tf.tpu.experimental.DeviceAssignment

Mapping from logical cores in a computation to the physical TPU topology.

tf.tpu.experimental.DeviceAssignment( topology: tf.tpu.experimental.Topology, core_assignment: np.ndarray )

Prefer to use the DeviceAssignment.build() helper to construct a DeviceAssignment; it is easier if less flexible than constructing a DeviceAssignment directly.

topology A Topology object that describes the physical TPU topology.
core_assignment A logical to physical core mapping, represented as a rank 3 numpy array. See the description of the core_assignment property for more details.

ValueError If topology is not Topology object.
ValueError If core_assignment is not a rank 3 numpy array.

core_assignment The logical to physical core mapping.
num_cores_per_replica The number of cores per replica.
num_replicas The number of replicas of the computation.
topology A Topology that describes the TPU topology.

Methods

build

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@classmethod build( topology: tf.tpu.experimental.Topology, computation_shape: Optional[np.ndarray] = None, computation_stride: Optional[np.ndarray] = None, num_replicas: int = 1, device_order_mode: tf.tpu.experimental.DeviceOrderMode = DeviceOrderMode.AUTO ) -> 'DeviceAssignment'

coordinates

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coordinates( replica: int, logical_core: int ) -> Tuple

Returns the physical topology coordinates of a logical core.

host_device

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host_device( replica: int = 0, logical_core: int = 0, job: Optional[str] = None ) -> str

Returns the CPU device attached to a logical core.

lookup_replicas

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lookup_replicas( task_id: int, logical_core: int ) -> List[int]

Lookup replica ids by task number and logical core.

Args
task_id TensorFlow task number.
logical_core An integer, identifying a logical core.

Returns
A sorted list of the replicas that are attached to that task and logical_core.

Raises
ValueError If no replica exists in the task which contains the logical core.

tpu_device

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tpu_device( replica: int = 0, logical_core: int = 0, job: Optional[str] = None ) -> str

Returns the name of the TPU device assigned to a logical core.

tpu_ordinal

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tpu_ordinal( replica: int = 0, logical_core: int = 0 ) -> int

Returns the ordinal of the TPU device assigned to a logical core.