utils.py 文件源码

def smart_cond(pred, fn1, fn2, name=None):
  """Return either fn1() or fn2() based on the boolean predicate/value `pred`.

  If `pred` is bool or has a constant value it would use `static_cond`,
  otherwise it would use `tf.cond`.

  Args:
    pred: A scalar determining whether to return the result of `fn1` or `fn2`.
    fn1: The callable to be performed if pred is true.
    fn2: The callable to be performed if pred is false.
    name: Optional name prefix when using tf.cond
  Returns:
    Tensors returned by the call to either `fn1` or `fn2`.
  """
  pred_value = constant_value(pred)
  if pred_value is not None:
    # Use static_cond if pred has a constant value.
    return static_cond(pred_value, fn1, fn2)
  else:
    # Use dynamic cond otherwise.
    return control_flow_ops.cond(pred, fn1, fn2, name)