python - 什么是 tf.losses.absolute_difference 的替代品

Question

我的问题是关于 TF2.0 的。没有 tf.losses.absolute_difference() 函数，也没有 tf.losses.Reduction.MEAN 属性。

我应该改用什么？TF2 中是否有已删除的 TF 函数列表，也许还有它们的替代品。

这是 TF1.x 代码，不能与 TF2 一起运行:

result = tf.losses.absolute_difference(a,b,reduction=tf.losses.Reduction.MEAN)

Answer 1

您仍然可以通过 tf.compat.v1 访问此功能:

import tensorflow as tf

labels = tf.constant([[0, 1], [1, 0], [0, 1]])
predictions = tf.constant([[0, 1], [0, 1], [1, 0]])

res = tf.compat.v1.losses.absolute_difference(labels,
                                              predictions,
                                              reduction=tf.compat.v1.losses.Reduction.MEAN)
print(res.numpy()) # 0.6666667

或者您可以自己实现:

import tensorflow as tf
from tensorflow.python.keras.utils import losses_utils

def absolute_difference(labels, predictions, weights=1.0, reduction='mean'):
    if reduction == 'mean':
        reduction_fn = tf.reduce_mean
    elif reduction == 'sum':
        reduction_fn = tf.reduce_sum
    else:
        # You could add more reductions
        pass
    labels = tf.cast(labels, tf.float32)
    predictions = tf.cast(predictions, tf.float32)
    losses = tf.abs(tf.subtract(predictions, labels))
    weights = tf.cast(tf.convert_to_tensor(weights), tf.float32)
    res = losses_utils.compute_weighted_loss(losses,
                                             weights,
                                             reduction=tf.keras.losses.Reduction.NONE)

    return reduction_fn(res, axis=None)

res = absolute_difference(labels, predictions)
print(res.numpy()) # 0.6666667