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computer_chess:engines:myrddin:index 2022/06/03 12:47 computer_chess:engines:myrddin:index 2023/06/11 14:00 current
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First of all, thanks very much to Ron Murawski for making this site available and hosting Myrddin here! =) First of all, thanks very much to Ron Murawski for making this site available and hosting Myrddin here! =)
-This version supports SMP via processes (up to 16 instances) and testing shows it is about 35 ELO stronger than v0.88 at 1 CPU and a further 110 ELO stronger at 4 CPUs. This version has not been formally tested above 4 CPUs so it is unknown how well it will scale above 4 CPUs.+Myrddin 0.90 supports SMP via processes (up to 16 instances) and is about 50 ELO stronger than v0.89 at 1 CPU and a further 80 ELO stronger at 4 CPUs. This version has not been formally tested above 4 CPUs so it is unknown how well it will scale above 4 CPUs.
==== Download ==== ==== Download ====
-[[https://www.dropbox.com/s/1ksfgbrtnpahg3o/Myrddin%20089.rar?dl=0 | Myrddin 0.89]] (released 6/3/22, CCRL rating estimated at 2590 at 1 CPU and 2700 at 4 CPUs)\\+Executable Package - [[https://www.dropbox.com/s/z2fkfkyxigohhp7/Myrddin%20090.rar?dl=0 | Myrddin 0.90]] (released 6/9/23, CCRL rating approximately 2650 at 1 CPU and 2730 at 4 CPUs)\\ 
 +Source Code - [[https://github.com/JVMerlino/Myrddin | Myrddin Source]]
== Old versions == == Old versions ==
-[[https://www.dropbox.com/s/v3amg3x4kkpjwqk/Myrddin%20088.rar?dl=0 | Myrddin 0.88]] (released 7/18/21, CCRL rating of 2552 at 1 CPU and 2629 at 4 CPUs)\\ +[[https://www.dropbox.com/s/1ksfgbrtnpahg3o/Myrddin%20089.rar?dl=0 | Myrddin 0.89]] (released 6/3/22, CCRL rating of 2597 at 1 CPU)\\ 
-{{myrddin087.rar | Myrddin 0.87}} (released 1/25/15, CCRL rating of 2395 at 1 CPU and 2481 at 4 CPUs)\\ +[[https://www.dropbox.com/s/v3amg3x4kkpjwqk/Myrddin%20088.rar?dl=0 | Myrddin 0.88]] (released 7/18/21, CCRL rating of 2560 at 1 CPU and 2629 at 4 CPUs)\\ 
-{{myrddin086-ja.zip | Myrddin 0.86}} (released 12/21/12, CCRL rating of 2358)\\+{{myrddin087.rar | Myrddin 0.87}} (released 1/25/15, CCRL rating of 2399 at 1 CPU and 2482 at 4 CPUs)\\ 
 +{{myrddin086-ja.zip | Myrddin 0.86}} (released 12/21/12, CCRL rating of 2365)\\
This package contains Windows32/64, Linux32/64, & Android executables compiled by [[http://jim-ablett.co.de/ | Jim Ablett]], and a Mac executable compiled by [[http://predateur-chess.blogspot.com | Julien Marcel]], author of the Prédateur chess engine.\\ This package contains Windows32/64, Linux32/64, & Android executables compiled by [[http://jim-ablett.co.de/ | Jim Ablett]], and a Mac executable compiled by [[http://predateur-chess.blogspot.com | Julien Marcel]], author of the Prédateur chess engine.\\
-{{myrddin085.rar | Myrddin 0.85}} (released 5/3/11, CCRL rating of 2218)\\ +{{myrddin085.rar | Myrddin 0.85}} (released 5/3/11, CCRL rating of 2223)\\ 
-{{myrddin084.rar | Myrddin 0.84}} (released 9/17/10, CCRL rating of 2111)\\ +{{myrddin084.rar | Myrddin 0.84}} (released 9/17/10, CCRL rating of 2115)\\ 
-{{myrddin083.rar | Myrddin 0.83}} (released 2/22/10, CCRL rating of 2006)\\+{{myrddin083.rar | Myrddin 0.83}} (released 2/22/10, CCRL rating of 2010)\\
{{myrddin082.rar | Myrddin 0.82}} (released 9/26/09, estimated CCRL rating of 1915)\\ {{myrddin082.rar | Myrddin 0.82}} (released 9/26/09, estimated CCRL rating of 1915)\\
{{myrddin_alpha_2.rar | Myrddin 0.81}} (released 5/26/09, estimated CCRL rating of 1550)\\ {{myrddin_alpha_2.rar | Myrddin 0.81}} (released 5/26/09, estimated CCRL rating of 1550)\\
-{{myrddin_alpha_1.rar | Myrddin 0.80}} (released 3/9/09, estimated CCRL rating of 1150)\\+{{myrddin_alpha_1.rar | Myrddin 0.80}} (released 3/9/09, estimated CCRL rating of 1250)\\
---- ----
==== Release Notes ==== ==== Release Notes ====
-Myrddin 0.89 -- 6/3/22+Myrddin 0.90 -- 6/9/23
Myrddin is a winboard-compliant chess engine to a reasonable degree. It supports protover 1 primarily to support the Chessmaster interface, and also protover 2. Myrddin is a winboard-compliant chess engine to a reasonable degree. It supports protover 1 primarily to support the Chessmaster interface, and also protover 2.
-The 64-bit version of Myrddin should play approximately 2590 ELO against chess engines at 1 CPU (using CCRL rating), and probably 100 points higher against humans. This is an improvement of about 35 points compared to the previous release. Myrddin should play about 100 points stronger at 4 CPU.+The 64-bit version of Myrddin should play approximately 2650 ELO against chess engines at 1 CPU (using CCRL rating), and probably 100 points higher against humans. This is an improvement of about 50 points compared to the previous release. Myrddin should play about 80 points stronger at 4 CPU.
