带有自定义对象的Keras load_model无法正常工作

Question

设置

正如标题中已经提到的，当我尝试加载保存的模型时，我的自定义丢失功能出现了问题。我的损失如下：

def weighted_cross_entropy(weights):

    weights = K.variable(weights)

    def loss(y_true, y_pred):
        y_pred = K.clip(y_pred, K.epsilon(), 1-K.epsilon())

        loss = y_true * K.log(y_pred) * weights
        loss = -K.sum(loss, -1)
        return loss

    return loss

weightes_loss = weighted_cross_entropy([0.1,0.9])

所以在训练期间，我使用weighted_loss函数作为损失函数，一切运行良好。训练结束后，我将模型保存为.h5file，使用keras API的标准model.save函数。

问题

当我试图加载模型时

model = load_model(path,custom_objects={"weighted_loss":weighted_loss})

我得到一个ValueError告诉我，损失是未知的。

错误

错误消息如下所示：

File "...\predict.py", line 29, in my_script
"weighted_loss": weighted_loss})
File "...\Continuum\anaconda3\envs\processing\lib\site-packages\keras\engine\saving.py", line 419, in load_model
model = _deserialize_model(f, custom_objects, compile)
File "...\Continuum\anaconda3\envs\processing\lib\site-packages\keras\engine\saving.py", line 312, in _deserialize_model
sample_weight_mode=sample_weight_mode)
File "...\Continuum\anaconda3\envs\processing\lib\site-packages\keras\engine\training.py", line 139, in compile
loss_function = losses.get(loss)
File "...\Continuum\anaconda3\envs\processing\lib\site-packages\keras\losses.py", line 133, in get
return deserialize(identifier)
File "...\Continuum\anaconda3\envs\processing\lib\site-packages\keras\losses.py", line 114, in deserialize
printable_module_name='loss function')
File "...\Continuum\anaconda3\envs\processing\lib\site-packages\keras\utils\generic_utils.py", line 165, in deserialize_keras_object
':' + function_name)
ValueError: Unknown loss function:loss

问题

我该如何解决这个问题？可能原因是我的包裹损失定义？所以keras不知道，如何处理weights变量？

Answer 1

你的损失函数的名字是loss（即def loss(y_true, y_pred):）。因此，在加载模型时，您需要指定'loss'作为其名称：

model = load_model(path, custom_objects={'loss': weighted_loss})