[You must be registered and logged in to see this link.] released this 11 hours ago
McBrain is a Stockfish based chess engine ( directly derived from the Stockfish source). Stockfish is currently the strongest chess engine in the world. McBrain also features the Cerebellum book and code used by Brainfish (a Stockfish (SF) based engine by Thomas Zipproth (
[You must be registered and logged in to see this link.]) - with the Cerebellum book enabled it will play about 30 ELO stronger than Standard Stockfish. It includes UCI options from SugaR (a SF based engine by Marco Zerbinati) - one can toggle search functions "off" and "on" real time ( Futility, LMR, NullMove, ProbCut, Pruning, Razoring). Click all of them off to have a Stockfish-based retro engine from the early 90's ;>). It has a FindMate option based on Matefinder (a SF based engine by Joe Ellis). Helps in finding mate and micro time controls less than a minute per game, turn off for best play at longer games ( greater than 1 minute). And as in prior versions, it has the "play fast" option when mate is found and UCI Limit Strength ( play by ELO).
In this version, "variety" has been toned down and and now has 8 different levels, with zero playing no variety and 8 playing the most variety. It will stop playing in variety mode it it fall behinds by a certain score that varies by the variety level selected.
Three new UCI options: LMRDepth, LMRDivisor, LMRMoveCount - these options control the weighting of depth and move count on the LMR table and hence, the value of reduction which is based on depth and move count used by the LMR function. This option idea was taken from Bob Hyatt's Crafty. Use with caution and try to keep the bench below 7.5 million nodes and over 5.5 million nodes for best play. LMR settings that fall outside that range will typically play weaker.
Also added "?" as an alternative method ( along with "stop") to force McBrain to move now. This idea is also from Crafty.
McBrain is very good at finding mates in normal mode, and out of 300 mate positions chosen at random from the file ChestUCI.EPD (
[You must be registered and logged in to see this link.]) , finds about 28 (222/300) more mates than Stockfish 8 (194/300) at one second per position. Matefinder, by Joe Ellis, finds even more mates, about 33 (227/300) more than Stockfish @ 1 second per move on my Mac Pro using one core.
There are two versions available to download since I still am undecided as to which version is strongest at this point in time : v2.1 and 2.1a. One of the objectives this time was to make McBrain play stronger at longer time controls, but that is also uncertain at this point. Anyway, I will keep working on this and try to make it better.
And, as always, a huge call out to to the Stockfish Development Team - this is only possible because of Stockfish's open source and the contributors and volunteers that make Stockfish happen. Without them, McBrain simply does not exist. If you have a decent hardware machine and would like to contribute CPU time, you might want to consider this:
[You must be registered and logged in to see this link.] when you have CPU some down time.
McBrain has the following keyboard shortcuts:
b = bench
p f = position fen
so = setoption
g i = go infinite
g d = go depth
q = quit
? = stop
try the example below when using McBrain at the command line:
b
p f 3q2k1/1r3p1n/p2p1P1r/n1pPpRp1/PpP1P1Pp/1P6/2B2QNP/5R1K w - - 0 40
so name hash value 512
so name threads value 4
g i
?
g d 20
q
The zipped files contain all flavors for Windows, Linux and macOS operating systems. The epd file contains 300 positions where mate can be found noted in the preamble above. The solution is not present, but the number after "bm" will indicate that it is a "mate in x" .
Downloads
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