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

View source

@staticmethod
build(
    topology: tf.tpu.experimental.Topology,
    computation_shape: Optional[np.ndarray] = None,
    computation_stride: Optional[np.ndarray] = None,
    num_replicas: int = 1
) -> "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[Text] = None
) -> Text

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[Text] = None
) -> Text

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.