Jan 31, 2007

[Other] A couple results

There is still an annoying bug lurking somewhere in the code. I am quite sure it has to do with the time management, sometimes the engine simply does not start searching. It does not crash, and it does not fail receiving a principal variation, it is just skips searching. Hopefully I can track it down soon.

Anyway here is a couple interesting tournament results.

The first was played between Mediocre v0.2b and Mediocre v0.12b.
   Engine          Score    Me v0.2b  Me v0.12b 
1: Mediocre v0.2b 9,0/10 ·········· 11==111111
2: Mediocre v0.12b 1,0/10 00==000000 ··········
As you can see the new version completely annihilated the old. The two draws were due to middle game repetitions, where v0.12b was up a fraction of a pawn and v0.2b took the draw. This will be solved with a contempt factor which I will add soon. It avoids taking draws if he engine is not behind a certain amount.

Since both engines used the same evaluation scheme the wins are explained solely by the deeper search possible with transposition tables (along with some of the other changes like faster move ordering).

Happy days! :)

After finishing with the transposition tables I went on to improve the evaluation slightly. I added some development evaluation like rewarding the king moving to the side with pawns protecting it (I will not add a bonus for castling since I prefer letting the engine decide if castling is the best option for protecting the king) and not leaving pieces on the first rank.

Also moving the king out in the ending is rewarded. The result from these simple changes was this:
      Engine       Score      Me dev   Me v0.2b
1: Mediocre dev 9,5/10 ·········· 11111111=1
2: Mediocre v0.2b 0,5/10 00000000=0 ··········
The draw was a forced perpetual check found by v0.2b while being down a piece in the ending.

Mediocre is quickly improving. Perhaps it is time for me to take it on and see if I stand a chance. In blitz games it beats me more often than not, but I am not so sure about how it stands in longer time controls.

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