namespace {
// Different node types, used as a template parameter
- enum NodeType { Root, PV, NonPV };
+ enum NodeType { NonPV, PV };
// Razoring and futility margin based on depth
const int razor_margin[4] = { 483, 570, 603, 554 };
}
else
{
- if (TB::Cardinality >= rootPos.count<ALL_PIECES>(WHITE)
- + rootPos.count<ALL_PIECES>(BLACK))
+ if ( TB::Cardinality >= rootPos.count<ALL_PIECES>(WHITE)
+ + rootPos.count<ALL_PIECES>(BLACK)
+ && !rootPos.can_castle(ANY_CASTLING))
{
// If the current root position is in the tablebases, then RootMoves
// contains only moves that preserve the draw or the win.
// high/low anymore.
while (true)
{
- bestValue = ::search<Root>(rootPos, ss, alpha, beta, rootDepth, 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
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
- const bool RootNode = NT == Root;
- const bool PvNode = NT == PV || NT == Root;
+ const bool PvNode = NT == PV;
+ const bool rootNode = PvNode && (ss-1)->ply == 0;
assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE);
assert(PvNode || (alpha == beta - 1));
if (PvNode && thisThread->maxPly < ss->ply)
thisThread->maxPly = ss->ply;
- if (!RootNode)
+ if (!rootNode)
{
// Step 2. Check for aborted search and immediate draw
if (Signals.stop.load(std::memory_order_relaxed) || pos.is_draw() || ss->ply >= MAX_PLY)
posKey = excludedMove ? pos.exclusion_key() : pos.key();
tte = TT.probe(posKey, ttHit);
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
- ttMove = RootNode ? thisThread->rootMoves[thisThread->PVIdx].pv[0]
+ ttMove = rootNode ? thisThread->rootMoves[thisThread->PVIdx].pv[0]
: ttHit ? tte->move() : MOVE_NONE;
// At non-PV nodes we check for an early TT cutoff
}
// Step 4a. Tablebase probe
- if (!RootNode && TB::Cardinality)
+ if (!rootNode && TB::Cardinality)
{
int piecesCnt = pos.count<ALL_PIECES>(WHITE) + pos.count<ALL_PIECES>(BLACK);
if ( piecesCnt <= TB::Cardinality
&& (piecesCnt < TB::Cardinality || depth >= TB::ProbeDepth)
- && pos.rule50_count() == 0)
+ && pos.rule50_count() == 0
+ && !pos.can_castle(ANY_CASTLING))
{
int found, v = Tablebases::probe_wdl(pos, &found);
}
// Step 7. Futility pruning: child node (skipped when in check)
- if ( !RootNode
+ if ( !rootNode
&& depth < 7 * ONE_PLY
&& eval - futility_margin(depth) >= beta
&& eval < VALUE_KNOWN_WIN // Do not return unproven wins
{
Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
ss->skipEarlyPruning = true;
- search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d, true);
+ search<NT>(pos, ss, alpha, beta, d, true);
ss->skipEarlyPruning = false;
tte = TT.probe(posKey, ttHit);
|| ss->staticEval == VALUE_NONE
||(ss-2)->staticEval == VALUE_NONE;
- singularExtensionNode = !RootNode
+ singularExtensionNode = !rootNode
&& depth >= 8 * ONE_PLY
&& ttMove != MOVE_NONE
/* && ttValue != VALUE_NONE Already implicit in the next condition */
// At root obey the "searchmoves" option and skip moves not listed in Root
// Move List. As a consequence any illegal move is also skipped. In MultiPV
// mode we also skip PV moves which have been already searched.
- if (RootNode && !std::count(thisThread->rootMoves.begin() + thisThread->PVIdx,
+ if (rootNode && !std::count(thisThread->rootMoves.begin() + thisThread->PVIdx,
thisThread->rootMoves.end(), move))
continue;
ss->moveCount = ++moveCount;
- if (RootNode && thisThread == Threads.main() && Time.elapsed() > 3000)
+ if (rootNode && thisThread == Threads.main() && Time.elapsed() > 3000)
sync_cout << "info depth " << depth / ONE_PLY
<< " currmove " << UCI::move(move, pos.is_chess960())
<< " currmovenumber " << moveCount + thisThread->PVIdx << sync_endl;
newDepth = depth - ONE_PLY + extension;
// Step 13. Pruning at shallow depth
- if ( !RootNode
+ if ( !rootNode
&& !captureOrPromotion
&& !inCheck
&& !givesCheck
prefetch(TT.first_entry(pos.key_after(move)));
// Check for legality just before making the move
- if (!RootNode && !pos.legal(move, ci.pinned))
+ if (!rootNode && !pos.legal(move, ci.pinned))
{
ss->moveCount = --moveCount;
continue;
// 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
// parent node fail low with value <= alpha and try another move.
- if (PvNode && (moveCount == 1 || (value > alpha && (RootNode || value < beta))))
+ if (PvNode && (moveCount == 1 || (value > alpha && (rootNode || value < beta))))
{
(ss+1)->pv = pv;
(ss+1)->pv[0] = MOVE_NONE;
if (Signals.stop.load(std::memory_order_relaxed))
return VALUE_ZERO;
- if (RootNode)
+ if (rootNode)
{
RootMove& rm = *std::find(thisThread->rootMoves.begin(),
thisThread->rootMoves.end(), move);
bestMove = move;
- if (PvNode && !RootNode) // Update pv even in fail-high case
+ if (PvNode && !rootNode) // Update pv even in fail-high case
update_pv(ss->pv, move, (ss+1)->pv);
if (PvNode && value < beta) // Update alpha! Always alpha < beta
const bool PvNode = NT == PV;
- assert(NT == PV || NT == NonPV);
assert(InCheck == !!pos.checkers());
assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
assert(PvNode || (alpha == beta - 1));