// History and stats update bonus, based on depth
int stat_bonus(Depth d) {
- return d > 14 ? 29 : 8 * d * d + 224 * d - 215;
+ return d > 14 ? 66 : 6 * d * d + 231 * d - 206;
}
// Add a small random component to draw evaluations to avoid 3-fold blindness
// Step 8. Null move search with verification search (~40 Elo)
if ( !PvNode
&& (ss-1)->currentMove != MOVE_NULL
- && (ss-1)->statScore < 22977
+ && (ss-1)->statScore < 22661
&& eval >= beta
&& eval >= ss->staticEval
- && ss->staticEval >= beta - 30 * depth - 28 * improving + 84 * ss->ttPv + 168
+ && ss->staticEval >= beta - 24 * depth - 34 * improving + 162 * ss->ttPv + 159
&& !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 = (1015 + 85 * depth) / 256 + std::min(int(eval - beta) / 191, 3);
+ Depth R = (1062 + 68 * depth) / 256 + std::min(int(eval - beta) / 190, 3);
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
}
}
- probCutBeta = beta + 194 - 49 * improving;
+ probCutBeta = beta + 209 - 44 * improving;
// Step 9. ProbCut (~10 Elo)
// If we have a good enough capture and a reduced search returns a value
// Futility pruning: parent node (~5 Elo)
if ( lmrDepth < 7
&& !ss->inCheck
- && ss->staticEval + 254 + 159 * lmrDepth <= alpha
+ && ss->staticEval + 174 + 157 * lmrDepth <= alpha
&& (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
+ (*contHist[3])[movedPiece][to_sq(move)]
- + (*contHist[5])[movedPiece][to_sq(move)] / 2 < 26394)
+ + (*contHist[5])[movedPiece][to_sq(move)] / 3 < 26237)
continue;
// Prune moves with negative SEE (~20 Elo)
+ (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
+ (*contHist[3])[movedPiece][to_sq(move)]
- - 5287;
+ - 5337;
// Decrease/increase reduction by comparing opponent's stat score (~10 Elo)
- if (ss->statScore >= -105 && (ss-1)->statScore < -103)
+ if (ss->statScore >= -89 && (ss-1)->statScore < -116)
r--;
- else if ((ss-1)->statScore >= -122 && ss->statScore < -129)
+ else if ((ss-1)->statScore >= -112 && ss->statScore < -100)
r++;
// Decrease/increase reduction for moves with a good/bad history (~30 Elo)
- r -= ss->statScore / 14884;
+ // If we are not in check use statScore, if we are in check
+ // use sum of main history and first continuation history with an offset
+ if (ss->inCheck)
+ r -= (thisThread->mainHistory[us][from_to(move)]
+ + (*contHist[0])[movedPiece][to_sq(move)] - 4341) / 16384;
+ else
+ r -= ss->statScore / 14382;
}
Depth d = std::clamp(newDepth - r, 1, newDepth);
PieceType captured = type_of(pos.piece_on(to_sq(bestMove)));
bonus1 = stat_bonus(depth + 1);
- bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus
- : stat_bonus(depth); // smaller bonus
+ bonus2 = bestValue > beta + PawnValueMg ? bonus1 // larger bonus
+ : std::min(bonus1, stat_bonus(depth)); // smaller bonus
if (!pos.capture_or_promotion(bestMove))
{