[英]Use tf.metrics in Keras?
I'm especially interested in specificity_at_sensitivity
. 我对specificity_at_sensitivity
特别感兴趣。 Looking through the Keras docs : 浏览Keras文档 :
from keras import metrics
model.compile(loss='mean_squared_error',
optimizer='sgd',
metrics=[metrics.mae, metrics.categorical_accuracy])
But it looks like the metrics
list must have functions of arity 2, accepting (y_true, y_pred)
and returning a single tensor value. 但看起来metrics
列表必须具有arity 2的函数,接受(y_true, y_pred)
并返回单个张量值。
EDIT: Currently here is how I do things: 编辑:目前这是我做的事情:
from sklearn.metrics import confusion_matrix
predictions = model.predict(x_test)
y_test = np.argmax(y_test, axis=-1)
predictions = np.argmax(predictions, axis=-1)
c = confusion_matrix(y_test, predictions)
print('Confusion matrix:\n', c)
print('sensitivity', c[0, 0] / (c[0, 1] + c[0, 0]))
print('specificity', c[1, 1] / (c[1, 1] + c[1, 0]))
The disadvantage of this approach, is I only get the output I care about when training has finished. 这种方法的缺点是,我只能在训练结束时得到我关心的输出。 Would prefer to get metrics every 10 epochs or so. 宁愿每10个纪元左右获得指标。
I've found a related issue on github , and it seems that tf.metrics
are still not supported by Keras models. 我在github上发现了一个相关的问题,似乎tf.metrics
模型仍然不支持tf.metrics
。 However, in case you are very interested in using tf.metrics.specificity_at_sensitivity , I would suggest the following workaround (inspired by BogdanRuzh's solution): 但是,如果您对使用tf.metrics.specificity_at_sensitivity非常感兴趣,我建议采用以下解决方法(受BogdanRuzh解决方案的启发):
def specificity_at_sensitivity(sensitivity, **kwargs):
def metric(labels, predictions):
# any tensorflow metric
value, update_op = tf.metrics.specificity_at_sensitivity(labels, predictions, sensitivity, **kwargs)
# find all variables created for this metric
metric_vars = [i for i in tf.local_variables() if 'specificity_at_sensitivity' in i.name.split('/')[2]]
# Add metric variables to GLOBAL_VARIABLES collection.
# They will be initialized for new session.
for v in metric_vars:
tf.add_to_collection(tf.GraphKeys.GLOBAL_VARIABLES, v)
# force to update metric values
with tf.control_dependencies([update_op]):
value = tf.identity(value)
return value
return metric
model.compile(loss='mean_squared_error',
optimizer='sgd',
metrics=[metrics.mae,
metrics.categorical_accuracy,
specificity_at_sensitivity(0.5)])
UPDATE: 更新:
You can use model.evaluate to retrieve the metrics after training. 您可以使用model.evaluate在培训后检索指标。
I don't think there is a strict limit to only two incoming arguments, in metrics.py the function is just three incoming arguments, but k selects the default value of 5. 我不认为只有两个传入的参数有严格的限制,在metrics.py中,函数只是三个传入参数,但k选择默认值5。
def sparse_top_k_categorical_accuracy(y_true, y_pred, k=5):
return K.mean(K.in_top_k(y_pred, K.cast(K.max(y_true, axis=-1), 'int32'), k), axis=-1)
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