/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
- Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, 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 "uci.h"
+
+#include <algorithm>
#include <cassert>
+#include <cctype>
+#include <cmath>
+#include <cstdint>
+#include <cstdlib>
+#include <deque>
#include <iostream>
+#include <memory>
+#include <optional>
#include <sstream>
#include <string>
+#include <vector>
+#include "benchmark.h"
#include "evaluate.h"
+#include "misc.h"
#include "movegen.h"
+#include "nnue/evaluate_nnue.h"
#include "position.h"
#include "search.h"
#include "thread.h"
-#include "timeman.h"
-#include "tt.h"
-#include "uci.h"
-#include "syzygy/tbprobe.h"
-using namespace std;
-
-extern vector<string> setup_bench(const Position&, istream&);
+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";
- // 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").
+ // 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) {
+ void position(Position& pos, std::istringstream& is, StateListPtr& states) {
Move m;
- string token, fen;
+ std::string token, fen;
is >> token;
if (token == "startpos")
{
fen = StartFEN;
- is >> token; // Consume "moves" token if any
+ is >> token; // Consume the "moves" token, if any
}
else if (token == "fen")
while (is >> token && token != "moves")
else
return;
- states = StateListPtr(new std::deque<StateInfo>(1)); // Drop old and create a new one
+ 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());
- // Parse move list (if any)
+ // Parse the move list, if any
while (is >> token && (m = UCI::to_move(pos, token)) != MOVE_NONE)
{
states->emplace_back();
}
}
+ // trace_eval() prints the evaluation of the current position, consistent with
+ // the UCI options set so far.
+
+ void trace_eval(Position& pos) {
+
+ StateListPtr states(new std::deque<StateInfo>(1));
+ Position p;
+ p.set(pos.fen(), Options["UCI_Chess960"], &states->back(), Threads.main());
+
+ Eval::NNUE::verify();
+
+ sync_cout << "\n" << Eval::trace(p) << sync_endl;
+ }
+
- // setoption() is called when engine receives the "setoption" UCI command. The
- // function updates the UCI option ("name") to the given value ("value").
+ // 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) {
+ void setoption(std::istringstream& is) {
- string token, name, value;
+ Threads.main()->wait_for_search_finished();
- is >> token; // Consume "name" token
+ std::string token, name, value;
- // Read option name (can contain spaces)
+ is >> token; // Consume the "name" token
+
+ // Read the option name (can contain spaces)
while (is >> token && token != "value")
name += (name.empty() ? "" : " ") + token;
- // Read option value (can contain spaces)
+ // Read the option value (can contain spaces)
while (is >> token)
value += (value.empty() ? "" : " ") + token;
}
- // go() is called when engine receives the "go" UCI command. The function sets
- // the thinking time and other parameters from the input string, then starts
- // the search.
+ // 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.
- void go(Position& pos, istringstream& is, StateListPtr& states) {
+ void go(Position& pos, std::istringstream& is, StateListPtr& states) {
Search::LimitsType limits;
- string token;
+ std::string token;
bool ponderMode = false;
- limits.startTime = now(); // As early as possible!
+ limits.startTime = now(); // The search starts as early as possible
while (is >> token)
- if (token == "searchmoves")
+ if (token == "searchmoves") // Needs to be the last command on the line
while (is >> token)
limits.searchmoves.push_back(UCI::to_move(pos, token));
}
- // bench() is called when engine receives the "bench" command. Firstly
- // a list of UCI commands is setup according to bench parameters, then
- // it is run one by one printing a summary at the end.
+ // bench() is called when the engine receives the "bench" command.
+ // First, 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.
- void bench(Position& pos, istream& args, StateListPtr& states) {
+ void bench(Position& pos, std::istream& args, StateListPtr& states) {
- string token;
+ std::string token;
uint64_t num, nodes = 0, cnt = 1;
- vector<string> list = setup_bench(pos, args);
- num = count_if(list.begin(), list.end(), [](string s) { return s.find("go ") == 0 || s.find("eval") == 0; });
+ std::vector<std::string> list = setup_bench(pos, args);
+ num = count_if(list.begin(), list.end(), [](const std::string& s) { return s.find("go ") == 0 || s.find("eval") == 0; });
TimePoint elapsed = now();
for (const auto& cmd : list)
{
- istringstream is(cmd);
- is >> skipws >> token;
+ std::istringstream is(cmd);
+ is >> std::skipws >> token;
if (token == "go" || token == "eval")
{
- cerr << "\nPosition: " << cnt++ << '/' << num << endl;
+ std::cerr << "\nPosition: " << cnt++ << '/' << num << " (" << pos.fen() << ")" << std::endl;
if (token == "go")
{
go(pos, is, states);
nodes += Threads.nodes_searched();
}
else
- sync_cout << "\n" << Eval::trace(pos) << sync_endl;
+ 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 some while
+ else if (token == "ucinewgame") { Search::clear(); elapsed = now(); } // Search::clear() may take a while
}
elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
- dbg_print(); // Just before exiting
+ dbg_print();
+
+ std::cerr << "\n==========================="
+ << "\nTotal time (ms) : " << elapsed
+ << "\nNodes searched : " << nodes
+ << "\nNodes/second : " << 1000 * nodes / elapsed << std::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) {
+
+ // The model only captures up to 240 plies, so limit the input and then rescale
+ double m = std::min(240, ply) / 64.0;
- cerr << "\n==========================="
- << "\nTotal time (ms) : " << elapsed
- << "\nNodes searched : " << nodes
- << "\nNodes/second : " << 1000 * nodes / elapsed << endl;
+ // 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[] = { 0.38036525, -2.82015070, 23.17882135, 307.36768407};
+ constexpr double bs[] = { -2.29434733, 13.27689788, -14.26828904, 63.45318330 };
+
+ // 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]));
+
+ 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];
+
+ // Transform the eval to centipawns with limited range
+ double x = std::clamp(double(v), -4000.0, 4000.0);
+
+ // Return the win rate in per mille units, rounded to the nearest integer
+ return int(0.5 + 1000 / (1 + std::exp((a - x) / b)));
}
} // namespace
-/// UCI::loop() waits for a command from stdin, parses it and calls the appropriate
-/// function. Also intercepts EOF from stdin to ensure gracefully exiting if the
-/// GUI dies unexpectedly. When called with some command line arguments, e.g. to
-/// run 'bench', once the command is executed the function returns immediately.
