A chess engine, like Crafty or gnuchess or Fruit, but much weaker. It would probable rate around 2100 on five-minute games.
Book (for versions 0.6.900 and up):
- 64-bit: http://organicrobot.com/smallpotato/book64.opn.bz2 or http://organicrobot.com/smallpotato/book64.zip
- 32-bit: http://organicrobot.com/smallpotato/book32.opn.bz2 or http://organicrobot.com/smallpotato/book32.zip
Old Windows binaries: http://organicrobot.com/smallpotato/smallpotato061.zip
Old book (versions up to 0.6.1): http://organicrobot.com/smallpotato/book32-0.6.1.zip or http://organicrobot.com/smallpotato/book32-0.6.1.opn.bz2
Uncompress the book and put in the same directory as the binary.
To run using xboard as a frontend, use
xboard -fcp smallpotato
To run it through WinBoard, you will need to add something like the following to your winboard.ini:
/fcp smallpotato /fd "full\path\to\smallpotato\directory"
/scp smallpotato /sd "full\path\to\smallpotato\directory"
Change engine settings by editing sp.rc
For the chess-engine enthusiast, it implements:
- Transposition table
- Quiescent search
- Null-move pruning
- History move ordering
- Run-time configurable value tables
More information on the README
- Works on 64-bit systems
- Extremely minor tweaking of evaluation (of most likely no consequence)
- Fixed a bug where it could make an illegal move on the 50th move of a 50-move draw.
- Note that the book format changed. Books are also not interchangeable between 32- and 64-bit systems
- Tweaked move ordering (including addition of killer move heuristic)
- Minor tweaking of evaluation (with unknown consequences)
- More configurable settings
- Removed MTD(f) and standard alpha-beta search as search options
- Bugfixes (including K v K draw claim)
- Added null-move pruning and aspiration window.
- Improved endgame evaluation (or, more precisely, it now has a separate endgame evaluation). Same with king execution phase.
- Now claims draw on insufficient material.
- Slightly friendlier command line mode.
- Minor bugfixes (fen/epd parsing).
- Now can be configured through file.
- It can now resign.
- Switched, and very slightly tweaked, default evaluation function.
- Speeded up by about 20%.
- Switched default search algorithm to negascout
- Now recover a PV line for display
- Minor transposition table tweaking
- Minor fixes of bugs introduced in 0.4.0
- Now compiles out-of-the-box in clig-less systems.
- Implemented move now and analyze.
- Switched to 0x88 move generation.
- Added opening book.
- EPD suites and lines can be solved
- Made it portable to cygwin
- Changed default hashtable size to 32MB.
- Can now specify hashtable size in kilobytes.
- Made aleweights.out be loaded by default
- No changes (reflex action release that shouldn't have
- happened due to unkown last release)
- Changed to delayed checking of check for speculated performance improvement (even though it does not seem to have materialised)
- Got rid of a couple of often used functions with array lookups for definite performance gains.
- Completed switch to move/unmove.
- Changed name to Small Potato
- Changed to move/unmove instead of move/copy struct (faster)
- Implemented undo and remove for xboard/protocol 2 programs
- (Note: Search instability noted in previous version is "meant" to be there. Caused by the nature of transposition tables, not by some bug in implementation)
- No bugfixes
- Better randomised play
- Switched to 64-bit random hashes
- Lots of bugfixes, including the crash on start introduced in v0.2.3, PGN output bugfixes, and some silliness in QuiescentSearch.
- (NOTE: Search instability still there)
- Added history ordering
- Better time management.
- PGN output for game recording.
- Changed GPL license
- Added quiescent search
- Added internal iterative deepening
- Switched to MTD(f)
- Bit of documentation.
- Fixed the hashtable (maybe)
- Improved packaging.
- Couple of bugfixes.
- Switched to Zobrist hashing.
- Switched to negamax
- Added runtime evaluation board loading
- Lots of bugfixes (especially hashtable)
- Added hashtable.
- Lots of bugfixes.
- Added first move move ordering.
- Improved FICS automation.
- Better logging and recording
- Lots of bugfixes
- Initial release
Comments, code, bugreports and patches are welcome.
Copyright (C) 2000 Alejandro Dubrovsky
Small Potato is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA