- // Decrease reduction if position is or has been on the PV
- // and node is not likely to fail low. (~3 Elo)
- if ( ss->ttPv
- && !likelyFailLow)
- r -= 2;
-
- // Decrease reduction if opponent's move count is high (~1 Elo)
- if ((ss-1)->moveCount > 7)
- r--;
-
- // Increase reduction for cut nodes (~3 Elo)
- if (cutNode && move != ss->killers[0])
- r += 2;
-
- // Increase reduction if ttMove is a capture (~3 Elo)
- if (ttCapture)
- r++;
-
- // Decrease reduction for PvNodes based on depth
- if (PvNode)
- r -= 1 + 15 / ( 3 + depth );
-
- // Increase reduction if next ply has a lot of fail high else reset count to 0
- if ((ss+1)->cutoffCnt > 3 && !PvNode)
- 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)]
- - 4334;
-
- // Decrease/increase reduction for moves with a good/bad history (~30 Elo)
- r -= ss->statScore / 15914;
-
- // 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 to be searched
- // deeper than the first move (this may lead to hidden double extensions).
- int deeper = r >= -1 ? 0
- : moveCount <= 4 ? 2
- : PvNode || cutNode ? 1
- : 0;
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);