/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2004-2021 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
*/
#include <cassert>
+#include <cmath>
#include <iostream>
#include <sstream>
#include <string>
-#include <vector>
#include "evaluate.h"
-#include "misc.h"
-#include "move.h"
+#include "movegen.h"
#include "position.h"
#include "search.h"
-#include "ucioption.h"
+#include "thread.h"
+#include "timeman.h"
+#include "tt.h"
+#include "uci.h"
+#include "syzygy/tbprobe.h"
using namespace std;
+namespace Stockfish {
+
+extern vector<string> setup_bench(const Position&, istream&);
+
namespace {
- // FEN string for the initial position
- const string StartPositionFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
+ // FEN string of the initial position, normal 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 ckeck at most 100 plies back.
- StateInfo StateRingBuf[102], *SetupState = StateRingBuf;
- // UCIParser is a class for parsing UCI input. The class
- // is actually a string stream built on a given input string.
- typedef istringstream UCIParser;
+ // 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 set_option(UCIParser& up);
- void set_position(Position& pos, UCIParser& up);
- bool go(Position& pos, UCIParser& up);
- void perft(Position& pos, UCIParser& up);
-}
+ void position(Position& pos, istringstream& is, StateListPtr& states) {
+ Move m;
+ string token, fen;
-/// execute_uci_command() takes a string as input, uses a UCIParser
-/// object to parse this text string as a UCI command, and calls
-/// the appropriate functions. In addition to the UCI commands,
-/// the function also supports a few debug commands.
+ is >> token;
-bool execute_uci_command(const string& cmd) {
+ if (token == "startpos")
+ {
+ fen = StartFEN;
+ is >> token; // Consume "moves" token if any
+ }
+ else if (token == "fen")
+ while (is >> token && token != "moves")
+ fen += token + " ";
+ else
+ return;
- static Position pos(StartPositionFEN, false, 0); // The root position
+ states = StateListPtr(new std::deque<StateInfo>(1)); // Drop old and create a new one
+ pos.set(fen, Options["UCI_Chess960"], &states->back(), Threads.main());
- UCIParser up(cmd);
- string token;
+ // Parse move list (if any)
+ while (is >> token && (m = UCI::to_move(pos, token)) != MOVE_NONE)
+ {
+ states->emplace_back();
+ pos.do_move(m, states->back());
+ }
+ }
- up >> skipws >> token;
+ // trace_eval() prints the evaluation for the current position, consistent with the UCI
+ // options set so far.
- if (token == "quit")
- return false;
+ void trace_eval(Position& pos) {
- if (token == "go")
- return go(pos, up);
+ StateListPtr states(new std::deque<StateInfo>(1));
+ Position p;
+ p.set(pos.fen(), Options["UCI_Chess960"], &states->back(), Threads.main());
- if (token == "ucinewgame")
- pos.from_fen(StartPositionFEN, false);
+ Eval::NNUE::verify();
- else if (token == "isready")
- cout << "readyok" << endl;
+ sync_cout << "\n" << Eval::trace(p) << sync_endl;
+ }
- else if (token == "position")
- set_position(pos, up);
- else if (token == "setoption")
- set_option(up);
+ // setoption() is called when engine receives the "setoption" UCI command. The
+ // function updates the UCI option ("name") to the given value ("value").
- else if (token == "perft")
- perft(pos, up);
+ void setoption(istringstream& is) {
- else if (token == "d")
- pos.print();
+ string token, name, value;
- else if (token == "flip")
- pos.flip();
+ is >> token; // Consume "name" token
- else if (token == "eval")
- {
- read_evaluation_uci_options(pos.side_to_move());
- cout << trace_evaluate(pos) << endl;
+ // Read option name (can contain spaces)
+ while (is >> token && token != "value")
+ name += (name.empty() ? "" : " ") + token;
+
+ // Read option value (can contain spaces)
+ while (is >> token)
+ value += (value.empty() ? "" : " ") + token;
+
+ if (Options.count(name))
+ Options[name] = value;
+ else
+ sync_cout << "No such option: " << name << sync_endl;
}
- else if (token == "key")
- cout << "key: " << hex << pos.get_key()
- << "\nmaterial key: " << pos.get_material_key()
- << "\npawn key: " << pos.get_pawn_key() << endl;
- else if (token == "uci")
- cout << "id name " << engine_name()
- << "\nid author " << engine_authors()
- << "\n" << Options.print_all()
- << "\nuciok" << endl;
- else
- cout << "Unknown command: " << cmd << endl;
+ // 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.
- return true;
-}
+ void go(Position& pos, istringstream& is, StateListPtr& states) {
+ Search::LimitsType limits;
+ string token;
+ bool ponderMode = false;
+
+ limits.startTime = now(); // 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 {
- // 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").
+ // 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.
- void set_position(Position& pos, UCIParser& up) {
+ void bench(Position& pos, istream& args, StateListPtr& states) {
- Move m;
- string token, fen;
+ string token;
+ uint64_t num, nodes = 0, cnt = 1;
- up >> token;
+ 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; });
- if (token == "startpos")
+ TimePoint elapsed = now();
+
+ for (const auto& cmd : list)
{
- pos.from_fen(StartPositionFEN, false);
- up >> 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 some while
}
- else if (token == "fen")
- {
- while (up >> token && token != "moves")
- fen += token + " ";
- pos.from_fen(fen, Options["UCI_Chess960"].value<bool>());
- }
- else return;
+ elapsed = now() - elapsed + 1; // Ensure positivity to avoid a 'divide by zero'
- // Parse move list (if any)
- while (up >> token && (m = move_from_uci(pos, token)) != MOVE_NONE)
- {
- pos.do_move(m, *SetupState);
+ dbg_print(); // Just before exiting
- // 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 (per mille) of winning given an eval
+ // and a game-ply. The model fits rather accurately the LTC fishtest statistics.
