Chess engine: Rengar 2.1.1

Rengar - chess engine with a simple evaluation function written in C++.

Rating Chess Engines Diary CEDR=2657

Rengar 2.0.0 - results:

Opponent	Score	+-	Games
Oxidation 0.7.2	7.5/8	+7	8 Games
Tcheran 3.0	7/8	+6	8 Games
Schoenemann 0.2.0	4.5/8	+1	8 Games
4ku 5.1	3.5/8	-1	8 Games
Radiance 3.3	6/6	+6	6 Games
CT800 1.46	4.5/6	+3	6 Games
Knightx 4.11	3.5/6	+1	6 Games
Cwtch 1	3.5/6	+1	6 Games
Integral v4	0/6	-6	6 Games
Amelia 0.12	2/2	+2	2 Games
Nectar 0.1.7	2/2	+2	2 Games
StoneChess 2024-09-13	2/2	+2	2 Games
Heimdall 1.0 JA	0/2	-2	2 Games
Fidelio 17 MPV	0/2	-2	2 Games
Fidelio 17	0/2	-2	2 Games
Patricia 3.1	0/2	-2	2 Games
Rems 150824	0/2	-2	2 Games
Rems MPV Sep24	0/2	-2	2 Games
Rems Sep24	0/2	-2	2 Games
Roc 2024Aug24	0/2	-2	2 Games
RubiChess 20240817	0/2	-2	2 Games

v.2.1.1:

Fixed an issue that caused illegal moves in games without increment. With increment, this release will behave almost identically to v2.1.0.

If Rengar is asked for a move with 33 milliseconds or less on the clock, it would previously skip the deepening loop and play some move interpreted from uninitialized garbage. In practice, I observed this to be the last move Rengar played. Now we search to depth at least 4 provided the search time stays under a millisecond.

This only matters for games played without increment. H/t to Lars for flagging the underperformance in such games.

Rengar 2.1.1 download