In the training loop below, you can see that train_loss represents the loss on the most recent batch.

Whereas the eval_loss is computed on the entire training dataset.

When I print it out, should I be recalculating the train_loss against the entire training split instead of the last batch?

for epoch in range(epochs):
    # Loop over batches.
    for i, batch in enumerate(samples_train['features']):
        train_preds = model(samples_train['features'][i])
        train_loss = loss_fn(train_preds, samples_train['labels'][i])

    # Only the training data is batched.
    eval_preds = model(samples_evaluate['features'])
    eval_loss = loss_fn(eval_preds, samples_evaluate['labels'])
    print(f"Epoch: {epoch}, Train_Loss: {float(train_loss)},  Eval_Loss: {float(eval_loss)}")
  • $\begingroup$ hmm now i am thinking about undersized batches and leaning toward the whole split $\endgroup$
    – Kalanos
    Apr 6, 2021 at 23:28

1 Answer 1


The losses should be calculated over the whole epoch (i.e. the whole dataset) instead of just the single batch. To implement this you could have a running count which adds up the losses of the individual batches and divides it by the number of batches after the epoch ends.

  • $\begingroup$ Nice yeah that would be much more efficient than loading the whole dataset again. $\endgroup$
    – Kalanos
    Apr 7, 2021 at 10:58

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