Chess engine: Lunarr 2.1.1

Lunarr - chess engine written in C#, compliant with the UCI protocol.

Run the excecutable file found in [Releases](https://github.com/Eliagiac/white-widow/releases), using a chess GUI such as [Arena](http://www.playwitharena.de/).

The project was renamed from White Widow to Lunarr.

This version is significantly more stable. There should be no more bugs with illegal moves being returned or other related issues: while the previous version would very often freeze or crash, this has not happened yet with the new version when testing.

There have been multiple optimizations and changes resulting in a significant performance increase. The engine is estimated to have an ELO of around 2000 in blitz.

There are still issues regarding the transposition table, both with its performance and with more specific bugs, such as failing to see a draw by repetition that would be caused by the ttMove (which was stored when the position hadn't yet been repeated).

Some of the features currently in development involve a better system for killer moves and improved draw by repetition detection, including finding draws one move before they happen (upcoming draw by repetition detection).

Other changes include draw by fifty-move rule detection, a correct implementation of null move pruning, as well as the new ability to write log files while in the Debug configuration. Moves are also now stored with just 16 bits in the Move struct, using a MoveValue with the first 4 bits used as a flag, middle 6 bits for the target square and last 6 bits for the start square.

v.2.1.1:

Fixed a major bug involving draws by repetition.

Previously, draws by repetition from positions before the root were not seen, because the position history was lost when making a copy of the board.

This issue is now fixed, resulting in a significant increase in playing strength, and an Elo difference of ~70 points in self-play against the previous version.

Lunarr 2.1.1 download