Keras，从回调追加到日志

Question

我有一个回调函数，它在on_epoch_end中为验证数据计算两个额外的指标，并为测试数据计算每10个时期。

我还有一个CSVLogger回调函数，可以将普通指标保存到日志文件中。

有没有一种简单的方法可以从我的回调中将一两列添加到由CSVLogger正确写入的日志中

Answer 1

您可以将其他指标插入到字典logs中。

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

只需记住在fit调用中将此回调放在CSVLogger之前。列表中后面出现的回调将接收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，您将看到另外两个列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