def is_valid_bitwidth_type_for_value_type(
bitwidth_type: computation_types.Type,
value_type: computation_types.Type) -> bool:
"""Whether or not `bitwidth_type` is a valid bitwidth type for `value_type`."""
# NOTE: this function is primarily a helper for `intrinsic_factory.py`'s
# `federated_secure_sum` function.
py_typecheck.check_type(bitwidth_type, computation_types.Type)
py_typecheck.check_type(value_type, computation_types.Type)
if value_type.is_tensor() and bitwidth_type.is_tensor():
# Here, `value_type` refers to a tensor. Rather than check that
# `bitwidth_type` is exactly the same, we check that it is a single integer,
# since we want a single bitwidth integer per tensor.
return bitwidth_type.dtype.is_integer and (
bitwidth_type.shape.num_elements() == 1)
elif value_type.is_struct() and bitwidth_type.is_struct():
bitwidth_name_and_types = list(structure.iter_elements(bitwidth_type))
value_name_and_types = list(structure.iter_elements(value_type))
if len(bitwidth_name_and_types) != len(value_name_and_types):
return False
for (inner_bitwidth_name,
inner_bitwidth_type), (inner_value_name, inner_value_type) in zip(
bitwidth_name_and_types, value_name_and_types):
if inner_bitwidth_name != inner_value_name:
return False
if not is_valid_bitwidth_type_for_value_type(inner_bitwidth_type,
inner_value_type):
return False
return True
else:
return False
def is_valid_bitwidth_type_for_value_type(
bitwidth_type: computation_types.Type,
value_type: computation_types.Type) -> bool:
"""Whether or not `bitwidth_type` is a valid bitwidth type for `value_type`."""
# NOTE: this function is primarily a helper for `intrinsic_factory.py`'s
# `federated_secure_sum` function.
py_typecheck.check_type(bitwidth_type, computation_types.Type)
py_typecheck.check_type(value_type, computation_types.Type)
if bitwidth_type.is_tensor():
# This condition applies to both `value_type` being a tensor or structure,
# as the same integer bitwidth can be used for all values in the structure.
return bitwidth_type.dtype.is_integer and (
bitwidth_type.shape.num_elements() == 1)
elif value_type.is_struct() and bitwidth_type.is_struct():
bitwidth_name_and_types = list(structure.iter_elements(bitwidth_type))
value_name_and_types = list(structure.iter_elements(value_type))
if len(bitwidth_name_and_types) != len(value_name_and_types):
return False
for (inner_bitwidth_name,
inner_bitwidth_type), (inner_value_name, inner_value_type) in zip(
bitwidth_name_and_types, value_name_and_types):
if inner_bitwidth_name != inner_value_name:
return False
if not is_valid_bitwidth_type_for_value_type(inner_bitwidth_type,
inner_value_type):
return False
return True
else:
return False
def is_sum_compatible(type_spec: computation_types.Type) -> bool:
"""Determines if `type_spec` is a type that can be added to itself.
Types that are sum-compatible are composed of scalars of numeric types,
possibly packaged into nested named tuples, and possibly federated. Types
that are sum-incompatible include sequences, functions, abstract types,
and placements.
Args:
type_spec: A `computation_types.Type`.
Returns:
`True` iff `type_spec` is sum-compatible, `False` otherwise.
"""
py_typecheck.check_type(type_spec, computation_types.Type)
if type_spec.is_tensor():
return is_numeric_dtype(
type_spec.dtype) and type_spec.shape.is_fully_defined()
elif type_spec.is_struct():
return all(
is_sum_compatible(v)
for _, v in structure.iter_elements(type_spec))
elif type_spec.is_federated():
return is_sum_compatible(type_spec.member)
else:
return False
def create_identity(type_signature: computation_types.Type) -> ProtoAndType:
"""Returns a tensorflow computation representing an identity function.
The returned computation has the type signature `(T -> T)`, where `T` is
`type_signature`. NOTE: if `T` contains `computation_types.StructType`s
without an associated container type, they will be given the container type
`tuple` by this function.
Args:
type_signature: A `computation_types.Type` to use as the parameter type and
result type of the identity function.
Raises:
TypeError: If `type_signature` contains any types which cannot appear in
TensorFlow bindings.
