// Step 7. Futility pruning: child node (~50 Elo).
// The depth condition is important for mate finding.
- if ( !PvNode
+ if ( !ss->ttPv
&& depth < 9
&& eval - futility_margin(depth, improving) >= beta
&& eval < 15000) // 50% larger than VALUE_KNOWN_WIN, but smaller than TB wins.
}
else
{
+ int history = (*contHist[0])[movedPiece][to_sq(move)]
+ + (*contHist[1])[movedPiece][to_sq(move)]
+ + (*contHist[3])[movedPiece][to_sq(move)];
+
// Continuation history based pruning (~20 Elo)
- if (lmrDepth < 5
- && (*contHist[0])[movedPiece][to_sq(move)]
- + (*contHist[1])[movedPiece][to_sq(move)]
- + (*contHist[3])[movedPiece][to_sq(move)] < -3000 * depth + 3000)
+ if ( lmrDepth < 5
+ && history < -3000 * depth + 3000)
continue;
+ history += thisThread->mainHistory[us][from_to(move)];
+
// Futility pruning: parent node (~5 Elo)
if ( !ss->inCheck
&& lmrDepth < 8
- && ss->staticEval + 172 + 145 * lmrDepth <= alpha)
+ && ss->staticEval + 172 + 145 * lmrDepth + history / 128 <= alpha)
continue;
// Prune moves with negative SEE (~20 Elo)