The following winboard commands are supported: The following winboard commands are supported:
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  * "divide N" -- extension to perft algorithm showing the number of leaf nodes of depth N from the current position, divided among each legal move from the current position.   * "divide N" -- extension to perft algorithm showing the number of leaf nodes of depth N from the current position, divided among each legal move from the current position.
  * "tb" -- toggles Gaviota endgame tablebase support   * "tb" -- toggles Gaviota endgame tablebase support
 +  * "rpt" -- runs a short pre-defined perft test, using bulk counting with only one thread
 +  * "see" -- returns the SEE value of a capture on the current position - example usage "see d4 e5"
None of these commands are supported while Myrddin is searching/analyzing. None of these commands are supported while Myrddin is searching/analyzing.
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-- Myrddin's "Very Lazy SMP" implementation uses (N-1) child processes to fill the transposition, eval and pawn hash tables so the parent process can search deeper in the same amount of time. I believe Myrddin is the only engine that has implemented SMP with this method (and probably rightly so!).\\ -- Myrddin's "Very Lazy SMP" implementation uses (N-1) child processes to fill the transposition, eval and pawn hash tables so the parent process can search deeper in the same amount of time. I believe Myrddin is the only engine that has implemented SMP with this method (and probably rightly so!).\\
-- Myrddin uses Pradyumna Kannan's [[http://www.pradu.us/old/Nov27_2008/Buzz/ | magicmoves]] code for move generation of sliding pieces.\\ -- Myrddin uses Pradyumna Kannan's [[http://www.pradu.us/old/Nov27_2008/Buzz/ | magicmoves]] code for move generation of sliding pieces.\\
--- Myrddin uses a tapered eval which was hand-tuned using a very rudimentary Texel tuning system.\\ +-- Myrddin uses a tapered eval which was tuned using a very rudimentary Texel tuning system.\\ 
--- Search is basic alpha/beta, with reasonable and generally conservative extensions and reductions.\\ +-- Search is basic alpha/beta, with typical extensions and reductions.\\
-- All user-modifiable parameters are supported in the INI file, an example of which is included in the download.\\ -- All user-modifiable parameters are supported in the INI file, an example of which is included in the download.\\
--- Max search depth is 128.\\+-- Max search depth is 128 ply.\\
-- The [[http://members.home.nl/matador/prodeo.htm | ProDeo opening book]] is used by kind permission of Ed Schröder.\\ -- The [[http://members.home.nl/matador/prodeo.htm | ProDeo opening book]] is used by kind permission of Ed Schröder.\\
-- Draw claims from the opponent are not supported. Myrddin does, however, claim all draws by rule, as well as checkmate.\\ -- Draw claims from the opponent are not supported. Myrddin does, however, claim all draws by rule, as well as checkmate.\\
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====Version/Change List==== ====Version/Change List====
 +
 +== Version 0.90 (6/9/23) ==
 +-- Fixed two bugs in SEE (stopped the calculation if the first capture was of equal value, and failed to include Kings in the calculation)\\
 +-- Fixed a bug that could cause a save to the hash table even if there was no best move\\
 +-- Tuned PST files for the first time, and re-tuned all other eval terms\\
 +-- Captures with negative SEE value can now be reduced\\
 +-- IID is now more aggressive in its depth reduction and can be applied in PV nodes\\
 +-- LMR reduction is now one depth less for PV nodes\\
 +-- No longer limiting the number of extensions for a single branch\\
 +-- Reduced the number of aspiration windows before performing a full-width search from six to two\\
 +-- Fixed a rare bug such that if a tt probe or IID returned an underpromotion it would not be moved to the front of the movelist\\
 +-- Fixed an issue when receiving the "force" command while pondering, which can happen with some GUIs\\
 +-- Modified the compiler options for magicmoves to improve perft results by 5%.\\
 +-- Various minor optimizations\\
 +-- Added "see" command to return the SEE value of a capture on the current position - example usage "see d4 e5"\\
 +-- Added "rpt" command to run a brief perft test (perft uses bulk counting)\\
 +-- Removed "-64" from version string as there is no longer a 32-bit version\\
== Version 0.89 (6/3/22) == == Version 0.89 (6/3/22) ==
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-- BitScan now uses an intrinsic function rather than MS Windows' BitScanForward64() - thank you to Pawel Osikowski and Bo Persson for the suggestion!\\ -- BitScan now uses an intrinsic function rather than MS Windows' BitScanForward64() - thank you to Pawel Osikowski and Bo Persson for the suggestion!\\
-- Null Move now uses a reduction of 3+(depth/6) instead of just 3\\ -- Null Move now uses a reduction of 3+(depth/6) instead of just 3\\
--- Myrddin will now move instantly if TBs are available and <=5 men on board. Previously it would "search" all the way to max depth (128) before moving, causing potential buffer problems with some GUIs at very fast time controls.\\+-- Myrddin will now move instantly if TBs are available and <= 5 men on board. Previously it would "search" all the way to max depth (128) before moving, causing potential buffer problems with some GUIs at very fast time controls.\\
-- Minor evaluation tuning adjustments, most notably adding code for Bishop Outposts and a significant increase for pawns on the 7th rank\\ -- Minor evaluation tuning adjustments, most notably adding code for Bishop Outposts and a significant increase for pawns on the 7th rank\\
-- Increased the aggressiveness of SMP depth adjustment for child processes\\ -- Increased the aggressiveness of SMP depth adjustment for child processes\\

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