// way we are guaranteed that PV moves are always sorted as first.
bool operator<(const RootMove& m) const {
return pv_score != m.pv_score ? pv_score < m.pv_score
- : non_pv_score <= m.non_pv_score;
+ : non_pv_score < m.non_pv_score;
}
- void set_pv(const Move newPv[]);
+
+ void extract_pv_from_tt(Position& pos);
+ void insert_pv_in_tt(Position& pos);
+ std::string pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine = 0);
int64_t nodes;
Value pv_score;
Value non_pv_score;
- Move move;
Move pv[PLY_MAX_PLUS_2];
};
- RootMove::RootMove() {
-
- nodes = 0;
- pv_score = non_pv_score = -VALUE_INFINITE;
- move = pv[0] = MOVE_NONE;
- }
-
- RootMove& RootMove::operator=(const RootMove& rm) {
-
- nodes = rm.nodes;
- pv_score = rm.pv_score;
- non_pv_score = rm.non_pv_score;
- move = rm.move;
- set_pv(rm.pv); // Skip costly full pv[] copy
- return *this;
- }
-
- void RootMove::set_pv(const Move newPv[]) {
-
- Move* p = pv;
-
- do *p++ = *newPv; while (*newPv++ != MOVE_NONE);
- }
-
// RootMoveList struct is essentially a std::vector<> of RootMove objects,
// with an handful of methods above the standard ones.
/// Local functions
Value id_loop(Position& pos, Move searchMoves[]);
- Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
+ Value root_search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, RootMoveList& rml);
template <NodeType PvNode, bool SpNode>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
void ponderhit();
void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack* ss, int size);
- void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value);
- void insert_pv_in_tt(const Position& pos, Move pv[]);
- void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]);
#if !defined(_MSC_VER)
void* init_thread(void* threadID);
Value id_loop(Position& pos, Move searchMoves[]) {
SearchStack ss[PLY_MAX_PLUS_2];
- Move pv[PLY_MAX_PLUS_2];
+ Depth depth;
Move EasyMove = MOVE_NONE;
Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
- // Moves to search are verified, copied, scored and sorted
+ // Moves to search are verified, scored and sorted
RootMoveList rml(pos, searchMoves);
// Handle special case of searching on a mate/stale position
return pos.is_check() ? -VALUE_MATE : VALUE_DRAW;
}
- // Print RootMoveList startup scoring to the standard output,
- // so to output information also for iteration 1.
- cout << set960(pos.is_chess960()) // Is enough to set once at the beginning
- << "info depth " << 1
- << "\ninfo depth " << 1
- << " score " << value_to_uci(rml[0].pv_score)
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv " << rml[0].move << "\n";
-
// Initialize
TT.new_search();
H.clear();
init_ss_array(ss, PLY_MAX_PLUS_2);
- pv[0] = pv[1] = MOVE_NONE;
ValueByIteration[1] = rml[0].pv_score;
Iteration = 1;
+ // Send initial RootMoveList scoring (iteration 1)
+ cout << set960(pos.is_chess960()) // Is enough to set once at the beginning
+ << "info depth " << Iteration
+ << "\n" << rml[0].pv_info_to_uci(pos, alpha, beta) << endl;
+
// Is one move significantly better than others after initial scoring ?
if ( rml.size() == 1
|| rml[0].pv_score > rml[1].pv_score + EasyMoveMargin)
- EasyMove = rml[0].move;
+ EasyMove = rml[0].pv[0];
// Iterative deepening loop
while (Iteration < PLY_MAX)
beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
}
- // Search to the current depth, rml is updated and sorted, alpha and beta could change
- value = root_search(pos, ss, pv, rml, &alpha, &beta);
+ depth = (Iteration - 2) * ONE_PLY + InitialDepth;
- // Write PV to transposition table, in case the relevant entries have
- // been overwritten during the search.
