// Futility margin
Value futility_margin(Depth d, bool noTtCutNode, bool improving) {
- return Value((125 - 43 * noTtCutNode) * (d - improving));
+ return Value((116 - 44 * noTtCutNode) * (d - improving));
}
// Reductions lookup table initialized at startup
Depth reduction(bool i, Depth d, int mn, Value delta, Value rootDelta) {
int reductionScale = Reductions[d] * Reductions[mn];
- return (reductionScale + 1487 - int(delta) * 976 / int(rootDelta)) / 1024
- + (!i && reductionScale > 808);
+ return (reductionScale + 1346 - int(delta) * 896 / int(rootDelta)) / 1024
+ + (!i && reductionScale > 880);
}
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(291 * d - 350, 1200); }
+int stat_bonus(Depth d) { return std::min(268 * d - 352, 1153); }
// History and stats update malus, based on depth
-int stat_malus(Depth d) { return std::min(361 * d - 361, 1182); }
+int stat_malus(Depth d) { return std::min(400 * d - 354, 1201); }
// Add a small random component to draw evaluations to avoid 3-fold blindness
Value value_draw(const Thread* thisThread) {
// Reset aspiration window starting size
Value avg = rootMoves[pvIdx].averageScore;
- delta = Value(10) + int(avg) * avg / 15335;
+ delta = Value(9) + int(avg) * avg / 14847;
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] = 110 * avg / (std::abs(avg) + 121);
+ optimism[us] = 121 * avg / (std::abs(avg) + 109);
optimism[~us] = -optimism[us];
// Start with a small aspiration window and, in the case of a fail
// 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(-14 * int((ss - 1)->staticEval + ss->staticEval), -1449, 1449);
+ int bonus = std::clamp(-13 * int((ss - 1)->staticEval + ss->staticEval), -1555, 1452);
thisThread->mainHistory[~us][from_to((ss - 1)->currentMove)] << bonus;
if (type_of(pos.piece_on(prevSq)) != PAWN && type_of((ss - 1)->currentMove) != PROMOTION)
thisThread->pawnHistory[pawn_structure(pos)][pos.piece_on(prevSq)][prevSq] << bonus / 4;
// If eval is really low check with qsearch if it can exceed alpha, if it can't,
// return a fail low.
// Adjust razor margin according to cutoffCnt. (~1 Elo)
- if (eval < alpha - 474 - (270 - 174 * ((ss + 1)->cutoffCnt > 3)) * depth * depth)
+ if (eval < alpha - 472 - (284 - 165 * ((ss + 1)->cutoffCnt > 3)) * depth * depth)
{
value = qsearch<NonPV>(pos, ss, alpha - 1, alpha);
if (value < alpha)
// The depth condition is important for mate finding.
if (!ss->ttPv && depth < 9
&& eval - futility_margin(depth, cutNode && !ss->ttHit, improving)
- - (ss - 1)->statScore / 321
+ - (ss - 1)->statScore / 337
>= beta
- && eval >= beta && eval < 29462 // smaller than TB wins
+ && eval >= beta && eval < 29008 // smaller than TB wins
&& (!ttMove || ttCapture))
return (eval + beta) / 2;
// Step 9. Null move search with verification search (~35 Elo)
- if (!PvNode && (ss - 1)->currentMove != MOVE_NULL && (ss - 1)->statScore < 17257 && eval >= beta
- && eval >= ss->staticEval && ss->staticEval >= beta - 24 * depth + 281 && !excludedMove
+ if (!PvNode && (ss - 1)->currentMove != MOVE_NULL && (ss - 1)->statScore < 17496 && eval >= beta
+ && eval >= ss->staticEval && ss->staticEval >= beta - 23 * depth + 304 && !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) / 152, 6) + depth / 3 + 4;
+ Depth R = std::min(int(eval - beta) / 144, 6) + depth / 3 + 4;
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
// Do not return unproven mate or TB scores
if (nullValue >= beta && nullValue < VALUE_TB_WIN_IN_MAX_PLY)
{
- if (thisThread->nmpMinPly || depth < 14)
+ if (thisThread->nmpMinPly || depth < 15)
return nullValue;
assert(!thisThread->nmpMinPly); // Recursive verification is not allowed
if (cutNode && depth >= 8 && !ttMove)
depth -= 2;
- probCutBeta = beta + 168 - 70 * improving;
+ probCutBeta = beta + 163 - 67 * improving;
// Step 11. ProbCut (~10 Elo)
// If we have a good enough capture (or queen promotion) and a reduced search returns a value
moves_loop: // When in check, search starts here
// Step 12. A small Probcut idea, when we are in check (~4 Elo)
- probCutBeta = beta + 416;
+ probCutBeta = beta + 425;
if (ss->inCheck && !PvNode && ttCapture && (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 4 && ttValue >= probCutBeta
&& abs(ttValue) < VALUE_TB_WIN_IN_MAX_PLY && abs(beta) < VALUE_TB_WIN_IN_MAX_PLY)
{
Piece capturedPiece = pos.piece_on(to_sq(move));
int futilityEval =
- ss->staticEval + 239 + 291 * lmrDepth + PieceValue[capturedPiece]
+ ss->staticEval + 238 + 305 * lmrDepth + PieceValue[capturedPiece]
+ captureHistory[movedPiece][to_sq(move)][type_of(capturedPiece)] / 7;
if (futilityEval < alpha)
continue;
}
// SEE based pruning for captures and checks (~11 Elo)
- if (!pos.see_ge(move, Value(-185) * depth))
+ if (!pos.see_ge(move, Value(-187) * depth))
continue;
}
else
+ thisThread->pawnHistory[pawn_structure(pos)][movedPiece][to_sq(move)];
// Continuation history based pruning (~2 Elo)
- if (lmrDepth < 6 && history < -3645 * depth)
+ if (lmrDepth < 6 && history < -3752 * depth)
continue;
history += 2 * thisThread->mainHistory[us][from_to(move)];
- lmrDepth += history / 7836;
+ lmrDepth += history / 7838;
lmrDepth = std::max(lmrDepth, -1);
// Futility pruning: parent node (~13 Elo)
- if (!ss->inCheck && lmrDepth < 13
- && ss->staticEval + (bestValue < ss->staticEval - 62 ? 123 : 77)
- + 127 * lmrDepth
+ if (!ss->inCheck && lmrDepth < 14
+ && ss->staticEval + (bestValue < ss->staticEval - 57 ? 124 : 71)
+ + 118 * lmrDepth
<= alpha)
continue;
// so changing them requires tests at these types of time controls.
