Loop+(Program)

a chess program by Fritz Reul with different board representations for 32-bit and 64-bit platforms as subject of Reul's Ph.D. thesis //New Architectures in Computer Chess//. Despite different board representation, both Loop versions presumably share same search and evaluation with similar features and weights. || toc =32-bit Loop= The 32-bit program, based on Reul's former program List, relies on a 15x12 board representation in conjunction with disjoint piece-lists with adequate move generation of blocker loops. It participated as //Loop Leiden// at the DOCCC 2006, becoming strong runner up behind Rybka. A specially adapted version called //Loop Express// became the engine of Wii Chess for the [|Nintendo] [|Wii] [|console] in 2008. The non-bitboard data-structure of Loop was also applied in Chrilly Donninger's chess machine Hydra.
 * Home * Engines * Loop**
 * [[image:320px-Tigerandturtle.jpg link="https://commons.wikimedia.org/wiki/File:Tigerandturtle.jpg"]] ||~ || **Loop**,
 * [|Tiger and Turtle] - illuminated looping ||~ ||^ ||

Reul in his thesis :

=64-bit Loop= The bitboard based Loop applies Magic Bitboards for sliding piece attack generation. Further, iterative alpha-beta bounded static exchange evaluation was applied to //Loop Amsterdam//, also performing a parallel search for a quad-core processor, which played a strong WCCC 2007 in [|Amsterdam], and became Third, behind the later disqualified Rybka, and Zappa.

Fritz Reul on an essential reason of Loop's success in Amsterdam in his thesis :

=Evaluation=

Preliminary Considerations
Evaluation was only marginally covered in Reul's thesis. In //Preliminary Considerations// he mentioned discussions with Chrilly Donninger, Fabien Letouzey and Tord Romstad, and the exchange of source codes :

Fruit Evaluation Overlap
During the ICGA Investigations concerning the Rybka Controversy and evaluation overlaps, 64-bit Loop was inspected by Mark Watkins who found congruence with the evaluation of Fruit 2.1. As confirmed by David Levy, the ICGA has received a complaint on Loop by Fruit author Fabien Letouzey and an investigation has been started about this case, as already mentioned by Watkins in August 2011.  =Complaints= ICGA President David Levy, May 09, 2014 ...

... || =See also=
 * Coiled
 * Iteration
 * Iterative Search
 * List
 * Wii Chess

=Publications=
 * Fritz Reul (**2009**). //New Architectures in Computer Chess//. Ph.D. Thesis
 * Fritz Reul (**2010**). //Static Exchange Evaluation with αβ-Approach//. ICGA Journal, Vol. 33, No. 1

=Forum Posts=

2005 ...
> [|Re: Loop List commercially available soon] by Günther Simon, CCC, October 11, 2005
 * [|Loop List available soon] by Fritz Reul, CCC, October 11, 2005
 * [|Loop 13.6 soon available] by Gerhard Sonnabend, CCC, April 20, 2007
 * [|doing undoing] by Fritz Reul, CCC, May 14, 2007
 * [|Iterative DTS] by Fritz Reul, CCC, July 02, 2007
 * [|Re: Bob Hyatt says that...] by Mike Scheidl, CCC, August 29, 2008
 * [|Re: Bob Hyatt says that...] by Uri Blass, CCC, August 30, 2008

2010 ...

 * [|Loop 2007 / Fruit 2.1] by BB+, OpenChess Forum, April 18, 2011 » Fruit
 * [|Loop as a Fruit clone] by Rebel, Rybka Forum, September 20, 2013
 * [|Complaints against the Chess programs LOOP and THINKER] by Harvey Williamson, Hiarcs Forum, May 12, 2014
 * [|Complaints against the Chess programs LOOP and THINKER] by Harvey Williamson, CCC, May 14, 2014

2015 ...

 * [|Re: FIDE Rules on ICGA - Rybka controversy] by BB+, OpenChess Forum, May 08, 2015

=External Links=

Chess Engine

 * [|List's ICGA Tournaments] (covers Loop)
 * [|Wii Chess from Wikipedia]
 * [|ICGA/Rybka controversy: Feedback - Allegations against another Chess Engine – The LOOP Program] by David Levy, ChessBase News, February 17, 2012
 * [|Allegations against two more Chess Engines – The LOOP Program] by David Levy, ICGA president, May 22, 2012 » Thinker
 * [|Complaints against the Chess programs LOOP and THINKER] by David Levy, ICGA President, May 9, 2014

Misc
> [|For loop] > [|Foreach loop] > [|While loop] > [|Do while loop] > [|Infinite loop]
 * [|Loop disambiguation page from Wikipedia]
 * [|The Loop disambiguation page from Wikipedia]
 * [|Looping disambiguation page from Wikipedia]
 * [|Loop control flow from Wikipedia]

=References= =What links here?= include page="Loop (Program)" component="backlinks" limit="60"
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