// RootMoveList struct is mainly a std::vector of RootMove objects
struct RootMoveList : public std::vector<RootMove> {
void init(Position& pos, Move searchMoves[]);
- RootMove* find(const Move &m);
+ RootMove* find(const Move &m, const int startIndex = 0);
int bestMoveChanges;
};
RootMoveList Rml;
// MultiPV mode
- int MultiPV, UCIMultiPV;
+ int MultiPV, UCIMultiPV, MultiPVIteration;
// Time management variables
bool StopOnPonderhit, FirstRootMove, StopRequest, QuitRequest, AspirationFailLow;
H.clear();
*ponderMove = bestMove = easyMove = skillBest = skillPonder = MOVE_NONE;
depth = aspirationDelta = 0;
- alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
+ value = alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update_gains()
// Moves to search are verified and copied
{
Rml.bestMoveChanges = 0;
- // Calculate dynamic aspiration window based on previous iterations
- if (MultiPV == 1 && depth >= 5 && abs(bestValues[depth - 1]) < VALUE_KNOWN_WIN)
- {
- int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2];
- int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3];
-
- aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
- aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
+ // Remember best moves and values from previous iteration
+ std::vector<Move> prevMoves;
+ std::vector<Value> prevValues;
- alpha = Max(bestValues[depth - 1] - aspirationDelta, -VALUE_INFINITE);
- beta = Min(bestValues[depth - 1] + aspirationDelta, VALUE_INFINITE);
+ for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++)
+ {
+ prevMoves.push_back(Rml[i].pv[0]);
+ prevValues.push_back(Rml[i].pv_score);
}
- // Start with a small aspiration window and, in case of fail high/low,
- // research with bigger window until not failing high/low anymore.
- do {
- // Search starting from ss+1 to allow calling update_gains()
- value = search<Root>(pos, ss+1, alpha, beta, depth * ONE_PLY);
-
- // It is critical that sorting is done with a stable algorithm
- // because all the values but the first are usually set to
- // -VALUE_INFINITE and we want to keep the same order for all
- // the moves but the new PV that goes to head.
- sort<RootMove>(Rml.begin(), Rml.end());
-
- // Write PV back to transposition table in case the relevant entries
- // have been overwritten during the search.
- for (int i = 0; i < Min(MultiPV, (int)Rml.size()); i++)
- Rml[i].insert_pv_in_tt(pos);
-
- // Value cannot be trusted. Break out immediately!
- if (StopRequest)
- break;
-
- // Send full PV info to GUI if we are going to leave the loop or
- // if we have a fail high/low and we are deep in the search.
- if ((value > alpha && value < beta) || current_search_time() > 2000)
- for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
- cout << "info"
- << depth_to_uci(depth * ONE_PLY)
- << score_to_uci(Rml[i].pv_score, alpha, beta)
- << speed_to_uci(pos.nodes_searched())
- << pv_to_uci(Rml[i].pv, i + 1, pos.is_chess960()) << endl;
-
- // In case of failing high/low increase aspiration window and research,
- // otherwise exit the fail high/low loop.
- if (value >= beta)
- {
- beta = Min(beta + aspirationDelta, VALUE_INFINITE);
- aspirationDelta += aspirationDelta / 2;
- }
- else if (value <= alpha)
+ // MultiPV iteration loop
+ for (MultiPVIteration = 0; MultiPVIteration < Min(MultiPV, (int)Rml.size()); MultiPVIteration++)
+ {
+ // Calculate dynamic aspiration window based on previous iterations
+ if (depth >= 5 && abs(prevValues[MultiPVIteration]) < VALUE_KNOWN_WIN)
{
- AspirationFailLow = true;
- StopOnPonderhit = false;
+ int prevDelta1 = bestValues[depth - 1] - bestValues[depth - 2];
+ int prevDelta2 = bestValues[depth - 2] - bestValues[depth - 3];
+
+ aspirationDelta = Min(Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16), 24);
+ aspirationDelta = (aspirationDelta + 7) / 8 * 8; // Round to match grainSize
- alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
- aspirationDelta += aspirationDelta / 2;
+ alpha = Max(prevValues[MultiPVIteration] - aspirationDelta, -VALUE_INFINITE);
+ beta = Min(prevValues[MultiPVIteration] + aspirationDelta, VALUE_INFINITE);
}
else
- break;
+ {
+ alpha = -VALUE_INFINITE;
+ beta = VALUE_INFINITE;
+ }
- } while (abs(value) < VALUE_KNOWN_WIN);
+ // Start with a small aspiration window and, in case of fail high/low,
+ // research with bigger window until not failing high/low anymore.
