TensorFlow定义数据流操作
2018-09-19 10:00 更新
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"" 数据流操作 ""
# pylint: disable=g-bad-name
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import collections
import hashlib
import threading
import six
from tensorflow.python.framework import dtypes as _dtypes
from tensorflow.python.framework import ops
from tensorflow.python.framework import random_seed
from tensorflow.python.framework import tensor_shape
from tensorflow.python.framework import tensor_util
from tensorflow.python.ops import array_ops
from tensorflow.python.ops import control_flow_ops
from tensorflow.python.ops import gen_data_flow_ops
from tensorflow.python.ops import math_ops
# go/tf-wildcard-import
# pylint: disable=wildcard-import
from tensorflow.python.ops.gen_data_flow_ops import *
# pylint: enable=wildcard-import
def _as_type_list(dtypes):
"""Convert dtypes to a list of types."""
assert dtypes is not None
if not (isinstance(dtypes, list) or isinstance(dtypes, tuple)):
# We have a single type.
return [dtypes]
else:
# We have a list or tuple of types.
return list(dtypes)
def _as_shape_list(shapes, dtypes, unknown_dim_allowed=False,
unknown_rank_allowed=False):
"""Convert shapes to a list of tuples of int (or None)."""
del dtypes
if unknown_dim_allowed:
if (not isinstance(shapes, collections.Sequence)
or not shapes
or any(shape is None or isinstance(shape, int) for shape in shapes)):
raise ValueError(
"When providing partial shapes, a list of shapes must be provided.")
if shapes is None: return None
if isinstance(shapes, tensor_shape.TensorShape):
shapes = [shapes]
if not isinstance(shapes, (tuple, list)):
raise TypeError(
"shapes must be a TensorShape or a list or tuple of TensorShapes.")
if all(shape is None or isinstance(shape, int) for shape in shapes):
# We have a single shape.
shapes = [shapes]
shapes = [tensor_shape.as_shape(shape) for shape in shapes]
if not unknown_dim_allowed:
if any([not shape.is_fully_defined() for shape in shapes]):
raise ValueError("All shapes must be fully defined: %s" % shapes)
if not unknown_rank_allowed:
if any([shape.dims is None for shape in shapes]):
raise ValueError("All shapes must have a defined rank: %s" % shapes)
return shapes
def _as_name_list(names, dtypes):
if names is None:
return None
if not isinstance(names, (list, tuple)):
names = [names]
if len(names) != len(dtypes):
raise ValueError("List of names must have the same length as the list "
"of dtypes")
return list(names)
def _shape_common(s1, s2):
"""The greatest lower bound (ordered by specificity) TensorShape."""
s1 = tensor_shape.TensorShape(s1)
s2 = tensor_shape.TensorShape(s2)
if s1.ndims is None or s2.ndims is None or s1.ndims != s2.ndims:
return tensor_shape.unknown_shape()
d = [
d1 if d1 is not None and d1 == d2 else None
for (d1, d2) in zip(s1.as_list(), s2.as_list())]
return tensor_shape.TensorShape(d)
# pylint: disable=protected-access
class QueueBase(object):
"""Base class for queue implementations.
A queue is a TensorFlow data structure that stores tensors across
multiple steps, and exposes operations that enqueue and dequeue
tensors.
Each queue element is a tuple of one or more tensors, where each
tuple component has a static dtype, and may have a static shape. The
queue implementations support versions of enqueue and dequeue that
handle single elements, versions that support enqueuing and
dequeuing a batch of elements at once.
See @{tf.FIFOQueue} and
@{tf.RandomShuffleQueue} for concrete
implementations of this class, and instructions on how to create
them.
"""
def __init__(self, dtypes, shapes, names, queue_ref):
"""Constructs a queue object from a queue reference.
The two optional lists, `shapes` and `names`, must be of the same length
as `dtypes` if provided. The values at a given index `i` indicate the
shape and name to use for the corresponding queue component in `dtypes`.
Args:
dtypes: A list of types. The length of dtypes must equal the number
of tensors in each element.
shapes: Constraints on the shapes of tensors in an element:
A list of shape tuples or None. This list is the same length
as dtypes. If the shape of any tensors in the element are constrained,
all must be; shapes can be None if the shapes should not be constrained.
names: Optional list of names. If provided, the `enqueue()` and
`dequeue()` methods will use dictionaries with these names as keys.
Must be None or a list or tuple of the same length as `dtypes`.
queue_ref: The queue reference, i.e. the output of the queue op.
Raises:
ValueError: If one of the arguments is invalid.
"""
self._dtypes = dtypes
if shapes is not None:
if len(shapes) != len(dtypes):
raise ValueError("Queue shapes must have the same length as dtypes")
self._shapes = [tensor_shape.TensorShape(s) for s in shapes]
else:
self._shapes = [tensor_shape.unknown_shape() for _ in self._dtypes]
if names is not None:
if len(names) != len(dtypes):
raise ValueError("Queue names must have the same length as dtypes")
self._names = names
else:
self._names = None
self._queue_ref = queue_ref
self._name = self._queue_ref.op.name.split("/")[-1]
@staticmethod
def from_list(index, queues):
"""Create a queue using the queue reference from `queues[index]`.
Args:
index: An integer scalar tensor that determines the input that gets
selected.
queues: A list of `QueueBase` objects.
