Rodent

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Eastern spiny mouse - a Rodent

Rodent,
an UCI compliant open source chess engine by Pawel Koziol licensed under the GPL, initially based on Sungorus 1.4 by Pablo Vazquez, with evaluation parameters borrowed from the Toga log user manual. Rodent may be regarded as a beefed up bitboard version of the CPW-Engine , and features adjustable playing strength and different personalities. Rodent II, released in February 2016 , was a complete rewrite, now using the magic bitboard implementation by Pradu Kannan. Rodent III, released in March 2017, has been programmed for tunability. One can turn it into a crazy attacker or an old-fashioned positional player .

Features

Board Representation

• 6+2 Bitboard Board Definition
• 8x8 Board
• Kindergarten Bitboards
• Kogge-Stone Fill Algorithm
• Magic Bitboards (since Rodent II)

Search

• Fail Soft Alpha-Beta with Principal Variation Search (from Sungorus)
• Fractional Extensions and Reductions
• Two-tier Aspiration Windows
• Transposition Table (from Sungorus)
• Null Move Pruning with variable R and Threat Detection
• Futility Pruning
• "Sliding" Late Move Reductions
• Late Move Pruning
• Eval Pruning (a.k.a. static null move)
• Internal Iterative Deepening in PV-Nodes

Evaluation

• NNUE (unofficial release of Rodent IV with Stockfish NNUE nets)
• Material Evaluation uses some of Larry Kaufman's formulas
• Piece-Square Tables
• Mobility
• Tapered Eval
• Pawn Hash Table
• Fruit-like Weak Pawns Eval
• Passed Pawns Eval

taking into account Blockade and Control of the Stop Square

• Candidate Passers Eval
• Strong Squares (B, N, even R)
• King Safety

Pawn Phalanx Bonus

Pawn Shelter Eval

• Hanging Piece Eval

Misc

• Own Opening Book Format
• Position Learning
• Weak levels

Selected Games

Rodent II 0.8.7 x64 vs. Gaviota 1.0 AVX x64, March 11, 1016 by Frank Quisinsky

[Event "40/10"]
[Site "rodentII_087-x64, FCP-3"]
[Date "2016.03.11"]
[Round "13.41"]
[White "Rodent II 0.8.7 x64"]
[Black "Gaviota 1.0 AVX x64"]
[Result "1-0"]
[ECO "C78"]
[Opening "Spanish"]
[Variation "Archangelsk, 7.c3 Nxe4"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O b5 6.Bb3 Bb7 7.c3 Nxe4 8.d4 Na5 9.Nxe5 Nxb3 
10.Qxb3 Qf6 11.f3 Nc5 12.Ng4 Nxb3 13.Nxf6+ Ke7 14.Bg5 Nxa1  15.Re1+ Kd6 16.Bf4+ Kc6 
17.d5+ Kc5 18.b4+ Kc4 19.Na3+ Kxc3 20.Ne4+ Kxb4 21.Rb1+ Ka5 22.Bxc7+ Ka4 23.Nc3+ Kxa3 
24.Bf4 Bc5+ 25.Kh1 Be3 26.Bxe3 Bxd5 27.Bc1# 1-0

OpenTal

OpenTal is a Rodent III incarnation with a fixed personality with evaluation weights provided by Brendan J. Norman, to some extend transforming playing strength into the risky and wonderful playing style of [Mikhail Tal] .

See also

• Chess System Tal
• CPW-Engine
• Sungorus
• Toga log user manual » Toga

Forum Posts

2011 ...

• open source gift for Christmas by Pawel Koziol, CCC, December 25, 2011

2012

• Rodent 0.11 by Pawel Koziol, CCC, February 16, 2012
• Rodent 0.11 for AMD compatibility by Denis P. Mendoza, CCRL Discussion Board, February 20, 2012
• Rodent 0.12 by Pawel Koziol, CCC, February 29, 2012
• Rodent 0.13 by Pawel Koziol, CCC, March 25, 2012
• Rodent 0.14 by Pawel Koziol, CCC, April 19, 2012
• Rodent 0.15 released by Pawel Koziol, CCC, May 27, 2012
• Rodent 0.16 by Pawel Koziol, CCC, October 08, 2012
• Rodent 0.17 for New Year! by Pawel Koziol, CCC, December 31, 2012

