Remove nine boolean arguments and the corresponding skipEarlyPruning variable.
Instead, skip early pruning only when there is an excluded move, and try null
move pruning only if the previous move was not itself a null move.
passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 33623 W: 6853 L: 6755 D: 20015
http://tests.stockfishchess.org/tests/view/
5aef462a0ebc5902a409a10e
passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39474 W: 5882 L: 5789 D: 27803
http://tests.stockfishchess.org/tests/view/
5aefd4b80ebc5902a409a164
Closes https://github.com/official-stockfish/Stockfish/pull/1585
Bench:
4953556
};
template <NodeType NT>
};
template <NodeType NT>
- Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning);
+ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
template <NodeType NT>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth = DEPTH_ZERO);
template <NodeType NT>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth = DEPTH_ZERO);
// high/low anymore.
while (true)
{
// high/low anymore.
while (true)
{
- bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false, false);
+ bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false);
// Bring the best move to the front. It is critical that sorting
// is done with a stable algorithm because all the values but the
// Bring the best move to the front. It is critical that sorting
// is done with a stable algorithm because all the values but the
// search<>() is the main search function for both PV and non-PV nodes
template <NodeType NT>
// search<>() is the main search function for both PV and non-PV nodes
template <NodeType NT>
- Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning) {
+ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
// Use quiescence search when needed
if (depth < ONE_PLY)
// Use quiescence search when needed
if (depth < ONE_PLY)
improving = ss->staticEval >= (ss-2)->staticEval
||(ss-2)->staticEval == VALUE_NONE;
improving = ss->staticEval >= (ss-2)->staticEval
||(ss-2)->staticEval == VALUE_NONE;
- if (skipEarlyPruning || !pos.non_pawn_material(pos.side_to_move()))
+ if (ss->excludedMove || !pos.non_pawn_material(pos.side_to_move()))
goto moves_loop;
// Step 7. Razoring (skipped when in check, ~2 Elo)
goto moves_loop;
// Step 7. Razoring (skipped when in check, ~2 Elo)
// Step 9. Null move search with verification search (~40 Elo)
if ( !PvNode
// Step 9. Null move search with verification search (~40 Elo)
if ( !PvNode
+ && (ss-1)->currentMove != MOVE_NULL
&& eval >= beta
&& ss->staticEval >= beta - 36 * depth / ONE_PLY + 225
&& (ss->ply >= thisThread->nmp_ply || ss->ply % 2 != thisThread->nmp_odd))
&& eval >= beta
&& ss->staticEval >= beta - 36 * depth / ONE_PLY + 225
&& (ss->ply >= thisThread->nmp_ply || ss->ply % 2 != thisThread->nmp_odd))
- Value nullValue = -search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true);
+ Value nullValue = -search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
thisThread->nmp_ply = ss->ply + 3 * (depth-R) / 4;
thisThread->nmp_odd = ss->ply % 2;
thisThread->nmp_ply = ss->ply + 3 * (depth-R) / 4;
thisThread->nmp_odd = ss->ply % 2;
- Value v = search<NonPV>(pos, ss, beta-1, beta, depth-R, false, true);
+ Value v = search<NonPV>(pos, ss, beta-1, beta, depth-R, false);
thisThread->nmp_odd = thisThread->nmp_ply = 0;
thisThread->nmp_odd = thisThread->nmp_ply = 0;
&& depth >= 5 * ONE_PLY
&& abs(beta) < VALUE_MATE_IN_MAX_PLY)
{
&& depth >= 5 * ONE_PLY
&& abs(beta) < VALUE_MATE_IN_MAX_PLY)
{
- assert(is_ok((ss-1)->currentMove));
-
Value rbeta = std::min(beta + 216 - 48 * improving, VALUE_INFINITE);
MovePicker mp(pos, ttMove, rbeta - ss->staticEval, &thisThread->captureHistory);
int probCutCount = 0;
Value rbeta = std::min(beta + 216 - 48 * improving, VALUE_INFINITE);
MovePicker mp(pos, ttMove, rbeta - ss->staticEval, &thisThread->captureHistory);
int probCutCount = 0;
// If the qsearch held perform the regular search
if (value >= rbeta)
// If the qsearch held perform the regular search
if (value >= rbeta)
- value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode, false);
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode);
&& !ttMove)
{
Depth d = 3 * depth / 4 - 2 * ONE_PLY;
&& !ttMove)
{
Depth d = 3 * depth / 4 - 2 * ONE_PLY;
- search<NT>(pos, ss, alpha, beta, d, cutNode, true);
+ search<NT>(pos, ss, alpha, beta, d, cutNode);
tte = TT.probe(posKey, ttHit);
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
tte = TT.probe(posKey, ttHit);
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
{
Value rBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE);
ss->excludedMove = move;
{
Value rBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE);
ss->excludedMove = move;
- value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode, true);
+ value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode);
ss->excludedMove = MOVE_NONE;
if (value < rBeta)
ss->excludedMove = MOVE_NONE;
if (value < rBeta)
Depth d = std::max(newDepth - r, ONE_PLY);
Depth d = std::max(newDepth - r, ONE_PLY);
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true, false);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
doFullDepthSearch = (value > alpha && d != newDepth);
}
doFullDepthSearch = (value > alpha && d != newDepth);
}
// Step 17. Full depth search when LMR is skipped or fails high
if (doFullDepthSearch)
// Step 17. Full depth search when LMR is skipped or fails high
if (doFullDepthSearch)
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode, false);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
// For PV nodes only, do a full PV search on the first move or after a fail
// high (in the latter case search only if value < beta), otherwise let the
// For PV nodes only, do a full PV search on the first move or after a fail
// high (in the latter case search only if value < beta), otherwise let the
(ss+1)->pv = pv;
(ss+1)->pv[0] = MOVE_NONE;
(ss+1)->pv = pv;
(ss+1)->pv[0] = MOVE_NONE;
- value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, false, false);
+ value = -search<PV>(pos, ss+1, -beta, -alpha, newDepth, false);