tte->save(posKey, VALUE_NONE, ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval);
}
- // Step 7. Razoring (~2 Elo)
+ // Step 7. Razoring (~1 Elo)
if ( !rootNode // The required rootNode PV handling is not available in qsearch
&& depth < 2
&& eval <= alpha - RazorMargin)
improving = (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval >= (ss-4)->staticEval
|| (ss-4)->staticEval == VALUE_NONE) : ss->staticEval >= (ss-2)->staticEval;
- // Step 8. Futility pruning: child node (~30 Elo)
+ // Step 8. Futility pruning: child node (~50 Elo)
if ( !PvNode
&& depth < 6
&& eval - futility_margin(depth, improving) >= beta
}
}
- // Step 11. Internal iterative deepening (~2 Elo)
+ // Step 11. Internal iterative deepening (~1 Elo)
if (depth >= 7 && !ttMove)
{
search<NT>(pos, ss, alpha, beta, depth - 7, cutNode);
// Calculate new depth for this move
newDepth = depth - 1;
- // Step 13. Pruning at shallow depth (~170 Elo)
+ // Step 13. Pruning at shallow depth (~200 Elo)
if ( !rootNode
&& pos.non_pawn_material(us)
&& bestValue > VALUE_MATED_IN_MAX_PLY)
&& (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
continue;
- // Futility pruning: parent node (~2 Elo)
+ // Futility pruning: parent node (~5 Elo)
if ( lmrDepth < 6
&& !inCheck
&& ss->staticEval + 255 + 182 * lmrDepth <= alpha
+ (*contHist[3])[movedPiece][to_sq(move)] < 30000)
continue;
- // Prune moves with negative SEE (~10 Elo)
+ // Prune moves with negative SEE (~20 Elo)
if (!pos.see_ge(move, Value(-(32 - std::min(lmrDepth, 18)) * lmrDepth * lmrDepth)))
continue;
}
- else if (!pos.see_ge(move, Value(-194) * depth)) // (~20 Elo)
+ else if (!pos.see_ge(move, Value(-194) * depth)) // (~25 Elo)
continue;
}
- // Step 14. Extensions (~70 Elo)
+ // Step 14. Extensions (~75 Elo)
- // Singular extension search (~60 Elo). If all moves but one fail low on a
+ // Singular extension search (~70 Elo). If all moves but one fail low on a
// search of (alpha-s, beta-s), and just one fails high on (alpha, beta),
// then that move is singular and should be extended. To verify this we do
// a reduced search on all the other moves but the ttMove and if the
// Step 15. Make the move
pos.do_move(move, st, givesCheck);
- // Step 16. Reduced depth search (LMR). If the move fails high it will be
+ // Step 16. Reduced depth search (LMR, ~200 Elo). If the move fails high it will be
// re-searched at full depth.
if ( depth >= 3
&& moveCount > 1 + 2 * rootNode
if (th.marked())
r++;
- // Decrease reduction if position is or has been on the PV
+ // Decrease reduction if position is or has been on the PV (~10 Elo)
if (ttPv)
r -= 2;
- // Decrease reduction if opponent's move count is high (~10 Elo)
+ // Decrease reduction if opponent's move count is high (~5 Elo)
if ((ss-1)->moveCount > 14)
r--;
- // Decrease reduction if ttMove has been singularly extended
+ // Decrease reduction if ttMove has been singularly extended (~3 Elo)
if (singularLMR)
r -= 2;
if (!captureOrPromotion)
{
- // Increase reduction if ttMove is a capture (~0 Elo)
+ // Increase reduction if ttMove is a capture (~5 Elo)
if (ttCapture)
r++;
- // Increase reduction for cut nodes (~5 Elo)
+ // Increase reduction for cut nodes (~10 Elo)
if (cutNode)
r += 2;
// Decrease reduction for moves that escape a capture. Filter out
// castling moves, because they are coded as "king captures rook" and
- // hence break make_move(). (~5 Elo)
+ // hence break make_move(). (~2 Elo)
else if ( type_of(move) == NORMAL
&& !pos.see_ge(reverse_move(move)))
r -= 2;