Hello all, It is known that MCTS's week point is tactics. How is AlphaZero able to resolve Go tactics such as ladders efficiently? If I recall correctly many people were asking the same question during the Lee Sedo match -- and it seemed it didn't have any problem with ladders and such.
In chess and shogi, there is lots of tactics and plain MCTS as used in AlphaZero shouldn't perform well (one would expect), but apparently AlphaZero didn't seem to have a problem in that regard against stockfish. First of all, I think that AlphaZero is resolving tactics by growing its MCTS tree very rapidly (expand after each visit) -- some people thought initially that NN may have some tactics in it but I don't believe it can do better than a quiescence_search. Tactics requires precise calculations with moves that maynot make sense (sacrfice) -- apparently AlphaZero's positional understanding led it to be superior in this regard as well. My simple MCTS chess engine (single thread) is now better in tactics than it used to be (after removing the rollouts), but it is still far far from the tactical ability of alpha-beta engines with LMR+nullmove. What do you think is AlphaZero's tactical strength coming from ? I am guessing parallel MCTS with larger exploration coefficient for each thread -- this should explore enough not so good moves closer to the root not to miss sshallow tactics. I just wanted to know the opinions of the MCTS experts here.. regards, Daniel
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