Returns:
A `QueueBase` object.
Raises:
TypeError: When `queues` is not a list of `QueueBase` objects,
or when the data types of `queues` are not all the same.
"""
if ((not queues) or
(not isinstance(queues, list)) or
(not all(isinstance(x, QueueBase) for x in queues))):
raise TypeError("A list of queues expected")
dtypes = queues[0].dtypes
if not all([dtypes == q.dtypes for q in queues[1:]]):
raise TypeError("Queues do not have matching component dtypes.")
names = queues[0].names
if not all([names == q.names for q in queues[1:]]):
raise TypeError("Queues do not have matching component names.")
queue_shapes = [q.shapes for q in queues]
reduced_shapes = [
six.moves.reduce(_shape_common, s) for s in zip(*queue_shapes)]
queue_refs = array_ops.stack([x.queue_ref for x in queues])
selected_queue = array_ops.gather(queue_refs, index)
return QueueBase(dtypes=dtypes, shapes=reduced_shapes, names=names,
queue_ref=selected_queue)
@property
def queue_ref(self):
"""The underlying queue reference."""
return self._queue_ref
@property
def name(self):
"""The name of the underlying queue."""
return self._queue_ref.op.name
@property
def dtypes(self):
"""The list of dtypes for each component of a queue element."""
return self._dtypes
@property
def shapes(self):
"""The list of shapes for each component of a queue element."""
return self._shapes
@property
def names(self):
"""The list of names for each component of a queue element."""
return self._names
def _check_enqueue_dtypes(self, vals):
"""Validate and convert `vals` to a list of `Tensor`s.
The `vals` argument can be a Tensor, a list or tuple of tensors, or a
dictionary with tensor values.
If it is a dictionary, the queue must have been constructed with a
`names` attribute and the dictionary keys must match the queue names.
If the queue was constructed with a `names` attribute, `vals` must
be a dictionary.
Args:
vals: A tensor, a list or tuple of tensors, or a dictionary..
Returns:
A list of `Tensor` objects.
Raises:
ValueError: If `vals` is invalid.
"""
if isinstance(vals, dict):
if not self._names:
raise ValueError("Queue must have names to enqueue a dictionary")
if sorted(self._names) != sorted(vals.keys()):
raise ValueError("Keys in dictionary to enqueue do not match "
"names of Queue. Dictionary: (%s), Queue: (%s)" %
(sorted(vals.keys()), sorted(self._names)))
# The order of values in `self._names` indicates the order in which the
# tensors in the dictionary `vals` must be listed.
vals = [vals[k] for k in self._names]
else:
if self._names:
raise ValueError("You must enqueue a dictionary in a Queue with names")
if not isinstance(vals, (list, tuple)):
vals = [vals]
tensors = []
for i, (val, dtype) in enumerate(zip(vals, self._dtypes)):
tensors.append(ops.convert_to_tensor(val, dtype=dtype,
name="component_%d" % i))
return tensors
def _scope_vals(self, vals):
"""Return a list of values to pass to `name_scope()`.
Args:
vals: A tensor, a list or tuple of tensors, or a dictionary.
Returns:
The values in vals as a list.
"""
if isinstance(vals, (list, tuple)):
return vals
elif isinstance(vals, dict):
return vals.values()
else:
return [vals]
def enqueue(self, vals, name=None):
"""Enqueues one element to this queue.
If the queue is full when this operation executes, it will block
until the element has been enqueued.
At runtime, this operation may raise an error if the queue is
@{tf.QueueBase.close} before or during its execution. If the
queue is closed before this operation runs,
`tf.errors.CancelledError` will be raised. If this operation is
blocked, and either (i) the queue is closed by a close operation
with `cancel_pending_enqueues=True`, or (ii) the session is
@{tf.Session.close},
`tf.errors.CancelledError` will be raised.
Args:
vals: A tensor, a list or tuple of tensors, or a dictionary containing
the values to enqueue.
name: A name for the operation (optional).
Returns:
The operation that enqueues a new tuple of tensors to the queue.
"""
with ops.name_scope(name, "%s_enqueue" % self._name,
self._scope_vals(vals)) as scope:
vals = self._check_enqueue_dtypes(vals)
# NOTE(mrry): Not using a shape function because we need access to
# the `QueueBase` object.
for val, shape in zip(vals, self._shapes):
val.get_shape().assert_is_compatible_with(shape)
if self._queue_ref.dtype == _dtypes.resource:
return gen_data_flow_ops._queue_enqueue_v2(
self._queue_ref, vals, name=scope)
else:
return gen_data_flow_ops._queue_enqueue(
self._queue_ref, vals, name=scope)
def enqueue_many(self, vals, name=None):
"""Enqueues zero or more elements to this queue.
This operation slices each component tensor along the 0th dimension to
make multiple queue elements. All of the tensors in `vals` must have the
same size in the 0th dimension.
If the queue is full when this operation executes, it will block
until all of the elements have been enqueued.
At runtime, this operation may raise an error if the queue is
@{tf.QueueBase.close} before or during its execution. If the
queue is closed before this operation runs,
`tf.errors.CancelledError` will be raised. If this operation is
blocked, and either (i) the queue is closed by a close operation
with `cancel_pending_enqueues=True`, or (ii) the session is
@{tf.Session.close},
`tf.errors.CancelledError` will be raised.