- insert_pv_in_tt(pos, pv);
+ // Search to the current depth, rml is updated and sorted
+ value = root_search(pos, ss, alpha, beta, depth, rml);
if (AbortSearch)
break; // Value cannot be trusted. Break out immediately!
ValueByIteration[Iteration] = value;
// Drop the easy move if differs from the new best move
- if (pv[0] != EasyMove)
+ if (rml[0].pv[0] != EasyMove)
EasyMove = MOVE_NONE;
if (UseTimeManagement)
// Stop search early if one move seems to be much better than the others
if ( Iteration >= 8
- && EasyMove == pv[0]
+ && EasyMove == rml[0].pv[0]
&& ( ( rml[0].nodes > (pos.nodes_searched() * 85) / 100
&& current_search_time() > TimeMgr.available_time() / 16)
||( rml[0].nodes > (pos.nodes_searched() * 98) / 100
<< " time " << current_search_time() << endl;
// Print the best move and the ponder move to the standard output
- if (pv[0] == MOVE_NONE || MultiPV > 1)
- {
- pv[0] = rml[0].move;
- pv[1] = MOVE_NONE;
- }
+ cout << "bestmove " << rml[0].pv[0];
- assert(pv[0] != MOVE_NONE);
-
- cout << "bestmove " << pv[0];
-
- if (pv[1] != MOVE_NONE)
- cout << " ponder " << pv[1];
+ if (rml[0].pv[1] != MOVE_NONE)
+ cout << " ponder " << rml[0].pv[1];
cout << endl;
LogFile << "\nNodes: " << pos.nodes_searched()
<< "\nNodes/second: " << nps(pos)
- << "\nBest move: " << move_to_san(pos, pv[0]);
+ << "\nBest move: " << move_to_san(pos, rml[0].pv[0]);
StateInfo st;
- pos.do_move(pv[0], st);
+ pos.do_move(rml[0].pv[0], st);
LogFile << "\nPonder move: "
- << move_to_san(pos, pv[1]) // Works also with MOVE_NONE
+ << move_to_san(pos, rml[0].pv[1]) // Works also with MOVE_NONE
<< endl;
}
return rml[0].pv_score;
// root_search() is the function which searches the root node. It is
- // similar to search_pv except that it uses a different move ordering
- // scheme, prints some information to the standard output and handles
- // the fail low/high loops.
-
- Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
+ // similar to search_pv except that it prints some information to the
+ // standard output and handles the fail low/high loops.
+ Value root_search(Position& pos, SearchStack* ss, Value alpha,
+ Value beta, Depth depth, RootMoveList& rml) {
StateInfo st;
CheckInfo ci(pos);
int64_t nodes;
Move move;
- Depth depth, ext, newDepth;
- Value value, alpha, beta;
+ Depth ext, newDepth;
+ Value value, oldAlpha;
bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
int researchCountFH, researchCountFL;
researchCountFH = researchCountFL = 0;
- alpha = *alphaPtr;
- beta = *betaPtr;
+ oldAlpha = alpha;
isCheck = pos.is_check();
- depth = (Iteration - 2) * ONE_PLY + InitialDepth;
// Step 1. Initialize node (polling is omitted at root)
ss->currentMove = ss->bestMove = MOVE_NONE;
// Pick the next root move, and print the move and the move number to
// the standard output.
- move = ss->currentMove = rml[i].move;
+ move = ss->currentMove = rml[i].pv[0];
if (current_search_time() >= 1000)
cout << "info currmove " << move
// We are failing high and going to do a research. It's important to update
// the score before research in case we run out of time while researching.
- rml[i].pv_score = value;
ss->bestMove = move;
- extract_pv_from_tt(pos, move, pv);
- rml[i].set_pv(pv);
+ rml[i].pv_score = value;
+ rml[i].extract_pv_from_tt(pos);
- // Print information to the standard output
- print_pv_info(pos, pv, alpha, beta, value);
+ // Inform GUI that PV has changed
+ cout << rml[i].pv_info_to_uci(pos, alpha, beta) << endl;
// Prepare for a research after a fail high, each time with a wider window
- *betaPtr = beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
+ beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
researchCountFH++;
} // End of fail high loop
// PV move or new best move!
