/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <cassert>
+#include <cmath>
#include <iostream>
#include <sstream>
#include <string>
+#include "benchmark.h"
#include "evaluate.h"
-#include "misc.h"
+#include "movegen.h"
#include "position.h"
#include "search.h"
#include "thread.h"
-#include "ucioption.h"
+#include "timeman.h"
+#include "tt.h"
+#include "uci.h"
+#include "syzygy/tbprobe.h"
using namespace std;
+namespace Stockfish {
+
namespace {
- // FEN string of the initial position, normal chess
+ // FEN string for the initial position in standard chess
const char* StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
- // Keep track of position keys along the setup moves (from start position to the
- // position just before to start searching). This is needed by draw detection
- // where, due to 50 moves rule, we need to check at most 100 plies back.
- StateInfo StateRingBuf[102], *SetupState = StateRingBuf;
- void set_option(istringstream& up);
- void set_position(Position& pos, istringstream& up);
- void go(Position& pos, istringstream& up);
- void perft(Position& pos, istringstream& up);
-}
+ // position() is called when the engine receives the "position" UCI command.
+ // It sets up the position that is described in the given FEN string ("fen") or
+ // the initial position ("startpos") and then makes the moves given in the following
+ // move list ("moves").
+ void position(Position& pos, istringstream& is, StateListPtr& states) {
-/// Wait for a command from the user, parse this text string as an UCI command,
-/// and call the appropriate functions. Also intercepts EOF from stdin to ensure
-/// that we exit gracefully if the GUI dies unexpectedly. In addition to the UCI
-/// commands, the function also supports a few debug commands.
+ Move m;
+ string token, fen;
-void uci_loop() {
+ is >> token;
- Position pos(StartFEN, false, 0); // The root position
- string cmd, token;
+ if (token == "startpos")
+ {
+ fen = StartFEN;
+ is >> token; // Consume the "moves" token, if any
+ }
+ else if (token == "fen")
+ while (is >> token && token != "moves")
+ fen += token + " ";
+ else
+ return;
- while (token != "quit")
- {
- if (!getline(cin, cmd)) // Block here waiting for input
- cmd = "quit";
+ states = StateListPtr(new std::deque<StateInfo>(1)); // Drop the old state and create a new one
+ pos.set(fen, Options["UCI_Chess960"], &states->back(), Threads.main());
- istringstream is(cmd);
+ // Parse the move list, if any
+ while (is >> token && (m = UCI::to_move(pos, token)) != MOVE_NONE)
+ {
+ states->emplace_back();
+ pos.do_move(m, states->back());
+ }
+ }
- is >> skipws >> token;
+ // trace_eval() prints the evaluation of the current position, consistent with
+ // the UCI options set so far.
- if (token == "quit" || token == "stop")
- {
- Search::Signals.stop = true;
+ void trace_eval(Position& pos) {
- if (token == "quit") // Cannot quit while threads are still running
- Threads.wait_for_search_finished();
- }
+ StateListPtr states(new std::deque<StateInfo>(1));
+ Position p;
+ p.set(pos.fen(), Options["UCI_Chess960"], &states->back(), Threads.main());
- else if (token == "ponderhit")
- {
- // The opponent has played the expected move. GUI sends "ponderhit" if
- // we were told to ponder on the same move the opponent has played. We
- // should continue searching but switching from pondering to normal search.
- Search::Limits.ponder = false;
+ Eval::NNUE::verify();
- if (Search::Signals.stopOnPonderhit)
- Search::Signals.stop = true;
- }
+ sync_cout << "\n" << Eval::trace(p) << sync_endl;
+ }
+
+
+ // setoption() is called when the engine receives the "setoption" UCI command.
+ // The function updates the UCI option ("name") to the given value ("value").
+
+ void setoption(istringstream& is) {
- else if (token == "go")
- go(pos, is);
+ string token, name, value;
- else if (token == "isready")
- cout << "readyok" << endl;
+ is >> token; // Consume the "name" token
- else if (token == "position")
- set_position(pos, is);
+ // Read the option name (can contain spaces)
+ while (is >> token && token != "value")
+ name += (name.empty() ? "" : " ") + token;
- else if (token == "setoption")
- set_option(is);
+ // Read the option value (can contain spaces)
+ while (is >> token)
+ value += (value.empty() ? "" : " ") + token;
- else if (token == "perft")
- perft(pos, is);
+ if (Options.count(name))
+ Options[name] = value;
+ else
+ sync_cout << "No such option: " << name << sync_endl;
+ }
- else if (token == "d")
- pos.print();
- else if (token == "flip")
- pos.flip_me();
+ // go() is called when the engine receives the "go" UCI command. The function
+ // sets the thinking time and other parameters from the input string, then starts
+ // with a search.
