[FIXED] Do Keras epoch-counting callbacks work across several fitting sessions?

Issue

Some Keras callbacks, like ModelCheckpoint or ReduceLROnPlateau, rely on counting the number of epochs that some condition is met until some action is taken.

For certain purposes I need to train a Keras model in several fitting sessions, so something like

for epoch in range(num_epochs):
   model.fit(data, epochs=1)

rather than

model.fit(data, epochs=num_epochs)

I was wondering if Keras callbacks work even if I use them across several fitting sessions.

Solution

Each time model.fit(...) is called callbacks.History is reset. So no, it will not work like that. While you could log yourself as @kacpo1 mentioned and save each, you may benefit from the train_on_batch(...) method. This performs a single update and you can set reset_metrics=False in the method call to retain your metrics.

https://keras.io/api/models/model_training_apis/#trainonbatch-method

Answered By - Aidan Costello