This tool is now embedded in the learn branch of stockfish. Please use stockfish.exe convert fromfile tofile [app] instead. Any further development will take place in the stockfish repository. The tool in this repository will not be updated.
NNUE Data Compressor is a tool to maximally compress NNUE training data for chess. It supports .plain and .bin formats. Functions effectively like a converter, i.e. it's possible to compress .plain but decompress to .bin and vice versa. On .plain files it achieves compression ratio between 40x to 50x which translates to ~15-20x on .bin files.
For example usage see "--help".
Requires a compiler with support for C++17.
make release