不允许迭代 `tf.Tensor`答案

【问题标题】：iterating over `tf.Tensor` is not allowed不允许迭代 `tf.Tensor`
【发布时间】：2021-09-30 13:47:09
【问题描述】：

我正在尝试将此函数用于 @tf.function 装饰：

h 和 h2 是一个形状为 [3,3] 的张量

def fn(h,i):
    print(h[i])
    return h[i]

tensor = [fn(h,i) for i in tf.range(tf.cast(tf.shape(h)[0],tf.int32)) if  tf.reduce_all(tf.equal(h[i],h2[i])) ]
tf.print(tensor)

但我得到了这个错误：

main_coat_rds.py:139 train_step  *
        pseudo_label_1,images_discard_rede1=predict_aug_images(rede_2,rede_1,img_rede1_aug_1,img_rede1_aug_2,img_rede1_aug_3,img_rede1_aug_4,img_rede1_aug_5,img_rede1_aug_6,img_rede1_aug_7,img_rede1_aug_8,images_discard_rede1,Correct_labels)
    /vitor/codigo_noise_label/codigo_rds/utils_loss_function.py:289 predict_aug_images  *
        pred_match = [get_value_labels(all_predics,i) for i in tf.range(tf.cast(tf.shape(all_predics)[0],tf.int32)) if  tf.reduce_all(tf.equal(all_predics[i],all_predics_aj[i])) ]
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/framework/ops.py:503 __iter__
        self._disallow_iteration()
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/framework/ops.py:496 _disallow_iteration
        self._disallow_when_autograph_enabled("iterating over `tf.Tensor`")
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/framework/ops.py:474 _disallow_when_autograph_enabled
        " indicate you are trying to use an unsupported feature.".format(task))

    OperatorNotAllowedInGraphError: iterating over `tf.Tensor` is not allowed: AutoGraph did convert this function. This might indicate you are trying to use an unsupported feature.

还有什么方法可以做到？

【问题讨论】：

标签： python tensorflow tensor tensorflow2

【解决方案1】：

当您想根据条件选择张量的某些部分时，一个不错的选择是使用tf.gather 和tf.where 的组合。

在这里，例如，要选择h 和h2 之间相等的行，您可以使用：

tf.gather_nd(h, tf.where(tf.reduce_all(tf.equal(h, h2),axis=1)))

【讨论】：