Faster move generation, Mate in X tests

24 Dec 2022

1:30 am

better uci handling, using istringstream to parse commands
better Mate Score output
added Mate in 2, 3, and 4 tests (and they pass! but slow)
inlined some functions (maybe faster now?)
added Search Type: Infinite, Fixed Depth, Time per Move, Time per Game, Ponder and Mate. Not all of them are working yet :')

3 am

movelist.reserve(40): doing this made move generation ~1.5x faster! Now reserving in all vectors.
modularized move generation
added get_threats function

Comments

Making moves with the Negamax algorithm

10 Sept 2022 after a loooonngg time!!! 4:50 am there's a lot to tell you, but firstly, i'm very happy now because i just teached my ai to capture pieces and guess what, it doesn't just look one move into the future. yes guys, i wrote the negamax algorithm!! it's much more fun to play with it now. but still it has to prioritize other things besides captures, like promotions, checks, pins etc. and obviously, mates! now i'm going to sleep as i got many works to do :(

Better algorithms and Evaluation function

11 Oct 2022 long time no see 3 am well, there's a lot of small and big changes. i'll try to explain by checking the diff. AI part: replaced minimax with alpha-beta (similar to negamax version) TODO : implement quiescence search added piece-square table scoring in eval function reduced branching in code move generation part: bugfix : moves like e1c1 were always interpreted as castling, fixed changed board representation from string to char[64] now king positions are incrementally saved, so faster to find kings several optimizations in move generation general: now engine trys to avoid moves leading to repetitions (but it is not always optimal, so should do something better) fixed several gui bugs in promotion and flipping gui supports (some) premoves fixed some bugs in move hints, still some remaining ig faster makefile BIGGEST UPDATES: uci protocol working! made a lichess bot running this engine!

Perft to find bugs in move generation

22 Jun 2022 after 2 am almost completed legal move generation function issue : sometimes switches black and white during random play issue : handling castling rights and enpassant squares while undoing a move 23 Jun 2022 after 12 am bugfix : san notation doesn't show promotion added perft and divide function now we can find corner cases easily! 2 am wasted 1 hour on why I'm getting 1 move less than expected reason: code generates kingside else queenside castling moves 🥲 3 am bugfix : now engine checks threatened squares during castling improved perft function still a lot of things to do (getting wrong perft results)

Yonder Chess

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