// Futility margin
Value futility_margin(Depth d, bool improving) {
- return Value(158 * (d - improving));
+ return Value(154 * (d - improving));
}
// Reductions lookup table, initialized at startup
Depth reduction(bool i, Depth d, int mn, Value delta, Value rootDelta) {
int r = Reductions[d] * Reductions[mn];
- return (r + 1460 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 937);
+ return (r + 1449 - int(delta) * 1032 / int(rootDelta)) / 1024 + (!i && r > 941);
}
constexpr int futility_move_count(bool improving, Depth depth) {
// History and stats update bonus, based on depth
int stat_bonus(Depth d) {
- return std::min(350 * d - 400, 1650);
+ return std::min(340 * d - 470, 1855);
}
// Add a small random component to draw evaluations to avoid 3-fold blindness
void Search::init() {
for (int i = 1; i < MAX_MOVES; ++i)
- Reductions[i] = int((20.26 + std::log(Threads.size()) / 2) * std::log(i));
+ Reductions[i] = int((19.47 + std::log(Threads.size()) / 2) * std::log(i));
}
if (rootDepth >= 4)
{
Value prev = rootMoves[pvIdx].averageScore;
- delta = Value(10) + int(prev) * prev / 15400;
+ delta = Value(10) + int(prev) * prev / 16502;
alpha = std::max(prev - delta,-VALUE_INFINITE);
beta = std::min(prev + delta, VALUE_INFINITE);
// Adjust optimism based on root move's previousScore
- int opt = 116 * prev / (std::abs(prev) + 170);
+ int opt = 120 * prev / (std::abs(prev) + 161);
optimism[ us] = Value(opt);
optimism[~us] = -optimism[us];
}
&& !Threads.stop
&& !mainThread->stopOnPonderhit)
{
- double fallingEval = (71 + 12 * (mainThread->bestPreviousAverageScore - bestValue)
- + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 656.7;
+ double fallingEval = (69 + 13 * (mainThread->bestPreviousAverageScore - bestValue)
+ + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 619.6;
fallingEval = std::clamp(fallingEval, 0.5, 1.5);
// If the bestMove is stable over several iterations, reduce time accordingly
- timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.37 : 0.65;
- double reduction = (1.4 + mainThread->previousTimeReduction) / (2.15 * timeReduction);
- double bestMoveInstability = 1 + 1.7 * totBestMoveChanges / Threads.size();
+ timeReduction = lastBestMoveDepth + 8 < completedDepth ? 1.57 : 0.65;
+ double reduction = (1.4 + mainThread->previousTimeReduction) / (2.08 * timeReduction);
+ double bestMoveInstability = 1 + 1.8 * totBestMoveChanges / Threads.size();
int complexity = mainThread->complexityAverage.value();
- double complexPosition = std::min(1.0 + (complexity - 261) / 1738.7, 1.5);
+ double complexPosition = std::min(1.03 + (complexity - 241) / 1552.0, 1.45);
double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability * complexPosition;
Threads.stop = true;
}
else if ( !mainThread->ponder
- && Time.elapsed() > totalTime * 0.53)
+ && Time.elapsed() > totalTime * 0.50)
Threads.increaseDepth = false;
else
Threads.increaseDepth = true;
// Use static evaluation difference to improve quiet move ordering (~4 Elo)
if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture)
{
- int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1940, 1940);
+ int bonus = std::clamp(-19 * int((ss-1)->staticEval + ss->staticEval), -1920, 1920);
thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus;
}
// margin and the improving flag are used in various pruning heuristics.
improvement = (ss-2)->staticEval != VALUE_NONE ? ss->staticEval - (ss-2)->staticEval
: (ss-4)->staticEval != VALUE_NONE ? ss->staticEval - (ss-4)->staticEval
- : 172;
+ : 156;
improving = improvement > 0;
// Step 7. Razoring (~1 Elo).
// If eval is really low check with qsearch if it can exceed alpha, if it can't,
// return a fail low.
- if (eval < alpha - 394 - 255 * depth * depth)
+ if (eval < alpha - 426 - 252 * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha)
// Step 8. Futility pruning: child node (~40 Elo).
