OpenSpiel state methods: mean_field_population
mean_field_population()
Returns the population that this state belongs to. This is relevant only for mean field games. Returns 0 by default (single-population games). Multi-population mean field games should override this to return the correct population index.
Examples:
import pyspiel
game = pyspiel.load_game("mfg_crowd_modelling_2d")
state = game.new_initial_state()
print(state.mean_field_population()) # Output: 0