I'm building a Feedforward Neural Network with Pytorch and doing hyperparameters tuning using Ray Tune. I have train, validation and test set, train and validation used during the training procedure. I have different versions of the model (different learning rates and numbers of neurons in the hidden layers) and I have to choose the best model. But I'm unsure on which metric should I use to choose the best model. Basically I don't know the XXXX in this line of code:
analysis.get_best_config(metric='XXXX', mode='min')
Should it be test loss or validation loss?