MadChess 3.2.1 Released

I have released version 3.2.1 of my chess engine.

This release fixes a bug that caused MadChess to report illegal principal variations. That is, PVs that contain illegal moves. To be clear, the bug never caused MadChess 3.2 to crash. Merely to report fantasy lines.

I didn’t notice the issue back in January because of my desire to transition from programming chess to playing chess- which involves fighting the urge to tinker with one more engine issue. I did wonder why MadChess occasionally reported truncated PVs in the CuteChess GUI. One factor contributing to my (chosen) ignorance is the CuteChess GUI (which I use to run tournaments so I can watch games in progress) silently truncates PVs that contain illegal moves. Whereas the CuteChess CLI (which I don’t use because I cannot watch games in progress) displays a warning. Despite my instinct that a bug infested the PV code, I decided not to go down that rabbit hole until this weekend.

This release does not add any features nor playing strength. Testers may substitute this version for version 3.2 without any need to restart or re-run tournaments.

Thanks to Steve who commented on the MadChess 3.2 Released post that CuteChess CLI complains of illegal PVs.

You may download x64 and x86 versions of MadChess 3.2.1 from the Downloads page. Install the appropriate version for your computer’s CPU. The x64 binary is the strongest version of the engine.