"""
type_analysis.check_tensorflow_compatible_type(type_signature)
parameter_type = type_signature
if parameter_type is None:
raise TypeError('TensorFlow identity cannot be created for NoneType.')
# TF relies on feeds not-identical to fetches in certain circumstances.
if type_signature.is_tensor() or type_signature.is_sequence():
identity_fn = tf.identity
elif type_signature.is_struct():
identity_fn = functools.partial(structure.map_structure, tf.identity)
else:
raise NotImplementedError(
f'TensorFlow identity cannot be created for type {type_signature}')
return create_computation_for_py_fn(identity_fn, parameter_type)
def type_to_tf_structure(type_spec: computation_types.Type):
"""Returns nested `tf.data.experimental.Structure` for a given TFF type.
Args:
type_spec: A `computation_types.Type`, the type specification must be
composed of only named tuples and tensors. In all named tuples that appear
in the type spec, all the elements must be named.
Returns:
An instance of `tf.data.experimental.Structure`, possibly nested, that
corresponds to `type_spec`.
Raises:
ValueError: if the `type_spec` is composed of something other than named
tuples and tensors, or if any of the elements in named tuples are unnamed.
"""
py_typecheck.check_type(type_spec, computation_types.Type)
if type_spec.is_tensor():
return tf.TensorSpec(type_spec.shape, type_spec.dtype)
elif type_spec.is_struct():
elements = structure.to_elements(type_spec)
if not elements:
raise ValueError('Empty tuples are unsupported.')
element_outputs = [(k, type_to_tf_structure(v)) for k, v in elements]
named = element_outputs[0][0] is not None
if not all((e[0] is not None) == named for e in element_outputs):
raise ValueError('Tuple elements inconsistently named.')
if type_spec.python_container is None:
if named:
output = collections.OrderedDict(element_outputs)
else:
output = tuple(v for _, v in element_outputs)
else:
container_type = type_spec.python_container
if (py_typecheck.is_named_tuple(container_type)
or py_typecheck.is_attrs(container_type)):
output = container_type(**dict(element_outputs))
elif named:
output = container_type(element_outputs)
else:
output = container_type(e if e[0] is not None else e[1]
for e in element_outputs)
return output
else:
raise ValueError('Unsupported type {}.'.format(
py_typecheck.type_string(type(type_spec))))
def transform_to_tff_known_type(
type_spec: computation_types.Type) -> Tuple[computation_types.Type, bool]:
"""Transforms `StructType` to `StructWithPythonType`."""
if type_spec.is_struct() and not type_spec.is_struct_with_python():
field_is_named = tuple(
name is not None for name, _ in structure.iter_elements(type_spec))
has_names = any(field_is_named)
is_all_named = all(field_is_named)
if is_all_named:
return computation_types.StructWithPythonType(
elements=structure.iter_elements(type_spec),
container_type=collections.OrderedDict), True
elif not has_names:
return computation_types.StructWithPythonType(
elements=structure.iter_elements(type_spec),
container_type=tuple), True
else:
raise TypeError('Cannot represent TFF type in TF because it contains '
f'partially named structures. Type: {type_spec}')
return type_spec, False
def is_structure_of_integers(type_spec: computation_types.Type) -> bool:
"""Determines if `type_spec` is a structure of integers.
Args:
type_spec: A `computation_types.Type`.
Returns:
`True` iff `type_spec` is a structure of integers, otherwise `False`.
"""
py_typecheck.check_type(type_spec, computation_types.Type)
if type_spec.is_tensor():
py_typecheck.check_type(type_spec.dtype, tf.DType)
return type_spec.dtype.is_integer
elif type_spec.is_struct():
return all(
is_structure_of_integers(v)
for _, v in structure.iter_elements(type_spec))
elif type_spec.is_federated():
return is_structure_of_integers(type_spec.member)
else:
return False
def create_identity(type_signature: computation_types.Type) -> ProtoAndType:
"""Returns a tensorflow computation representing an identity function.
The returned computation has the type signature `(T -> T)`, where `T` is
`type_signature`. NOTE: if `T` contains `computation_types.StructType`s
without an associated container type, they will be given the container type
`tuple` by this function.