-/// In addition to the UCI ones, also some additional debug commands are supported.
+// 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.
void UCI::loop(int argc, char* argv[]) {
Position pos;
- string token, cmd;
+ std::string token, cmd;
StateListPtr states(new std::deque<StateInfo>(1));
pos.set(StartFEN, false, &states->back(), Threads.main());
cmd += std::string(argv[i]) + " ";
do {
- if (argc == 1 && !getline(cin, cmd)) // Block here waiting for input or EOF
+ if (argc == 1 && !getline(std::cin, cmd)) // Wait for an input or an end-of-file (EOF) indication
cmd = "quit";
- istringstream is(cmd);
+ std::istringstream is(cmd);
- token.clear(); // Avoid a stale if getline() returns empty or blank line
- is >> skipws >> token;
+ token.clear(); // Avoid a stale if getline() returns nothing or a blank line
+ is >> std::skipws >> token;
if ( token == "quit"
|| token == "stop")
Threads.stop = true;
- // The GUI sends 'ponderhit' to tell us the user has played the expected move.
- // So 'ponderhit' will be sent if we were told to ponder on the same move the
- // user has played. We should continue searching but switch from pondering to
- // normal search.
+ // 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 normal search
+ Threads.main()->ponder = false; // Switch to the normal search
else if (token == "uci")
sync_cout << "id name " << engine_info(true)
else if (token == "ucinewgame") Search::clear();
else if (token == "isready") sync_cout << "readyok" << sync_endl;
- // Additional custom non-UCI commands, mainly for debugging.
- // Do not use these commands 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") sync_cout << Eval::trace(pos) << sync_endl;
- else
- sync_cout << "Unknown command: " << cmd << sync_endl;
-
- } while (token != "quit" && argc == 1); // Command line args are one-shot
+ // 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 >> std::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
}
-/// UCI::value() converts a Value to a string suitable for use with 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
-/// use negative values for y.
+// Turns a Value to an integer centipawn number,
+// without treatment of mate and similar special scores.
+int UCI::to_cp(Value v) {
-string UCI::value(Value v) {
+ return 100 * v / UCI::NormalizeToPawnValue;
+}
+
+// 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'.
+
+std::string UCI::value(Value v) {
assert(-VALUE_INFINITE < v && v < VALUE_INFINITE);
- stringstream ss;
+ std::stringstream ss;
- if (abs(v) < VALUE_MATE - MAX_PLY)
- ss << "cp " << v * 100 / PawnValueEg;
+ if (abs(v) < VALUE_TB_WIN_IN_MAX_PLY)
+ ss << "cp " << UCI::to_cp(v);
+ else if (abs(v) < VALUE_MATE_IN_MAX_PLY)
+ {
+ const int ply = VALUE_MATE_IN_MAX_PLY - 1 - std::abs(v); // recompute ss->ply
+ ss << "cp " << (v > 0 ? 20000 - ply : -20000 + ply);
+ }
else
ss << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
}
-/// UCI::square() converts a Square to a string in algebraic notation (g1, a7, etc.)
+// 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.
+
+std::string UCI::wdl(Value v, int ply) {
+
+ std::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 we print in the e1g1 notation in
-/// normal chess mode, and in e1h1 notation in chess960 mode. Internally all
-/// castling moves are always encoded as 'king captures rook'.
-
-string UCI::move(Move m, bool chess960) {
+// 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'.
- Square from = from_sq(m);
- Square to = to_sq(m);
+std::string UCI::move(Move m, bool chess960) {
if (m == MOVE_NONE)
return "(none)";
if (m == MOVE_NULL)
return "0000";
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+
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);
+ std::string move = UCI::square(from) + UCI::square(to);
if (type_of(m) == PROMOTION)
move += " pnbrqk"[promotion_type(m)];
}
-/// UCI::to_move() converts a string representing a move in coordinate notation
-/// (g1f3, a7a8q) to the corresponding legal Move, if any.
+// 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) {
+Move UCI::to_move(const Position& pos, std::string& str) {
- if (str.length() == 5) // Junior could send promotion piece in uppercase
- str[4] = char(tolower(str[4]));
+ 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 MOVE_NONE;
}
+
+} // namespace Stockfish
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