Residual discrete autoencoder model.

def autoencoder_residual_discrete():
  """Residual discrete autoencoder model."""
  hparams = autoencoder_residual()
  hparams.bottleneck_bits = 1024
  hparams.bottleneck_noise = 0.05
  hparams.add_hparam("discretize_warmup_steps", 16000)
  hparams.add_hparam("bottleneck_kind", "tanh_discrete")
  hparams.add_hparam("isemhash_noise_dev", 0.5)
  hparams.add_hparam("isemhash_mix_prob", 0.5)
  hparams.add_hparam("isemhash_filter_size_multiplier", 2.0)
  hparams.add_hparam("vq_beta", 0.25)
  hparams.add_hparam("vq_decay", 0.999)
  hparams.add_hparam("vq_epsilon", 1e-5)
  return hparams