Use a constant reduction instead of a depth dependent reduction.
passed STC:
http://tests.stockfishchess.org/tests/view/
5b06eb600ebc5914abc12ba8
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 58086 W: 11710 L: 11657 D: 34719
passed LTC:
http://tests.stockfishchess.org/tests/view/
5b07b25e0ebc5914abc12c6d
LLR: 3.09 (-2.94,2.94) [-3.00,1.00]
Total: 110414 W: 16217 L: 16219 D: 77978
Bench:
4521056
if ( depth >= 8 * ONE_PLY
&& !ttMove)
{
- Depth d = 3 * depth / 4 - 2 * ONE_PLY;
- search<NT>(pos, ss, alpha, beta, d, cutNode);
+ search<NT>(pos, ss, alpha, beta, depth - 7 * ONE_PLY, cutNode);
tte = TT.probe(posKey, ttHit);
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;