// Futility margin
Value futility_margin(Depth d, bool noTtCutNode, bool improving, bool oppWorsening) {
- Value futilityMult = 109 - 40 * noTtCutNode;
- Value improvingDeduction = 59 * improving * futilityMult / 32;
+ Value futilityMult = 122 - 37 * noTtCutNode;
+ Value improvingDeduction = 58 * improving * futilityMult / 32;
Value worseningDeduction = oppWorsening * futilityMult / 3;
return futilityMult * d - improvingDeduction - worseningDeduction;
// Add correctionHistory value to raw staticEval and guarantee evaluation does not hit the tablebase range
Value to_corrected_static_eval(Value v, const Worker& w, const Position& pos) {
auto cv = w.correctionHistory[pos.side_to_move()][pawn_structure_index<Correction>(pos)];
- v += cv / 10;
+ v += cv * std::abs(cv) / 5073;
return std::clamp(v, VALUE_TB_LOSS_IN_MAX_PLY + 1, VALUE_TB_WIN_IN_MAX_PLY - 1);
}
// History and stats update bonus, based on depth
-int stat_bonus(Depth d) { return std::clamp(191 * d - 285, 20, 1412); }
+int stat_bonus(Depth d) { return std::clamp(190 * d - 298, 20, 1596); }
// History and stats update malus, based on depth
-int stat_malus(Depth d) { return (d < 4 ? 727 * d - 260 : 1908); }
+int stat_malus(Depth d) { return (d < 4 ? 736 * d - 268 : 2044); }
// Add a small random component to draw evaluations to avoid 3-fold blindness
Value value_draw(size_t nodes) { return VALUE_DRAW - 1 + Value(nodes & 0x2); }
// Reset aspiration window starting size
Value avg = rootMoves[pvIdx].averageScore;
- delta = 9 + avg * avg / 10182;
+ delta = 9 + avg * avg / 10424;
alpha = std::max(avg - delta, -VALUE_INFINITE);
beta = std::min(avg + delta, VALUE_INFINITE);
// Adjust optimism based on root move's averageScore (~4 Elo)
- optimism[us] = 127 * avg / (std::abs(avg) + 86);
+ optimism[us] = 125 * avg / (std::abs(avg) + 89);
optimism[~us] = -optimism[us];
// Start with a small aspiration window and, in the case of a fail
counterMoves.fill(Move::none());
mainHistory.fill(0);
captureHistory.fill(-700);
- pawnHistory.fill(-1193);
+ pawnHistory.fill(-1188);
correctionHistory.fill(0);
for (bool inCheck : {false, true})
for (StatsType c : {NoCaptures, Captures})
for (auto& to : continuationHistory[inCheck][c])
for (auto& h : to)
- h->fill(-56);
+ h->fill(-58);
for (size_t i = 1; i < reductions.size(); ++i)
- reductions[i] = int((19.26 + std::log(size_t(options["Threads"])) / 2) * std::log(i));
+ reductions[i] = int((18.62 + std::log(size_t(options["Threads"])) / 2) * std::log(i));
refreshTable.clear(networks[numaAccessToken]);
}
// Use static evaluation difference to improve quiet move ordering (~9 Elo)
if (((ss - 1)->currentMove).is_ok() && !(ss - 1)->inCheck && !priorCapture)
{
- int bonus = std::clamp(-10 * int((ss - 1)->staticEval + ss->staticEval), -1590, 1371) + 800;
+ int bonus = std::clamp(-10 * int((ss - 1)->staticEval + ss->staticEval), -1664, 1471) + 752;
thisThread->mainHistory[~us][((ss - 1)->currentMove).from_to()] << bonus;
if (type_of(pos.piece_on(prevSq)) != PAWN && ((ss - 1)->currentMove).type_of() != PROMOTION)
thisThread->pawnHistory[pawn_structure_index(pos)][pos.piece_on(prevSq)][prevSq]
// 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 - 512 - 293 * depth * depth)
+ if (eval < alpha - 494 - 290 * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha && std::abs(value) < VALUE_TB_WIN_IN_MAX_PLY)
// The depth condition is important for mate finding.