Args:
type_signature: A `computation_types.Type` to use as the parameter type and
result type of the identity function.
Raises:
TypeError: If `type_signature` contains any types which cannot appear in
TensorFlow bindings.
"""
type_analysis.check_tensorflow_compatible_type(type_signature)
parameter_type = type_signature
if parameter_type is None:
raise TypeError('TensorFlow identity cannot be created for NoneType.')
with tf.Graph().as_default() as graph:
parameter_value, parameter_binding = tensorflow_utils.stamp_parameter_in_graph(
'x', parameter_type, graph)
# TF relies on feeds not-identical to fetches in certain circumstances.
if type_signature.is_tensor():
parameter_value = tf.identity(parameter_value)
elif type_signature.is_struct():
parameter_value = structure.map_structure(tf.identity, parameter_value)
result_type, result_binding = tensorflow_utils.capture_result_from_graph(
parameter_value, graph)
type_signature = computation_types.FunctionType(parameter_type, result_type)
tensorflow = pb.TensorFlow(
graph_def=serialization_utils.pack_graph_def(graph.as_graph_def()),
parameter=parameter_binding,
result=result_binding)
return _tensorflow_comp(tensorflow, type_signature)
def is_average_compatible(type_spec: computation_types.Type) -> bool:
"""Determines if `type_spec` can be averaged.
Types that are average-compatible are composed of numeric tensor types,
either floating-point or complex, possibly packaged into nested named tuples,
and possibly federated.
Args:
type_spec: a `computation_types.Type`.
Returns:
`True` iff `type_spec` is average-compatible, `False` otherwise.
"""
py_typecheck.check_type(type_spec, computation_types.Type)
if type_spec.is_tensor():
return type_spec.dtype.is_floating or type_spec.dtype.is_complex
elif type_spec.is_struct():
return all(
is_average_compatible(v) for _, v in structure.iter_elements(type_spec))
elif type_spec.is_federated():
return is_average_compatible(type_spec.member)
else:
return False
def is_structure_of_floats(type_spec: computation_types.Type) -> bool:
"""Determines if `type_spec` is a structure of floats.
Note that an empty `computation_types.StructType` will return `True`, as it
does not contain any non-floating types.
Args:
type_spec: A `computation_types.Type`.
Returns:
`True` iff `type_spec` is a structure of floats, otherwise `False`.
"""
py_typecheck.check_type(type_spec, computation_types.Type)
if type_spec.is_tensor():
py_typecheck.check_type(type_spec.dtype, tf.DType)
return type_spec.dtype.is_floating
elif type_spec.is_struct():
return all(
is_structure_of_floats(v)
for _, v in structure.iter_elements(type_spec))
elif type_spec.is_federated():
return is_structure_of_floats(type_spec.member)
else:
return False
def type_to_tf_dtypes_and_shapes(type_spec: computation_types.Type):
"""Returns nested structures of tensor dtypes and shapes for a given TFF type.
The returned dtypes and shapes match those used by `tf.data.Dataset`s to
indicate the type and shape of their elements. They can be used, e.g., as
arguments in constructing an iterator over a string handle.
Args:
type_spec: A `computation_types.Type`, the type specification must be
composed of only named tuples and tensors. In all named tuples that appear
in the type spec, all the elements must be named.
Returns:
A pair of parallel nested structures with the dtypes and shapes of tensors
defined in `type_spec`. The layout of the two structures returned is the
same as the layout of the nested type defined by `type_spec`. Named tuples
are represented as dictionaries.
Raises:
ValueError: if the `type_spec` is composed of something other than named
tuples and tensors, or if any of the elements in named tuples are unnamed.
"""
py_typecheck.check_type(type_spec, computation_types.Type)
if type_spec.is_tensor():
return (type_spec.dtype, type_spec.shape)
elif type_spec.is_struct():
elements = structure.to_elements(type_spec)
if not elements:
output_dtypes = []
output_shapes = []
elif elements[0][0] is not None:
output_dtypes = collections.OrderedDict()
output_shapes = collections.OrderedDict()
for e in elements:
element_name = e[0]
element_spec = e[1]
if element_name is None:
raise ValueError(
'When a sequence appears as a part of a parameter to a section '
'of TensorFlow code, in the type signature of elements of that '
'sequence all named tuples must have their elements explicitly '
'named, and this does not appear to be the case in {}.'
