What is the difference between the predict and predict_on_batch methods of a Keras model?

Question

According to the keras documentation:

predict_on_batch(self, x)
Returns predictions for a single batch of samples.

However, there does not

Answer 1

It seems predict_on_batch is a lot faster compared to predict if executed on a single batch.

• batch & model information
  • batch shape: (1024, 333)
  • batch dtype: float32
  • model parameters: ~150k
• timeit result:
  • predict: ~1.45 seconds
  • predict_on_batch: ~95.5 ms

In summary, predict method has extra operations to ensure a collection of batches are processed right, whereas, predict_on_batch is a lightweight alternative to predict that should be used on a single batch.