Validation loss measures how poorly a model performs on held-out data that it did not use for training. It shows whether improvements on training samples generalize to unseen samples. section 5.5.3
Compare validation loss with training loss to interpret learning:
- If both losses decrease together, the model is learning and generalizing. section 5.5.3
- If training loss decreases while validation loss increases, the model is overfitting. section 5.5.3
- If neither loss decreases, the data may lack useful information or the model may have insufficient capacity. section 5.5.3
Evaluating each training epoch
Split the data into training and validation subsets, compute validation predictions with the current model parameters, and evaluate them with the same loss function. Print both values to monitor their trends.




