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**[[Home]] * [[People]] * Ronald de Man**
**Ronald de Man**, [[https://en.wikipedia.org/wiki/Alias|alias]] [[https://en.wikipedia.org/wiki/Syzygy|Syzygy]],
a Dutch mathematician, computer scientist and IP lawyer, in the 90s researcher at [[https://en.wikipedia.org/wiki/Eindhoven_University_of_Technology|Eindhoven University of Technology]], competitor at the [[https://en.wikipedia.org/wiki/International_Mathematical_Olympiad|International Mathematical Olympiad]] 1990, winning the Silver medal <ref>[[http://www.imo-official.org/participant_r.aspx?id=2462|International Mathematical Olympiad - Ronald de Man]]</ref> , and the [[https://en.wikipedia.org/wiki/ACM_International_Collegiate_Programming_Contest|ACM International Collegiate Programming Contest]] 1995, to win Bronze within the //ARoMA// team from [[Delft University of Technology]] <ref>[[http://www.delta.tudelft.nl/artikel/-programmeren-hoef-je-niet-te-kunnen/10155|'Programmeren hoef je niet te kunnen' - TU Delta - Weekblad van de Technische Universiteit Delft]], March 16, 1995 (Dutch)</ref> <ref>[[http://icpc.baylor.edu/past/|ACM Programming Contest World Finals]]</ref> . He is co-developer of the [[Linux]] [[https://en.wikipedia.org/wiki/Desktop_environment|desktop environment]] and [[https://en.wikipedia.org/wiki/Graphical_user_interface|graphical user interface]] [[https://en.wikipedia.org/wiki/GNOME|GNOME]] <ref>[[http://rpmfind.net/linux/RPM/opensuse/11.1/x86_64/gnome-libs-32bit-1.4.2-11.1.x86_64.html|gnome-libs-32bit-1.4.2-11.1.x86_64 RPM]]</ref> , and as chess programmer author of the chess and [[Losing Chess|Antichess]] <ref>[[http://ilk.uvt.nl/icga/games/losingchess/|ICGA: Losing Chess]] by [[Guy Haworth]]</ref> playing program [[Sjaak]], which plays at [[FICS]] under the handle //TrojanKnight// <ref>[[http://www.nicklong.net/chess/atomic/mewis/trojanknight.txt|Statistics for TrojanKnight(C)]]</ref> <ref>[[http://groups.google.com/group/rec.games.chess.computer/msg/6bb58a0605f7e2f1|Re: AEGON 97/ 1st round: HIARCS lost]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], April 25 1997</ref> <ref>[[http://poincare.matf.bg.ac.rs/~andrew/suicide/fics/en0404C.htm|FICS Statistics - April 2004, Best Ratings - Computer List]]</ref>. He further ported [[Stockfish]] to plain [[C]], dubbed [[CFish]].
[[#ScoringRootMoves]]
=Scoring Root Moves=
[[Ronald de Man]] proposed a method to apply [[Search with Random Leaf Values|randomness]] <ref>[[https://groups.google.com/d/msg/rec.games.chess.computer/AI3xadkLEIk/UUqnp9J3BaMJ|Re: random play]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], November 28, 1996</ref> and/or bonuses, i.e. developing bonus, or penalties suggested by an [[Oracle|oracle]], in [[Score|scoring]] [[Moves|moves]] at the [[Root|root]] without any changes in [[Alpha-Beta|alpha-beta search]] or [[Evaluation|leaf evaluation]], and without any problems with the [[Transposition Table|transposition table]] <ref>[[https://groups.google.com/d/msg/rec.games.chess.computer/me7GkjsEgds/iC_ZJm5UwswJ|Re: computer chess "oracle" ideas...]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], April 7, 1997, see also [[http://www.stmintz.com/ccc/index.php?id=390268|Re: mate threat extension/null move]] by [[Don Beal]], [[CCC]], October 04, 2004 » [[Mate Threat Extensions]], [[Null Move Pruning|Null Move]] and [[Win at Chess|WAC]] booster</ref>:
|| {{First of all, don't worry, it is possible. But you should not try to pass the bonus to the tip nodes. That would indeed give hash problems. The solution is to not change anything in your Search() procedure. That already solves all potential hash problems. You just add the bonus AFTER Search() has returned a value for a particular root move. So that would be done in your SearchRoot(). What you basically do there is change every occurrence of}} ||
[[code]]
value = -Search(-beta, -alpha,...)