+ int win_rate_model(Value v, int ply) {
- // set_option() is called when engine receives the "setoption" UCI
- // command. The function updates the corresponding UCI option ("name")
- // to the given value ("value").
+ // The model captures only up to 240 plies, so limit input (and rescale)
+ double m = std::min(240, ply) / 64.0;
- void set_option(UCIParser& up) {
+ // Coefficients of a 3rd order polynomial fit based on fishtest data
+ // for two parameters needed to transform eval to the argument of a
+ // logistic function.
+ double as[] = {-3.68389304, 30.07065921, -60.52878723, 149.53378557};
+ double bs[] = {-2.0181857, 15.85685038, -29.83452023, 47.59078827};
+ 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];
- string token, name, value;
+ // Transform eval to centipawns with limited range
+ double x = std::clamp(double(100 * v) / PawnValueEg, -2000.0, 2000.0);
- up >> token; // Consume "name" token
+ // Return win rate in per mille (rounded to nearest)
+ return int(0.5 + 1000 / (1 + std::exp((a - x) / b)));
+ }
- // Read option name (can contain spaces)
- while (up >> token && token != "value")
- name += string(" ", !name.empty()) + token;
+} // 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.
+
+void UCI::loop(int argc, char* argv[]) {
+
+ Position pos;
+ string token, cmd;
+ StateListPtr states(new std::deque<StateInfo>(1));
+
+ pos.set(StartFEN, false, &states->back(), Threads.main());
+
+ for (int i = 1; i < argc; ++i)
+ cmd += std::string(argv[i]) + " ";
+
+ do {
+ if (argc == 1 && !getline(cin, cmd)) // Block here waiting for input or EOF
+ cmd = "quit";
+
+ istringstream is(cmd);
+
+ token.clear(); // Avoid a stale if getline() returns empty or blank line
+ is >> 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.
+ else if (token == "ponderhit")
+ Threads.main()->ponder = false; // Switch to 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;
+
+ // 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") 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.empty() && token[0] != '#')
+ sync_cout << "Unknown command: " << cmd << sync_endl;
+
+ } while (token != "quit" && argc == 1); // Command line args are one-shot
+}
- // Read option value (can contain spaces)
- while (up >> token)
- value += string(" ", !value.empty()) + token;
- if (Options.find(name) != Options.end())
- Options[name].set_value(value.empty() ? "true" : value); // UCI buttons don't have "value"
- else
- cout << "No such option: " << name << endl;
- }
+/// 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.
+string UCI::value(Value v) {
- // 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 calls think(). Returns false if a quit command
- // is received while thinking, true otherwise.
+ assert(-VALUE_INFINITE < v && v < VALUE_INFINITE);
- bool go(Position& pos, UCIParser& up) {
+ stringstream ss;
- string token;
- SearchLimits limits;
- std::vector<Move> searchMoves;
- int time[] = { 0, 0 }, inc[] = { 0, 0 };
+ if (abs(v) < VALUE_MATE_IN_MAX_PLY)
+ ss << "cp " << v * 100 / PawnValueEg;
+ else
+ ss << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;
- while (up >> token)
- {
- if (token == "infinite")
- limits.infinite = true;
- else if (token == "ponder")
- limits.ponder = true;
- else if (token == "wtime")
- up >> time[WHITE];
- else if (token == "btime")
- up >> time[BLACK];
- else if (token == "winc")
- up >> inc[WHITE];
- else if (token == "binc")
- up >> inc[BLACK];
- else if (token == "movestogo")
- up >> limits.movesToGo;
- else if (token == "depth")
- up >> limits.maxDepth;
- else if (token == "nodes")
- up >> limits.maxNodes;
- else if (token == "movetime")
- up >> limits.maxTime;
- else if (token == "searchmoves")
- while (up >> token)
- searchMoves.push_back(move_from_uci(pos, token));
- }
+ return ss.str();
+}
- searchMoves.push_back(MOVE_NONE);
- limits.time = time[pos.side_to_move()];
- limits.increment = inc[pos.side_to_move()];
- return think(pos, limits, &searchMoves[0]);
- }
+/// UCI::wdl() report WDL statistics given an evaluation and a game ply, based on
+/// data gathered for fishtest LTC games.
+string UCI::wdl(Value v, int ply) {
- // perft() is called when engine receives the "perft" command.
- // The function calls perft() passing the required search depth
- // then prints counted leaf nodes and elapsed time.
+ stringstream ss;
- void perft(Position& pos, UCIParser& up) {
+ 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;
- int depth, time;
- int64_t n;
+ return ss.str();
+}
- if (!(up >> depth))
- return;
- time = get_system_time();
+/// UCI::square() converts a Square to a string in algebraic notation (g1, a7, etc.)
- n = perft(pos, depth * ONE_PLY);
+std::string UCI::square(Square s) {
+ return std::string{ char('a' + file_of(s)), char('1' + rank_of(s)) };
+}
- time = get_system_time() - time;
- std::cout << "\nNodes " << n
- << "\nTime (ms) " << time
- << "\nNodes/second " << int(n / (time / 1000.0)) << std::endl;
- }
+/// 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) {
+
+ 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) // Junior could send promotion piece in uppercase
+ str[4] = char(tolower(str[4]));
+
+ for (const auto& m : MoveList<LEGAL>(pos))
+ if (str == UCI::move(m, pos.is_chess960()))
+ return m;
+
+ return MOVE_NONE;
+}
+
+} // namespace Stockfish