Arasan 18.2

[jdart]

Arasan 18.2 is available from http://www.arasanchess.org.

Changes in Arasan 18.2:

1) Make more parameters tunable, including TRADE_DOWN array. Fix gradient
computation for Q + minor vs Q material param.
2) Revise and simplify endgame scoring. Combine endgame score cache
with king cover cache (since they can use the same hash signature).
Allow larger values for king endgame scores. Add distance function to
Scoring. Use local calc instead of array lookup for this function.
3) Re-tune all parameters using latest rating gauntlet games as training
file.
4) Add MSVC project files to repository.
5) For Linux builds with gcc, turn on Link Time Optimization along with PGO.
6) Lots of book changes/improvements.

This version is measurably stronger than 18.1 in my tests (+20 ELO or so).

-Jon

[MikeB]

Arasan 18.2 is available from http://www.arasanchess.org.

...

This version is measurably stronger than 18.1 in my tests (+20 ELO or so).

-Jon

Very nice - that's not easy! Will have to grab the latest and run it against the latest crafty.

Mike

[jdart]

I have rebuilt the Windows GUI + installer since the title bar was still showing 18.1 as the version. No change to the engine.

--Jon

[cdani]

Nice!
Will see it in action in Ed's tournament

[Sylwy]

http://talkchess.com/forum/viewtopic.ph ... 99&t=50060

[styx]

Arasan will always have a special place on my hard disk drive since it's one of the first computer chess programs I came in touch with, many many moons ago (1996 or so ...)

Today it is much stronger (I remember it losing to WAXMAN all the time back in the days)

Thank you for doing what you do

[MikeB]

Hi Jon.

FYI - it's not very stable on the Mac under xBoard. Same with earlier versions. Ok with a game here and there - but running it in tournament mode it invariably crashes. So I can't really use it as part of my engine stable. Let me know if you would like me to help trouble shoot it.

Mike

[styx]

I've spotted a problem. If you check UCI_LimitStrength in the engine settings in xboard, and limit the strength to a low value, it will stay limited even after unchecking "UCI_LimitStrength" and starting a new game. It will play limited until you reload the engine.

This may be a GUI issue. I don't know. At least Stockfish does not show such a behaviour.

- Ubuntu 15.10
- Arasan 18.2 x64
- xboard 4.8.0

*EDIT*
xboard seems to be the problem here. in pychess GUI it all works as intended

[jdart]

I have to confess, I hardly test it on Mac, except to see that it comes up and runs a couple of test problems.

If you find a way to make it crash repeatedly I'd like to hear about it.

The best way to debug it would be to run a debug build (-g and optimization off) and attach a debugger to it. Then at least you can get a stack trace if it crashes. I can try that but if I don't know what might trigger it, it might take a while to see.

--Jon

[supersharp77]

Arasan 18.2 is available from http://www.arasanchess.org.

Changes in Arasan 18.2:

1) Make more parameters tunable, including TRADE_DOWN array. Fix gradient
computation for Q + minor vs Q material param.
2) Revise and simplify endgame scoring. Combine endgame score cache
with king cover cache (since they can use the same hash signature).
Allow larger values for king endgame scores. Add distance function to
Scoring. Use local calc instead of array lookup for this function.
3) Re-tune all parameters using latest rating gauntlet games as training
file.
4) Add MSVC project files to repository.
5) For Linux builds with gcc, turn on Link Time Optimization along with PGO.
6) Lots of book changes/improvements.

This version is measurably stronger than 18.1 in my tests (+20 ELO or so).

-Jon

Thx Jon Will test it (and 18.1) soon as I get a chance........AR