Args:
vals: A tensor, a list or tuple of tensors, or a dictionary
from which the queue elements are taken.
name: A name for the operation (optional).
Returns:
The operation that enqueues a batch of tuples of tensors to the queue.
"""
with ops.name_scope(name, "%s_EnqueueMany" % self._name,
self._scope_vals(vals)) as scope:
vals = self._check_enqueue_dtypes(vals)
# NOTE(mrry): Not using a shape function because we need access to
# the `QueueBase` object.
batch_dim = vals[0].get_shape().with_rank_at_least(1)[0]
for val, shape in zip(vals, self._shapes):
batch_dim = batch_dim.merge_with(
val.get_shape().with_rank_at_least(1)[0])
val.get_shape()[1:].assert_is_compatible_with(shape)
return gen_data_flow_ops._queue_enqueue_many_v2(
self._queue_ref, vals, name=scope)
def _dequeue_return_value(self, tensors):
"""Return the value to return from a dequeue op.
If the queue has names, return a dictionary with the
names as keys. Otherwise return either a single tensor
or a list of tensors depending on the length of `tensors`.
Args:
tensors: List of tensors from the dequeue op.
Returns:
A single tensor, a list of tensors, or a dictionary
of tensors.
"""
if self._names:
# The returned values in `tensors` are in the same order as
# the names in `self._names`.
return {n: tensors[i] for i, n in enumerate(self._names)}
elif len(tensors) == 1:
return tensors[0]
else:
return tensors
def dequeue(self, name=None):
"""Dequeues one element from this queue.
If the queue is empty when this operation executes, it will block
until there is an element to dequeue.
At runtime, this operation may raise an error if the queue is
@{tf.QueueBase.close} before or during its execution. If the
queue is closed, the queue is empty, and there are no pending
enqueue operations that can fulfill this request,
`tf.errors.OutOfRangeError` will be raised. If the session is
@{tf.Session.close},
`tf.errors.CancelledError` will be raised.
Args:
name: A name for the operation (optional).
Returns:
The tuple of tensors that was dequeued.
"""
if name is None:
name = "%s_Dequeue" % self._name
if self._queue_ref.dtype == _dtypes.resource:
ret = gen_data_flow_ops._queue_dequeue_v2(
self._queue_ref, self._dtypes, name=name)
else:
ret = gen_data_flow_ops._queue_dequeue(
self._queue_ref, self._dtypes, name=name)
# NOTE(mrry): Not using a shape function because we need access to
# the `QueueBase` object.
op = ret[0].op
for output, shape in zip(op.values(), self._shapes):
output.set_shape(shape)
return self._dequeue_return_value(ret)
def dequeue_many(self, n, name=None):
"""Dequeues and concatenates `n` elements from this queue.
This operation concatenates queue-element component tensors along
the 0th dimension to make a single component tensor. All of the
components in the dequeued tuple will have size `n` in the 0th dimension.
If the queue is closed and there are less than `n` elements left, then an
`OutOfRange` exception is raised.
At runtime, this operation may raise an error if the queue is
@{tf.QueueBase.close} before or during its execution. If the
queue is closed, the queue contains fewer than `n` elements, and
there are no pending enqueue operations that can fulfill this
request, `tf.errors.OutOfRangeError` will be raised. If the
session is @{tf.Session.close},
`tf.errors.CancelledError` will be raised.
Args:
n: A scalar `Tensor` containing the number of elements to dequeue.
name: A name for the operation (optional).
Returns:
The tuple of concatenated tensors that was dequeued.
"""
if name is None:
name = "%s_DequeueMany" % self._name
ret = gen_data_flow_ops._queue_dequeue_many_v2(
self._queue_ref, n=n, component_types=self._dtypes, name=name)
# NOTE(mrry): Not using a shape function because we need access to
# the Queue object.
op = ret[0].op
batch_dim = tensor_shape.Dimension(tensor_util.constant_value(op.inputs[1]))
for output, shape in zip(op.values(), self._shapes):
output.set_shape(tensor_shape.TensorShape([batch_dim]).concatenate(shape))
return self._dequeue_return_value(ret)
def dequeue_up_to(self, n, name=None):
"""Dequeues and concatenates `n` elements from this queue.
**Note** This operation is not supported by all queues. If a queue does not
support DequeueUpTo, then a `tf.errors.UnimplementedError` is raised.
This operation concatenates queue-element component tensors along
the 0th dimension to make a single component tensor. If the queue
has not been closed, all of the components in the dequeued tuple
will have size `n` in the 0th dimension.
If the queue is closed and there are more than `0` but fewer than
`n` elements remaining, then instead of raising a
`tf.errors.OutOfRangeError` like @{tf.QueueBase.dequeue_many},
less than `n` elements are returned immediately. If the queue is
closed and there are `0` elements left in the queue, then a
`tf.errors.OutOfRangeError` is raised just like in `dequeue_many`.
Otherwise the behavior is identical to `dequeue_many`.
Args:
n: A scalar `Tensor` containing the number of elements to dequeue.
name: A name for the operation (optional).
Returns:
The tuple of concatenated tensors that was dequeued.
