void Search::init() {
for (int i = 1; i < MAX_MOVES; ++i)
- Reductions[i] = int((22.0 + 2 * std::log(Threads.size())) * std::log(i));
+ Reductions[i] = int((22.0 + 2 * std::log(Threads.size())) * std::log(i + 0.25 * std::log(i)));
}
// Start with a small aspiration window and, in the case of a fail
// high/low, re-search with a bigger window until we don't fail
// high/low anymore.
- int failedHighCnt = 0;
+ failedHighCnt = 0;
while (true)
{
Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt - searchAgainCounter);
constexpr bool PvNode = NT == PV;
const bool rootNode = PvNode && ss->ply == 0;
+ const Depth maxNextDepth = rootNode ? depth : depth + 1;
// Check if we have an upcoming move which draws by repetition, or
// if the opponent had an alternative move earlier to this position.
assert(eval - beta >= 0);
// Null move dynamic reduction based on depth and value
- Depth R = (817 + 71 * depth) / 213 + std::min(int(eval - beta) / 192, 3);
+ Depth R = (982 + 85 * depth) / 256 + std::min(int(eval - beta) / 192, 3);
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
&& captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] < 0)
continue;
- // Futility pruning for captures
- if ( !givesCheck
- && lmrDepth < 6
- && !(PvNode && abs(bestValue) < 2)
- && !ss->inCheck
- && ss->staticEval + 169 + 244 * lmrDepth
- + PieceValue[MG][type_of(pos.piece_on(to_sq(move)))] <= alpha)
- continue;
-
// See based pruning
if (!pos.see_ge(move, Value(-221) * depth)) // (~25 Elo)
continue;
if (ttCapture)
r++;
+ // Increase reduction at root if failing high
+ r += rootNode ? thisThread->failedHighCnt * thisThread->failedHighCnt * moveCount / 512 : 0;
+
// Increase reduction for cut nodes (~10 Elo)
if (cutNode)
r += 2;
(ss+1)->pv = pv;
(ss+1)->pv[0] = MOVE_NONE;
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, false);
+ value = -search<PV>(pos, ss+1, -beta, -alpha,
+ std::min(maxNextDepth, newDepth), false);
}
// Step 18. Undo move