tff.program.PrefetchingDataSourceIterator

A tff.program.FederatedDataSourceIterator that prefetches data.

Inherits From: FederatedDataSourceIterator

tff.program.PrefetchingDataSourceIterator(
    iterator: tff.program.FederatedDataSourceIterator,
    context: tff.framework.AsyncExecutionContext,
    total_rounds: int,
    num_rounds_to_prefetch: int,
    num_clients_to_prefetch: int,
    prefetch_threshold: int = 0
)

Args
iterator	A tff.program.FederatedDataSourceIterator used to prefetch data from.
context	The tff.framework.AsyncExecutionContext to prefetch data in.
total_rounds	The total number of rounds.
num_rounds_to_prefetch	The number of rounds to prefetch.
num_clients_to_prefetch	The number of clients to prefetch per round. Must be greater than 1 and must be identical across all rounds; attempts to select any other number of clients will fail.
prefetch_threshold	The threshold below which the data source starts prefetching.

Raises
ValueError	If num_clients_to_prefetch is not greater than 1.

Attributes
federated_type	The type of the data returned by calling select.

Methods

select

View source

select(
    num_clients: Optional[int] = None
) -> Any

Returns a new selection of data from this iterator.

Args
num_clients	A number of clients to use when selecting data. Must be a positive integer and equal to num_clients_to_prefetch.

Raises
ValueError	If num_clients is not a positive integer or if num_clients is not equal to num_clients_to_prefetch.