regularizers.py 文件源码

def apply_regularization(regularizer, weights_list=None):
  """Returns the summed penalty by applying `regularizer` to the `weights_list`.

  Adding a regularization penalty over the layer weights and embedding weights
  can help prevent overfitting the training data. Regularization over layer
  biases is less common/useful, but assuming proper data preprocessing/mean
  subtraction, it usually shouldn't hurt much either.

  Args:
    regularizer: A function that takes a single `Tensor` argument and returns
      a scalar `Tensor` output.
    weights_list: List of weights `Tensors` or `Variables` to apply
      `regularizer` over. Defaults to the `GraphKeys.WEIGHTS` collection if
      `None`.

  Returns:
    A scalar representing the overall regularization penalty.

  Raises:
    ValueError: If `regularizer` does not return a scalar output, or if we find
        no weights.
  """
  if not weights_list:
    weights_list = ops.get_collection(ops.GraphKeys.WEIGHTS)
  if not weights_list:
    raise ValueError('No weights to regularize.')
  with ops.name_scope('get_regularization_penalty',
                      values=weights_list) as scope:
    penalties = [regularizer(w) for w in weights_list]
    for p in penalties:
      if p.get_shape().ndims != 0:
        raise ValueError('regularizer must return a scalar Tensor instead of a '
                         'Tensor with rank %d.' % p.get_shape().ndims)

    summed_penalty = math_ops.add_n(penalties, name=scope)
    ops.add_to_collection(ops.GraphKeys.REGULARIZATION_LOSSES, summed_penalty)
    return summed_penalty