pytorch - connection between loss.backward() and optimizer.step()

Question

Where is an explicit connection between the optimizer and the loss?

How does the optimizer know where to get the gradients of the loss wit

Answer 1

Short answer:

loss.backward() # do gradient of all parameters for which we set required_grad= True. parameters could be any variable defined in code, like h2h or i2h.

optimizer.step() # according to the optimizer function (defined previously in our code), we update those parameters to finally get the minimum loss(error).