[[code]]
in
[[code]]
value = bonus[n] - Search(bonus[n]-beta, bonus[n]-alpha,...)
[[code]]
|| {{where bonus[n] is the development bonus value for the move you are currently searching. It is all very natural when you think about it. You should consider Search() as a black box. You give it some numbers alpha and beta, and Search() gives you a number x, with the properties that, relative to the real value v of this move,}}
# If v <= alpha, then x <= alpha,
# If v >= beta, then x >= beta,
# If alpha < v < beta, then x = v.
{{If you search a move, you want to know if its real value + bonus[n] is bigger than alpha. So you want to know if its real value is bigger than alpha-bonus[n]. So you give Search() the bounds alpha-bonus[n] and beta-bonus[n], and add bonus[n] to the result. And you do this in SearchRoot().}}
{{So no fudging with hash table scores whatsoever!}}
{{Of course this trick gives all kinds of possibilities. Not only can you stimulate development, or add in some randomization. It is also easy to solve the 'underpromotion' problem: to prevent the program from under-promoting to a rook (in situations where the piece will probably be captured the next move anyway), you give underpromotion moves a penalty. Or in trivially drawn endgames like KRKR you give captures a bonus. Or in not-so-trivially drawn endgames for which tablebases give draw values you give moves that give away a piece (but do not change the outcome) a penalty, hoping that the opponent will make a fatal mistake further on in the game :-)}}
{{Ronald de Man}} ||
=Bloom Filter=
Ronald de Man revealed the trick to speed up [[Repetitions|repetition detection]] with a [[https://en.wikipedia.org/wiki/Bloom_filter|Bloom filter]], implemented as a small [[Hash Table|hash table]] indexed by some lower bits of the hash-key, to increment a counter while entering and decrement the counter while leaving a node <ref>[[http://groups.google.com/group/rec.games.chess.computer/browse_frm/thread/c431ac1739de871b/d8f8d6ee1b252b86|Re: triple repetition]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], October 27, 1997</ref> <ref>[[Marcel van Kervinck]] (**2002**). //The design and implementation of the Rookie 2.0 Chess Playing Program//. Masters Thesis, [[http://alexandria.tue.nl/extra2/afstversl/wsk-i/kervinck2002.pdf|pdf]]</ref> .
=Syzygy Bases=
In April 2013, Ronald de Man published his [[Syzygy Bases]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=47681&start=45|Re: New 6-piece tablebases]] by [[Ronald de Man]], [[CCC]], April 10, 2013</ref> , a compact [[Endgame Tablebases|endgame tablebase]] of up to six pieces. It consist of two sets of files, **WDL** files storing win/draw/loss information considering the [[Fifty-move Rule|fifty-move rule]], for access during search, and **DTZ** files with [[Endgame Tablebases#DTZ|distance-to-zero]] information for access at the [[Root|root]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=47681|New 6-piece tablebases]] by [[Ronald de Man]], [[CCC]], April 01, 2013</ref> <ref>[[https://github.com/syzygy1/tb|syzygy1/tb · GitHub]] by [[Ronald de Man]]</ref> .