"""
if name is None:
name = "%s_DequeueUpTo" % self._name
ret = gen_data_flow_ops._queue_dequeue_up_to_v2(
self._queue_ref, n=n, component_types=self._dtypes, name=name)
# NOTE(mrry): Not using a shape function because we need access to
# the Queue object.
op = ret[0].op
for output, shape in zip(op.values(), self._shapes):
output.set_shape(tensor_shape.TensorShape([None]).concatenate(shape))
return self._dequeue_return_value(ret)
def close(self, cancel_pending_enqueues=False, name=None):
"""Closes this queue.
This operation signals that no more elements will be enqueued in
the given queue. Subsequent `enqueue` and `enqueue_many`
operations will fail. Subsequent `dequeue` and `dequeue_many`
operations will continue to succeed if sufficient elements remain
in the queue. Subsequent `dequeue` and `dequeue_many` operations
that would block will fail immediately.
If `cancel_pending_enqueues` is `True`, all pending requests will also
be cancelled.
Args:
cancel_pending_enqueues: (Optional.) A boolean, defaulting to
`False` (described above).
name: A name for the operation (optional).
Returns:
The operation that closes the queue.
"""
if name is None:
name = "%s_Close" % self._name
if self._queue_ref.dtype == _dtypes.resource:
return gen_data_flow_ops._queue_close_v2(
self._queue_ref, cancel_pending_enqueues=cancel_pending_enqueues,
name=name)
else:
return gen_data_flow_ops._queue_close(
self._queue_ref, cancel_pending_enqueues=cancel_pending_enqueues,
name=name)
def size(self, name=None):
"""Compute the number of elements in this queue.
Args:
name: A name for the operation (optional).
Returns:
A scalar tensor containing the number of elements in this queue.
"""
if name is None:
name = "%s_Size" % self._name
if self._queue_ref.dtype == _dtypes.resource:
return gen_data_flow_ops._queue_size_v2(self._queue_ref, name=name)
else:
return gen_data_flow_ops._queue_size(self._queue_ref, name=name)
class RandomShuffleQueue(QueueBase):
"""A queue implementation that dequeues elements in a random order.
See @{tf.QueueBase} for a description of the methods on
this class.
"""
def __init__(self, capacity, min_after_dequeue, dtypes, shapes=None,
names=None, seed=None, shared_name=None,
name="random_shuffle_queue"):
"""Create a queue that dequeues elements in a random order.
A `RandomShuffleQueue` has bounded capacity; supports multiple
concurrent producers and consumers; and provides exactly-once
delivery.
A `RandomShuffleQueue` holds a list of up to `capacity`
elements. Each element is a fixed-length tuple of tensors whose
dtypes are described by `dtypes`, and whose shapes are optionally
described by the `shapes` argument.
If the `shapes` argument is specified, each component of a queue
element must have the respective fixed shape. If it is
unspecified, different queue elements may have different shapes,
but the use of `dequeue_many` is disallowed.
The `min_after_dequeue` argument allows the caller to specify a
minimum number of elements that will remain in the queue after a
`dequeue` or `dequeue_many` operation completes, to ensure a
minimum level of mixing of elements. This invariant is maintained
by blocking those operations until sufficient elements have been
enqueued. The `min_after_dequeue` argument is ignored after the
queue has been closed.
Args:
capacity: An integer. The upper bound on the number of elements
that may be stored in this queue.
min_after_dequeue: An integer (described above).
dtypes: A list of `DType` objects. The length of `dtypes` must equal
the number of tensors in each queue element.
shapes: (Optional.) A list of fully-defined `TensorShape` objects
with the same length as `dtypes`, or `None`.
names: (Optional.) A list of string naming the components in the queue
with the same length as `dtypes`, or `None`. If specified the dequeue
methods return a dictionary with the names as keys.
seed: A Python integer. Used to create a random seed. See
@{tf.set_random_seed}
for behavior.
shared_name: (Optional.) If non-empty, this queue will be shared under
the given name across multiple sessions.
name: Optional name for the queue operation.
"""
dtypes = _as_type_list(dtypes)
shapes = _as_shape_list(shapes, dtypes)
names = _as_name_list(names, dtypes)
seed1, seed2 = random_seed.get_seed(seed)
if seed1 is None and seed2 is None:
seed1, seed2 = 0, 0
elif seed is None and shared_name is not None:
# This means that graph seed is provided but op seed is not provided.
# If shared_name is also provided, make seed2 depend only on the graph
# seed and shared_name. (seed2 from get_seed() is generally dependent on
# the id of the last op created.)
string = (str(seed1) + shared_name).encode("utf-8")
seed2 = int(hashlib.md5(string).hexdigest()[:8], 16) & 0x7FFFFFFF
queue_ref = gen_data_flow_ops._random_shuffle_queue_v2(
component_types=dtypes, shapes=shapes, capacity=capacity,
min_after_dequeue=min_after_dequeue, seed=seed1, seed2=seed2,
shared_name=shared_name, name=name)
super(RandomShuffleQueue, self).__init__(dtypes, shapes, names, queue_ref)
class FIFOQueue(QueueBase):
"""A queue implementation that dequeues elements in first-in first-out order.
See @{tf.QueueBase} for a description of the methods on
this class.
"""
def __init__(self, capacity, dtypes, shapes=None, names=None,
shared_name=None, name="fifo_queue"):
"""Creates a queue that dequeues elements in a first-in first-out order.
A `FIFOQueue` has bounded capacity; supports multiple concurrent
producers and consumers; and provides exactly-once delivery.
