// for match (TC 60+0.6) results spanning a wide range of k values.
PRNG rng(now());
double floatLevel = Options["UCI_LimitStrength"] ?
- Utility::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) :
+ std::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) :
double(Options["Skill Level"]);
int intLevel = int(floatLevel) +
((floatLevel - int(floatLevel)) * 1024 > rng.rand<unsigned>() % 1024 ? 1 : 0);
{
double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue)
+ 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0;
- fallingEval = Utility::clamp(fallingEval, 0.5, 1.5);
+ 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;
&& eval <= alpha - RazorMargin)
return qsearch<NT>(pos, ss, alpha, beta);
- improving = (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval > (ss-4)->staticEval
- || (ss-4)->staticEval == VALUE_NONE) : ss->staticEval > (ss-2)->staticEval;
+ improving = (ss-2)->staticEval == VALUE_NONE
+ ? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE
+ : ss->staticEval > (ss-2)->staticEval;
// Step 8. Futility pruning: child node (~50 Elo)
if ( !PvNode
// there and in further interactions with transposition table cutoff depth is set to depth - 3
// because probCut search has depth set to depth - 4 but we also do a move before it
// so effective depth is equal to depth - 3
- && !( ttHit
- && tte->depth() >= depth - 3
+ && !( ttHit
+ && tte->depth() >= depth - 3
&& ttValue != VALUE_NONE
&& ttValue < probCutBeta))
{
}
}
- // Step 11. Internal iterative deepening (~1 Elo)
- if (depth >= 7 && !ttMove)
- {
- search<NT>(pos, ss, alpha, beta, depth - 7, cutNode);
-
- tte = TT.probe(posKey, ttHit);
- ttValue = ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE;
- ttMove = ttHit ? tte->move() : MOVE_NONE;
- }
+ // Step 11. If the position is not in TT, decrease depth by 2
+ if ( PvNode
+ && depth >= 6
+ && !ttMove)
+ depth -= 2;
moves_loop: // When in check, search starts from here
r++;
}
- Depth d = Utility::clamp(newDepth - r, 1, newDepth);
+ Depth d = std::clamp(newDepth - r, 1, newDepth);
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
{
assert(type_of(move) != ENPASSANT); // Due to !pos.advanced_pawn_push
+ // moveCount pruning
+ if (moveCount > abs(depth) + 2)
+ continue;
+
futilityValue = futilityBase + PieceValue[EG][pos.piece_on(to_sq(move))];
if (futilityValue <= alpha)
}
// Do not search moves with negative SEE values
- if ( !ss->inCheck && !pos.see_ge(move))
+ if (!ss->inCheck && !pos.see_ge(move))
continue;
// Speculative prefetch as early as possible
[pos.moved_piece(move)]
[to_sq(move)];
+ if ( !captureOrPromotion
+ && moveCount >= abs(depth) + 1
+ && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold
+ && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold)
+ continue;
+
// Make and search the move
pos.do_move(move, st, givesCheck);
value = -qsearch<NT>(pos, ss+1, -beta, -alpha, depth - 1);