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Subject: Re: S-chess 1.2

Author: David Dahlem

Date: 10:56:25 09/18/02

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Hi Stan
Has the name of your engine changed from Stan's Chess to S-chess?
Regards
Dave

On September 18, 2002 at 13:14:03, Stan Arts wrote:

>Hello!
>
>I have finished my third version of S-chess, and it has many new features,
>and it is a little bit stronger again.
>I describe the new things in my new readme.txt, so I paste it in! :
>
>--------------------------------------------------------------------
>
>This is the README.TXT file with extra info about my chess-program.
>
>S-chess is my own attempt at writing a computer-chessplaying program, And I am
>a 21 year old hobbyist-programmer from holland. After doing some first computer-
>chess experiments in february and onwards, I started on S-chess the 7th of May
>2002. And since then I work on it almost every day and I think I have put a bit
>too much time into it.. :-)
>My program is freeware, and can be distributed freely, as long as all the files
>are unmodified.
>
>Version 1.2 is the third release of my program, the main improvements (over
>version 1.1) are:
>
>It's stronger, and I estimate it 100 to 200 ELO stronger than version 1.1 .
>Implemented 16MB of Hashtables, that mainly improve move-ordening on great
>depths to make alpha-beta slightly more efficient.
>I now use and tweaked a different Alpha-beta technique, and it makes my program
>nearly twice as efficient. (In some positions that's nearly an extra ply)
>Especially under longer timecontrols the difference is huge.
>Check-detections everywhere in the searchtree now (instead of just on the 1st
>ply) so illegal positions in the searchtree are avoided, and mates are always
>correctly scored that way.
>Shows a PV (=principle variation/expected best line) but because of the new
>alpha-beta technique it's sometimes difficult to determine. Also I retrieve this
>PV from the hashtable instead of directly out of the searchtree which causes it
>to be shorter than it could of been sometimes, (values in the hashtable get over
>written a lot) and also some of the "best" moves might be noncense. But overal
>it still gives a good impression of the expected best line, or any great
>threats.
>New chessknowledge that improves play. Centreplay is different now, and also it
>now knows how to solve a king/king+queen or king/king+rook endgame.. And some
>other small tweaks, overal it doesn't play so bad positionally, as it knows a
>lot of things about pawnstructure and general piece-play etc.
>I implemented a small randomfactor.
>
>New features under winboard:
>Edit position! So it is now possible to set up a position and continue play
>from this position. Best way to do this is to skip edit-game mode, as this
>sometimes confuses my program. So it would be best to create the position, then
>set my program (whichever colour you want it to be) on move, and then click
>directly "machine white" or "machine black" so edit-game mode is skipped.
>Edit-game mode is implemented too though, and generally won't give problems.
>Retract move command is now implemented, and will make my program take back
>2 halfmoves, so the move my program played after your move and your move get
>retracted with you set on move again. (It's possible to keep taking back as
>far as you want) Please always use the retract move command directly in play
>mode instead of going into edit-game mode and using the undo command to take
>back moves with S-chess.
>
>
>Some general features of my program are:
>
>I estimate my programs strength to atleast 1600-1700 ELO (on an average
>computer) against human players under tournament controls, (should be more in
>quick games) but I am not sure about these figures though, I don't have much
>testing against human players and I am the human most testing has been done
>against..:-)
>Knows all rules of chess, including en-passant, underpromotions, and all
>special moves, also it knows draws by 3x repetition, stalemate and by the 50
>move rule.
>Technicaly it does a minimaxing search, and has alpha-beta pruning to make
>this efficient. Null-move isn't used yet, and I think this will be the last
>version without this technique :-)
>My program relies mostly on it's full-width searching, and doesn't do too
>much extending, (So it might miss some very deep combinations, but will find
>shallower quiet combinations more quickly.) but it does however extend a lot
>of capture-lines deeper than the full-width depth.
>My program is also a good problem solver, because I am still not using null-
>move pruning or any other agressive pruning that might make a program
>sometimes miss a tactical line, and therefore my programs search is very
>accurate, and it will always find a (tactical) combination upto the depth
>that's seen on screen, and it might even find a deeper one than the full-width
>depth. By the way, the maximum full-width depth for my program is 30 ply, but
>I doubt it'll ever reach that..
>There is a very small opening-book implemented in my program, it has just
>about 50 moves.. :-) But this way my program knows most common openings and
>it will randomize it's openingplay a bit.
>S-chess is written in Pascal, and compiled with the 32-bit Free Pascal for
>win32 aplications. S-chess requires an MMX processor to run. If you encounter
>a problem with this though, just email me and I send you a version that'll
>run on any processor. Same goes when you encounter a problem with the 16MB
>hashtables, I will send you one with them switched off or made smaller.
>
>There is also a stand alone version that has a fully 3D chessboard and pieces
>and chessclock and room and and..well everything is 3D and you can move/fly
>around in it freely, and it gives a very neat experience for a chessprogram. I
>wanted to "include" this version with the winboard-version, but I wasn´t
>able to complete the 3D version along with the new winboard version. :-(
>So I am currently still developing this version, but it's already possible to
>play against a beta version, (with the chesscode of S-chess version 1.1, will
>have the 1.2 code soon) and email me if you would like to receave it!
>(The 3D code I already developed years ago for some other experimenting and
>games and mainly for my flight simulator I wrote back in 1997, and now I
>thought it would be a good idea to use this code for my chessprogram.. )
>Please take a look at the screenshots!!
>
>Enjoy!
>--------------------------------------------------------------------
>
>Stan



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