A `FIFOQueue` holds a list of up to `capacity` elements. Each
element is a fixed-length tuple of tensors whose dtypes are
described by `dtypes`, and whose shapes are optionally described
by the `shapes` argument.
If the `shapes` argument is specified, each component of a queue
element must have the respective fixed shape. If it is
unspecified, different queue elements may have different shapes,
but the use of `dequeue_many` is disallowed.
Args:
capacity: An integer. The upper bound on the number of elements
that may be stored in this queue.
dtypes: A list of `DType` objects. The length of `dtypes` must equal
the number of tensors in each queue element.
shapes: (Optional.) A list of fully-defined `TensorShape` objects
with the same length as `dtypes`, or `None`.
names: (Optional.) A list of string naming the components in the queue
with the same length as `dtypes`, or `None`. If specified the dequeue
methods return a dictionary with the names as keys.
shared_name: (Optional.) If non-empty, this queue will be shared under
the given name across multiple sessions.
name: Optional name for the queue operation.
"""
dtypes = _as_type_list(dtypes)
shapes = _as_shape_list(shapes, dtypes)
names = _as_name_list(names, dtypes)
queue_ref = gen_data_flow_ops._fifo_queue_v2(
component_types=dtypes, shapes=shapes, capacity=capacity,
shared_name=shared_name, name=name)
super(FIFOQueue, self).__init__(dtypes, shapes, names, queue_ref)
class PaddingFIFOQueue(QueueBase):
"""A FIFOQueue that supports batching variable-sized tensors by padding.
A `PaddingFIFOQueue` may contain components with dynamic shape, while also
supporting `dequeue_many`. See the constructor for more details.
See @{tf.QueueBase} for a description of the methods on
this class.
"""
def __init__(self, capacity, dtypes, shapes, names=None, shared_name=None,
name="padding_fifo_queue"):
"""Creates a queue that dequeues elements in a first-in first-out order.
A `PaddingFIFOQueue` has bounded capacity; supports multiple concurrent
producers and consumers; and provides exactly-once delivery.
A `PaddingFIFOQueue` holds a list of up to `capacity` elements. Each
element is a fixed-length tuple of tensors whose dtypes are
described by `dtypes`, and whose shapes are described by the `shapes`
argument.
The `shapes` argument must be specified; each component of a queue
element must have the respective shape. Shapes of fixed
rank but variable size are allowed by setting any shape dimension to None.
In this case, the inputs' shape may vary along the given dimension, and
`dequeue_many` will pad the given dimension with zeros up to the maximum
shape of all elements in the given batch.
Args:
capacity: An integer. The upper bound on the number of elements
that may be stored in this queue.
dtypes: A list of `DType` objects. The length of `dtypes` must equal
the number of tensors in each queue element.
shapes: A list of `TensorShape` objects, with the same length as
`dtypes`. Any dimension in the `TensorShape` containing value
`None` is dynamic and allows values to be enqueued with
variable size in that dimension.
names: (Optional.) A list of string naming the components in the queue
with the same length as `dtypes`, or `None`. If specified the dequeue
methods return a dictionary with the names as keys.
shared_name: (Optional.) If non-empty, this queue will be shared under
the given name across multiple sessions.
name: Optional name for the queue operation.
Raises:
ValueError: If shapes is not a list of shapes, or the lengths of dtypes
and shapes do not match, or if names is specified and the lengths of
dtypes and names do not match.
"""
dtypes = _as_type_list(dtypes)
shapes = _as_shape_list(shapes, dtypes, unknown_dim_allowed=True)
names = _as_name_list(names, dtypes)
if len(dtypes) != len(shapes):
raise ValueError("Shapes must be provided for all components, "
"but received %d dtypes and %d shapes."
% (len(dtypes), len(shapes)))
queue_ref = gen_data_flow_ops._padding_fifo_queue_v2(
component_types=dtypes, shapes=shapes, capacity=capacity,
shared_name=shared_name, name=name)
super(PaddingFIFOQueue, self).__init__(dtypes, shapes, names, queue_ref)
class PriorityQueue(QueueBase):
"""A queue implementation that dequeues elements in prioritized order.
See @{tf.QueueBase} for a description of the methods on
this class.
"""
def __init__(self, capacity, types, shapes=None, names=None, shared_name=None,
name="priority_queue"):
"""Creates a queue that dequeues elements in a first-in first-out order.
A `PriorityQueue` has bounded capacity; supports multiple concurrent
producers and consumers; and provides exactly-once delivery.
A `PriorityQueue` holds a list of up to `capacity` elements. Each
element is a fixed-length tuple of tensors whose dtypes are
described by `types`, and whose shapes are optionally described
by the `shapes` argument.
If the `shapes` argument is specified, each component of a queue
element must have the respective fixed shape. If it is
unspecified, different queue elements may have different shapes,
but the use of `dequeue_many` is disallowed.
Enqueues and Dequeues to the `PriorityQueue` must include an additional
tuple entry at the beginning: the `priority`. The priority must be
an int64 scalar (for `enqueue`) or an int64 vector (for `enqueue_many`).
