Inverse-decay linearly from 0.01 to 1.0 reached at max_step.

def inverse_lin_decay(max_step, min_value=0.01, step=None):
  """Inverse-decay linearly from 0.01 to 1.0 reached at max_step."""
  if step is None:
    step = tf.train.get_global_step()
  if step is None:
    return 1.0
  step = to_float(step)
  progress = tf.minimum(step / float(max_step), 1.0)
  return progress * (1.0 - min_value) + min_value