Butcher Chess
(Version 1.64, 25 IV 2012)
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I. Download DOS
== DJGPP (x86-32) == http://butcher-chess.cba.pl/dos32.zip CWSDPMI – small tool required to run
Butcher under plain DOS Linux
== GCC (x86-32)
== http://butcher-chess.cba.pl/lin32.zip
== GCC (x86-64)
==
http://butcher-chess.cba.pl/lin64.zip Windows
== (x86-32) == http://butcher-chess.cba.pl/win32.zip == (x86-64) == http://butcher-chess.cba.pl/win64.zip == (x86-64 Core
i7) == http://butcher-chess.cba.pl/win64i7.zip == (x86-64 Core i7, IOPCCC 2012 Compilation, 1-2 December
2012) == http://butcher-chess.cba.pl/win64i7(iopccc2012).zip Opening book(s)
Due to server limitations I’ve split an opening book
into two chunks. Chunk
1 (5000000 bytes) Chunk
2 (4654130 bytes) In order to get a valid book for Butcher you may
follow the steps below: 1) Download
two parts of the book (links above). 2) Copy downloaded
files (book.001 and book.002) into the same
directory/folder. 3) Run
windows console (i.e. cmd.exe in Windows 2000/XP) and go to the
directory/folder where files book.001
and book.002 were copied. 4) Join
files into one book.zip archive using command: 5) Unpack book.zip into Butcher’s
directory/folder (use WinZIP application for
example). |
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II. Additional Information After nearly three year period an
update of Butcher chess engine is released. Although Butcher 1.59 series had
been ready last year and later successfully used during the 7th IOPCCC 2008
it was never released. Many small changes and lots of bug fixes were
implemented over the time, e.g.: ·
some minor speed improvements, ·
move generation bug fixes, ·
hash table structure/access redesign, ·
search extensions redesigned, ·
endgame knowledge added, ·
evaluation function adjustments, ·
improved time management, ·
hundred hours of testing, ·
many small improvements. Apart from the
above there is one new significant feature in Butcher 1.60 series - multiple
CPU support. Since it was not my intention to completely redesign the code I
decided to adapt the existing code to support multiple CPUs. This work was
supposed to get me some experience before I start a new project which shall
also support multiple CPUs. Here are some facts regarding Butcher's parallel
search implementation: ·
Parallel search is available only on Windows
platform. ·
Separate processes are used to implement the search.
There is one master process (the one which starts first) that spawns worker
processes. Worker processes (excluding initialization) run independently
without master process supervision (It is possible to kill worker processes
during the search with no hurt to the search). Master process prepares all
the structures necessary to split the node and continues the search. Worker
processes simply use existing "split nodes" to start their search
and report the results. Master process shall kill worker processes upon exit
(if everything goes well :) ) ·
Hash tables are shared by all processes in the
search group. ·
Internal synchronization mechanism is used to access
and protect vital shared data (e.g. split node structure, flags) - no
operating system overhead. ·
Split occurs in 3-9 ply range. ·
Unique character string is used to identify
different instances of parallel Butcher engines (it is possible to start two
parallel Butcher engines on the same machine - each of these shall use unique
string to identify its group members). ·
Supports up to 30 CPUs. Never tested with more than
8 though ;). How do I use more than one CPU with Butcher? There is a new
"-par" command line switch which should be used to make Butcher use
more than one CPU (If you don't want to use more than one CPU just use your
old launch command line). butcher.exe -ht
ht_size -par unique_string num_of_cpus_x2 where: ht_size - size of all
hash tables in megabytes. All processes will share hash tables unique_string - unique
character string to identify processes search group you are about to start.
It does not need to be unnecessarily long num_of_cpus_x2 - number of worker processes
multiplied by two. If num_of_cpus_x2&1 equals 1 each worker process will
pop up a statistics window. Otherwise, the worker processes will run silently
in the background. Example 1: butcher.exe -ht
1024 -par match_2cpu_verbose 3 Two CPUs are used.
Master process and one worker process which will display status and
statistics window. Example 2: butcher.exe -ht
2048 -egtb
256 -par game_4cpu_quiet 6 Four CPUs are used.
Master process and three worker processes running silently in the background. |
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III. Links http://lpps.maciej.szmit.info/ Marek Kołacz |