.format(type_spec))
element_output = type_to_tf_dtypes_and_shapes(element_spec)
output_dtypes[element_name] = element_output[0]
output_shapes[element_name] = element_output[1]
else:
output_dtypes = []
output_shapes = []
for e in elements:
element_name = e[0]
element_spec = e[1]
if element_name is not None:
raise ValueError(
'When a sequence appears as a part of a parameter to a section '
'of TensorFlow code, in the type signature of elements of that '
'sequence all named tuples must have their elements explicitly '
'named, and this does not appear to be the case in {}.'
.format(type_spec))
element_output = type_to_tf_dtypes_and_shapes(element_spec)
output_dtypes.append(element_output[0])
output_shapes.append(element_output[1])
if type_spec.python_container is not None:
container_type = type_spec.python_container
def build_py_container(elements):
if (py_typecheck.is_named_tuple(container_type)
or py_typecheck.is_attrs(container_type)):
return container_type(**dict(elements))
else:
return container_type(elements)
output_dtypes = build_py_container(output_dtypes)
output_shapes = build_py_container(output_shapes)
else:
output_dtypes = tuple(output_dtypes)
output_shapes = tuple(output_shapes)
return (output_dtypes, output_shapes)
else:
raise ValueError('Unsupported type {}.'.format(
py_typecheck.type_string(type(type_spec))))
def _is_compatible(t: computation_types.Type) -> bool:
return type_analysis.contains_only(
t,
lambda t: t.is_struct() or t.is_tensor() or t.is_federated())
def _is_two_tuple(t: computation_types.Type) -> bool:
return t.is_struct() and len(t) == 2
def create_binary_operator(
operator, operand_type: computation_types.Type) -> ProtoAndType:
"""Returns a tensorflow computation computing a binary operation.
The returned computation has the type signature `(<T,T> -> U)`, where `T` is
`operand_type` and `U` is the result of applying the `operator` to a tuple of
type `<T,T>`
Note: If `operand_type` is a `computation_types.StructType`, then
`operator` will be applied pointwise. This places the burden on callers of
this function to construct the correct values to pass into the returned
function. For example, to divide `[2, 2]` by `2`, first `2` must be packed
into the data structure `[x, x]`, before the division operator of the
appropriate type is called.
Args:
operator: A callable taking two arguments representing the operation to
encode For example: `tf.math.add`, `tf.math.multiply`, and
`tf.math.divide`.
operand_type: A `computation_types.Type` to use as the argument to the
constructed binary operator; must contain only named tuples and tensor
types.
Raises:
TypeError: If the constraints of `operand_type` are violated or `operator`
is not callable.
"""
if not type_analysis.is_generic_op_compatible_type(operand_type):
raise TypeError(
'The type {} contains a type other than `computation_types.TensorType` '
'and `computation_types.StructType`; this is disallowed in the '
'generic operators.'.format(operand_type))
py_typecheck.check_callable(operator)
with tf.Graph().as_default() as graph:
operand_1_value, operand_1_binding = tensorflow_utils.stamp_parameter_in_graph(
'x', operand_type, graph)
operand_2_value, operand_2_binding = tensorflow_utils.stamp_parameter_in_graph(
'y', operand_type, graph)
if operand_type is not None:
if operand_type.is_tensor():
result_value = operator(operand_1_value, operand_2_value)
elif operand_type.is_struct():
result_value = structure.map_structure(operator, operand_1_value,
operand_2_value)
else:
raise TypeError(
'Operand type {} cannot be used in generic operations. The call to '
'`type_analysis.is_generic_op_compatible_type` has allowed it to '
'pass, and should be updated.'.format(operand_type))
result_type, result_binding = tensorflow_utils.capture_result_from_graph(
result_value, graph)
type_signature = computation_types.FunctionType(
computation_types.StructType((operand_type, operand_type)), result_type)
parameter_binding = pb.TensorFlow.Binding(
struct=pb.TensorFlow.StructBinding(
element=[operand_1_binding, operand_2_binding]))
tensorflow = pb.TensorFlow(
graph_def=serialization_utils.pack_graph_def(graph.as_graph_def()),
parameter=parameter_binding,
result=result_binding)
return _tensorflow_comp(tensorflow, type_signature)
def _concretize_abstract_types(
abstract_type_spec: computation_types.Type,
concrete_type_spec: computation_types.Type) -> computation_types.Type:
"""Recursive helper function to construct concrete type spec."""