// Recursive singular search is avoided.
if (!rootNode && move == ttMove && !excludedMove
- && depth >= 4 - (thisThread->completedDepth > 24) + 2 * (PvNode && tte->is_pv())
+ && depth >= 4 - (thisThread->completedDepth > 27) + 2 * (PvNode && tte->is_pv())
&& abs(ttValue) < VALUE_TB_WIN_IN_MAX_PLY && (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3)
{
- Value singularBeta = ttValue - (64 + 57 * (ss->ttPv && !PvNode)) * depth / 64;
+ Value singularBeta = ttValue - (66 + 58 * (ss->ttPv && !PvNode)) * depth / 64;
Depth singularDepth = newDepth / 2;
ss->excludedMove = move;
singularQuietLMR = !ttCapture;
// Avoid search explosion by limiting the number of double extensions
- if (!PvNode && value < singularBeta - 18 && ss->doubleExtensions <= 11)
+ if (!PvNode && value < singularBeta - 17 && ss->doubleExtensions <= 11)
{
extension = 2;
depth += depth < 15;
}
// Check extensions (~1 Elo)
- else if (givesCheck && depth > 9)
+ else if (givesCheck && depth > 10)
extension = 1;
// Quiet ttMove extensions (~1 Elo)
else if (PvNode && move == ttMove && move == ss->killers[0]
- && (*contHist[0])[movedPiece][to_sq(move)] >= 4194)
+ && (*contHist[0])[movedPiece][to_sq(move)] >= 4325)
extension = 1;
// Recapture extensions (~1 Elo)
else if (PvNode && move == ttMove && to_sq(move) == prevSq
&& captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))]
- > 4000)
+ > 4146)
extension = 1;
}
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)] - 3848;
+ + (*contHist[3])[movedPiece][to_sq(move)] - 3817;
// Decrease/increase reduction for moves with a good/bad history (~25 Elo)
- r -= ss->statScore / 14200;
+ r -= ss->statScore / 14767;
// 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 the result
// was good enough search deeper, if it was bad enough search shallower.
- const bool doDeeperSearch = value > (bestValue + 50 + 2 * newDepth); // (~1 Elo)
+ const bool doDeeperSearch = value > (bestValue + 53 + 2 * newDepth); // (~1 Elo)
const bool doShallowerSearch = value < bestValue + newDepth; // (~2 Elo)
newDepth += doDeeperSearch - doShallowerSearch;
else
{
// Reduce other moves if we have found at least one score improvement (~2 Elo)
- if (depth > 2 && depth < 12 && beta < 13828 && value > -11369)
+ if (depth > 2 && depth < 12 && beta < 13782 && value > -11541)
depth -= 2;
assert(depth > 0);
// Bonus for prior countermove that caused the fail low
else if (!priorCapture && prevSq != SQ_NONE)
{
- int bonus = (depth > 6) + (PvNode || cutNode) + (bestValue < alpha - 657)
+ int bonus = (depth > 6) + (PvNode || cutNode) + (bestValue < alpha - 656)
+ ((ss - 1)->moveCount > 10);
update_continuation_histories(ss - 1, pos.piece_on(prevSq), prevSq,
stat_bonus(depth) * bonus);
if (bestValue > alpha)
alpha = bestValue;
- futilityBase = ss->staticEval + 200;
+ futilityBase = ss->staticEval + 182;
}
const PieceToHistory* contHist[] = {(ss - 1)->continuationHistory,
continue;
// Do not search moves with bad enough SEE values (~5 Elo)
- if (!pos.see_ge(move, Value(-90)))
+ if (!pos.see_ge(move, Value(-77)))
continue;
}
if (!pos.capture_stage(bestMove))
{
- int bestMoveBonus = bestValue > beta + 168 ? quietMoveBonus // larger bonus
+ int bestMoveBonus = bestValue > beta + 173 ? quietMoveBonus // larger bonus
: stat_bonus(depth); // smaller bonus
// Increase stats for the best move in case it was a quiet move
projects / stockfish / blobdiff