6
我试图实现keras的AUC度量,以便在model.fit()运行期间运行验证集后运行AUC度量。定义keras的AUC度量标准以支持验证数据集的评估
我定义的指标,因为这:
def auc(y_true, y_pred):
keras.backend.get_session().run(tf.global_variables_initializer())
keras.backend.get_session().run(tf.initialize_all_variables())
keras.backend.get_session().run(tf.initialize_local_variables())
#return K.variable(value=tf.contrib.metrics.streaming_auc(
# y_pred, y_true)[0], dtype='float32')
return tf.contrib.metrics.streaming_auc(y_pred, y_true)[0]
这将导致以下错误,我不知道理解。
tensorflow.python.framework.errors_impl.FailedPreconditionError:
Attempting to use uninitialized value auc/true_positives...
从网上阅读,似乎问题是2倍,在tensorflow/keras中的错误和部分和问题与tensorflow暂时无法从推理初始化局部变量。鉴于这两个问题,我不明白为什么我会得到这个错误或如何克服它。有什么建议么?
为了证明我不是懒惰的,我写了2个其他指标可以正常工作。
# PFA, prob false alert for binary classifier
def binary_PFA(y_true, y_pred, threshold=K.variable(value=0.5)):
y_pred = K.cast(y_pred >= threshold, 'float32')
# N = total number of negative labels
N = K.sum(1 - y_true)
# FP = total number of false alerts, alerts from the negative class labels
FP = K.sum(y_pred - y_pred * y_true)
return FP/N
# P_TA prob true alerts for binary classifier
def binary_PTA(y_true, y_pred, threshold=K.variable(value=0.5)):
y_pred = K.cast(y_pred >= threshold, 'float32')
# P = total number of positive labels
P = K.sum(y_true)
# TP = total number of correct alerts, alerts from the positive class labels
TP = K.sum(y_pred * y_true)
return TP/P