tff.program.FilteringReleaseManager

A tff.program.ReleaseManager that filters values before releasing them.

Inherits From: ReleaseManager

tff.program.FilteringReleaseManager(
    release_manager: ReleaseManager[ReleasableStructure, Key],
    filter_fn: Callable[[tuple[Union[str, int], ...]], bool]
)

A tff.program.FilteringReleaseManager is a utility for filtering values before releasing the values and is used to release values from platform storage to customer storage in a federated program.

Values are filtered using a filter_fn and released to the release_manager.

The filter_fn is a Callable that has a single parameter path and returns a bool, and is used to filter values before they are released. A path is a tuple of indices and/or keys which uniquely identifies the position of the corresponding item in the value; path matches the expectations of the tree library.

The filter_fn is applied to the items in the structure but not the structure itself. If all the items in a structure are filtered out, then the structure will be filtered out as well.

For example:

filtering_manager = tff.program.FilteringReleaseManager(
    release_manager=...,
    filter_fn=...,
)

value = {
  'loss': 1.0,
  'accuracy': 0.5,
}
await filtering_manager.release(value, ...)

If filter_fn is:

• lambda _: True then the entire structure is released.
• lambda _: False then nothing is released.
• lambda path: path == ('loss',) then {'loss': 1.0} is released.

Note: The path () corresponds to the root of the structure; because the filter_fn is applied to the items in the structure but not the structure itself, this path can be used to filter individual values from structures of values.

Important: Most tff.program.ReleasableStructure can be filtered, including individual values, structures, and structures nested in NamedTuples. However, the fields of a NamedTuple cannot be filtered.

Args
release_manager	A tff.program.ReleaseManager used to release values to.
filter_fn	A Callable used to filter values before they are released, this function has a single parameter path and returns a bool.

Methods

release

View source

release(
    value, key
) -> Optional[Union[ReleasableStructure, type(_FILTERED_SUBTREE)]]

Releases value from a federated program.

Args
value	A tff.program.ReleasableStructure to release.
key	A value used to reference the released value.

Raises
NotFilterableError	If the value cannot be filtered.