Arasan 14.0

[jdart]

Arasan 14.0 is available from http://www.arasanchess.org. This is basically the same version that played in the recent CCT14 tournament, plus minor fixes.

Changes in Arasan 14.0:
1) Board::wouldCheck function handles promotions.
2) Much simplifed time management, functions better in particular under very
short time controls.
3) LMR is performed at root node (formerly was not).
4) Null move uses R=3 with verification.
5) Simplified hash table implementation.
6) Move generator defers SEE test on captures until the move is used (this
was done previously in the qsearch but not elsewhere).
7) Better sort algorithm in move generator.
8) Fixes to learning code. Hash table (w/ learn info) was being cleared
at each new game, now learn info is retained.
10) Some code cleanup, esp. conversion from char * to C++ string usage.
11) Arasan uses Gaviota tablebases. Fix tb probing when en passant
capture possible. Tablebase hits now are cached in the hash table.
12) Additional UCI & winboard options supported. GUI now uses the standard
winboard options command to send options to the engine.
13) Fix bug involving mate scores in UCI analysis mode.
14) Makebook program can directly consume PGN.
15) Arasan engine source is released under the MIT license (same license used by the Gaviota tablebase code).

Re 15 - I am releasing the engine code under the MIT license. While Arasan is far from the strength level of top open source or commercial engines, I think it is the strongest engine under this permissive source license. Of course Nalimov tablebase code is not included under this license - it is now packaged separately from the Arasan engine source, and is optional (Arasan can be built with Gaviota tablebase support, or Nalimov, or both, or neither). But binaries I distribute have both Gaviota and Nalimov support.

In addition to Mac binaries, I am now supplying Linux binaries as well. These are not statically linked so there is some chance they may not work on your system, but most likely they will.

--Jon

[Olivier Deville]

Hi Jon

I have set hashsize to 256 in Arasan.rc.

If I start it in console mode, the correct size is shown in the task manager. But if I start it under Winboard, it uses onlly around 100Mb.

In winboard.ini I have the following :

/defaultHashSize=256

Olivier

[jdart]

It is a bug. It is losing the 1st digit of the memory setting, so a really kludgy workaround is to send "memory 2256" to Arasan.

Another, better, workaround is to put the memory setting on the command line, like this "arasanx -H 256m".

Will fix in the next release.

--Jon

[H.G.Muller]

Does Arasan support the UCI searchmoves command, and does it also have a provision for that in WB mode? (The standard protocol does not support anything like it, so I am curious if there are people who solved it, and how.)

My first thought was to add a GUI->engine command to disable the current best move in analysis mode.

[Olivier Deville]

It is a bug. It is losing the 1st digit of the memory setting, so a really kludgy workaround is to send "memory 2256" to Arasan.

Another, better, workaround is to put the memory setting on the command line, like this "arasanx -H 256m".

Will fix in the next release.

--Jon

Thanks Jon, I'll use the second trick

I tried it un UCI mode + polyglot, and it takes more that 400Mb, when I tell it to use 256Mb.

Olivier

[H.G.Muller]

Well, I guess many UCI engines cheat. The UCI specs define the meaning of the Hash option as given the size for hash tables (plural!), obviously meaning the size of all tables together. But most engines use it just as the size of their main hash table. So if they use Pawn hash, they just grab that memory on top of it, if they use huge EGTB cache or giga-bytes of bitbases, they use it on top of it, etc.