- else if (token == "eval")
- cout << Eval::trace(pos) << endl;
+ void go(Position& pos, istringstream& is, StateListPtr& states) {
- else if (token == "key")
- cout << "key: " << hex << pos.key()
- << "\nmaterial key: " << pos.material_key()
- << "\npawn key: " << pos.pawn_key() << endl;
+ Search::LimitsType limits;
+ string token;
+ bool ponderMode = false;
- else if (token == "uci")
- cout << "id name " << engine_info(true)
- << "\n" << Options
- << "\nuciok" << endl;
- else
- cout << "Unknown command: " << cmd << endl;
+ limits.startTime = now(); // The search starts as early as possible
+
+ while (is >> token)
+ if (token == "searchmoves") // Needs to be the last command on the line
+ while (is >> token)
+ limits.searchmoves.push_back(UCI::to_move(pos, token));
+
+ else if (token == "wtime") is >> limits.time[WHITE];
+ else if (token == "btime") is >> limits.time[BLACK];
+ else if (token == "winc") is >> limits.inc[WHITE];
+ else if (token == "binc") is >> limits.inc[BLACK];
+ else if (token == "movestogo") is >> limits.movestogo;
+ else if (token == "depth") is >> limits.depth;
+ else if (token == "nodes") is >> limits.nodes;
+ else if (token == "movetime") is >> limits.movetime;
+ else if (token == "mate") is >> limits.mate;
+ else if (token == "perft") is >> limits.perft;
+ else if (token == "infinite") limits.infinite = 1;
+ else if (token == "ponder") ponderMode = true;
+
+ Threads.start_thinking(pos, states, limits, ponderMode);
}
-}
-namespace {
+ // bench() is called when the engine receives the "bench" command.
+ // Firstly, a list of UCI commands is set up according to the bench
+ // parameters, then it is run one by one, printing a summary at the end.
- // set_position() is called when engine receives the "position" UCI
- // command. The function sets up the position described in the given
- // fen string ("fen") or the starting position ("startpos") and then
- // makes the moves given in the following move list ("moves").
+ void bench(Position& pos, istream& args, StateListPtr& states) {
- void set_position(Position& pos, istringstream& is) {
+ string token;
+ uint64_t num, nodes = 0, cnt = 1;
- Move m;
- string token, fen;
+ vector<string> list = setup_bench(pos, args);
+ num = count_if(list.begin(), list.end(), [](const string& s) { return s.find("go ") == 0 || s.find("eval") == 0; });
- is >> token;
+ TimePoint elapsed = now();
- if (token == "startpos")
+ for (const auto& cmd : list)
{
- fen = StartFEN;
- is >> token; // Consume "moves" token if any
+ istringstream is(cmd);
+ is >> skipws >> token;
+
+ if (token == "go" || token == "eval")
+ {
+ cerr << "\nPosition: " << cnt++ << '/' << num << " (" << pos.fen() << ")" << endl;
+ if (token == "go")
+ {
+ go(pos, is, states);
+ Threads.main()->wait_for_search_finished();
+ nodes += Threads.nodes_searched();
+ }
+ else
+ trace_eval(pos);
+ }
+ else if (token == "setoption") setoption(is);
+ else if (token == "position") position(pos, is, states);
+ else if (token == "ucinewgame") { Search::clear(); elapsed = now(); } // Search::clear() may take a while
}
- else if (token == "fen")
- while (is >> token && token != "moves")
- fen += token + " ";
- else
- return;
- pos.from_fen(fen, Options["UCI_Chess960"]);
+ elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
- // Parse move list (if any)
- while (is >> token && (m = move_from_uci(pos, token)) != MOVE_NONE)
- {
- pos.do_move(m, *SetupState);
+ dbg_print();
- // Increment pointer to StateRingBuf circular buffer
- if (++SetupState - StateRingBuf >= 102)
- SetupState = StateRingBuf;
- }
+ cerr << "\n==========================="
+ << "\nTotal time (ms) : " << elapsed
+ << "\nNodes searched : " << nodes
+ << "\nNodes/second : " << 1000 * nodes / elapsed << endl;
}
+ // The win rate model returns the probability of winning (in per mille units) given an
+ // eval and a game ply. It fits the LTC fishtest statistics rather accurately.
+ int win_rate_model(Value v, int ply) {
- // set_option() is called when engine receives the "setoption" UCI command. The
- // function updates the UCI option ("name") to the given value ("value").
+ // The model only captures up to 240 plies, so limit the input and then rescale
+ double m = std::min(240, ply) / 64.0;
- void set_option(istringstream& is) {
+ // The coefficients of a third-order polynomial fit is based on the fishtest data
+ // for two parameters that need to transform eval to the argument of a logistic
+ // function.
