// for match (TC 60+0.6) results spanning a wide range of k values.
PRNG rng(now());
double floatLevel = Options["UCI_LimitStrength"] ?
- clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) :
+ Utility::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);
if (rootDepth >= 4)
{
Value previousScore = rootMoves[pvIdx].previousScore;
- delta = Value(21 + abs(previousScore) / 256);
+ delta = Value(21);
alpha = std::max(previousScore - delta,-VALUE_INFINITE);
beta = std::min(previousScore + delta, VALUE_INFINITE);
{
double fallingEval = (332 + 6 * (mainThread->previousScore - bestValue)
+ 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 704.0;
- fallingEval = clamp(fallingEval, 0.5, 1.5);
+ fallingEval = Utility::clamp(fallingEval, 0.5, 1.5);
// If the bestMove is stable over several iterations, reduce time accordingly
timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.94 : 0.91;
ss->staticEval = eval = evaluate(pos) + bonus;
}
else
- ss->staticEval = eval = -(ss-1)->staticEval + 2 * Eval::Tempo;
+ ss->staticEval = eval = -(ss-1)->staticEval + 2 * Tempo;
tte->save(posKey, VALUE_NONE, ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval);
}
// Step 7. Razoring (~1 Elo)
if ( !rootNode // The required rootNode PV handling is not available in qsearch
- && depth < 2
+ && depth == 1
&& eval <= alpha - RazorMargin)
return qsearch<NT>(pos, ss, alpha, beta);
contHist,
countermove,
ss->killers,
- depth > 12 && ttPv ? ss->ply : MAX_PLY);
+ depth > 12 ? ss->ply : MAX_PLY);
value = bestValue;
singularLMR = moveCountPruning = false;
ttCapture = ttMove && pos.capture_or_promotion(ttMove);
+ bool formerPv = ttPv && !PvNode;
// Mark this node as being searched
ThreadHolding th(thisThread, posKey, ss->ply);
if ( lmrDepth < 6
&& !inCheck
&& ss->staticEval + 235 + 172 * lmrDepth <= alpha
- && thisThread->mainHistory[us][from_to(move)]
- + (*contHist[0])[movedPiece][to_sq(move)]
+ && (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
- + (*contHist[3])[movedPiece][to_sq(move)] < 25000)
+ + (*contHist[3])[movedPiece][to_sq(move)] < 27400)
continue;
// Prune moves with negative SEE (~20 Elo)
&& tte->depth() >= depth - 3
&& pos.legal(move))
{
- Value singularBeta = ttValue - (((ttPv && !PvNode) + 4) * depth) / 2;
- Depth halfDepth = depth / 2;
+ Value singularBeta = ttValue - ((formerPv + 4) * depth) / 2;
+ Depth singularDepth = (depth - 1 + 3 * formerPv) / 2;
ss->excludedMove = move;
- value = search<NonPV>(pos, ss, singularBeta - 1, singularBeta, halfDepth, cutNode);
+ value = search<NonPV>(pos, ss, singularBeta - 1, singularBeta, singularDepth, cutNode);
ss->excludedMove = MOVE_NONE;
if (value < singularBeta)
if (ttPv)
r -= 2;
+ if (moveCountPruning && !formerPv)
+ r++;
+
// Decrease reduction if opponent's move count is high (~5 Elo)
if ((ss-1)->moveCount > 14)
r--;
// Decrease reduction if ttMove has been singularly extended (~3 Elo)
if (singularLMR)
- r -= 2;
+ r -= 1 + formerPv;
if (!captureOrPromotion)
{
+ (*contHist[3])[movedPiece][to_sq(move)]
- 4926;
- // Reset statScore to zero if negative and most stats shows >= 0
- if ( ss->statScore < 0
- && (*contHist[0])[movedPiece][to_sq(move)] >= 0
- && (*contHist[1])[movedPiece][to_sq(move)] >= 0
- && thisThread->mainHistory[us][from_to(move)] >= 0)
- ss->statScore = 0;
-
// Decrease/increase reduction by comparing opponent's stat score (~10 Elo)
if (ss->statScore >= -102 && (ss-1)->statScore < -114)
r--;
r++;
// Decrease/increase reduction for moves with a good/bad history (~30 Elo)
- r -= ss->statScore / 16384;
+ r -= ss->statScore / 16434;
}
// Increase reduction for captures/promotions if late move and at low depth
else if (depth < 8 && moveCount > 2)
r++;
- Depth d = clamp(newDepth - r, 1, newDepth);
+ Depth d = Utility::clamp(newDepth - r, 1, newDepth);
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
- doFullDepthSearch = (value > alpha && d != newDepth), didLMR = true;
+ doFullDepthSearch = value > alpha && d != newDepth;
+
+ didLMR = true;
}
else
- doFullDepthSearch = !PvNode || moveCount > 1, didLMR = false;
+ {
+ doFullDepthSearch = !PvNode || moveCount > 1;
+
+ didLMR = false;
+ }
// Step 17. Full depth search when LMR is skipped or fails high
if (doFullDepthSearch)
if (PvNode)
bestValue = std::min(bestValue, maxValue);
- if (!excludedMove)
+ if (!excludedMove && !(rootNode && thisThread->pvIdx))
tte->save(posKey, value_to_tt(bestValue, ss->ply), ttPv,
bestValue >= beta ? BOUND_LOWER :
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
else
ss->staticEval = bestValue =
(ss-1)->currentMove != MOVE_NULL ? evaluate(pos)
- : -(ss-1)->staticEval + 2 * Eval::Tempo;
+ : -(ss-1)->staticEval + 2 * Tempo;
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta)
{
if (!ttHit)
- tte->save(posKey, value_to_tt(bestValue, ss->ply), pvHit, BOUND_LOWER,
+ tte->save(posKey, value_to_tt(bestValue, ss->ply), false, BOUND_LOWER,
DEPTH_NONE, MOVE_NONE, ss->staticEval);
return bestValue;
// update_continuation_histories() updates histories of the move pairs formed
- // by moves at ply -1, -2, and -4 with current move.
+ // by moves at ply -1, -2, -4, and -6 with current move.
void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) {
projects / stockfish / blobdiff