Onno

**[[Home]] * [[Engines]] * Onno**
|| [[image:logo.png link="http://www.onnochess.com/index.html"]] ||~ || **Onno**,
was a commercial chess engine developed by [[Onno Garms]], written in [[Cpp|C++]] and released in May 2009. After announcing the end of Onno's development in March 2011 <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=38403|Development of Onno ends]] by [[Onno Garms]], [[CCC]], March 13, 2011</ref>, Onno Garms revealed several ideas that made Onno stronger. The 32/64-bit [[Windows]] or 64-bit [[Linux]] executables communicate with a chess [[GUI]] via the [[UCI]]. ||
|| Onno logo <ref>[[http://www.onnochess.com/index.html?onno.html|Onno Chess Software]]</ref> ||~ ||^ ||
[[toc]]
=Description=
==Basics==
Onno uses a fixed shift variation of [[Magic Bitboards|Magic bitboards]] <ref>[[http://www.open-aurec.com/wbforum/viewtopic.php?f=4&t=50043|Magic with fixed shift]] by [[Onno Garms]],  [[Computer Chess Forums|Winboard Forum]], March 18, 2009</ref> to determine [[Sliding Piece Attacks|sliding piece attacks]]. Its [[Static Exchange Evaluation|static exchange evaluation]] considers [[Alpha|alpha]] and [[Beta|beta]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=40054|SEE with alpha beta]] by [[Onno Garms]], [[CCC]], August 14, 2011</ref>. [[Evaluation]] features were [[Automated Tuning|tuned automaticly]] performing a [[Genetic Programming#GeneticAlgorithm|Genetic algorithm]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=38412|Parameter tuning]] by [[Onno Garms]], [[CCC]], March 13, 2011</ref>.
[[#Search]]
==Search==
Onno applies an [[Iterative Search#Onno|iterative search]] along with [[Principal Variation Search|PVS]], [[Null Move Pruning|null move pruning]] and [[Null Move Pruning#ZugzwangVerification|verification search]]. Onno further uses a technique dubbed **bad pruning** similar to [[Razoring|razoring]]. The idea is to apply a [[Reductions|reduced search]] with a reduced [[Window|window]] - if the search at depth d-3 says that one loses more then a pawn, it does not search the move with the current depth d <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=38407|Bad Pruning]] by [[Onno Garms]], [[CCC]], March 13, 2011</ref>. 

===Parallel Search===
The MP version of Onno searches in [[Parallel Search|parallel]] utilizing [[Young Brothers Wait Concept|YBWC]] by following [[Rainer Feldmann|Rainer Feldmann's]] 1993 Ph.D. thesis //Game Tree Search on Massively Parallel Systems// <ref>[[Rainer Feldmann]] (**1993**). //Game Tree Search on Massively Parallel Systems//. Phd-Thesis, [[http://www2.cs.uni-paderborn.de/fachbereich/AG/monien/PUBLICATIONS/POSTSCRIPTS/feldmann_phd.pdf|pdf]]</ref> using [[http://en.wikipedia.org/wiki/Virtual_synchrony|virtual messaging]].

===Node Types===
Onno determines expected [[Node Types]] to perform [[Internal Iterative Deepening|IID]] not only at [[Node Types#PV|PV-nodes]] but also at expected [[Node Types#CUT|Cut-nodes]]. Onno Garms gave following rules <ref>[[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=399511&t=38408|Re: On internal iterative deeping]] by [[Onno Garms]], [[CCC]], March 17, 2011</ref>
* The [[Root|root node]] is a PV-node.
* The first child of a PV-node is a PV-node
* The further children are searched by a [[Scout|scout search]] as CUT-nodes
* [[Principal Variation Search|PVS]] re-search is done as PV-node
* The first node of bad pruning is a CUT-node
* The node after a [[Null Move|null move]] is a CUT-node
* The first node of [[Null Move Pruning#ZugzwangVerification|null move verification]] is a CUT-node
* [[Internal Iterative Deepening|Internal iterative deepening]] does not change the node type
* The first child of a CUT-node is an [[Node Types#ALL|ALL-node]]
* Further children of a CUT-node are CUT-nodes
* Children of ALL-nodes are CUT-nodes

=See also=
* [[Various Classifications#GivenName|Given Name]]
* [[Iterative Search#Onno|Iterative Search in Onno]]

=Forum Posts=
==2009==
* [[http://www.open-aurec.com/wbforum/viewtopic.php?f=4&t=50043|Magic with fixed shift]] by [[Onno Garms]],  [[Computer Chess Forums|Winboard Forum]], March 18, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=27316|Onno 0.12]] by Ted Summers, [[CCC]], April 04, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=27952|New commercial engine soon: Onno]] by [[Jouni Uski]], [[CCC]], May 17, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=28170|Onno 1.0 is now available]] by [[Graham Banks]], [[CCC]],  May 30, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=28221|About becoming Commercial. The Onno Case]] by [[Fernando Villegas]], [[CCC]], June 02, 2009
* [[http://www.talkchess.com/forum/viewtopic.php?t=29598|Onno 1-1-1 released]] by [[Eduard Nemeth]], [[CCC]], August 30, 2009
==2010==
* [[http://www.talkchess.com/forum/viewtopic.php?t=32945|Onno MP beta has been released to customers]] by [[Martin Thoresen]], [[CCC]], February 27, 2010
* [[http://www.talkchess.com/forum/viewtopic.php?topic_view=threads&p=351576&t=34561|Re: DTS Structure]] by [[Onno Garms]], [[CCC]], May 28, 2010  » [[Iterative Search#Onno|Iterative Search in Onno]]
==2011 ...==
* [[http://www.talkchess.com/forum/viewtopic.php?t=38403|Development of Onno ends]] by [[Onno Garms]], [[CCC]], March 13, 2011
* [[http://www.talkchess.com/forum/viewtopic.php?t=38404|Root node search]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Root]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38406|Software Engineering]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[History Heuristic]], [[Toga]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38407|Bad Pruning]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Pruning]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38408|On internal iterative deepening]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Internal Iterative Deepening]], [[Node Types]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38409|Less null move pruning by trans map]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Null Move Pruning]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38410|Playing better moves in drawish positions (anti-0.00)]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Draw]], [[Contempt Factor]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38411|On parallelization]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Parallel Search]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38412|Parameter tuning]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Automated Tuning]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38413|Memory-PV-Search]] by [[Onno Garms]], [[CCC]], March 13, 2011 » [[Principal Variation Search]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=38766|Move ordering by PST]] by [[Onno Garms]], [[CCC]], April 16, 2011 » [[Piece-Square Tables]], [[History Heuristic]], [[Move Ordering]]
* [[http://www.talkchess.com/forum/viewtopic.php?t=40054|SEE with alpha beta]] by [[Onno Garms]], [[CCC]], August 14, 2011 » [[Static Exchange Evaluation]], [[SEE - The Swap Algorithm]]

=External Links=
==Chess Engine==
* [[http://www.onnochess.com/index.html?onno.html|Onno Chess Software]]
* [[http://www.schach-welt.de/interviews/onno-garms|Computerschach, Interview mit Onno Garms]] by [[Frank Quisinsky]], December 25, 2009 (German)
==Misc==
* [[http://de.wikipedia.org/wiki/Onno|Onno – Wikipedia.de]] - [[http://en.wikipedia.org/wiki/Frisian_languages|Frisian]] [[https://en.wikipedia.org/wiki/Given_name|Given Name]] (German)

=References= 
<references />
=What links here?= 
[[include page="Onno" component="backlinks" limit="80"]]
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