if (!ss->ttPv && depth < 13
&& eval - futility_margin(depth, cutNode && !ss->ttHit, improving, opponentWorsening)
- - (ss - 1)->statScore / 263
+ - (ss - 1)->statScore / 260
>= beta
&& eval >= beta && (!ttData.move || ttCapture) && beta > VALUE_TB_LOSS_IN_MAX_PLY
&& eval < VALUE_TB_WIN_IN_MAX_PLY)
return beta + (eval - beta) / 3;
// Step 9. Null move search with verification search (~35 Elo)
- if (!PvNode && (ss - 1)->currentMove != Move::null() && (ss - 1)->statScore < 14369
- && eval >= beta && ss->staticEval >= beta - 21 * depth + 393 && !excludedMove
+ if (!PvNode && (ss - 1)->currentMove != Move::null() && (ss - 1)->statScore < 14389
+ && eval >= beta && ss->staticEval >= beta - 21 * depth + 390 && !excludedMove
&& pos.non_pawn_material(us) && ss->ply >= thisThread->nmpMinPly
&& beta > VALUE_TB_LOSS_IN_MAX_PLY)
{
assert(eval - beta >= 0);
// Null move dynamic reduction based on depth and eval
- Depth R = std::min(int(eval - beta) / 197, 6) + depth / 3 + 5;
+ Depth R = std::min(int(eval - beta) / 202, 6) + depth / 3 + 5;
ss->currentMove = Move::null();
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
// For cutNodes, if depth is high enough, decrease depth by 2 if there is no ttMove, or
// by 1 if there is a ttMove with an upper bound.
- if (cutNode && depth >= 8 && (!ttData.move || ttData.bound == BOUND_UPPER))
+ if (cutNode && depth >= 7 && (!ttData.move || ttData.bound == BOUND_UPPER))
depth -= 1 + !ttData.move;
// Step 11. ProbCut (~10 Elo)
// If we have a good enough capture (or queen promotion) and a reduced search returns a value
// much above beta, we can (almost) safely prune the previous move.
- probCutBeta = beta + 177 - 57 * improving;
+ probCutBeta = beta + 184 - 53 * improving;
if (
!PvNode && depth > 3
&& std::abs(beta) < VALUE_TB_WIN_IN_MAX_PLY
moves_loop: // When in check, search starts here
// Step 12. A small Probcut idea, when we are in check (~4 Elo)
- probCutBeta = beta + 388;
+ probCutBeta = beta + 390;
if (ss->inCheck && (ttData.bound & BOUND_LOWER) && ttData.depth >= depth - 4
&& ttData.value >= probCutBeta && std::abs(ttData.value) < VALUE_TB_WIN_IN_MAX_PLY
&& std::abs(beta) < VALUE_TB_WIN_IN_MAX_PLY)
// Skip quiet moves if movecount exceeds our FutilityMoveCount threshold (~8 Elo)
moveCountPruning =
moveCount >= futility_move_count(improving, depth)
- - (singularBound == BOUND_UPPER && singularValue < alpha - 50);
+ - (singularBound == BOUND_UPPER && singularValue < alpha - 51);
// Reduced depth of the next LMR search
int lmrDepth = newDepth - r;
// Futility pruning for captures (~2 Elo)
if (!givesCheck && lmrDepth < 7 && !ss->inCheck)
{
- Value futilityValue = ss->staticEval + 294 + 246 * lmrDepth
+ Value futilityValue = ss->staticEval + 285 + 251 * lmrDepth
+ PieceValue[capturedPiece] + captHist / 7;
if (futilityValue <= alpha)
continue;
}
// SEE based pruning for captures and checks (~11 Elo)
- int seeHist = std::clamp(captHist / 32, -180 * depth, 163 * depth);
- if (!pos.see_ge(move, -163 * depth - seeHist))
+ int seeHist = std::clamp(captHist / 32, -182 * depth, 166 * depth);
+ if (!pos.see_ge(move, -168 * depth - seeHist))
continue;
}
else
+ thisThread->pawnHistory[pawn_structure_index(pos)][movedPiece][move.to_sq()];
// Continuation history based pruning (~2 Elo)
- if (lmrDepth < 6 && history < -3899 * depth)
+ if (lmrDepth < 6 && history < -4165 * depth)
continue;
history += 2 * thisThread->mainHistory[us][move.from_to()];
- lmrDepth += history / 4040;
+ lmrDepth += history / 3853;
Value futilityValue =
- ss->staticEval + (bestValue < ss->staticEval - 51 ? 135 : 56) + 140 * lmrDepth;
+ ss->staticEval + (bestValue < ss->staticEval - 51 ? 143 : 52) + 135 * lmrDepth;
// Futility pruning: parent node (~13 Elo)
if (!ss->inCheck && lmrDepth < 12 && futilityValue <= alpha)
// margins scale well.
