Arasan 11.3

jdart · Post by **jdart** » Tue Mar 24, 2009 4:53 am

Arasan 11.3 is available from http://www.arasanchess.org.

This is the same version that played in the recent CCT11 tourney, plus a few last minute book fixes.

Changes in Arasan 11.3:
1) Fix bug that caused occasional early search termination.
2) Fix Winboard communication to use a thread for greater reliablity.
3) Keep game file open - fixes some occasional failures to save games.
4) Fix Makefile to build "pgn2book" utility (some code fixes in this too).
5) Some search changes: Lessen futility margin. Enable additional extensions at ply 0. Enable a version of razoring.
6) Improved move ordering based on node counts.
7) Bug fix in outpost scoring.
8) Passed pawn scores increased.
9) Bug fix in GUI: bad PV display at high search depths.
10) Larger opening book.

swami · Post by **swami** » Tue Mar 24, 2009 4:57 am

Thanks for the release, Jon.

1) Fix bug that caused occasional early search termination.
5) Some search changes: Lessen futility margin. Enable additional extensions at ply 0. Enable a version of razoring.
7) Bug fix in outpost scoring.
8) Passed pawn scores increased.

Is it safe to assume that either of the above fixes/addition caused the gain in playing strength that put up better performance at CCT?

jdart · Post by **jdart** » Tue Mar 24, 2009 5:12 am

I don't think you can make a lot of strength judgments based on a 9-round tourney. But this version does better on some test suites and has played generally well on ICC recently and in offline test games. The passed pawn scoring change helps especially in endgames with unbalanced material. It now seems to evaluate several pawns vs. a piece about right. The search changes have reduced tree size in general but you can find positions where they hurt solving time: but this is true for most all forward pruning algorithms.

--Jon

Graham Banks · Post by **Graham Banks** » Tue Mar 24, 2009 5:17 am

Thanks Jon.

tjfroh · Post by **tjfroh** » Tue Mar 24, 2009 6:24 am

Danke Sehr, Mein Herr,

You had fantastic scores in the CC11 tournament. I will enjoy playing and losing against your latest Arasan program.

Tim

Dr.Wael Deeb · Post by **Dr.Wael Deeb** » Tue Mar 24, 2009 10:17 am

tjfroh wrote:Danke Sehr, Mein Herr,

You had fantastic scores in the CC11 tournament. I will enjoy playing and losing against your latest Arasan program.

Tim

Didn't know that you can play chess uncle Timbo

Nimzovik · Post by **Nimzovik** » Tue Mar 24, 2009 8:35 pm

I thought TIm's job here was to advertise avatars.............

Dr.Wael Deeb · Post by **Dr.Wael Deeb** » Tue Mar 24, 2009 9:59 pm

Nimzovik wrote:I thought TIm's job here was to advertise avatars.............

Damn,is uncle Timbo advertising Nestle along with Intel processors and getting paid regulary

Damn

Werner · Post by **Werner** » Wed Mar 25, 2009 8:54 am

Thanks Jon,
my very first results look very promising. After 34 games against AnMon 5.66 the new version 11.3 leads 21 - 13 (around 60%)
Version 11.2 only reached 40%.
If Arasan can hold this we will have an advantage of more than 100 elos...

best
Werner

Kirk · Post by **Kirk** » Wed Mar 25, 2009 2:22 pm

Thank you Mr Dart!

How long has your program been around? I seem to remember DOS versions many moons ago

Arasan 11.3

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