// Update PV
- rml[i].pv_score = value;
ss->bestMove = move;
- extract_pv_from_tt(pos, move, pv);
- rml[i].set_pv(pv);
+ rml[i].pv_score = value;
+ rml[i].extract_pv_from_tt(pos);
- if (MultiPV == 1)
- {
- // We record how often the best move has been changed in each
- // iteration. This information is used for time managment: When
- // the best move changes frequently, we allocate some more time.
- if (i > 0)
- BestMoveChangesByIteration[Iteration]++;
+ // We record how often the best move has been changed in each
+ // iteration. This information is used for time managment: When
+ // the best move changes frequently, we allocate some more time.
+ if (MultiPV == 1 && i > 0)
+ BestMoveChangesByIteration[Iteration]++;
+
+ // Inform GUI that PV has changed, in case of multi-pv UCI protocol
+ // requires we send all the PV lines properly sorted.
+ rml.sort_multipv(i);
- // Print information to the standard output
- print_pv_info(pos, pv, alpha, beta, value);
+ for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++)
+ cout << rml[j].pv_info_to_uci(pos, alpha, beta, j) << endl;
+ // Update alpha. In multi-pv we don't use aspiration window
+ if (MultiPV == 1)
+ {
// Raise alpha to setup proper non-pv search upper bound
if (value > alpha)
alpha = value;
}
- else // MultiPV > 1
- {
- rml.sort_multipv(i);
- for (int j = 0; j < Min(MultiPV, (int)rml.size()); j++)
- {
- cout << "info multipv " << j + 1
- << " score " << value_to_uci(rml[j].pv_score)
- << " depth " << (j <= i ? Iteration : Iteration - 1)
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv ";
-
- for (int k = 0; rml[j].pv[k] != MOVE_NONE && k < PLY_MAX; k++)
- cout << rml[j].pv[k] << " ";
-
- cout << endl;
- }
+ else // Set alpha equal to minimum score among the PV lines
alpha = rml[Min(i, MultiPV - 1)].pv_score;
- }
+
} // PV move or new best move
- assert(alpha >= *alphaPtr);
+ assert(alpha >= oldAlpha);
- AspirationFailLow = (alpha == *alphaPtr);
+ AspirationFailLow = (alpha == oldAlpha);
if (AspirationFailLow && StopOnPonderhit)
StopOnPonderhit = false;
- }
+
+ } // Root moves loop
// Can we exit fail low loop ?
if (AbortSearch || !AspirationFailLow)
break;
// Prepare for a research after a fail low, each time with a wider window
- *alphaPtr = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
+ oldAlpha = alpha = Max(alpha - AspirationDelta * (1 << researchCountFL), -VALUE_INFINITE);
researchCountFL++;
} // Fail low loop
// Sort the moves before to return
rml.sort();
+ // Write PV lines to transposition table, in case the relevant entries
+ // have been overwritten during the search.
+ for (int i = 0; i < MultiPV; i++)
+ rml[i].insert_pv_in_tt(pos);
+
return alpha;
}
}
- // value_to_uci() converts a value to a string suitable for use with the UCI protocol
+ // value_to_uci() converts a value to a string suitable for use with the UCI
+ // protocol specifications:
+ //
+ // cp <x> The score from the engine's point of view in centipawns.
