Subversion Repositories Games.Chess Giants

                 Gaviota Tablebases Probing Code API

                Copyright (c) 2010 Miguel A. Ballicora

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This software provides C code to probe the Gaviota Endgame Tablebases.

It is released under then X11 ("MIT") license (see license.txt).

This API (Application Programming Interface) is designed to be as portable 

as possible. Functions could be called from Linux or Windows. 

Most likely it will work in other operating systems but that has not been 

tested. This API is a beta version and as such, it is not guaranteed any 

type of backward compatibility or to remain untouched, at least until 

version 1.0 is released. 

A very small set of tablebase files is included in this distribution 

for testing purposes (only 3 pieces). They are compressed with four

different compression schemes. For a more complete set, please download 

Gaviota from

http://sites.google.com/site/gaviotachessengine/

and generate the 4 and 5 piece tablebases. Instructions how to generate

and compressed them are in the website. More information can always be found:

http://sites.google.com/site/gaviotachessengine/Home/endgame-tablebases-1

Alternatively, already compressed tablebase files (ready to go!) can be 

downloaded from

http://www.olympuschess.com/egtb/gaviota/ (Many thanks to Josh Shriver)

"tbprobe" is distributed here as a tablebase probing example. The current API

is relatively "low level" to optimize performance. We hope the small program 

tbprobe is self explanatory. A more complete and detailed documentation may be 

released later.

We plan to support an interface with a FEN notation; thus, it is expected 

that some other functions maybe added to this API.

Four different types of compression are included. It is possible that in the

future some other compression schemes could be provided, but only if they

represent a serious improvement in speed or memory size. To maximize

backward compatibility between versions of programs and TBs, it is strongly

recommended that engine developers always support at least scheme 4 (tb_CP4), 

which is considered the default at this point. For that reason, it is 

suggested that testers always have a set of TBs compressed with scheme 4.

This API is designed to be multithreading friendly. Regions where different 

threads could access data from this API were protected with a mutex to avoid

problems.

-------------------------- How to use this API ------------------------------

To include this code in any engine or GUI, the following files should be

compiled and linked:

gtb-probe.c

gtb-dec.c

gtb-att.c

sysport/sysport.c  

compression/wrap.c

compression/huffman/hzip.c 

compression/liblzf/lzf_c.c

compression/liblzf/lzf_d.c

compression/zlib/zcompress.c

compression/zlib/uncompr.c

compression/zlib/inflate.c

compression/zlib/deflate.c

compression/zlib/adler32.c   

compression/zlib/crc32.c    

compression/zlib/infback.c  

compression/zlib/inffast.c  

compression/zlib/inftrees.c  

compression/zlib/trees.c     

compression/zlib/zutil.c

compression/lzma/LzmaEnc.c 

compression/lzma/LzmaDec.c 

compression/lzma/Alloc.c 

compression/lzma/LzFind.c 

compression/lzma/Lzma86Enc.c 

compression/lzma/Lzma86Dec.c 

compression/lzma/Bra86.c

The following files will be "included" 

gtb-probe.h  

gtb-dec.h  

gtb-att.h

gtb-types.h

plus all the *.h files in the folders, so set the proper -I flags:

sysport/

compression/

compression/huffman/

compression/liblzf/

compression/zlib/

compression/lzma/

The following libraries should be linked in Linux

-lpthread

-lm

In Windows, the appropriate MT (multithreaded library should be linked too)

These switches should be set in the compiler

-D NDEBUG

-D Z_PREFIX

The first one removes the assert code, and the second

one makes sure that some names in the zlib library will not

collision with names in other compression libraries.

-------------------------- COMPILATION EXAMPLE ------------------------------

The file compile.sh is an example of how tbprobe can be

compiled in Linux using gcc.

Rakefile.rb is the ruby version of Makefile. You have to install 'rake'

to execute it. This is what I use but you don't have to. It is provided

out of laziness. I should probably remove it.

------------------ COMPILING A STATIC LIBRARY (optional) --------------------

Aaron Becker wrote a Makefile to compile a static library --> libgtb.a

I just applied this modification from his fork.

For now, this for Linux only. Type 'make' to compile it.

Some people may find this approach more convenient since the library

has to be compiled only once. Of course, this library needs to be included

at linking time, when you compile your own program

---------------------------- For UCI Authors --------------------------------

Generally, UCI (Universal Chess Interface) GUIs use standard labels for

Tablebase paths and cache sizes. For instance, NalimovPath and NalimovCache

are used for the Nalimov tablebases. Therefore, engine authors are strongly 

encouraged (Please!) to follow a common standard to simplify the life of GUI 

developers and users. For that reason, it is suggested to implement as 

parameters: GaviotaTbPath and GaviotaTbCache in their communication with a

UCI graphical user interface.

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Good luck with the tablebases!

Miguel

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