// The depth condition is important for mate finding.
if ( !ss->ttPv
- && depth < 8
- && eval - futility_margin(depth, improving) - (ss-1)->statScore / 304 >= beta
+ && depth < 9
+ && eval - futility_margin(depth, improving) - (ss-1)->statScore / 280 >= beta
&& eval >= beta
- && eval < 28580) // larger than VALUE_KNOWN_WIN, but smaller than TB wins
+ && eval < 25128) // larger than VALUE_KNOWN_WIN, but smaller than TB wins
return eval;
// Step 9. Null move search with verification search (~35 Elo)
if ( !PvNode
&& (ss-1)->currentMove != MOVE_NULL
- && (ss-1)->statScore < 18200
+ && (ss-1)->statScore < 18755
&& eval >= beta
&& eval >= ss->staticEval
- && ss->staticEval >= beta - 20 * depth - improvement / 14 + 235 + complexity / 24
+ && ss->staticEval >= beta - 19 * depth - improvement / 13 + 253 + complexity / 25
&& !excludedMove
&& pos.non_pawn_material(us)
&& (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
assert(eval - beta >= 0);
// Null move dynamic reduction based on depth, eval and complexity of position
- Depth R = std::min(int(eval - beta) / 165, 6) + depth / 3 + 4 - (complexity > 800);
+ Depth R = std::min(int(eval - beta) / 168, 6) + depth / 3 + 4 - (complexity > 825);
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
}
}
- probCutBeta = beta + 180 - 54 * improving;
+ probCutBeta = beta + 186 - 54 * improving;
// Step 10. ProbCut (~10 Elo)
// If we have a good enough capture and a reduced search returns a value
return qsearch<PV>(pos, ss, alpha, beta);
if ( cutNode
- && depth >= 9
+ && depth >= 7
&& !ttMove)
depth -= 2;
moves_loop: // When in check, search starts here
// Step 12. A small Probcut idea, when we are in check (~4 Elo)
- probCutBeta = beta + 402;
+ probCutBeta = beta + 391;
if ( ss->inCheck
&& !PvNode
&& depth >= 2
// Futility pruning for captures (~2 Elo)
if ( !givesCheck
&& !PvNode
- && lmrDepth < 7
+ && lmrDepth < 6
&& !ss->inCheck
- && ss->staticEval + 185 + 203 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))]
- + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 6 < alpha)
+ && ss->staticEval + 182 + 230 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))]
+ + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 7 < alpha)
continue;
// SEE based pruning (~11 Elo)
- if (!pos.see_ge(move, Value(-220) * depth))
+ if (!pos.see_ge(move, Value(-206) * depth))
continue;
}
else
// Continuation history based pruning (~2 Elo)
if ( lmrDepth < 5
- && history < -4180 * (depth - 1))
+ && history < -4405 * (depth - 1))
continue;
history += 2 * thisThread->mainHistory[us][from_to(move)];
- lmrDepth += history / 7208;
+ lmrDepth += history / 7278;
lmrDepth = std::max(lmrDepth, -2);
// Futility pruning: parent node (~13 Elo)
if ( !ss->inCheck
&& lmrDepth < 13
- && ss->staticEval + 103 + 136 * lmrDepth <= alpha)
+ && ss->staticEval + 103 + 138 * lmrDepth <= alpha)
continue;
lmrDepth = std::max(lmrDepth, 0);
// Prune moves with negative SEE (~4 Elo)
- if (!pos.see_ge(move, Value(-25 * lmrDepth * lmrDepth - 16 * lmrDepth)))
+ if (!pos.see_ge(move, Value(-24 * lmrDepth * lmrDepth - 15 * lmrDepth)))
continue;
}
}
// a reduced search on all the other moves but the ttMove and if the
// result is lower than ttValue minus a margin, then we will extend the ttMove.