+ // mate <y> Mate in y moves, not plies. If the engine is getting mated
+ // use negative values for y.
std::string value_to_uci(Value v) {
std::stringstream s;
if (abs(v) < VALUE_MATE - PLY_MAX * ONE_PLY)
- s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to pawn = 100
+ s << "cp " << int(v) * 100 / int(PawnValueMidgame); // Scale to centipawns
else
s << "mate " << (v > 0 ? (VALUE_MATE - v + 1) / 2 : -(VALUE_MATE + v) / 2 );
}
- // print_pv_info() prints to standard output and eventually to log file information on
- // the current PV line. It is called at each iteration or after a new pv is found.
-
- void print_pv_info(const Position& pos, Move pv[], Value alpha, Value beta, Value value) {
-
- cout << "info depth " << Iteration
- << " score " << value_to_uci(value)
- << (value >= beta ? " lowerbound" : value <= alpha ? " upperbound" : "")
- << " time " << current_search_time()
- << " nodes " << pos.nodes_searched()
- << " nps " << nps(pos)
- << " pv ";
-
- for (Move* m = pv; *m != MOVE_NONE; m++)
- cout << *m << " ";
-
- cout << endl;
-
- if (UseLogFile)
- {
- ValueType t = value >= beta ? VALUE_TYPE_LOWER :
- value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
-
- LogFile << pretty_pv(pos, current_search_time(), Iteration, value, t, pv) << endl;
- }
- }
-
-
- // insert_pv_in_tt() is called at the end of a search iteration, and inserts
- // the PV back into the TT. This makes sure the old PV moves are searched
- // first, even if the old TT entries have been overwritten.
-
- void insert_pv_in_tt(const Position& pos, Move pv[]) {
-
- StateInfo st;
- TTEntry* tte;
- Position p(pos, pos.thread());
- Value v, m = VALUE_NONE;
-
- for (int i = 0; pv[i] != MOVE_NONE; i++)
- {
- tte = TT.retrieve(p.get_key());
- if (!tte || tte->move() != pv[i])
- {
- v = (p.is_check() ? VALUE_NONE : evaluate(p, m));
- TT.store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[i], v, m);
- }
- p.do_move(pv[i], st);
- }
- }
-
-
- // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
- // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
- // allow to always have a ponder move even when we fail high at root and also a
- // long PV to print that is important for position analysis.
-
- void extract_pv_from_tt(const Position& pos, Move bestMove, Move pv[]) {
-
- StateInfo st;
- TTEntry* tte;
- Position p(pos, pos.thread());
- int ply = 0;
-
- assert(bestMove != MOVE_NONE);
-
- pv[ply] = bestMove;
- p.do_move(pv[ply++], st);
-
- while ( (tte = TT.retrieve(p.get_key())) != NULL
- && tte->move() != MOVE_NONE
- && move_is_legal(p, tte->move())
- && ply < PLY_MAX
- && (!p.is_draw() || ply < 2))
- {
- pv[ply] = tte->move();
- p.do_move(pv[ply++], st);
- }
- pv[ply] = MOVE_NONE;
- }
-
-
// init_thread() is the function which is called when a new thread is
// launched. It simply calls the idle_loop() function with the supplied
// threadID. There are two versions of this function; one for POSIX
}
- /// The RootMoveList class
+ /// RootMove and RootMoveList method's definitions
+
+ RootMove::RootMove() {
+
+ nodes = 0;
+ pv_score = non_pv_score = -VALUE_INFINITE;
+ pv[0] = MOVE_NONE;
+ }
+
+ RootMove& RootMove::operator=(const RootMove& rm) {
+
+ const Move* src = rm.pv;
+ Move* dst = pv;
+
+ // Avoid a costly full rm.pv[] copy
+ do *dst++ = *src; while (*src++ != MOVE_NONE);
+
+ nodes = rm.nodes;
+ pv_score = rm.pv_score;
+ non_pv_score = rm.non_pv_score;
+ return *this;
+ }
+
+ // extract_pv_from_tt() builds a PV by adding moves from the transposition table.