+ constexpr double as[] = { -0.58270499, 2.68512549, 15.24638015, 344.49745382};
+ constexpr double bs[] = { -2.65734562, 15.96509799, -20.69040836, 73.61029937 };
- string token, name, value;
+ // Enforce that NormalizeToPawnValue corresponds to a 50% win rate at ply 64
+ static_assert(UCI::NormalizeToPawnValue == int(as[0] + as[1] + as[2] + as[3]));
- is >> token; // Consume "name" token
+ double a = (((as[0] * m + as[1]) * m + as[2]) * m) + as[3];
+ double b = (((bs[0] * m + bs[1]) * m + bs[2]) * m) + bs[3];
- // Read option name (can contain spaces)
- while (is >> token && token != "value")
- name += string(" ", !name.empty()) + token;
-
- // Read option value (can contain spaces)
- while (is >> token)
- value += string(" ", !value.empty()) + token;
+ // Transform the eval to centipawns with limited range
+ double x = std::clamp(double(v), -4000.0, 4000.0);
- if (Options.count(name))
- Options[name] = value;
- else
- cout << "No such option: " << name << endl;
+ // Return the win rate in per mille units rounded to the nearest value
+ return int(0.5 + 1000 / (1 + std::exp((a - x) / b)));
}
+} // namespace
- // go() is called when engine receives the "go" UCI command. The function sets
- // the thinking time and other parameters from the input string, and then starts
- // the main searching thread.
- void go(Position& pos, istringstream& is) {
+/// UCI::loop() waits for a command from the stdin, parses it and then calls the appropriate
+/// function. It also intercepts an end-of-file (EOF) indication from the stdin to ensure a
+/// graceful exit if the GUI dies unexpectedly. When called with some command-line arguments,
+/// like running 'bench', the function returns immediately after the command is executed.
+/// In addition to the UCI ones, some additional debug commands are also supported.
- string token;
- Search::LimitsType limits;
- std::set<Move> searchMoves;
- int time[] = { 0, 0 }, inc[] = { 0, 0 };
+void UCI::loop(int argc, char* argv[]) {
- while (is >> token)
- {
- if (token == "infinite")
- limits.infinite = true;
- else if (token == "ponder")
- limits.ponder = true;
- else if (token == "wtime")
- is >> time[WHITE];
- else if (token == "btime")
- is >> time[BLACK];
- else if (token == "winc")
- is >> inc[WHITE];
- else if (token == "binc")
- is >> inc[BLACK];
- else if (token == "movestogo")
- is >> limits.movesToGo;
- else if (token == "depth")
- is >> limits.maxDepth;
- else if (token == "nodes")
- is >> limits.maxNodes;
- else if (token == "movetime")
- is >> limits.maxTime;
- else if (token == "searchmoves")
- while (is >> token)
- searchMoves.insert(move_from_uci(pos, token));
- }
+ Position pos;
+ string token, cmd;
+ StateListPtr states(new std::deque<StateInfo>(1));
- limits.time = time[pos.side_to_move()];
- limits.increment = inc[pos.side_to_move()];
+ pos.set(StartFEN, false, &states->back(), Threads.main());
- Threads.start_searching(pos, limits, searchMoves, true);
- }
+ for (int i = 1; i < argc; ++i)
+ cmd += std::string(argv[i]) + " ";
+ do {
+ if (argc == 1 && !getline(cin, cmd)) // Wait for an input or an end-of-file (EOF) indication
+ cmd = "quit";
- // perft() is called when engine receives the "perft" command. The function
- // calls perft() with the required search depth then prints counted leaf nodes
- // and elapsed time.
+ istringstream is(cmd);
- void perft(Position& pos, istringstream& is) {
+ token.clear(); // Avoid a stale if getline() returns nothing or a blank line
+ is >> skipws >> token;
- int depth;
+ if ( token == "quit"
+ || token == "stop")
+ Threads.stop = true;
- if (!(is >> depth))
- return;
+ // The GUI sends 'ponderhit' to tell that the user has played the expected move.
+ // So, 'ponderhit' is sent if pondering was done on the same move that the user
+ // has played. The search should continue, but should also switch from pondering
+ // to the normal search.
+ else if (token == "ponderhit")
+ Threads.main()->ponder = false; // Switch to the normal search
+
+ else if (token == "uci")
+ sync_cout << "id name " << engine_info(true)
+ << "\n" << Options
+ << "\nuciok" << sync_endl;
+
+ else if (token == "setoption") setoption(is);
+ else if (token == "go") go(pos, is, states);
+ else if (token == "position") position(pos, is, states);
+ else if (token == "ucinewgame") Search::clear();
+ else if (token == "isready") sync_cout << "readyok" << sync_endl;
+
+ // Add custom non-UCI commands, mainly for debugging purposes.