Args:
capacity: An integer. The upper bound on the number of elements
that may be stored in this queue.
types: A list of `DType` objects. The length of `types` must equal
the number of tensors in each queue element, except the first priority
element. The first tensor in each element is the priority,
which must be type int64.
shapes: (Optional.) A list of fully-defined `TensorShape` objects,
with the same length as `types`, or `None`.
names: (Optional.) A list of strings naming the components in the queue
with the same length as `dtypes`, or `None`. If specified, the dequeue
methods return a dictionary with the names as keys.
shared_name: (Optional.) If non-empty, this queue will be shared under
the given name across multiple sessions.
name: Optional name for the queue operation.
"""
types = _as_type_list(types)
shapes = _as_shape_list(shapes, types)
queue_ref = gen_data_flow_ops._priority_queue_v2(
component_types=types, shapes=shapes, capacity=capacity,
shared_name=shared_name, name=name)
priority_dtypes = [_dtypes.int64] + types
priority_shapes = [()] + shapes if shapes else shapes
super(PriorityQueue, self).__init__(
priority_dtypes, priority_shapes, names, queue_ref)
# TODO(josh11b): class BatchQueue(QueueBase):
class Barrier(object):
"""Represents a key-value map that persists across graph executions."""
def __init__(self, types, shapes=None, shared_name=None, name="barrier"):
"""Creates a barrier that persists across different graph executions.
A barrier represents a key-value map, where each key is a string, and
each value is a tuple of tensors.
At runtime, the barrier contains 'complete' and 'incomplete'
elements. A complete element has defined tensors for all
components of its value tuple, and may be accessed using
take_many. An incomplete element has some undefined components in
its value tuple, and may be updated using insert_many.
The barrier call `take_many` outputs values in a particular order.
First, it only outputs completed values. Second, the order in which
completed values are returned matches the order in which their very
first component was inserted into the barrier. So, for example, for this
sequence of insertions and removals:
barrier = Barrier((tf.string, tf.int32), shapes=((), ()))
barrier.insert_many(0, keys=["k1", "k2"], values=["a", "b"]).run()
barrier.insert_many(1, keys=["k1"], values=[1]).run()
barrier.insert_many(0, keys=["k3"], values=["c"]).run()
barrier.insert_many(1, keys=["k3"], values=[3]).run()
barrier.insert_many(1, keys=["k2"], values=[2]).run()
(indices, keys, values) = barrier.take_many(2)
(indices_val, keys_val, values0_val, values1_val) =
session.run([indices, keys, values[0], values[1]])
The output will be (up to permutation of "k1" and "k2"):
indices_val == (-2**63, -2**63)
keys_val == ("k1", "k2")
values0_val == ("a", "b")
values1_val == (1, 2)
Note the key "k2" was inserted into the barrier before "k3". Even though
"k3" was completed first, both are complete by the time
take_many is called. As a result, "k2" is prioritized and "k1" and "k2"
are returned first. "k3" remains in the barrier until the next execution
of `take_many`. Since "k1" and "k2" had their first insertions into
the barrier together, their indices are the same (-2**63). The index
of "k3" will be -2**63 + 1, because it was the next new inserted key.
Args:
types: A single dtype or a tuple of dtypes, corresponding to the
dtypes of the tensor elements that comprise a value in this barrier.
shapes: Optional. Constraints on the shapes of tensors in the values:
a single tensor shape tuple; a tuple of tensor shape tuples
for each barrier-element tuple component; or None if the shape should
not be constrained.
shared_name: Optional. If non-empty, this barrier will be shared under
the given name across multiple sessions.
name: Optional name for the barrier op.
Raises:
ValueError: If one of the `shapes` indicate no elements.
"""
self._types = _as_type_list(types)
if shapes is not None:
shapes = _as_shape_list(shapes, self._types)
self._shapes = [tensor_shape.TensorShape(s) for s in shapes]
for i, shape in enumerate(self._shapes):
if shape.num_elements() == 0:
raise ValueError("Empty tensors are not supported, but received "
"shape '%s' at index %d" % (shape, i))
else:
self._shapes = [tensor_shape.unknown_shape() for _ in self._types]
self._barrier_ref = gen_data_flow_ops._barrier(
component_types=self._types, shapes=self._shapes,
shared_name=shared_name, name=name)
self._name = self._barrier_ref.op.name.split("/")[-1]
@property
def barrier_ref(self):
"""Get the underlying barrier reference."""
return self._barrier_ref
@property
def name(self):
"""The name of the underlying barrier."""
return self._barrier_ref.op.name
def insert_many(self, component_index, keys, values, name=None):
"""For each key, assigns the respective value to the specified component.
This operation updates each element at component_index.
Args:
component_index: The component of the value that is being assigned.
keys: A vector of keys, with length n.
values: An any-dimensional tensor of values, which are associated with the
respective keys. The first dimension must have length n.
name: Optional name for the op.
Returns:
The operation that performs the insertion.
Raises:
InvalidArgumentsError: If inserting keys and values without elements.
"""
if name is None:
name = "%s_BarrierInsertMany" % self._name
return gen_data_flow_ops._barrier_insert_many(
self._barrier_ref, keys, values, component_index, name=name)
def take_many(self,
num_elements,
allow_small_batch=False,
timeout=None,
name=None):
"""Takes the given number of completed elements from this barrier.
This operation concatenates completed-element component tensors along
the 0th dimension to make a single component tensor.
If barrier has no completed elements, this operation will block
until there are 'num_elements' elements to take.
