// Futility margin
Value futility_margin(Depth d, bool improving) {
- return Value(214 * (d - improving));
+ return Value(168 * (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 + 1358 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 904);
+ return (r + 1463 - int(delta) * 1024 / int(rootDelta)) / 1024 + (!i && r > 1010);
}
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((6 * d + 229) * d - 215 , 2000);
+ return std::min((9 * d + 270) * d - 311 , 2145);
}
// 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((21.9 + std::log(Threads.size()) / 2) * std::log(i));
+ Reductions[i] = int((20.81 + std::log(Threads.size()) / 2) * std::log(i));
}
multiPV = std::min(multiPV, rootMoves.size());
- complexityAverage.set(232, 1);
+ complexityAverage.set(202, 1);
trend = SCORE_ZERO;
- optimism[ us] = Value(25);
+ optimism[ us] = Value(39);
optimism[~us] = -optimism[us];
int searchAgainCounter = 0;
if (rootDepth >= 4)
{
Value prev = rootMoves[pvIdx].averageScore;
- delta = Value(17) + int(prev) * prev / 16384;
+ delta = Value(16) + int(prev) * prev / 19178;
alpha = std::max(prev - delta,-VALUE_INFINITE);
beta = std::min(prev + delta, VALUE_INFINITE);
// Adjust trend and optimism based on root move's previousScore
- int tr = sigmoid(prev, 0, 0, 147, 113, 1);
+ int tr = sigmoid(prev, 3, 8, 90, 125, 1);
trend = (us == WHITE ? make_score(tr, tr / 2)
: -make_score(tr, tr / 2));
- int opt = sigmoid(prev, 0, 25, 147, 14464, 256);
+ int opt = sigmoid(prev, 8, 17, 144, 13966, 183);
optimism[ us] = Value(opt);
optimism[~us] = -optimism[us];
}
else
break;
- delta += delta / 4 + 5;
+ delta += delta / 4 + 2;
assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
}
&& !Threads.stop
&& !mainThread->stopOnPonderhit)
{
- double fallingEval = (142 + 12 * (mainThread->bestPreviousAverageScore - bestValue)
- + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
+ double fallingEval = (69 + 12 * (mainThread->bestPreviousAverageScore - bestValue)
+ + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 781.4;
fallingEval = std::clamp(fallingEval, 0.5, 1.5);
// If the bestMove is stable over several iterations, reduce time accordingly
- timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.92 : 0.95;
- double reduction = (1.47 + mainThread->previousTimeReduction) / (2.32 * timeReduction);
+ timeReduction = lastBestMoveDepth + 10 < completedDepth ? 1.63 : 0.73;
+ double reduction = (1.56 + mainThread->previousTimeReduction) / (2.20 * timeReduction);
double bestMoveInstability = 1.073 + std::max(1.0, 2.25 - 9.9 / rootDepth)
* totBestMoveChanges / Threads.size();
int complexity = mainThread->complexityAverage.value();
- double complexPosition = std::clamp(1.0 + (complexity - 232) / 1750.0, 0.5, 1.5);
+ double complexPosition = std::clamp(1.0 + (complexity - 326) / 1618.1, 0.5, 1.5);
double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability * complexPosition;
}
else if ( Threads.increaseDepth
&& !mainThread->ponder
- && Time.elapsed() > totalTime * 0.58)
+ && Time.elapsed() > totalTime * 0.43)
Threads.increaseDepth = false;
else
Threads.increaseDepth = true;
// 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
- : 200;
+ : 175;
improving = improvement > 0;
complexity = abs(ss->staticEval - (us == WHITE ? eg_value(pos.psq_score()) : -eg_value(pos.psq_score())));
// Step 7. Razoring.
// If eval is really low check with qsearch if it can exceed alpha, if it can't,
// return a fail low.
- if (!PvNode && depth <= 6 && eval < alpha - 400 - 300 * depth * depth)
+ if ( !PvNode
+ && depth <= 7
+ && eval < alpha - 348 - 258 * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha)
// Step 8. Futility pruning: child node (~25 Elo).
// The depth condition is important for mate finding.
if ( !ss->ttPv
- && depth < 9
+ && depth < 8
&& eval - futility_margin(depth, improving) - (ss-1)->statScore / 256 >= beta
&& eval >= beta
- && eval < 15000) // 50% larger than VALUE_KNOWN_WIN, but smaller than TB wins.
+ && eval < 26305) // larger than VALUE_KNOWN_WIN, but smaller than TB wins.
