shirui-japina:

So that means no updating for the weights in the model, during the learning rate finder working, Is it right?


No, the weights are updated in the algorithm you can see this from the :
loss.backward()
optimizer.step()

part of the algorithm S. Googer created.
However, I am not saying it is not possible to create LR finder even without updating the weights, but this would not be one cycle learning paper.

I did not verify with my own model and input data.

Yeah, good point. We need to check everything, else we don’t know anything.
You may try this exact S. Googer algorithm from his article, but just instead go trough different batches, try on a single (first) batch.
Hope you will get more feedback from the fastai blog.