TODO(b/25743580): the semantics of `allow_small_batch` are experimental
and may be extended to other cases in the future.
TODO(ebrevdo): If a take_many(allow_small_batch=True) is blocking
already when the barrier is closed, it will block for ever. Fix this
by using asynchronous operations.
Args:
num_elements: The number of elements to take.
allow_small_batch: If the barrier is closed, don't block if there are less
completed elements than requested, but instead return all available
completed elements.
timeout: This specifies the number of milliseconds to block
before returning with DEADLINE_EXCEEDED. (This option is not
supported yet.)
name: A name for the operation (optional).
Returns:
A tuple of (index, key, value_list).
"index" is a int64 tensor of length num_elements containing the
index of the insert_many call for which the very first component of
the given element was inserted into the Barrier, starting with
the value -2**63. Note, this value is different from the
index of the insert_many call for which the element was completed.
"key" is a string tensor of length num_elements containing the keys.
"value_list" is a tuple of tensors, each one with size num_elements
in the 0th dimension for each component in the barrier's values.
"""
if name is None:
name = "%s_BarrierTakeMany" % self._name
ret = gen_data_flow_ops._barrier_take_many(self._barrier_ref,
num_elements,
self._types,
allow_small_batch,
timeout,
name=name)
# NOTE(mrry): Not using a shape function because we need access to
# the Barrier object.
op = ret[0].op
if allow_small_batch:
batch_dim = None
else:
batch_dim = tensor_shape.Dimension(
tensor_util.constant_value(op.inputs[1]))
op.outputs[0].set_shape(tensor_shape.vector(batch_dim)) # indices
op.outputs[1].set_shape(tensor_shape.vector(batch_dim)) # keys
for output, shape in zip(op.outputs[2:], self._shapes): # value_list
output.set_shape(tensor_shape.TensorShape([batch_dim]).concatenate(shape))
return ret
def close(self, cancel_pending_enqueues=False, name=None):
"""Closes this barrier.
This operation signals that no more new key values will be inserted in the
given barrier. Subsequent InsertMany operations with new keys will fail.
InsertMany operations that just complement already existing keys with other
components, will continue to succeed. Subsequent TakeMany operations will
continue to succeed if sufficient elements remain in the barrier. Subsequent
TakeMany operations that would block will fail immediately.
If `cancel_pending_enqueues` is `True`, all pending requests to the
underlying queue will also be cancelled, and completing of already
started values is also not acceptable anymore.
Args:
cancel_pending_enqueues: (Optional.) A boolean, defaulting to
`False` (described above).
name: Optional name for the op.
Returns:
The operation that closes the barrier.
"""
if name is None:
name = "%s_BarrierClose" % self._name
return gen_data_flow_ops._barrier_close(
self._barrier_ref,
cancel_pending_enqueues=cancel_pending_enqueues,
name=name)
def ready_size(self, name=None):
"""Compute the number of complete elements in the given barrier.
Args:
name: A name for the operation (optional).
Returns:
A single-element tensor containing the number of complete elements in the
given barrier.
"""
if name is None:
name = "%s_BarrierReadySize" % self._name
return gen_data_flow_ops._barrier_ready_size(self._barrier_ref, name=name)
def incomplete_size(self, name=None):
"""Compute the number of incomplete elements in the given barrier.
Args:
name: A name for the operation (optional).
Returns:
A single-element tensor containing the number of incomplete elements in
the given barrier.
"""
if name is None:
name = "%s_BarrierIncompleteSize" % self._name
return gen_data_flow_ops._barrier_incomplete_size(
self._barrier_ref, name=name)
class ConditionalAccumulatorBase(object):
"""A conditional accumulator for aggregating gradients.
Up-to-date gradients (i.e., time step at which gradient was computed is
equal to the accumulator's time step) are added to the accumulator.
Extraction of the average gradient is blocked until the required number of
gradients has been accumulated.
"""
def __init__(self, dtype, shape, accumulator_ref):
"""Creates a new ConditionalAccumulator.
Args:
dtype: Datatype of the accumulated gradients.
shape: Shape of the accumulated gradients.
accumulator_ref: A handle to the conditional accumulator, created by sub-
classes
"""
self._dtype = dtype
if shape is not None:
self._shape = tensor_shape.TensorShape(shape)
else:
self._shape = tensor_shape.unknown_shape()
self._accumulator_ref = accumulator_ref
self._name = self._accumulator_ref.op.name.split("/")[-1]
@property
def accumulator_ref(self):
"""The underlying accumulator reference."""
return self._accumulator_ref
@property
def name(self):
"""The name of the underlying accumulator."""
return self._name
@property
def dtype(self):
"""The datatype of the gradients accumulated by this accumulator."""
return self._dtype
def num_accumulated(self, name=None):
"""Number of gradients that have currently been aggregated in accumulator.
Args:
name: Optional name for the operation.
Returns:
Number of accumulated gradients currently in accumulator.
"""
if name is None:
name = "%s_NumAccumulated" % self._name
return gen_data_flow_ops.accumulator_num_accumulated(
self._accumulator_ref, name=name)
def set_global_step(self, new_global_step, name=None):
"""Sets the global time step of the accumulator.
The operation logs a warning if we attempt to set to a time step that is
lower than the accumulator's own time step.
Args:
new_global_step: Value of new time step. Can be a variable or a constant
name: Optional name for the operation.
