What is the use of train_on_batch() in keras?

Question

How train_on_batch() is different from fit()? What are the cases when we should use train_on_batch()?

Answer 1

Indeed @nbro answer helps, just to add few more scenarios, lets say you are training some seq to seq model or a large network with one or more encoders. We can create custom training loops using train_on_batch and use a part of our data to validate on the encoder directly without using callbacks. Writing callbacks for a complex validation process could be difficult. There are several cases where we wish to train on batch.

Regards, Karthick