TimeManager TimeMgr;
int BestMoveChanges;
Value DrawValue[COLOR_NB];
- History Hist;
- Gains Gain;
+ HistoryStats History;
+ GainsStats Gains;
+ CountermovesStats Countermoves;
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
// Init futility move count array
for (d = 0; d < 32; d++)
- FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(double(d), 2.0));
+ FutilityMoveCounts[d] = int(3.001 + 0.3 * pow(double(d), 1.8));
}
size_t cnt = 0;
CheckInfo ci(pos);
- for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
+ for (MoveList<LEGAL> it(pos); *it; ++it)
{
- pos.do_move(ml.move(), st, ci, pos.move_gives_check(ml.move(), ci));
+ pos.do_move(*it, st, ci, pos.move_gives_check(*it, ci));
cnt += perft(pos, depth - ONE_PLY);
- pos.undo_move(ml.move());
+ pos.undo_move(*it);
}
return cnt;
finalize:
+ // When search is stopped this info is not printed
+ sync_cout << "info nodes " << RootPos.nodes_searched()
+ << " time " << Time::now() - SearchTime + 1 << sync_endl;
+
// When we reach max depth we arrive here even without Signals.stop is raised,
// but if we are pondering or in infinite search, according to UCI protocol,
// we shouldn't print the best move before the GUI sends a "stop" or "ponderhit"
bestValue = delta = -VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update gains
TT.new_search();
- Hist.clear();
- Gain.clear();
+ History.clear();
+ Gains.clear();
+ Countermoves.clear();
PVSize = Options["MultiPV"];
Skill skill(Options["Skill Level"]);
bestValue = -VALUE_INFINITE;
ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
+ ss->futilityMoveCount = 0;
(ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
&& type_of(move) == NORMAL)
{
Square to = to_sq(move);
- Gain.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
+ Gains.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
}
// Step 6. Razoring (is omitted in PV nodes)
&& !ss->skipNullMove
&& depth < 4 * ONE_PLY
&& !inCheck
- && eval - futility_margin(depth, (ss-1)->futMc) >= beta
+ && eval - futility_margin(depth, (ss-1)->futilityMoveCount) >= beta
&& abs(beta) < VALUE_MATE_IN_MAX_PLY
+ && abs(eval) < VALUE_KNOWN_WIN
&& pos.non_pawn_material(pos.side_to_move()))
- return eval - futility_margin(depth, (ss-1)->futMc);
+ return eval - futility_margin(depth, (ss-1)->futilityMoveCount);
// Step 8. Null move search with verification search (is omitted in PV nodes)
if ( !PvNode
assert((ss-1)->currentMove != MOVE_NONE);
assert((ss-1)->currentMove != MOVE_NULL);
- MovePicker mp(pos, ttMove, Hist, pos.captured_piece_type());
+ MovePicker mp(pos, ttMove, History, pos.captured_piece_type());
CheckInfo ci(pos);
while ((move = mp.next_move<false>()) != MOVE_NONE)
split_point_start: // At split points actual search starts from here
- MovePicker mp(pos, ttMove, depth, Hist, ss, PvNode ? -VALUE_INFINITE : beta);
+ Square prevMoveSq = to_sq((ss-1)->currentMove);
+ Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
+ Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
+
+ MovePicker mp(pos, ttMove, depth, History, countermoves, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
singularExtensionNode = !RootNode
// Update current move (this must be done after singular extension search)
newDepth = depth - ONE_PLY + ext;
- ss->futMc = 0;
-
// Step 13. Futility pruning (is omitted in PV nodes)
if ( !PvNode
&& !captureOrPromotion
// Value based pruning
// We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth,
// but fixing this made program slightly weaker.
- ss->futMc = moveCount;
-
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
futilityValue = ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
- + Gain[pos.piece_moved(move)][to_sq(move)];
+ + Gains[pos.piece_moved(move)][to_sq(move)];
if (futilityValue < beta)
{
continue;
}
+
+ // We have not pruned the move that will be searched, but remember how
+ // far in the move list we are to be more aggressive in the child node.
+ ss->futilityMoveCount = moveCount;
}
+ else
+ ss->futilityMoveCount = 0;
// Check for legality only before to do the move
if (!RootNode && !SpNode && !pos.pl_move_is_legal(move, ci.pinned))
&& move != ss->killers[1])
{
ss->reduction = reduction<PvNode>(depth, moveCount);
+ if (move == countermoves[0] || move == countermoves[1])
+ ss->reduction = std::max(DEPTH_ZERO, ss->reduction-ONE_PLY);
+
Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
if (SpNode)
alpha = splitPoint->alpha;
// Increase history value of the cut-off move
Value bonus = Value(int(depth) * int(depth));
- Hist.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
+ History.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
+ if (is_ok((ss-1)->currentMove))
+ Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, bestMove);
// Decrease history of all the other played non-capture moves
for (int i = 0; i < playedMoveCount - 1; i++)
{
Move m = movesSearched[i];
- Hist.update(pos.piece_moved(m), to_sq(m), -bonus);
+ History.update(pos.piece_moved(m), to_sq(m), -bonus);
}
}
}
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
- MovePicker mp(pos, ttMove, depth, Hist, to_sq((ss-1)->currentMove));
+ MovePicker mp(pos, ttMove, depth, History, to_sq((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
// Prune moves with negative or equal SEE and also moves with positive
// SEE where capturing piece loses a tempo and SEE < beta - futilityBase.
if ( futilityBase < beta
- && depth < DEPTH_ZERO
&& pos.see(move, beta - futilityBase) <= 0)
{
bestValue = std::max(bestValue, futilityBase);