util.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)