ValueError：在 Keras 中使用自定义指标时出现未知指标函数

Question

Keras 2.x 取消了一堆我需要使用的有用指标，所以我将旧 metrics.py 文件中的函数复制到我的代码中，然后按如下方式包含它们。

 def precision(y_true, y_pred): #taken from old keras source code
     true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1)))
     predicted_positives = K.sum(K.round(K.clip(y_pred, 0, 1)))
     precision = true_positives / (predicted_positives + K.epsilon())
     return precision
def recall(y_true, y_pred): #taken from old keras source code
     true_positives = K.sum(K.round(K.clip(y_true * y_pred, 0, 1)))
     possible_positives = K.sum(K.round(K.clip(y_true, 0, 1)))
     recall = true_positives / (possible_positives + K.epsilon())
     return recall

…

 model.compile(loss='categorical_crossentropy', optimizer='adam',
metrics=['accuracy', precision, recall])

这导致

ValueError: Unknown metric function:precision

我究竟做错了什么？根据 Keras 文档，我看不到我做错了什么。

编辑：

这是完整的追溯：

  Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/keras/models.py", line 274, in
load_model
    sample_weight_mode=sample_weight_mode)
  File "/Library/Python/2.7/site-packages/keras/models.py", line 824, in
compile
     **kwargs)
  File "/Library/Python/2.7/site-packages/keras/engine/training.py", line
934, in compile
     handle_metrics(output_metrics)
   File "/Library/Python/2.7/site-packages/keras/engine/training.py", line
901, in handle_metrics
    metric_fn = metrics_module.get(metric)
  File "/Library/Python/2.7/site-packages/keras/metrics.py", line 75, in get
     return deserialize(str(identifier))
  File "/Library/Python/2.7/site-packages/keras/metrics.py", line 67, in
deserialize
    printable_module_name='metric function')
  File "/Library/Python/2.7/site-packages/keras/utils/generic_utils.py",
line 164, in deserialize_keras_object
    ':' + function_name)
ValueError: Unknown metric function:precision
<FATAL>                         : Failed to load Keras model from file:
model.h5
***> abort program execution
Traceback (most recent call last):
  File "classification.py", line 84, in <module>
    'H:!V:FilenameModel=model.h5:NumEpochs=20:BatchSize=32')
#:VarTransform=D,G
TypeError: none of the 3 overloaded methods succeeded. Full details:
  TMVA::MethodBase* TMVA::Factory::BookMethod(TMVA::DataLoader* loader,
TString theMethodName, TString methodTitle, TString theOption = "") =>
    could not convert argument 2
  TMVA::MethodBase* TMVA::Factory::BookMethod(TMVA::DataLoader* loader,
TMVA::Types::EMVA theMethod, TString methodTitle, TString theOption = "") =>
    FATAL error (C++ exception of type runtime_error)
  TMVA::MethodBase* TMVA::Factory::BookMethod(TMVA::DataLoader*,
TMVA::Types::EMVA, TString, TString, TMVA::Types::EMVA, TString) =>
    takes at least 6 arguments (4 given)

原文由 failedentertainment 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

从回溯看来，当您尝试加载保存的模型时，问题似乎发生了：

  Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/keras/models.py", line 274, in
load_model
    sample_weight_mode=sample_weight_mode)
...
ValueError: Unknown metric function:precision
<FATAL>                         : Failed to load Keras model from file:
model.h5

看看这个问题： https ://github.com/keras-team/keras/issues/10104

加载模型时需要添加自定义对象。例如：

 dependencies = {
    'auc_roc': auc_roc
}

model = keras.models.load_model(self.output_directory + 'best_model.hdf5', custom_objects=dependencies)

原文由 kevin 发布，翻译遵循 CC BY-SA 4.0 许可协议