from other group at a particular time. Note that `diversity_penalty` is only effective if `group beam search` is enabled. num_beams (`int`): Number of beams used for group beam search. See [this paper](https://arxiv.org/pdf/1610.02424.pdf) for more details. num_beam_groups (`int`): Number of groups to divide `num_beams` into in order to ensure diversity among different groups of beams. See [this paper](https://arxiv.org/pdf/1610.02424.pdf) for more details. Ú