From my searching result, seems tensorflow 2 automatically will use available gpu. I have a rtx 2080, but when i run the code  `print("Num GPUs Available: ", len(tf.config.experimental.list_physical_devices('GPU')))` it gives `Num GPUs Available: 0`. My tensorflow version is 2.4.x. And I am using jupyter notebook.
What should I do to enable the gpu?