Halcyon is a command line program and is not meant to be used directly by the user. Instead add it as an engine in a UCI-supported GUI such as Cute Chess, Scid, or Arena.

The following options are supported:

The following UCI commands are supported:

• uci: Tell the engine to use the UCI protocol.
• ucinewgame: Sent when the next search is from a different game.
• isready: Wait until the engine is ready for input.
• position: Sets the current board state.
  • startpos [moves [move]...]: Use the starting position and apply moves.
  • fen <fen> [moves [move]...]: Use a FEN board state and apply moves.
• go: Start evaluating the position.
  • depth <depth>: Maximum depth to search.
  • movetime <ms>: How long to search for.
  • wtime <ms>: How much time white has remaining.
  • btime <ms>: How much time black has remaining.
  • winc <ms>: How much increment white has each turn.
  • binc <ms>: How much increment black has each turn.
  • perft <depth>: Run perft instead of evaluation.
• stop: Stop evaluating the position and return the best move.
• setoption: Sets a customizable option (listed above).
  • name <name>: Case-sensitive option name.
  • value <value>: New value for the option.
• quit: Exit the program.

Halcyon also supports some custom commands:

• print: Prints the current board position.
• seval: Prints the static evaluation of the position.
• gettune: Prints the values of all tunable parameters.
• settune [value]...: Sets the values of tunable parameters.
• datagen: Generates self-play games.
  • <output>: File to write to.
  • <positions>: Total number of positions to generate.
  • <depth>: Maximum depth to search to for each position.
  • <time>: Maximum time to search each position in milliseconds.
  • <best ply>: Ply to start using best moves instead of random moves.
  • <max ply>: Maximum ply before starting a new game.

This project uses CMake and has only been tested with GCC on Linux and MinGW-w64 on Windows. Other compilers are not guaranteed to work. Not all combinations have been testing, so it is possible that some operating systems and/or architectures may require modifications to the project to compile.

The following x86 instruction set extension options are available:

• NONE
• POPCNT
• BMI2
• AVX2
• AVX512

If CMake cannot determine your operating system, you can manually assign it with -DEXE_OS=<os>. CPU architecture can be assigned with -DEXE_ARCH=<arch>. Neither of these options affect the build and are only for file naming.

To build, do the following:

cd Build
cmake .. -DCPU_EXT=<ext>
make

To build, do the following:

cd Build
cmake .. -G "MinGW Makefiles" -DCPU_EXT=<ext> -DSTATIC_THREADS=1
mingw32-make.exe