tf.tpu.experimental.DeviceAssignment

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

View aliases

Compat aliases for migration

See Migration guide for more details.

tf.compat.v1.tpu.experimental.DeviceAssignment

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.

Args
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.

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

Attributes
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

View source

@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

View source

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

Returns the physical topology coordinates of a logical core.

host_device

View source

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

View source

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

View source

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

View source

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

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