Jan 22, 2007

[Other] Draw repetition left

After taking a long look at King's Out's implementation of transposition tables I finally understood what I had to do to get everything working correctly in Mediocre.

Man that was a hard piece of code to write... All in all 10 lines or so in the alpha-beta method, and almost two weeks to get them working right. :)

The speed gains are noticeable but not enormous. But with the transposition tables as a foundation there are a lot of optimization that can be done.

Where it really made a difference is in the endgame though. In the null move example a couple of posts back Mediocre can now reach 16 ply in under a second, while without transposition tables it reaches only 9 ply in the same time.

Now I just need to replace my crude repetition detection and possibly take another look at the replacement scheme the transposition table uses (uses depth replacement now).

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