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Return a list of physical devices visible to the runtime.



Used in the guide:

Used in the tutorials:

Physical devices are hardware devices locally present on the current machine. By default all discovered CPU and GPU devices are considered visible. The list_physical_devices allows querying the hardware prior to runtime initialization.

The following example ensures the machine can see at least 1 GPU.

physical_devices = tf.config.experimental.list_physical_devices('GPU')
assert len(physical_devices) > 0, "No GPUs found."


  • device_type: (optional) Device type to filter by such as "CPU" or "GPU"


List of PhysicalDevice objects