if abstract_type_spec.is_abstract():
bound_type = bound_abstract_types.get(str(abstract_type_spec.label))
if bound_type:
return bound_type
else:
bound_abstract_types[str(abstract_type_spec.label)] = concrete_type_spec
return concrete_type_spec
elif abstract_type_spec.is_tensor():
return abstract_type_spec
elif abstract_type_spec.is_struct():
if not concrete_type_spec.is_struct():
raise TypeError(type_error_string)
abstract_elements = structure.to_elements(abstract_type_spec)
concrete_elements = structure.to_elements(concrete_type_spec)
if len(abstract_elements) != len(concrete_elements):
raise TypeError(type_error_string)
concretized_tuple_elements = []
for k in range(len(abstract_elements)):
if abstract_elements[k][0] != concrete_elements[k][0]:
raise TypeError(type_error_string)
concretized_tuple_elements.append(
(abstract_elements[k][0],
_concretize_abstract_types(abstract_elements[k][1],
concrete_elements[k][1])))
return computation_types.StructType(concretized_tuple_elements)
elif abstract_type_spec.is_sequence():
if not concrete_type_spec.is_sequence():
raise TypeError(type_error_string)
return computation_types.SequenceType(
_concretize_abstract_types(abstract_type_spec.element,
concrete_type_spec.element))
elif abstract_type_spec.is_function():
if not concrete_type_spec.is_function():
raise TypeError(type_error_string)
if abstract_type_spec.parameter is None:
if concrete_type_spec.parameter is not None:
return TypeError(type_error_string)
concretized_param = None
else:
concretized_param = _concretize_abstract_types(
abstract_type_spec.parameter, concrete_type_spec.parameter)
concretized_result = _concretize_abstract_types(abstract_type_spec.result,
concrete_type_spec.result)
return computation_types.FunctionType(concretized_param,
concretized_result)
elif abstract_type_spec.is_placement():
if not concrete_type_spec.is_placement():
raise TypeError(type_error_string)
return abstract_type_spec
elif abstract_type_spec.is_federated():
if not concrete_type_spec.is_federated():
raise TypeError(type_error_string)
new_member = _concretize_abstract_types(abstract_type_spec.member,
concrete_type_spec.member)
return computation_types.FederatedType(new_member,
abstract_type_spec.placement,
abstract_type_spec.all_equal)
else:
raise TypeError(
'Unexpected abstract typespec {}.'.format(abstract_type_spec))
def transform_type_postorder(
type_signature: computation_types.Type,
transform_fn: Callable[[computation_types.Type],
Tuple[computation_types.Type, bool]]):
"""Walks type tree of `type_signature` postorder, calling `transform_fn`.
Args:
type_signature: Instance of `computation_types.Type` to transform
recursively.
transform_fn: Transformation function to apply to each node in the type tree
of `type_signature`. Must be instance of Python function type.
Returns:
A possibly transformed version of `type_signature`, with each node in its
tree the result of applying `transform_fn` to the corresponding node in
`type_signature`.
Raises:
TypeError: If the types don't match the specification above.