2013

• Rodent 0.18 released by Pawel Koziol, CCC, February 02, 2013
• Rodent turns 1.0 ! by Pawel Koziol, CCC, March 05, 2013
• Rodent 1.1 released by Pawel Koziol, CCC, September 30, 2013
• Rodent 1.2 released by Pawel Koziol, CCC, November 02, 2013
• Rodent goes online by Pawel Koziol, CCC, November 26, 2013
• new Rodent book by Pawel Koziol, CCC, December 31, 2013

2014

• Rodent 1.3 by Pawel Koziol, CCC, January 21, 2014
• Rodent 1.4 by Pawel Koziol, CCC, April 30, 2014
• Rodent 1.5 by Pawel Koziol, CCC, September 08, 2014
• Rodent 1.6 released by Pawel Koziol, CCC, November 02, 2014
• Rodent's new soul? by Pawel Koziol, CCC, November 17, 2014

2015 ...

• Rodent 1.7 is out by Pawel Koziol, CCC, March 18, 2015
• Mini Rodent asks for code review by Pawel Koziol, CCC, October 01, 2015
• Mini Rodent 1.0 by Pawel Koziol, CCC, October 26, 2015

2016

• Rodent II is out by Pawel Koziol, CCC, February 15, 2016
• Very nice game ... Rodent - Gaviota, 1:0 by Frank Quisinsky, CCC, March 12, 2016
• Rodent II 0.9.33 by Pawel Koziol, CCC, May 23, 2016
• Rodent II 0.9.64 released by Pawel Koziol, CCC, September 22, 2016
• Rodent online personality creator by Pawel Koziol, CCC, October 25, 2016
• Rodent Karpov+Topalov REALISTIC Personalities (coming soon) by Brendan J. Norman, CCC, November 04, 2016

2017

• Rodent needs a new developer by Pawel Koziol, CCC, February 15, 2017
• Rodent III released by Pawel Koziol, March 11, 2017
• Rodent news by Pawel Koziol, August 21, 2017
• A group of angry Rodents by Brendan J. Norman, CCC, November 10, 2017
• OpenTal - almost new engine by Pawel Koziol, CCC, December 17, 2017
• Rodent III with multi-pv (unofficial release) by Pawel Koziol, CCC, December 31, 2017

2018

• OpenTal 1.1 by Pawel Koziol, CCC, January 05, 2018
• The Most Interesting Chess Game Ever? by Brendan J. Norman, CCC, January 11, 2018
• Rodent III 0.273 - official release by Pawel Koziol, CCC, September 01, 2018

2019

• Rodent needs a test by Pawel Koziol, CCC, May 09, 2019
• Rodent III personalities <2000 Elo? by PeterO, CCC, May 31, 2019
• Rodent IV beta by Pawel Koziol, CCC, August 31, 2019
• The Final Rodent by Pawel Koziol, CCC, November 17, 2019

2020 ...

• Rodent FRC/960 by Pawel Koziol, CCC, April 21, 2020 » Chess960
• My statement from Rodent homepage by Pawel Koziol, ProDeo Forum, December 05, 2020 » CCC
• Engine choosing between sets of piece/square tables by Pawel Koziol, ProDeo Forum, December 05, 2020 » Piece-Square Tables

2021

• a book about Rodent (in French) by Pawel Koziol, ProDeo Forum, May 31, 2021
• Rodent NNUE (works with the old SF networks) by Pawel Koziol, CCC, December 18, 2021

External Links

Chess Engine

• GitHub - nescitus/rodent-iv: trying to start a community effort based on Rodent IV
• GitHub - nescitus/Rodent III
• GitHub - nescitus/Rodent II
• rodent chess at SourceForge.net
• Rodent Chess
• OpenTal 1.1
• Rodent in CCRL 40/4
• Chess Engine Review: Rodent II by Brendan J. Norman, ChessnCognac
• Rodent Chess Engine: The AMAZING Strangler Personality by Brendan J. Norman, ChessnCognac

Misc

• Rodent from Wikipedia
• Rodent - Simple English Wikipedia
• List of rodents from Wikipedia
• Rodentia - Wikispecies

References

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