Base set of hparams for model-free PPO.

def rlmf_tictactoe():
  """Base set of hparams for model-free PPO."""
  hparams = rlmf_original()
  hparams.game = "tictactoe"
  hparams.rl_env_name = "T2TEnv-TicTacToeEnv-v0"
  # Since we don't have any no-op actions, otherwise we have to have an
  # attribute called `get_action_meanings`.
  hparams.eval_max_num_noops = 0
  hparams.max_num_noops = 0
  hparams.rl_should_derive_observation_space = False

  hparams.policy_network = "feed_forward_categorical_policy"
  hparams.base_algo_params = "ppo_ttt_params"

  # Number of last observations to feed to the agent
  hparams.frame_stack_size = 1
  return hparams