"""
py_typecheck.check_type(type_signature, computation_types.Type)
py_typecheck.check_callable(transform_fn)
if type_signature.is_federated():
transformed_member, member_mutated = transform_type_postorder(
type_signature.member, transform_fn)
if member_mutated:
type_signature = computation_types.FederatedType(transformed_member,
type_signature.placement,
type_signature.all_equal)
type_signature, type_signature_mutated = transform_fn(type_signature)
return type_signature, type_signature_mutated or member_mutated
elif type_signature.is_sequence():
transformed_element, element_mutated = transform_type_postorder(
type_signature.element, transform_fn)
if element_mutated:
type_signature = computation_types.SequenceType(transformed_element)
type_signature, type_signature_mutated = transform_fn(type_signature)
return type_signature, type_signature_mutated or element_mutated
elif type_signature.is_function():
if type_signature.parameter is not None:
transformed_parameter, parameter_mutated = transform_type_postorder(
type_signature.parameter, transform_fn)
else:
transformed_parameter, parameter_mutated = (None, False)
transformed_result, result_mutated = transform_type_postorder(
type_signature.result, transform_fn)
if parameter_mutated or result_mutated:
type_signature = computation_types.FunctionType(transformed_parameter,
transformed_result)
type_signature, type_signature_mutated = transform_fn(type_signature)
return type_signature, (
type_signature_mutated or parameter_mutated or result_mutated)
elif type_signature.is_struct():
elements = []
elements_mutated = False
for element in structure.iter_elements(type_signature):
transformed_element, element_mutated = transform_type_postorder(
element[1], transform_fn)
elements_mutated = elements_mutated or element_mutated
elements.append((element[0], transformed_element))
if elements_mutated:
if type_signature.is_struct_with_python():
type_signature = computation_types.StructWithPythonType(
elements, type_signature.python_container)
else:
type_signature = computation_types.StructType(elements)
type_signature, type_signature_mutated = transform_fn(type_signature)
return type_signature, type_signature_mutated or elements_mutated
elif type_signature.is_abstract() or type_signature.is_placement(
) or type_signature.is_tensor():
return transform_fn(type_signature)
def _deserialize_dataset_from_graph_def(serialized_graph_def: bytes,
element_type: computation_types.Type):
"""Deserializes a serialized `tf.compat.v1.GraphDef` to a `tf.data.Dataset`.
Args:
serialized_graph_def: `bytes` object produced by
`tensorflow_serialization.serialize_dataset`
element_type: a `tff.Type` object representing the type structure of the
elements yielded from the dataset.
Returns:
A `tf.data.Dataset` instance.
"""
py_typecheck.check_type(element_type, computation_types.Type)
type_analysis.check_tensorflow_compatible_type(element_type)
def transform_to_tff_known_type(
type_spec: computation_types.Type
) -> Tuple[computation_types.Type, bool]:
"""Transforms `StructType` to `StructWithPythonType`."""
if type_spec.is_struct() and not type_spec.is_struct_with_python():
field_is_named = tuple(
name is not None
for name, _ in structure.iter_elements(type_spec))
has_names = any(field_is_named)
is_all_named = all(field_is_named)
if is_all_named:
return computation_types.StructWithPythonType(
elements=structure.iter_elements(type_spec),
container_type=collections.OrderedDict), True
elif not has_names:
return computation_types.StructWithPythonType(
elements=structure.iter_elements(type_spec),
container_type=tuple), True
else:
raise TypeError(
'Cannot represent TFF type in TF because it contains '
f'partially named structures. Type: {type_spec}')
return type_spec, False
if element_type.is_struct():
# TF doesn't suppor `structure.Strut` types, so we must transform the
# `StructType` into a `StructWithPythonType` for use as the
# `tf.data.Dataset.element_spec` later.
tf_compatible_type, _ = type_transformations.transform_type_postorder(
element_type, transform_to_tff_known_type)
else:
# We've checked this is only a struct or tensors, so we know this is a
# `TensorType` here and will use as-is.
tf_compatible_type = element_type
def type_to_tensorspec(t: computation_types.TensorType) -> tf.TensorSpec:
return tf.TensorSpec(shape=t.shape, dtype=t.dtype)
element_spec = type_conversions.structure_from_tensor_type_tree(
type_to_tensorspec, tf_compatible_type)
ds = tf.data.experimental.from_variant(
tf.raw_ops.DatasetFromGraph(graph_def=serialized_graph_def),
structure=element_spec)
# If a serialized dataset had elements of nested structes of tensors (e.g.
# `dict`, `OrderedDict`), the deserialized dataset will return `dict`,
# `tuple`, or `namedtuple` (loses `collections.OrderedDict` in a conversion).
#
# Since the dataset will only be used inside TFF, we wrap the dictionary
# coming from TF in an `OrderedDict` when necessary (a type that both TF and
# TFF understand), using the field order stored in the TFF type stored during
# serialization.
return tensorflow_utils.coerce_dataset_elements_to_tff_type_spec(
ds, tf_compatible_type)