+ // We consider also failing high nodes and not only VALUE_TYPE_EXACT nodes. This
+ // allow to always have a ponder move even when we fail high at root and also a
+ // long PV to print that is important for position analysis.
+
+ void RootMove::extract_pv_from_tt(Position& pos) {
+
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ TTEntry* tte;
+ int ply = 1;
+
+ assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+
+ pos.do_move(pv[0], *st++);
+
+ while ( (tte = TT.retrieve(pos.get_key())) != NULL
+ && tte->move() != MOVE_NONE
+ && move_is_legal(pos, tte->move())
+ && ply < PLY_MAX
+ && (!pos.is_draw() || ply < 2))
+ {
+ pv[ply] = tte->move();
+ pos.do_move(pv[ply++], *st++);
+ }
+ pv[ply] = MOVE_NONE;
+
+ do pos.undo_move(pv[--ply]); while (ply);
+ }
+
+ // insert_pv_in_tt() is called at the end of a search iteration, and inserts
+ // the PV back into the TT. This makes sure the old PV moves are searched
+ // first, even if the old TT entries have been overwritten.
+
+ void RootMove::insert_pv_in_tt(Position& pos) {
+
+ StateInfo state[PLY_MAX_PLUS_2], *st = state;
+ TTEntry* tte;
+ Key k;
+ Value v, m = VALUE_NONE;
+ int ply = 0;
+
+ assert(pv[0] != MOVE_NONE && move_is_legal(pos, pv[0]));
+
+ do {
+ k = pos.get_key();
+ tte = TT.retrieve(k);
+
+ // Don't overwrite exsisting correct entries
+ if (!tte || tte->move() != pv[ply])
+ {
+ v = (pos.is_check() ? VALUE_NONE : evaluate(pos, m));
+ TT.store(k, VALUE_NONE, VALUE_TYPE_NONE, DEPTH_NONE, pv[ply], v, m);
+ }
+ pos.do_move(pv[ply], *st++);
+
+ } while (pv[++ply] != MOVE_NONE);
+
+ do pos.undo_move(pv[--ply]); while (ply);
+ }
+
+ // pv_info_to_uci() returns a string with information on the current PV line
+ // formatted according to UCI specification and eventually writes the info
+ // to a log file. It is called at each iteration or after a new pv is found.
+
+ std::string RootMove::pv_info_to_uci(const Position& pos, Value alpha, Value beta, int pvLine) {
+
+ std::stringstream s;
+
+ s << "info depth " << Iteration // FIXME
+ << " multipv " << pvLine + 1
+ << " score " << value_to_uci(pv_score)
+ << (pv_score >= beta ? " lowerbound" : pv_score <= alpha ? " upperbound" : "")
+ << " time " << current_search_time()
+ << " nodes " << pos.nodes_searched()
+ << " nps " << nps(pos)
+ << " pv ";
+
+ for (Move* m = pv; *m != MOVE_NONE; m++)
+ s << *m << " ";
+
+ if (UseLogFile && pvLine == 0)
+ {
+ ValueType t = pv_score >= beta ? VALUE_TYPE_LOWER :
+ pv_score <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT;
+
+ LogFile << pretty_pv(pos, current_search_time(), Iteration, pv_score, t, pv) << endl;
+ }
+ return s.str();
+ }
+
RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) {
pos.do_move(cur->move, st);
RootMove rm;
- rm.move = ss[0].currentMove = rm.pv[0] = cur->move;
+ rm.pv[0] = ss[0].currentMove = cur->move;
rm.pv[1] = MOVE_NONE;
rm.pv_score = -qsearch<PV>(pos, ss+1, -VALUE_INFINITE, VALUE_INFINITE, DEPTH_ZERO, 1);
push_back(rm);
while ((move = mp.get_next_move()) != MOVE_NONE)
for (Base::iterator it = begin(); it != end(); ++it)
- if (it->move == move)
+ if (it->pv[0] == move)
{
it->non_pv_score = score--;
break;