Leorik 2.3

All previous versions had their evaluation tuned on a dataset of 725k annotated positions from Zurichess. The labels of these positions were derived by using Stockfish, so previously Leorik owed a part of his chess knowledge to two other engines.

In this version all previously handcrafted evaluation terms have become tunable weights and all weights are tuned from scratch on selfplay games. The initial batch of selfplay games were played with a version that evaluated positions only using the commonly accepted Point Values of Chess Pieces. Even though this version lost about 700 Elo in strength the games were good enough to tune a new set of weights, compile a stronger version and repeat the process. After half a dozen iterations Leorik surpassed it's old playing strength. And it's showing a new aggressive playstyle discovered by playing thousands of matches against itself.

In addition to this major change there have been a few bugfixes and tweaks to existing functionality like an improved Move-History but no new features were added.