void Search::init() {
for (int i = 1; i < MAX_MOVES; ++i)
- Reductions[i] = int(21.3 * std::log(i + 0.25 * std::log(i)));
+ Reductions[i] = int(21.9 * std::log(i));
}
ss->staticEval = eval = -(ss-1)->staticEval;
// Save static evaluation into transposition table
+ if(!excludedMove)
tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval);
}
// Step 7. Futility pruning: child node (~50 Elo)
if ( !PvNode
- && depth < 9
&& eval - futility_margin(depth, improving) >= beta
&& eval < VALUE_KNOWN_WIN) // Do not return unproven wins
return eval;
&& !ttMove)
depth -= 2;
-moves_loop: // When in check, search starts from here
+moves_loop: // When in check, search starts here
ttCapture = ttMove && pos.capture_or_promotion(ttMove);
{
// Continuation history based pruning (~20 Elo)
if ( lmrDepth < 5
- && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
- && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
+ && (*contHist[0])[movedPiece][to_sq(move)] < (depth == 1 ? 0 : -stat_bonus(depth-1))
+ && (*contHist[1])[movedPiece][to_sq(move)] < (depth == 1 ? 0 : -stat_bonus(depth-1)))
continue;
// Futility pruning: parent node (~5 Elo)
- if ( lmrDepth < 7
- && !ss->inCheck
+ if ( !ss->inCheck
&& ss->staticEval + 174 + 157 * lmrDepth <= alpha
&& (*contHist[0])[movedPiece][to_sq(move)]
+ (*contHist[1])[movedPiece][to_sq(move)]
r--;
// Increase reduction for cut nodes (~3 Elo)
- if (cutNode)
- r += 1 + !captureOrPromotion;
+ if (cutNode && move != ss->killers[0])
+ r += 2;
- if (!captureOrPromotion)
- {
- // Increase reduction if ttMove is a capture (~3 Elo)
- if (ttCapture)
- r++;
-
- ss->statScore = thisThread->mainHistory[us][from_to(move)]
- + (*contHist[0])[movedPiece][to_sq(move)]
- + (*contHist[1])[movedPiece][to_sq(move)]
- + (*contHist[3])[movedPiece][to_sq(move)]
- - 4923;
-
- // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
- if (!ss->inCheck)
- r -= ss->statScore / 14721;
- }
+ // Increase reduction if ttMove is a capture (~3 Elo)
+ if (ttCapture)
+ r++;
+
+ ss->statScore = thisThread->mainHistory[us][from_to(move)]
+ + (*contHist[0])[movedPiece][to_sq(move)]
+ + (*contHist[1])[movedPiece][to_sq(move)]
+ + (*contHist[3])[movedPiece][to_sq(move)]
+ - 4923;
+
+ // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
+ r -= ss->statScore / 14721;
// In general we want to cap the LMR depth search at newDepth. But if
// reductions are really negative and movecount is low, we allow this move
{
assert(is_ok(move));
+ // Check for legality
+ if (!pos.legal(move))
+ continue;
+
givesCheck = pos.gives_check(move);
captureOrPromotion = pos.capture_or_promotion(move);
// Speculative prefetch as early as possible
prefetch(TT.first_entry(pos.key_after(move)));
- // Check for legality just before making the move
- if (!pos.legal(move))
- {
- moveCount--;
- continue;
- }
-
ss->currentMove = move;
ss->continuationHistory = &thisThread->continuationHistory[ss->inCheck]
[captureOrPromotion]