>> In other words UCT works well when evaluation/playouts is/are
>> strong. I
>> believe
>> there are still improvements possible to the UCT algorithm as
>> shown by the
>> recent papers by Mogo and Crazystone authors, but what really will
>> make a
>> difference is in the quality in the playouts.
>
> Sylvain said that good moves in the playouts do not always improve
> the performance of UCT. What do you think about this claim?
>
I believe this claim is true in two senses:
1) If the computation necessary to find better moves is too
expensive, performing many "dumb" playouts may be a better investment.
Sure, this is true. But even with the same number of simulations,
stonger playouts do not necessarily perform better than "dumb"
playouts. This is the real mystery!
2) If the playouts are too deterministic, and the moves are merely
pretty good, the program may avoid an important move and thus
misjudge the value of a position.
We tried the whole spectrum from completely random to completely
deterministic playouts, but we never came close to the performance of
the "dumb" playouts!
We have seen a similar effect many times in MoGo. Often we try
something that seems like it should improve the quality of the
simulation player, but it makes the overall performance worse. It is
frustrating and surprising! Has anyone else encountered this?
-Dave
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