Question about symmetries

[smart-fr]

Hello!
Not an issue but a question regarding GameInterface.symmetries (cf the documentation):

symmetries(::Type{G}, state) where {G <: AbstractGame}
Return the vector of all pairs (s, σ) where:

• s is the image of state by a nonidentical symmetry
• σ is the associated actions permutation, as an integer vector of size num_actions(Game).

When applying to the game g with state state1 and actions mask actions_mask1 the symmetry corresponding to a given (state2, σ) pair, I suppose AlphaZero.jl affects state2 as the new state of g and determines the updated actions mask actions_mask2 according to one of the following propositions, but which one?

1. actions_mask2[action_index] == actions_mask1[σ(action_index)]
2. actions_mask2[σ(action_index)] == actions_mask1[action_index]

In other words, how is the permutation supposed to be used?
(Does it really matters in the end? ;-)

[jonathan-laurent]

Very good question! I should disambiguate in the documentation indeed.
The answer is 1.

[smart-fr]

Thank you!