How can I save my learning rate on each finished epoch using Callbacks?

Question

I used LearningRateScheduler for my model training. I want to save learning rates on each epoch in CSV file (or other document files).
Is there any way to save those learning rates using callbacks?

Answer 1

You may write a Custom Callback and save the LR in a file.
You will get it by - self.model.optimizer.learning_rate
Custom Callback - Keras docs

class CustomCallback(keras.callbacks.Callback):
def on_epoch_end(self, epoch, logs=None):

    print("LR - {}".format(self.model.optimizer.learning_rate))


my_callbacks = [ CustomCallback() ]

LR - <tf.Variable 'Adam/learning_rate:0' shape=() dtype=float32, numpy=0.001>