Oldre.com

'cause I've got something to say!

The Latista Chess Engine

A chess program written by Eric Oldre.

License

Latista is free for personal use.

Download

• Latista 1.5 (Released 1/14/06) 
• Latista 1.4 (Released 12/23/05) 
• End-game bitbase files for use with Latista 1.4 and up (Developed by Daniel Shawul) 
• Latista 1.3 (Released 7/1/05) 
• Latista 1.2 (Released 1/1/05)

How do I play?

Latista supports the xboard chess engine protocol. This means that you need a graphical user interface (GUI) in order to be able to play against it. Examples of some interfaces that you can use to play Latista are:

• Winboard
• Arena

Latista also plays on the Free Internet Chess Server (FICS) whenever my computer is free. It plays under the handle "Murderhole". It has a rating of about 2100.

What has changed since 1.4?

• Latista nows uses more agressive null move pruning. R=3, with a verification search in the endgame
• The evaluation function has been tweaked with a few special cases. Other parts have been simplified to make a more smooth transition from the middle to end game.
• New configuration option: [book]selectivity. The higher the number the "closer to the vest" Latista will play during the opening. With a value of 100 it will always play the most popular move in it's book.
• New configuration option: [logging]createlogfile (1 or 0). Now you have the option to not create a log file and conserve hard disk space.
• Changes to the way Latista handles searching on a "ponderhit". It will now simply continue the ponder search, instead of restarting. This should increase it effectiveness in game with pondering on.

How do I use the endgame bitbases?

1. Download the endgame bitbase dll and data files.
2. Put the files in a directory on your PC. Put both the dll and data files in the same directory.
3. Edit the latista.ini file, enter the location of the files in the [egbb] section under "path".

How does Latista work?

board representation: Latista is a chess engine built on the concept of rotated bitboards, a concept developed by Robert Hyatt. Information about them can be found at http://www.cis.uab.edu/info/faculty/hyatt/pubs.html search features: Latista uses a Alpha-Beta search algorithim with several enhancements which include:

• Iterative deepening.
• Aspiration window.
• Null move cutoffs
• Quiesent search (captures and promotions only)
• Move ordering by:
  • Hash table entries
  • Internal Iterative deepening
  • Static exchange evaluation
  • Killer moves
• Fractional extensions for:
  • Checks
  • Pawn to 7th rank.
• Evaluation features:
  • Material
  • Pawn hash table
  • Piece square table
  • Piece activity
  • Pawn shelter for king
  • King safety
  • Pawn Races
  • Development

What can I expect in future releases?

There are many improvements that I'd like to make in future releases.

• Configurable hash table size.
• Configurable evaluation and search parameters.
• Hopefully, much stronger play.
• Improved king-safety.

Special thanks to

• The members of the computer chess club.
• All the directors of winboard engine tournaments.
• Jim Ablett for creating the Latista logo image.
• Daniel Shawul for developing the shared endgame bitbase library.