24 November 2016

Arasan 19.2 Android Chess Engine

Arasan Chess by Jon Dart

The main change is that almost all of the few parts of Arasan's eval that were not previously automatically tuned are now tuned via Texel's method. This includes particularly king safety and king cover scoring. It was not easy to improve over Arasan's previous hand-tuned king safety code, but I have managed to make the auto-tuned version perform better. It is actually pretty similar in structure though to what was there previously. Arasan like many programs awards a bonus varying by piece type for attacks on the opposing King or squares near it. But in addition if the king cover is damaged then an extra bonus is given, and also there is a bonus for multiple pieces (>=2) attacking the king, if at least one of them is a major (Queen or Rook).
The main difficulty in auto-tuning this is that Arasan uses a non-linear lookup table to convert attacking piece weight + bonuses into a king safety score. So 19.2 does this too, but then in tuning it needs the gradient of the non-linear table. The tuning program does this by finite differences, which is inexact and will cause some warnings from the gradient verification code I have. But it works well enough.

Download

armv7, arm64v8 : HERE

20 comments:

  1. arm7 working fine, arm8 engine exits android 6 Kernel.
    Thank you, your work is appreciated!!

    ReplyDelete
  2. How about CorChess and new matefinder http://chess.ultimaiq.net/stockfish.html

    Thank you.

    ReplyDelete
  3. ARM7, ARM8 can't run with message: "Engine ended" (CfA). Android 6.0.1, SONY E6553.

    ReplyDelete
  4. Aprijal,you can make a compilation of Ivanhoe(the latest version)?This is a very strong engine.Here is the source code:
    https://chess.cygnitec.com/engine/ivanhoe/source/

    ReplyDelete
    Replies
    1. Here are even more new versions(including new Robbolito)
      http://digilander.libero.it/taioscacchi/programmi/robbolito-p.html

      Delete
    2. Ivanhoe-beta-999966(the strongest version).
      Robbolito 0.085g3 (latest version).

      Delete
    3. Aprijal,here new version ivanhoe+source:
      https://app.box.com/s/v0ssm6g7649h6a9o0kpp9cuszdda0qqq

      Delete
    4. This comment has been removed by the author.

      Delete
    5. Sorry,downlad source here: http://immortalchess.net/forum/showthread.php?t=212&page=334

      Post WHMoweryJ ivanhoe 2015 02c

      Delete
    6. I don't have account in that's forum yet :(

      Delete
  5. NEW CorChess,please???.Link:http://chess.ultimaiq.net/stockfish.html.

    ReplyDelete
  6. Aprijal,I updated the link:https://m.box.com/view/105431851729

    Ivanhoe 2015 02c

    ReplyDelete
    Replies
    1. Error : The item you are trying to access has either been deleted or is unavailable to you.

      Delete
    2. I forgot sharing to include,try it now:https://app.box.com/s/xcniamm2zd3josyyvnc5pxmg3s2zgglj

      Delete
  7. Both arm7 and arm8 work ok on my MTK6752. I will rate this one soon in Rapidroid.

    ReplyDelete