if ( !rootNode
- && depth >= 4 - (thisThread->completedDepth > 22) + 2 * (PvNode && tte->is_pv())
+ && depth >= 4 - (thisThread->completedDepth > 21) + 2 * (PvNode && tte->is_pv())
&& move == ttMove
&& !excludedMove // Avoid recursive singular search
/* && ttValue != VALUE_NONE Already implicit in the next condition */
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3)
{
- Value singularBeta = ttValue - (3 + (ss->ttPv && !PvNode)) * depth;
+ Value singularBeta = ttValue - (2 + (ss->ttPv && !PvNode)) * depth;
Depth singularDepth = (depth - 1) / 2;
ss->excludedMove = move;
&& ss->doubleExtensions <= 10)
{
extension = 2;
- depth += depth < 12;
+ depth += depth < 13;
}
}
// Check extensions (~1 Elo)
else if ( givesCheck
- && depth > 9
- && abs(ss->staticEval) > 78)
+ && depth > 10
+ && abs(ss->staticEval) > 88)
extension = 1;
// Quiet ttMove extensions (~1 Elo)
else if ( PvNode
&& move == ttMove
&& move == ss->killers[0]
- && (*contHist[0])[movedPiece][to_sq(move)] >= 5600)
+ && (*contHist[0])[movedPiece][to_sq(move)] >= 5705)
extension = 1;
}
// Decrease reduction for PvNodes based on depth
if (PvNode)
- r -= 1 + 11 / (3 + depth);
+ r -= 1 + 12 / (3 + depth);
// Decrease reduction if ttMove has been singularly extended (~1 Elo)
if (singularQuietLMR)
// Decrease reduction if move is a killer and we have a good history
if (move == ss->killers[0]
- && (*contHist[0])[movedPiece][to_sq(move)] >= 3600)
+ && (*contHist[0])[movedPiece][to_sq(move)] >= 3722)
r--;
ss->statScore = 2 * thisThread->mainHistory[us][from_to(move)]
+ (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
+ (*contHist[3])[movedPiece][to_sq(move)]
- - 4467;
+ - 4182;
// Decrease/increase reduction for moves with a good/bad history (~30 Elo)
- r -= ss->statScore / (12800 + 4410 * (depth > 7 && depth < 19));
+ r -= ss->statScore / (11791 + 3992 * (depth > 6 && depth < 19));
// Step 17. Late moves reduction / extension (LMR, ~117 Elo)
// We use various heuristics for the sons of a node after the first son has
{
// Adjust full depth search based on LMR results - if result
// was good enough search deeper, if it was bad enough search shallower
- const bool doDeeperSearch = value > (alpha + 66 + 11 * (newDepth - d));
- const bool doEvenDeeperSearch = value > alpha + 582 && ss->doubleExtensions <= 5;
+ const bool doDeeperSearch = value > (alpha + 58 + 12 * (newDepth - d));
+ const bool doEvenDeeperSearch = value > alpha + 588 && ss->doubleExtensions <= 5;
const bool doShallowerSearch = value < bestValue + newDepth;
ss->doubleExtensions = ss->doubleExtensions + doEvenDeeperSearch;
// Reduce other moves if we have found at least one score improvement
if ( depth > 1
&& depth < 6
- && beta < VALUE_KNOWN_WIN
- && alpha > -VALUE_KNOWN_WIN)
+ && beta < 10534
+ && alpha > -10534)
depth -= 1;
assert(depth > 0);
else if (!priorCapture)
{
// Extra bonuses for PV/Cut nodes or bad fail lows
- int bonus = (depth > 4) + (PvNode || cutNode) + (bestValue < alpha - 88 * depth);
+ int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 97 * depth);
update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * bonus);
}
if (PvNode && bestValue > alpha)
alpha = bestValue;
- futilityBase = bestValue + 158;
+ futilityBase = bestValue + 168;
}
const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
continue;
// Do not search moves with bad enough SEE values (~5 Elo)
- if (!pos.see_ge(move, Value(-108)))
+ if (!pos.see_ge(move, Value(-110)))
continue;
}
if (!pos.capture(bestMove))
{
- int bonus2 = bestValue > beta + 146 ? bonus1 // larger bonus
+ int bonus2 = bestValue > beta + 153 ? bonus1 // larger bonus
: stat_bonus(depth); // smaller bonus
// Increase stats for the best move in case it was a quiet move
projects / stockfish / commitdiff