+ // These commands must not be used during a search!
+ else if (token == "flip") pos.flip();
+ else if (token == "bench") bench(pos, is, states);
+ else if (token == "d") sync_cout << pos << sync_endl;
+ else if (token == "eval") trace_eval(pos);
+ else if (token == "compiler") sync_cout << compiler_info() << sync_endl;
+ else if (token == "export_net")
+ {
+ std::optional<std::string> filename;
+ std::string f;
+ if (is >> skipws >> f)
+ filename = f;
+ Eval::NNUE::save_eval(filename);
+ }
+ else if (token == "--help" || token == "help" || token == "--license" || token == "license")
+ sync_cout << "\nStockfish is a powerful chess engine for playing and analyzing."
+ "\nIt is released as free software licensed under the GNU GPLv3 License."
+ "\nStockfish is normally used with a graphical user interface (GUI) and implements"
+ "\nthe Universal Chess Interface (UCI) protocol to communicate with a GUI, an API, etc."
+ "\nFor any further information, visit https://github.com/official-stockfish/Stockfish#readme"
+ "\nor read the corresponding README.md and Copying.txt files distributed along with this program.\n" << sync_endl;
+ else if (!token.empty() && token[0] != '#')
+ sync_cout << "Unknown command: '" << cmd << "'. Type help for more information." << sync_endl;
+
+ } while (token != "quit" && argc == 1); // The command-line arguments are one-shot
+}
- Time time = Time::current_time();
- int64_t n = Search::perft(pos, depth * ONE_PLY);
+/// UCI::value() converts a Value to a string by adhering to the UCI protocol specification:
+///
+/// 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,
+/// uses negative values for 'y'.
- int e = time.elapsed();
+string UCI::value(Value v) {
- std::cout << "\nNodes " << n
- << "\nTime (ms) " << e
- << "\nNodes/second " << int(n / (e / 1000.0)) << std::endl;
- }
+ assert(-VALUE_INFINITE < v && v < VALUE_INFINITE);
+
+ stringstream ss;
+
+ if (abs(v) < VALUE_MATE_IN_MAX_PLY)
+ ss << "cp " << v * 100 / NormalizeToPawnValue;
+ else
+ ss << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
+
+ return ss.str();
}
+
+
+/// UCI::wdl() reports the win-draw-loss (WDL) statistics given an evaluation
+/// and a game ply based on the data gathered for fishtest LTC games.
+
+string UCI::wdl(Value v, int ply) {
+
+ stringstream ss;
+
+ int wdl_w = win_rate_model( v, ply);
+ int wdl_l = win_rate_model(-v, ply);
+ int wdl_d = 1000 - wdl_w - wdl_l;
+ ss << " wdl " << wdl_w << " " << wdl_d << " " << wdl_l;
+
+ return ss.str();
+}
+
+
+/// UCI::square() converts a Square to a string in algebraic notation (g1, a7, etc.)
+
+std::string UCI::square(Square s) {
+ return std::string{ char('a' + file_of(s)), char('1' + rank_of(s)) };
+}
+
+
+/// UCI::move() converts a Move to a string in coordinate notation (g1f3, a7a8q).
+/// The only special case is castling where the e1g1 notation is printed in
+/// standard chess mode and in e1h1 notation it is printed in Chess960 mode.
+/// Internally, all castling moves are always encoded as 'king captures rook'.
+
+string UCI::move(Move m, bool chess960) {
+
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+
+ if (m == MOVE_NONE)
+ return "(none)";
+
+ if (m == MOVE_NULL)
+ return "0000";
+
+ if (type_of(m) == CASTLING && !chess960)
+ to = make_square(to > from ? FILE_G : FILE_C, rank_of(from));
+
+ string move = UCI::square(from) + UCI::square(to);
+
+ if (type_of(m) == PROMOTION)
+ move += " pnbrqk"[promotion_type(m)];
+
+ return move;
+}
+
+
+/// UCI::to_move() converts a string representing a move in coordinate notation
+/// (g1f3, a7a8q) to the corresponding legal Move, if any.
+
+Move UCI::to_move(const Position& pos, string& str) {
+
+ if (str.length() == 5)
+ str[4] = char(tolower(str[4])); // The promotion piece character must be lowercased
+
+ for (const auto& m : MoveList<LEGAL>(pos))
+ if (str == UCI::move(m, pos.is_chess960()))
+ return m;
+
+ return MOVE_NONE;
+}
+
+} // namespace Stockfish
projects / stockfish / blobdiff