What is the difference between FP and EP？

[lordemyj]

    if self.state_type == "EP":
        data = (
            share_obs[:, 0],  # (n_threads, share_obs_dim)
            obs,  # (n_agents, n_threads, obs_dim)
            actions,  # (n_agents, n_threads, action_dim)
            available_actions,  # None or (n_agents, n_threads, action_number)
            rewards[:, 0],  # (n_threads, 1)
            np.expand_dims(dones_env, axis=-1),  # (n_threads, 1)
            valid_transitions.transpose(1, 0, 2),  # (n_agents, n_threads, 1)
            terms,  # (n_threads, 1)
            next_share_obs[:, 0],  # (n_threads, next_share_obs_dim)
            next_obs.transpose(1, 0, 2),  # (n_agents, n_threads, next_obs_dim)
            next_available_actions,  # None or (n_agents, n_threads, next_action_number)
        )
    elif self.state_type == "FP":
        data = (
            share_obs,  # (n_threads, n_agents, share_obs_dim)
            obs,  # (n_agents, n_threads, obs_dim)
            actions,  # (n_agents, n_threads, action_dim)
            available_actions,  # None or (n_agents, n_threads, action_number)
            rewards,  # (n_threads, n_agents, 1)
            np.expand_dims(dones, axis=-1),  # (n_threads, n_agents, 1)
            valid_transitions.transpose(1, 0, 2),  # (n_agents, n_threads, 1)
            terms,  # (n_threads, n_agents, 1)
            next_share_obs,  # (n_threads, n_agents, next_share_obs_dim)
            next_obs.transpose(1, 0, 2),  # (n_agents, n_threads, next_obs_dim)
            next_available_actions,  # None or (n_agents, n_threads, next_action_number)
        )

When self.state_type == "EP", why is only the reward of the first agent taken rewards[:, 0]， and why the reward of the second agent ignored?