+ do {
+ // Search starting from ss+1 to allow calling update_gains()
+ value = search<Root>(pos, ss+1, alpha, beta, depth * ONE_PLY);
+
+ // It is critical that sorting is done with a stable algorithm
+ // because all the values but the first are usually set to
+ // -VALUE_INFINITE and we want to keep the same order for all
+ // the moves but the new PV that goes to head.
+ if (value > alpha && value < beta)
+ sort<RootMove>(Rml.begin(), Rml.end());
+ else
+ // In MultiPV mode, sort only the tail of the list
+ // until all fail-highs and fail-lows have been resolved
+ sort<RootMove>(Rml.begin() + MultiPVIteration, Rml.end());
+
+ // Write PV back to transposition table in case the relevant entries
+ // have been overwritten during the search.
+ for (int i = 0; i <= MultiPVIteration; i++)
+ Rml[i].insert_pv_in_tt(pos);
+
+ // Value cannot be trusted. Break out immediately!
+ if (StopRequest)
+ break;
+
+ // Send full PV info to GUI if we are going to leave the loop or
+ // if we have a fail high/low and we are deep in the search.
+ if ((value > alpha && value < beta) || current_search_time() > 2000)
+ for (int i = 0; i < Min(UCIMultiPV, (int)Rml.size()); i++)
+ {
+ bool updated = (i <= MultiPVIteration);
+ bool match = (i == MultiPVIteration);
+
+ if (!updated && depth == 1)
+ continue;
+
+ cout << "info"
+ << depth_to_uci((updated ? depth : depth - 1) * ONE_PLY)
+ << score_to_uci(updated ? Rml[i].pv_score : prevValues[i],
+ match ? alpha : -VALUE_INFINITE,
+ match ? beta : VALUE_INFINITE)
+ << speed_to_uci(pos.nodes_searched())
+ << pv_to_uci(updated ? Rml[i].pv : Rml.find(prevMoves[i])->pv,
+ i + 1, pos.is_chess960())
+ << endl;
+ }
+
+ // In case of failing high/low increase aspiration window and research,
+ // otherwise exit the fail high/low loop.
+ if (value >= beta)
+ {
+ beta = Min(beta + aspirationDelta, VALUE_INFINITE);
+ aspirationDelta += aspirationDelta / 2;
+ }
+ else if (value <= alpha)
+ {
+ AspirationFailLow = true;
+ StopOnPonderhit = false;
+
+ alpha = Max(alpha - aspirationDelta, -VALUE_INFINITE);
+ aspirationDelta += aspirationDelta / 2;
+ }
+ else
+ break;
+
+ } while (abs(value) < VALUE_KNOWN_WIN);
+ }
// Collect info about search result
bestMove = Rml[0].pv[0];
split_point_start: // At split points actual search starts from here
// Initialize a MovePicker object for the current position
- MovePickerExt<NT> mp(pos, RootNode ? Rml[0].pv[0] : ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
+ MovePickerExt<NT> mp(pos, RootNode ? Rml[MultiPVIteration].pv[0] : ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
ss->bestMove = MOVE_NONE;
futilityBase = ss->eval + ss->evalMargin;
if (move == excludedMove)
continue;
- // At root obey the "searchmoves" option and skip moves not listed in Root Move List
- if (RootNode && !Rml.find(move))
+ // At root obey the "searchmoves" option and skip moves not listed in Root Move List.
+ // Also in MultiPV mode we skip moves which already have got an exact score
+ // in previous MultiPV Iteration.
+ if (RootNode && !Rml.find(move, MultiPVIteration))
continue;
// At PV and SpNode nodes we want all moves to be legal since the beginning
// For long searches send current move info to GUI
if (current_search_time() > 2000)
cout << "info" << depth_to_uci(depth)
- << " currmove " << move << " currmovenumber " << moveCount << endl;
+ << " currmove " << move << " currmovenumber " << moveCount + MultiPVIteration << endl;
}
// At Root and at first iteration do a PV search on all the moves to score root moves
- isPvMove = (PvNode && moveCount <= (!RootNode ? 1 : depth <= ONE_PLY ? MAX_MOVES : MultiPV));
+ isPvMove = (PvNode && moveCount <= ((RootNode && depth <= ONE_PLY) ? MAX_MOVES : 1));
givesCheck = pos.move_gives_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
}
}
- RootMove* RootMoveList::find(const Move &m) {
+ RootMove* RootMoveList::find(const Move &m, const int startIndex) {
- for (int i = 0; i < int(size()); i++)
+ for (int i = startIndex; i < int(size()); i++)
{
if ((*this)[i].pv[0] == m)
return &(*this)[i];