigned>();
// RootMoves are already sorted by score in descending order
// Choose best move. For each move score we add two terms both dependent on
// weakness, one deterministic and bigger for weaker moves, and one random,
// then we choose the move with the resulting highest score.
- for (size_t i = 0; i < PVSize; i++)
+ for (size_t i = 0; i < PVSize; ++i)
{
int s = RootMoves[i].score;
size_t uciPVSize = std::min((size_t)Options["MultiPV"], RootMoves.size());
int selDepth = 0;
- for (size_t i = 0; i < Threads.size(); i++)
+ for (size_t i = 0; i < Threads.size(); ++i)
if (Threads[i]->maxPly > selDepth)
selDepth = Threads[i]->maxPly;
- for (size_t i = 0; i < uciPVSize; i++)
+ for (size_t i = 0; i < uciPVSize; ++i)
{
bool updated = (i <= PVIdx);
<< " multipv " << i + 1
<< " pv";
- for (size_t j = 0; RootMoves[i].pv[j] != MOVE_NONE; j++)
+ for (size_t j = 0; RootMoves[i].pv[j] != MOVE_NONE; ++j)
s << " " << move_to_uci(RootMoves[i].pv[j], pos.is_chess960());
}
void RootMove::extract_pv_from_tt(Position& pos) {
- StateInfo state[MAX_PLY_PLUS_2], *st = state;
+ StateInfo state[MAX_PLY_PLUS_6], *st = state;
const TTEntry* tte;
int ply = 0;
Move m = pv[0];
tte = TT.probe(pos.key());
} while ( tte
- && pos.is_pseudo_legal(m = tte->move()) // Local copy, TT could change
- && pos.pl_move_is_legal(m, pos.pinned_pieces())
+ && pos.pseudo_legal(m = tte->move()) // Local copy, TT could change
+ && pos.legal(m, pos.pinned_pieces())
&& ply < MAX_PLY
&& (!pos.is_draw() || ply < 2));
void RootMove::insert_pv_in_tt(Position& pos) {
- StateInfo state[MAX_PLY_PLUS_2], *st = state;
+ StateInfo state[MAX_PLY_PLUS_6], *st = state;
const TTEntry* tte;
int ply = 0;
Threads.mutex.lock();
assert(searching);
+ assert(activeSplitPoint);
SplitPoint* sp = activeSplitPoint;
Threads.mutex.unlock();
- Stack stack[MAX_PLY_PLUS_2], *ss = stack+1; // To allow referencing (ss-1)
+ Stack stack[MAX_PLY_PLUS_6], *ss = stack+2; // To allow referencing (ss-2)
Position pos(*sp->pos, this);
- memcpy(ss-1, sp->ss-1, 4 * sizeof(Stack));
+ std::memcpy(ss-2, sp->ss-2, 5 * sizeof(Stack));
ss->splitPoint = sp;
sp->mutex.lock();
// Loop across all split points and sum accumulated SplitPoint nodes plus
// all the currently active positions nodes.
- for (size_t i = 0; i < Threads.size(); i++)
- for (int j = 0; j < Threads[i]->splitPointsSize; j++)
+ for (size_t i = 0; i < Threads.size(); ++i)
+ for (int j = 0; j < Threads[i]->splitPointsSize; ++j)
{
SplitPoint& sp = Threads[i]->splitPoints[j];
projects / stockfish / blobdiff