// Multi-cut pruning
// Our ttMove is assumed to fail high, and now we failed high also on a reduced
// search without the ttMove. So we assume this expected Cut-node is not singular,
- // that is multiple moves fail high, and we can prune the whole subtree by returning
- // the hard beta bound.
- else if (cutNode && singularBeta > beta)
- return beta;
+ // that multiple moves fail high, and we can prune the whole subtree by returning
+ // a soft bound.
+ else if ( eval >= beta
+ && singularBeta >= beta)
+ return singularBeta;
}
// Check extension (~2 Elo)
else if ( PvNode
&& pos.rule50_count() > 18
&& depth < 3 * ONE_PLY
- && ss->ply < 3 * thisThread->rootDepth / ONE_PLY) // To avoid too deep searches
+ && ++thisThread->shuffleExts < thisThread->nodes.load(std::memory_order_relaxed) / 4) // To avoid too many extensions
extension = ONE_PLY;
// Passed pawn extension
if (dtz_available || rootMoves[0].tbScore <= VALUE_DRAW)
Cardinality = 0;
}
+ else
+ {
+ // Clean up if root_probe() and root_probe_wdl() have failed
+ for (auto& m : rootMoves)
+ m.tbRank = 0;
+ }
}