return eval;
// Step 9. Null move search with verification search (~22 Elo)
if ( !PvNode
&& (ss-1)->currentMove != MOVE_NULL
- && (ss-1)->statScore < 23767
+ && (ss-1)->statScore < 14695
&& eval >= beta
&& eval >= ss->staticEval
- && ss->staticEval >= beta - 20 * depth - improvement / 15 + 204 + complexity / 25
+ && ss->staticEval >= beta - 15 * depth - improvement / 15 + 198 + complexity / 28
&& !excludedMove
&& pos.non_pawn_material(us)
&& (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor))
{
assert(eval - beta >= 0);
- // Null move dynamic reduction based on depth and value
- Depth R = std::min(int(eval - beta) / 205, 3) + depth / 3 + 4;
+ // Null move dynamic reduction based on depth, eval and complexity of position
+ Depth R = std::min(int(eval - beta) / 147, 5) + depth / 3 + 4 - (complexity > 753);
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
}
}
- probCutBeta = beta + 209 - 44 * improving;
+ probCutBeta = beta + 179 - 46 * improving;
// Step 10. ProbCut (~4 Elo)
// If we have a good enough capture and a reduced search returns a value
if (move != excludedMove && pos.legal(move))
{
assert(pos.capture_or_promotion(move));
- assert(depth >= 5);
captureOrPromotion = true;
// Step 11. If the position is not in TT, decrease depth by 2 or 1 depending on node type (~3 Elo)
if ( PvNode
- && depth >= 6
+ && depth >= 3
&& !ttMove)
depth -= 2;
if ( cutNode
- && depth >= 9
+ && depth >= 8
&& !ttMove)
depth--;
moves_loop: // When in check, search starts here
// Step 12. A small Probcut idea, when we are in check (~0 Elo)
- probCutBeta = beta + 409;
+ probCutBeta = beta + 481;
if ( ss->inCheck
&& !PvNode
- && depth >= 4
+ && depth >= 2
&& ttCapture
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3
&& !PvNode
&& lmrDepth < 6
&& !ss->inCheck
- && ss->staticEval + 342 + 238 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))]
- + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 8 < alpha)
+ && ss->staticEval + 281 + 179 * lmrDepth + PieceValue[EG][pos.piece_on(to_sq(move))]
+ + captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] / 6 < alpha)
continue;
// SEE based pruning (~9 Elo)
- if (!pos.see_ge(move, Value(-217) * depth))
+ if (!pos.see_ge(move, Value(-203) * depth))
continue;
}
else
// Futility pruning: parent node (~9 Elo)
if ( !ss->inCheck
- && lmrDepth < 8
- && ss->staticEval + 138 + 137 * lmrDepth + history / 64 <= alpha)
+ && lmrDepth < 11
+ && ss->staticEval + 122 + 138 * lmrDepth + history / 60 <= alpha)
continue;
// Prune moves with negative SEE (~3 Elo)
- if (!pos.see_ge(move, Value(-21 * lmrDepth * lmrDepth - 21 * lmrDepth)))
+ if (!pos.see_ge(move, Value(-25 * lmrDepth * lmrDepth - 20 * 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 >= 6 + 2 * (PvNode && tte->is_pv())
+ && depth >= 4 + 2 * (PvNode && tte->is_pv())
&& move == ttMove
&& !excludedMove // Avoid recursive singular search
/* && ttValue != VALUE_NONE Already implicit in the next condition */
// Avoid search explosion by limiting the number of double extensions
if ( !PvNode
- && value < singularBeta - 75
- && ss->doubleExtensions <= 6)
+ && value < singularBeta - 26
+ && ss->doubleExtensions <= 8)
extension = 2;
}
// Check extensions (~1 Elo)
else if ( givesCheck
- && depth > 6
- && abs(ss->staticEval) > 100)
+ && depth > 9
+ && abs(ss->staticEval) > 71)
extension = 1;
// Quiet ttMove extensions (~0 Elo)
else if ( PvNode
&& move == ttMove
&& move == ss->killers[0]
- && (*contHist[0])[movedPiece][to_sq(move)] >= 10000)
+ && (*contHist[0])[movedPiece][to_sq(move)] >= 5491)
extension = 1;
}
// We use various heuristics for the sons of a node after the first son has
// been searched. In general we would like to reduce them, but there are many
// cases where we extend a son if it has good chances to be "interesting".
- if ( depth >= 3
- && moveCount > 1 + 2 * rootNode
+ if ( depth >= 2
+ && moveCount > 1 + (PvNode && ss->ply <= 1)
&& ( !ss->ttPv
|| !captureOrPromotion
|| (cutNode && (ss-1)->moveCount > 1)))
r -= 2;
// Decrease reduction if opponent's move count is high (~1 Elo)
- if ((ss-1)->moveCount > 13)
+ if ((ss-1)->moveCount > 7)
r--;
// Increase reduction for cut nodes (~3 Elo)
+ (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
+ (*contHist[3])[movedPiece][to_sq(move)]
- - 4923;
+ - 4334;
// Decrease/increase reduction for moves with a good/bad history (~30 Elo)
- r -= ss->statScore / 14721;
+ r -= ss->statScore / 15914;
// In general we want to cap the LMR depth search at newDepth. But if reductions
// are really negative and movecount is low, we allow this move to be searched
// deeper than the first move (this may lead to hidden double extensions).
int deeper = r >= -1 ? 0
- : moveCount <= 5 ? 2
- : PvNode && depth > 6 ? 1
- : cutNode && moveCount <= 7 ? 1
+ : moveCount <= 4 ? 2
+ : PvNode && depth > 4 ? 1
+ : cutNode && moveCount <= 8 ? 1
: 0;
Depth d = std::clamp(newDepth - r, 1, newDepth + deeper);
// If the son is reduced and fails high it will be re-searched at full depth
doFullDepthSearch = value > alpha && d < newDepth;
- doDeeperSearch = value > (alpha + 62 + 20 * (newDepth - d));
+ doDeeperSearch = value > (alpha + 78 + 11 * (newDepth - d));
didLMR = true;
}
else
: -stat_bonus(newDepth);
if (captureOrPromotion)
- bonus /= 4;
+ bonus /= 6;
update_continuation_histories(ss, movedPiece, to_sq(move), bonus);
}
quietsSearched, quietCount, capturesSearched, captureCount, depth);
// Bonus for prior countermove that caused the fail low
- else if ( (depth >= 3 || PvNode)
+ else if ( (depth >= 4 || PvNode)
&& !priorCapture)
{
//Assign extra bonus if current node is PvNode or cutNode
//or fail low was really bad
bool extraBonus = PvNode
|| cutNode
- || bestValue < alpha - 94 * depth;
+ || bestValue < alpha - 70 * depth;
update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + extraBonus));
}
if (PvNode && bestValue > alpha)
alpha = bestValue;
- futilityBase = bestValue + 155;
+ futilityBase = bestValue + 118;
}
const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory,
projects / stockfish / blobdiff