3 ms·

I don’t understand the comment about Leela. Why isn’t own move prediction deterministic?

• thomasahle 6y ago
  Because Leela (like fastchess mentioned above) has two parts: A neural network predicting good moves, and a tree search exploring the moves suggested and evaluating the resulting positions (with a second net). If the prediction (policy) net had a 100% accuracy, you wouldn't need the tree search part at all.
  • heavenlyblue 6y ago
    You haven’t mentioned any nondeterministic behaviour, therefore Leela is supposed to predict it’s own moves with a 100% accuracy.
    • tel 6y ago
      It's not non-determinism, it's partial information. The NN part guesses the best move that will be found by search X% of the time. If you just ditched the search part, Leela would be faster and lose out on (1-X)% of the better moves.
  • nuclearnice1 6y ago
    Got it. Thanks for clarifying. Let me restate. Part one of Leela ranks several chess moves. Part two picks among those. 60% of the time part 2 chooses the #1 ranked move.
    • thomasahle 6y ago
      That works :-) One addition: The second part can be run for an arbitrary amount of time, gradually improving the quality of the returned move. The 60% figure comes from the training games, which are played very quickly, and so don't have a lot of time for refining, thus increasing the prediction accuracy. In real games, tcec-chess.com/ this "self accuracy" would probably be a bit lower.