I tried the following:
torch.save(net.state_dict(), f"file")
weights = torch.load('file1', map_location=device)

net1 = Net()
net1.load_state_dict(weights)

net2 = Net()
net2.load_state_dict(weights)

torch.save(net1.state_dict(), f"file1")
torch.save(net2.state_dict(), f"file2")

Then I find that file1 and file2 are different. How can it be? My goal is to find out if the weights of a net has changed since last time.