如何将变量添加到 Keras 中的进度条？

Question

我想监控例如。进度条和 Tensorboard 中 Keras 训练期间的学习率。我认为必须有一种方法来指定记录哪些变量，但是 Keras website.

上没有立即澄清这个问题

我想这与创建自定义 Callback 函数有关，但是，应该可以修改已经存在的进度条回调，不是吗？

Answer 1

可以通过自定义指标来实现。以学习率为例：

def get_lr_metric(optimizer):
    def lr(y_true, y_pred):
        return optimizer.lr
    return lr

x = Input((50,))
out = Dense(1, activation='sigmoid')(x)
model = Model(x, out)

optimizer = Adam(lr=0.001)
lr_metric = get_lr_metric(optimizer)
model.compile(loss='binary_crossentropy', optimizer=optimizer, metrics=['acc', lr_metric])

# reducing the learning rate by half every 2 epochs
cbks = [LearningRateScheduler(lambda epoch: 0.001 * 0.5 ** (epoch // 2)),
        TensorBoard(write_graph=False)]
X = np.random.rand(1000, 50)
Y = np.random.randint(2, size=1000)
model.fit(X, Y, epochs=10, callbacks=cbks)

LR会打印在进度条中：

Epoch 1/10
1000/1000 [==============================] - 0s 103us/step - loss: 0.8228 - acc: 0.4960 - lr: 0.0010
Epoch 2/10
1000/1000 [==============================] - 0s 61us/step - loss: 0.7305 - acc: 0.4970 - lr: 0.0010
Epoch 3/10
1000/1000 [==============================] - 0s 62us/step - loss: 0.7145 - acc: 0.4730 - lr: 5.0000e-04
Epoch 4/10
1000/1000 [==============================] - 0s 58us/step - loss: 0.7129 - acc: 0.4800 - lr: 5.0000e-04
Epoch 5/10
1000/1000 [==============================] - 0s 58us/step - loss: 0.7124 - acc: 0.4810 - lr: 2.5000e-04
Epoch 6/10
1000/1000 [==============================] - 0s 63us/step - loss: 0.7123 - acc: 0.4790 - lr: 2.5000e-04
Epoch 7/10
1000/1000 [==============================] - 0s 61us/step - loss: 0.7119 - acc: 0.4840 - lr: 1.2500e-04
Epoch 8/10
1000/1000 [==============================] - 0s 61us/step - loss: 0.7117 - acc: 0.4880 - lr: 1.2500e-04
Epoch 9/10
1000/1000 [==============================] - 0s 59us/step - loss: 0.7116 - acc: 0.4880 - lr: 6.2500e-05
Epoch 10/10
1000/1000 [==============================] - 0s 63us/step - loss: 0.7115 - acc: 0.4880 - lr: 6.2500e-05

然后，您可以在TensorBoard中可视化LR曲线。

Answer 2

另一种方式（实际上是 encouraged one) of how to pass custom values to TensorBoard is by sublcassing the keras.callbacks.TensorBoard class。这允许您应用自定义函数来获取所需的指标并将它们直接传递给 TensorBoard。

这里是 Adam 优化器学习率的例子：

class SubTensorBoard(TensorBoard):
    def __init__(self, *args, **kwargs):
        super(SubTensorBoard, self).__init__(*args, **kwargs)

    def lr_getter(self):
        # Get vals
        decay = self.model.optimizer.decay
        lr = self.model.optimizer.lr
        iters = self.model.optimizer.iterations # only this should not be const
        beta_1 = self.model.optimizer.beta_1
        beta_2 = self.model.optimizer.beta_2
        # calculate
        lr = lr * (1. / (1. + decay * K.cast(iters, K.dtype(decay))))
        t = K.cast(iters, K.floatx()) + 1
        lr_t = lr * (K.sqrt(1. - K.pow(beta_2, t)) / (1. - K.pow(beta_1, t)))
        return np.float32(K.eval(lr_t))

    def on_epoch_end(self, episode, logs = {}):
        logs.update({"lr": self.lr_getter()})
        super(SubTensorBoard, self).on_epoch_end(episode, logs)

Answer 3

我来到这个问题是因为我想在 Keras 进度条中记录更多变量。这是我阅读此处答案后的做法：

class UpdateMetricsCallback(tf.keras.callbacks.Callback):
  def on_batch_end(self, batch, logs):
    logs.update({'my_batch_metric' : 0.1, 'my_other_batch_metric': 0.2})
  def on_epoch_end(self, epoch, logs):
    logs.update({'my_epoch_metric' : 0.1, 'my_other_epoch_metric': 0.2})

model.fit(...,
  callbacks=[UpdateMetricsCallback()]
)

希望对大家有所帮助。

如何将变量添加到 Keras 中的进度条？

How to add variables to progress bar in Keras?

python

keras

tensorboard

keras-2