Improved semantic hashing un-bottleneck.

def isemhash_unbottleneck(x, hidden_size, isemhash_filter_size_multiplier=1.0):
  """Improved semantic hashing un-bottleneck."""
  filter_size = int(hidden_size * isemhash_filter_size_multiplier)
  x = 0.5 * (x - 1.0)  # Move from [-1, 1] to [0, 1].
  with tf.variable_scope("isemhash_unbottleneck"):
    h1a = tf.layers.dense(x, filter_size, name="hidden1a")
    h1b = tf.layers.dense(1.0 - x, filter_size, name="hidden1b")
    h2 = tf.layers.dense(tf.nn.relu(h1a + h1b), filter_size, name="hidden2")
    return tf.layers.dense(tf.nn.relu(h2), hidden_size, name="final")