update docs

Author: awaelchli

docs/source/advanced/multi_gpu.rst

@@ -222,9 +222,9 @@ Note in particular the difference between `gpus=0`, `gpus=[0]` and `gpus="0"`.
 +---------------+-----------+---------------------+---------------------------------+
 | [1, 3]        | list      | [1, 3]              | GPUs 1 and 3                    |
 +---------------+-----------+---------------------+---------------------------------+
-| "0"           | str       | [0]                 | GPU 0                           |
+| "0"           | str       | None                | CPU                             |
 +---------------+-----------+---------------------+---------------------------------+
-| "3"           | str       | [3]                 | GPU 3                           |
+| "3"           | str       | [0, 1, 2]           | first 3 GPUs                    |
 +---------------+-----------+---------------------+---------------------------------+
 | "1, 3"        | str       | [1, 3]              | GPUs 1 and 3                    |
 +---------------+-----------+---------------------+---------------------------------+