Notebook 07: Cannot save model checkpoint for FoodVision Big

[mrdbourke]

Getting an error when training FoodVision Big:

# Fit the model with callbacks
history_101_food_classes_feature_extract = model.fit(train_data, 
                                                     epochs=3,
                                                     steps_per_epoch=len(train_data),
                                                     validation_data=test_data,
                                                     validation_steps=int(0.15 * len(test_data)),
                                                     callbacks=[create_tensorboard_callback("training_logs", 
                                                                                            "efficientnetb0_101_classes_all_data_feature_extract"),
                                                                model_checkpoint])

>>>WARNING:tensorflow:Can save best model only with val_acc available, skipping.

Looks like it's an issue with the model_checkpoint callback.

This causes the assertion for the cloned model later on to fail:

# Evalaute cloned model with loaded weights (should be same score as trained model)
results_cloned_model_with_loaded_weights = cloned_model.evaluate(test_data)

>>> ---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
/tmp/ipykernel_1443486/1110829135.py in <module>
      1 # Loaded checkpoint weights should return very similar results to checkpoint weights prior to saving
      2 import numpy as np
----> 3 assert np.isclose(results_feature_extract_model, results_cloned_model_with_loaded_weights).all() # check if all elements in array are close

AssertionError: 

Need to update the model checkpoint to make sure it can save a model whilst training.

[mrdbourke]

Also getting this in Google Colab: