Range of hyperparameters for vizier.

def imagetransformer_cifar_tpu_range(rhp):
  """Range of hyperparameters for vizier."""
  # After starting from base, set intervals for some parameters.
  rhp.set_float("learning_rate", 0.01, 1.0, scale=rhp.LOG_SCALE)
  rhp.set_discrete("num_decoder_layers", [8, 10, 12, 14, 16])
  rhp.set_discrete("hidden_size", [256, 512, 1024])
  rhp.set_discrete("block_length", [128, 256, 512])
  rhp.set_categorical("dec_attention_type", [
      cia.AttentionType.RELATIVE_LOCAL_1D, cia.AttentionType.LOCAL_1D])