Question

我有一个回调函数，可以在on_epoch_end中为验证数据和每10个测试数据的时期计算一些额外的指标。

我还有一个CSVLogger回调，可将正常的指标保存到日志文件中。

我的回调是否有一种简单的方法可以在CSVLogger正确编写的日志中添加一两列？

Answer 1

您可以将其他指标插入字典logs。

from keras.callbacks import Callback

class ComputeMetrics(Callback):
    def on_epoch_end(self, epoch, logs):
        logs['val_metric'] = epoch ** 2  # replace it with your metrics
        if (epoch + 1) % 10 == 0:
            logs['test_metric'] = epoch ** 3  # same
        else:
            logs['test_metric'] = np.nan

请记住在CSVLogger来电之前将此回调置于fit之前。稍后出现在列表中的回调将收到logs的修改版本。例如，

model = Sequential([Dense(1, input_shape=(10,))])
model.compile(loss='mse', optimizer='adam')
model.fit(np.random.rand(100, 10),
          np.random.rand(100),
          epochs=30,
          validation_data=(np.random.rand(100, 10), np.random.rand(100)),
          callbacks=[ComputeMetrics(), CSVLogger('1.log')])

现在，如果您查看输出日志文件，您会看到另外两列test_metric和val_metric：

epoch,loss,test_metric,val_loss,val_metric
0,0.547923130989,nan,0.370979120433,0
1,0.525437340736,nan,0.35585285902,1
2,0.501358469725,nan,0.341958616376,4
3,0.479624577463,nan,0.329370084703,9
4,0.460121934414,nan,0.317930338383,16
5,0.440655426979,nan,0.307486981452,25
6,0.422990380526,nan,0.298160370588,36
7,0.406809270382,nan,0.289906248748,49
8,0.3912438941,nan,0.282540213466,64
9,0.377326357365,729,0.276457450986,81
10,0.364721306562,nan,0.271435074806,100
11,0.353612961769,nan,0.266939682364,121
12,0.343238875866,nan,0.263228923082,144
13,0.333940329552,nan,0.260326927304,169
14,0.325931007862,nan,0.25773427248,196
15,0.317790198028,nan,0.255648627281,225
16,0.310636150837,nan,0.25411529541,256
17,0.304091459513,nan,0.252928718328,289
18,0.298703012466,nan,0.252127869725,324
19,0.292693507671,6859,0.251701972485,361
20,0.287824733257,nan,0.251610517502,400
21,0.283586999774,nan,0.251790778637,441
22,0.27927801609,nan,0.252100949883,484
23,0.276239238977,nan,0.252632959485,529
24,0.273072380424,nan,0.253150621653,576
25,0.270296501517,nan,0.253555388451,625
26,0.268056542277,nan,0.254015884399,676
27,0.266158599854,nan,0.254496408701,729
28,0.264166412354,nan,0.254723013639,784
29,0.262506003976,24389,0.255338237286,841

Keras，附加回调

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