If you're experienced with machine learning, you may be wondering why I would opt for Hold-Out (train/val/test) validation over K-Fold cross-validation. Training a deep neural network is a very expensive operation, and put very simply, training K of them per set of hyperparameters we'd like to explore is usually not very practical.
We can be somewhat confident that Hold-Out validation does a very good job, given a large enough val and test set. Most of the time, we are hopefully applying deep learning in situations where we have an abundance of data, resulting in an adequate val and test set.
Ultimately, it's up to you. As we will see later, Keras provides a scikit-learn interface that allows Keras models to be integrated ...
