ValueError:在Keras中使用自定义指标时，未知指标函数 [英] ValueError: Unknown metric function when using custom metric in Keras

问题描述

Keras 2.x淘汰了我需要使用的许多有用指标，因此我将功能从旧的metrics.py文件复制到了我的代码中，然后按如下方式包含了它们.

Keras 2.x killed off a bunch of useful metrics that I need to use, so I copied the functions from the old metrics.py file into my code, then included them as follows.

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])

这将导致

ValueError: Unknown metric function:precision

我做错了什么?根据Keras文档，我看不到我做错了什么.

What am I doing wrong? I can't see anything I'm doing wrong according to Keras documentation.

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)

推荐答案

从回溯来看，当您尝试加载保存的模型时，似乎出现了问题:

From the traceback it seems that the problem occurs when you try to load the saved model:

 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，您需要添加自定义对象.例如:

You need to add your custom objects when loading the model. For example:

dependencies = {
    'auc_roc': auc_roc
}

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

这篇关于ValueError:在Keras中使用自定义指标时，未知指标函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！