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Helper class for representing fully-specified data-yielding computations.
Inherits From: Ingestable
, TypedObject
, CardinalityCarrying
tff.framework.DataDescriptor(
comp: Optional[tff.Computation
],
arg: Any,
arg_type: tff.types.Type
,
cardinality: Optional[int] = None
)
Instances of this class are objects that may combine a federated computation that returns a portion of federated data and an argument to be supplied as input to this computation, or the argument alone. These objects are designed to be recognized by the runtime. When ingesting those objects (e.g., as they are passed as arguments to a computation invocation), the runtime ingests the argument, and (if provided) optionally invokes the computation contained in this descriptor on the argument to cause the data to materialize within the runtime (but without marshaling it out and returning it to user).
In the typical usage of this helper class, the embedded argument is a set of
handles, and the embedded computation transforms those handles into physical
tf.data.Dataset
instances. This transformation occurs on the clients (i.e.,
in the TFF runtime worker processes).
Alternatively, the argument itself may consist of computations to be locally executed on the clients. In this case, the computation can be omitted.
Args | |
---|---|
comp
|
The computation that materializes the data, of some type (T -> U)
where T is the type of the argument arg and U is the type of the
materialzied data that's being produces. This can be None , in which
case it's assumed to be an identity function (and T in that case must
be identical to U ).
|
arg
|
The argument to be passed as input to comp if comp is not None ,
or to be treated as the computed result. Must be recognized by the TFF
runtime as a payload of type T .
|
arg_type
|
The type of the argument (T references above). An instance of
tff.Type .
|
cardinality
|
Optional cardinality (e.g., number of clients) to supply if this descriptor represents an instance of federated data. |
Raises | |
---|---|
ValueError
|
if the arguments don't satisfy the constraints listed above. |
Attributes | |
---|---|
cardinality
|
Returns the cardinality information associated with this object. |
type_signature
|
Returns the TFF type of this object (an instance of tff.Type ).
|
Methods
ingest
ingest(
executor
)
Causes this object to ingest itself into the given executor.
Args | |
---|---|
executor
|
An instance of executor_base.Executor to ingest into.
|
Returns | |
---|---|
An instance of executor_value_base.ExecutorValue returned by the
executor.
|