I am a senior at Washington University at St. Louis, majoring in Mathematics. Soon to be entering a Ph.D. program in Mathematics at UC Santa Barbara.

A paper on an unsolved problem relating to magic squares.

NEW. Minor changes to repetition detection. This will be the last version for awhile, maybe forever.
Betsy 6.51

A much improved version of Betsy that plays Fischer Random Chess. The new release of Arena fully supports FRC so no need ot use the winboard hack anymore.
Betsy For Fischer Random Chess

Added space evaluation, it looks to be a rather good improvement for such a small change.
Betsy 6.24

Found a major bug in the repetition detection. It should be fixed now. Also, it now runs almost twice as fast since I fixed a bug in the evaluation that was slowing it down a lot.
Betsy 6.23

Eval is now done completely at leaf nodes, I think this fixes some problems with game stage transitions. Also, some experimental extensions that seem to work and some minor changes to the king safety evaluation.
Betsy 6.09

Betsy now plays Fischer Random Chess. As of yesterday, there was no interface that supported the castling rules correctly (Arena has some problems currently). I hacked up winboard and it works now. Here it is. In this zip is the source code for the hacked Winboard, the Winboard executable and betsyfischer.exe. To run it, just unzip it and run go batch file. Or just look at the command string required and do whatever you normally do. The command line is the same as Betsy, but the book option has been removed. EGTB's still work.

The castling rules are implemented like this:
Castling Rules

To make Betsy castle in Winboard, drag the rook you want to castle with and drop it on top of your king. This was the best way I could think of to do it since there can be a lot of ambiguity.

Betsy for Fischer Random Chess

If any other program authors are thinking about making a Fischer Random version and have questions about castling or whatever, email me.





I am working on Betsy again and I will be posting versions up here frequently when I think it is better. This was a semi-major rewrite, so there are probably bugs. The engine looks much stronger than previous versions. I forget all the improvements that have been made, but some highlights:

Pondering added
Better opening book format and can build books from PGN
Improved king safety, slightly asymmetrical favoring attacking opponent king
Donkey?
Score pieces pinned to king
Various other additions to eval

I have put Nalimov endgame tablebase support back in.
Betsy 6.0 sigma2

Fixed major bug in search. Also, now Betsy will use more time on a move if the score drops suddenly. There seems to be a bug somewhere in the book and extremely rarely it will play something insane like here you go have my queen. Looking for it.
Betsy 6.07

I may have fixed the bug in the book. In any case, it plays a wider variety of openings and better ones I think.
Betsy 6.08

book generated from gm2600.pgn
Sample command line:
"c:\betsy67\release\betsy607.exe -xboard 32 c:\betsy67\betsy.bk c:\betsy66\egtb\"
The 32 means to use 32Mb maximum for the hash tables. You must specify a hash table size.
That book seems to be pretty good. If you don't like it, you can build a book from within the text interface. If you can't figure it out, email me.

Previous version of my chess program Betsy 5.26.





Janneke and I at Skylla christmas party 2001, in Utrecht. You can send me email at lwr1@cec.wustl.edu