Catto v0.9.0

• Evaluation: Gives bonus points if rooks are on half-open file.
• Evaluation: Gives bonus points to passed pawns.
• Added a depth option for "go" command in UCI client.
• Added a build option for Bun in package.json.

Catto v0.8.1

Added delta pruning based on futility pruning.

Catto v0.8.0

Added futility pruning which improves the performance a little bit.

Catto v0.7.0

• Added iterative deepening and aspiration windows, removed fixed depth searching. Info at each depth will now be logged out as the engine searches.
• Added simple time control: Fixed time limit of 1/30 of the remaining time. Catto will now search infinitely if wtime, btime or movetime are not provided.
• Small optimizations which removes duplicated function calls.
• Fixed "position fen" command not working properly with "moves".

Catto v0.6.1

• Added "info" to uci client which currently includes depth, nodes, score cp, time, pv.
• Removed "debug" and "stable" options because they are currently useless. Debug info is in also uci's info now so no reason to have it.

Catto v0.6.0

• Add principal variation search.
• Minor optimization by reducing duplications.
• Raise search extension limit to 2.
• Add comments to config file.
• Only use UCI.

Catto v0.5.2

• Fixed LMR: if moves with reduced depth can raise alpha, we would have to do full search again. Otherwise, a move that has a high score in low depth might not have a high score in high depth, and we potentially miss a better move too.
• Fixed Zobrist hashing: hash piece color as well. FEN string is removed too.
• Reduced depth to 4, increase search extension to 2. This is not fast, but not terribly slow like the previous version.

Catto v0.5.1

• Fixed LMR:
  • Fixed an error where rather than searching the first 4 moves of each depth at full depth, it will just search the first 4 moves it found at full depth.
  • Fixed an error where it might still perform LMR on moves that cause extensions.
• Added hash move ordering.
• Reduced search extensions limit due to it being too slow.

Catto v0.5.0

• Added check extensions, extend search depth by 1 when king is in check.
• Added one reply extensions, extend search depth by 1 when only one move is possible (likely forced).

Catto v0.4.2

Hotfix:

• Fixed a mistake where the lower depth hash node is actually chosen.
• Temporarily use FEN rather than Zobrist because there are some problems with it.