if (!rootNode && move == ttData.move && !excludedMove
- && depth >= 4 - (thisThread->completedDepth > 35) + ss->ttPv
+ && depth >= 4 - (thisThread->completedDepth > 36) + ss->ttPv
&& std::abs(ttData.value) < VALUE_TB_WIN_IN_MAX_PLY && (ttData.bound & BOUND_LOWER)
&& ttData.depth >= depth - 3)
{
- Value singularBeta = ttData.value - (52 + 80 * (ss->ttPv && !PvNode)) * depth / 64;
+ Value singularBeta = ttData.value - (54 + 76 * (ss->ttPv && !PvNode)) * depth / 64;
Depth singularDepth = newDepth / 2;
ss->excludedMove = move;
if (value < singularBeta)
{
- int doubleMargin = 290 * PvNode - 200 * !ttCapture;
- int tripleMargin = 107 + 247 * PvNode - 278 * !ttCapture + 99 * ss->ttPv;
+ int doubleMargin = 293 * PvNode - 195 * !ttCapture;
+ int tripleMargin = 107 + 259 * PvNode - 260 * !ttCapture + 98 * ss->ttPv;
extension = 1 + (value < singularBeta - doubleMargin)
+ (value < singularBeta - tripleMargin);
- depth += ((!PvNode) && (depth < 18));
+ depth += ((!PvNode) && (depth < 16));
}
// Multi-cut pruning
else if (PvNode && move.to_sq() == prevSq
&& thisThread->captureHistory[movedPiece][move.to_sq()]
[type_of(pos.piece_on(move.to_sq()))]
- > 3922)
+ > 3994)
extension = 1;
}
ss->statScore = 2 * thisThread->mainHistory[us][move.from_to()]
+ (*contHist[0])[movedPiece][move.to_sq()]
- + (*contHist[1])[movedPiece][move.to_sq()] - 4747;
+ + (*contHist[1])[movedPiece][move.to_sq()] - 4664;
// Decrease/increase reduction for moves with a good/bad history (~8 Elo)
- r -= ss->statScore / 11125;
+ r -= ss->statScore / 10898;
// Step 17. Late moves reduction / extension (LMR, ~117 Elo)
if (depth >= 2 && moveCount > 1 + rootNode)
else
{
// Reduce other moves if we have found at least one score improvement (~2 Elo)
- if (depth > 2 && depth < 13 && std::abs(value) < VALUE_TB_WIN_IN_MAX_PLY)
+ if (depth > 2 && depth < 14 && std::abs(value) < VALUE_TB_WIN_IN_MAX_PLY)
depth -= 2;
assert(depth > 0);
// Bonus for prior countermove that caused the fail low
else if (!priorCapture && prevSq != SQ_NONE)
{
- int bonus = (113 * (depth > 5) + 118 * (PvNode || cutNode) + 119 * ((ss - 1)->moveCount > 8)
- + 64 * (!ss->inCheck && bestValue <= ss->staticEval - 107)
- + 147 * (!(ss - 1)->inCheck && bestValue <= -(ss - 1)->staticEval - 75));
+ int bonus = (114 * (depth > 5) + 116 * (PvNode || cutNode) + 123 * ((ss - 1)->moveCount > 8)
+ + 64 * (!ss->inCheck && bestValue <= ss->staticEval - 108)
+ + 153 * (!(ss - 1)->inCheck && bestValue <= -(ss - 1)->staticEval - 76));
// Proportional to "how much damage we have to undo"
- if ((ss - 1)->statScore < -7850)
- bonus += std::clamp(-(ss - 1)->statScore / 100, 0, 224);
+ if ((ss - 1)->statScore < -7865)
+ bonus += std::clamp(-(ss - 1)->statScore / 103, 0, 258);
update_continuation_histories(ss - 1, pos.piece_on(prevSq), prevSq,
stat_bonus(depth) * bonus / 100);
if (bestValue > alpha)
alpha = bestValue;
- futilityBase = ss->staticEval + 294;
+ futilityBase = ss->staticEval + 299;
}
const PieceToHistory* contHist[] = {(ss - 1)->continuationHistory,
+ (*contHist[1])[pos.moved_piece(move)][move.to_sq()]
+ thisThread->pawnHistory[pawn_structure_index(pos)][pos.moved_piece(move)]
[move.to_sq()]
- <= 4452)
+ <= 4643)
continue;
// Do not search moves with bad enough SEE values (~5 Elo)
- if (!pos.see_ge(move, -74))
+ if (!pos.see_ge(move, -83))
continue;
}
Depth Search::Worker::reduction(bool i, Depth d, int mn, int delta) const {
int reductionScale = reductions[d] * reductions[mn];
- return (reductionScale + 1236 - delta * 746 / rootDelta) / 1024 + (!i && reductionScale > 1326);
+ return (reductionScale + 1274 - delta * 746 / rootDelta) / 1024 + (!i && reductionScale > 1293);
}
// elapsed() returns the time elapsed since the search started. If the
if (!pos.capture_stage(bestMove))
{
- int bestMoveBonus = bestValue > beta + 166 ? quietMoveBonus // larger bonus
+ int bestMoveBonus = bestValue > beta + 172 ? quietMoveBonus // larger bonus
: stat_bonus(depth); // smaller bonus
update_quiet_stats(pos, ss, workerThread, bestMove, bestMoveBonus);
// by moves at ply -1, -2, -3, -4, and -6 with current move.
void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) {
- bonus = bonus * 51 / 64;
+ bonus = bonus * 52 / 64;
for (int i : {1, 2, 3, 4, 6})
{
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