Model parallel ImageNet parameters.

def mtf_image_transformer_base_imagenet_mp128():
  """Model parallel ImageNet parameters."""
  hparams = mtf_image_transformer_base_imagenet()
  hparams.mesh_shape = "model:8;batch:4"
  hparams.layout = "batch:batch;d_ff:model;heads:model"
  hparams.batch_size = 8
  hparams.img_len = 128
  hparams.block_length = 128
  hparams.num_heads = 8
  hparams.num_decoder_layers = 4
  hparams.d_ff = 4096
  hparams.learning_rate_warmup_steps = 31250
  hparams.unconditional = True
  hparams.max_length = 256*256*3
  return hparams