Apr 4, 2007

[Other] Finally futility

After hours of despair and a bunch of helpful tips that I could not get to work, I decided to post one of my implementations of futility on the Talkchess.com forum. And finally I got the mystery solved. :)

I had overlooked the possibility of all moves in a node fitting the requirements for futility pruning. In some of my implementations this caused a very faulty value being recorded for the node, and in other the mate detection thought no legal moves existed and returned the stalemate score (0).

After having sorted this out, the new implementation of fuility pruning in Mediocre is working like a charm.

I started a little tournament to test it out and the results so far looks quite promising:
   Engine            Score                              Me
1: Mediocre dev 0.31 20,5/30 ..............................
2: Mediocre 0.3 9,5/30 00=0=010101=110=0=00=0000=0001
And this is with futility pruning for only non-captures, so there is still some in there up for grabs.

2 comments:

genorb said...

I cannot wait to do the LCT II test with the next version of Mediocre!!!

Very good job so far!

Jonatan Pettersson said...

I have a few more things to do before releasing the new version.

Futility for captures, along with a few new additions to the evaluation.

Hopefully it will be ready this weekend.