=Selected Publications=
<ref>[[http://www.informatik.uni-trier.de/~ley/db/indices/a-tree/m/Man:Ronald_de.html|DBLP: Ronald de Man]]</ref>
* [[Ronald de Man]] (**1995**). //[[http://www.ams.org/journals/era/1995-01-02/S1079-6762-95-02005-1/home.html|On Composants of Solenoids]]//. [[https://en.wikipedia.org/wiki/Fundamenta_Mathematicae|Fundamenta Mathematicae]] 147, [[http://matwbn.icm.edu.pl/ksiazki/fm/fm147/fm14726.pdf|pdf]] <ref>[[https://en.wikipedia.org/wiki/Solenoidal_vector_field|Solenoidal vector field from Wikipedia]]</ref>
* [[Ronald de Man]] (**1999**). //[[http://dl.acm.org/citation.cfm?id=312392|The Generating Function for the Number of Roots of a Coxeter Group]]//. [[http://www.informatik.uni-trier.de/~ley/db/journals/jsc/jsc27.html#Man99|Journal of Symbolic Computation, Vol. 27, No.6]] <ref>[[https://en.wikipedia.org/wiki/Coxeter_group|Coxeter group from Wikipedia]]</ref>
* [[http://www.informatik.uni-trier.de/~ley/db/indices/a-tree/m/Malhotra:Richa.html|Richa Malhotra]], [[http://www.informatik.uni-trier.de/~ley/db/indices/a-tree/h/Haalen:Ronald_van.html|Ronald van Haalen]], [[Ronald de Man]], [[http://nl.linkedin.com/in/michielvaneverdingen|Michiel van Everdingen]] (**2003**) //[[http://onlinelibrary.wiley.com/doi/10.1002/bltj.10065/abstract|Managing service-level agreements in metro ethernet networks using backpressure]]//. [[http://www.informatik.uni-trier.de/~ley/db/journals/bell/bell8.html#MalhotraHME03|Bell Labs Technical Journal, Vol. 8, No. 2]] <ref>[[https://en.wikipedia.org/wiki/Metro_Ethernet|Metro Ethernet from Wikipedia]]</ref> .
=Forum Posts=
* [[http://groups.google.com/group/rec.games.chess.computer/msg/a30577d2a7a74a51|Re: random play]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], November 28, 1996 <ref>[[http://groups.google.com/group/rec.games.chess.computer/browse_frm/thread/ba5f8759ec0ce454|Randomness in move selection]] by [[Robert Hyatt]], [[Computer Chess Forums|rgcc]], December 01, 1996</ref>
* [[http://groups.google.com/group/rec.games.chess.computer/msg/9b240379394bc968|Re: Hash functions for use with a transition table]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], March 7, 1997 » [[BCH Hashing]]
* [[http://groups.google.com/group/rec.games.chess.computer/msg/0df39371422a600c|Re: computer chess "oracle" ideas...]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], April 3, 1997 » [[Oracle]]
* [[http://groups.google.com/group/rec.games.chess.computer/msg/ccc2546e26d92f88|Re: computer chess "oracle" ideas...]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], April 7, 1997
* [[http://groups.google.com/group/rec.games.chess.computer/browse_frm/thread/c431ac1739de871b/d8f8d6ee1b252b86|Re: triple repetition]] by [[Ronald de Man]], [[Computer Chess Forums|rgcc]], October 27, 1997
* [[http://www.talkchess.com/forum/viewtopic.php?t=47681|New 6-piece tablebases]] by [[Ronald de Man]], [[CCC]], April 01, 2013 » [[Syzygy Bases]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=49702|tablebase caching / mmap() / page cache]] by [[Ronald de Man]], [[CCC]], October 13, 2013 » [[Memory]], [[Endgame Tablebases]], [[Syzygy Bases]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=59947|Question to syzygy author]] by [[Marco Costalba]], [[CCC]], April 24, 2016
* [[http://www.talkchess.com/forum/viewtopic.php?t=60222|tablebase compression / academic integrity]] by [[Ronald de Man]], [[CCC]], May 19, 2016 <ref>[[Victor Zakharov]], [[Michael G. Malkovsky]], [[Vladislav Y. Shchukin]] (**2016**). //[[http://link.springer.com/article/10.3103%2FS0278641916010076|Compression of underdetermined data in a 7-piece chess table]]//. [[http://www.springer.com/mathematics/journal/11968|Moscow University Computational Mathematics and Cybernetics]], Vol. 40, No. 1</ref>
=External Links=
* [[https://github.com/syzygy1/tb|syzygy1/tb · GitHub]] by [[Ronald de Man]] » [[Syzygy Bases]]
* [[https://en.wikipedia.org/wiki/Syzygy|Syzygy from Wikipedia]]
> [[https://en.wikipedia.org/wiki/Syzygy_%28mathematics%29|Syzygy (mathematics) from Wikipedia]]
* [[http://ilk.uvt.nl/icga/games/losingchess/|ICGA: Losing Chess]] by [[Guy Haworth]]
=References=
<references />
=What links here?=
[[include page="Ronald de Man" component="backlinks" limit="100"]]
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