Basic autoencoder model.

def autoencoder_basic():
  """Basic autoencoder model."""
  hparams = common_hparams.basic_params1()
  hparams.optimizer = "adam"
  hparams.learning_rate_constant = 0.0002
  hparams.learning_rate_warmup_steps = 500
  hparams.learning_rate_schedule = "constant * linear_warmup"
  hparams.label_smoothing = 0.0
  hparams.batch_size = 128
  hparams.hidden_size = 64
  hparams.num_hidden_layers = 5
  hparams.initializer = "uniform_unit_scaling"
  hparams.initializer_gain = 1.0
  hparams.weight_decay = 0.0
  hparams.kernel_height = 4
  hparams.kernel_width = 4
  hparams.dropout = 0.05
  hparams.add_hparam("max_hidden_size", 1024)
  hparams.add_hparam("bottleneck_bits", 128)
  hparams.add_hparam("bottleneck_shared_bits", 0)
  hparams.add_hparam("bottleneck_shared_bits_start_warmup", 0)
  hparams.add_hparam("bottleneck_shared_bits_stop_warmup", 0)
  hparams.add_hparam("bottleneck_noise", 0.1)
  hparams.add_hparam("bottleneck_warmup_steps", 2000)
  hparams.add_hparam("sample_height", 32)
  hparams.add_hparam("sample_width", 32)
  hparams.add_hparam("discriminator_batchnorm", True)
  hparams.add_hparam("num_sliced_vecs", 20000)
  hparams.add_hparam("sliced_do_tanh", int(True))
  hparams.add_hparam("discriminator_size", 256)
  hparams.add_hparam("discriminator_kernel_size", 6)
  hparams.add_hparam("discriminator_strides", 4)
  hparams.add_hparam("discriminator_pure_mean", int(False))
  hparams.add_hparam("code_loss_factor", 1.0)
  hparams.add_hparam("gan_codes_warmup_steps", 16000)
  hparams.add_hparam("gan_loss_factor", 0.0)
  hparams.add_hparam("bottleneck_l2_factor", 0.05)
  hparams.add_hparam("gumbel_temperature", 0.5)
  hparams.add_hparam("gumbel_noise_factor", 0.5)
  hparams.add_hparam("vq_temperature", 0.001)
  hparams.add_hparam("use_vq_loss", int(False))
  hparams.add_hparam("discriminator", "double")
  return hparams