Returns:
Operation that sets the accumulator's time step.
"""
return gen_data_flow_ops.accumulator_set_global_step(
self._accumulator_ref,
math_ops.to_int64(ops.convert_to_tensor(new_global_step)),
name=name)
class ConditionalAccumulator(ConditionalAccumulatorBase):
"""A conditional accumulator for aggregating gradients.
Up-to-date gradients (i.e., time step at which gradient was computed is
equal to the accumulator's time step) are added to the accumulator.
Extraction of the average gradient is blocked until the required number of
gradients has been accumulated.
"""
def __init__(self,
dtype,
shape=None,
shared_name=None,
name="conditional_accumulator"):
"""Creates a new ConditionalAccumulator.
Args:
dtype: Datatype of the accumulated gradients.
shape: Shape of the accumulated gradients.
shared_name: Optional. If non-empty, this accumulator will be shared under
the given name across multiple sessions.
name: Optional name for the accumulator.
"""
accumulator_ref = gen_data_flow_ops.conditional_accumulator(
dtype=dtype, shape=shape, shared_name=shared_name, name=name)
super(ConditionalAccumulator, self).__init__(dtype, shape, accumulator_ref)
def apply_grad(self, grad, local_step=0, name=None):
"""Attempts to apply a gradient to the accumulator.
The attempt is silently dropped if the gradient is stale, i.e., local_step
is less than the accumulator's global time step.
Args:
grad: The gradient tensor to be applied.
local_step: Time step at which the gradient was computed.
name: Optional name for the operation.
Returns:
The operation that (conditionally) applies a gradient to the accumulator.
Raises:
ValueError: If grad is of the wrong shape
"""
grad = ops.convert_to_tensor(grad, self._dtype)
grad.get_shape().assert_is_compatible_with(self._shape)
local_step = math_ops.to_int64(ops.convert_to_tensor(local_step))
return gen_data_flow_ops.accumulator_apply_gradient(
self._accumulator_ref, local_step=local_step, gradient=grad, name=name)
def take_grad(self, num_required, name=None):
"""Attempts to extract the average gradient from the accumulator.
The operation blocks until sufficient number of gradients have been
successfully applied to the accumulator.
Once successful, the following actions are also triggered:
- Counter of accumulated gradients is reset to 0.
- Aggregated gradient is reset to 0 tensor.
- Accumulator's internal time step is incremented by 1.
Args:
num_required: Number of gradients that needs to have been aggregated
name: Optional name for the operation
Returns:
A tensor holding the value of the average gradient.
Raises:
InvalidArgumentError: If num_required < 1
"""
out = gen_data_flow_ops.accumulator_take_gradient(
self._accumulator_ref, num_required, dtype=self._dtype, name=name)
out.set_shape(self._shape)
return out
class SparseConditionalAccumulator(ConditionalAccumulatorBase):
"""A conditional accumulator for aggregating sparse gradients.
Sparse gradients are represented by IndexedSlices.
Up-to-date gradients (i.e., time step at which gradient was computed is
equal to the accumulator's time step) are added to the accumulator.
Extraction of the average gradient is blocked until the required number of
gradients has been accumulated.
Args:
dtype: Datatype of the accumulated gradients.
shape: Shape of the accumulated gradients.
shared_name: Optional. If non-empty, this accumulator will be shared under
the given name across multiple sessions.
name: Optional name for the accumulator.
"""
def __init__(self,
dtype,
shape=None,
shared_name=None,
name="sparse_conditional_accumulator"):
accumulator_ref = gen_data_flow_ops.sparse_conditional_accumulator(
dtype=dtype, shape=shape, shared_name=shared_name, name=name)
super(SparseConditionalAccumulator,
self).__init__(dtype, shape, accumulator_ref)
def apply_indexed_slices_grad(self, grad, local_step=0, name=None):
"""Attempts to apply a gradient to the accumulator.
The attempt is silently dropped if the gradient is stale, i.e., local_step
is less than the accumulator's global time step.
Args:
grad: The gradient IndexedSlices to be applied.
local_step: Time step at which the gradient was computed.
name: Optional name for the operation.
Returns:
The operation that (conditionally) applies a gradient to the accumulator.
Raises:
InvalidArgumentError: If grad is of the wrong shape
"""
return self.apply_grad(
grad_indices=grad.indices,
grad_values=grad.values,
grad_shape=grad.dense_shape,
local_step=local_step,
name=name)
def apply_grad(self,
grad_indices,
grad_values,
grad_shape=None,
local_step=0,
name=None):
"""Attempts to apply a sparse gradient to the accumulator.
The attempt is silently dropped if the gradient is stale, i.e., local_step
is less than the accumulator's global time step.
A sparse gradient is represented by its indices, values and possibly empty
or None shape. Indices must be a vector representing the locations of
non-zero entries in the tensor. Values are the non-zero slices of the
gradient, and must have the same first dimension as indices, i.e., the nnz
represented by indices and values must be consistent. Shape, if not empty or
None, must be consistent with the accumulator's shape (if also provided).
Example:
A tensor [[0, 0], [0. 1], [2, 3]] can be represented
indices: [1,2]
values: [[0,1],[2,3]]
shape: [3, 2]
Args:
grad_indices: Indices of the sparse gradient to be applied.
grad_values: Values of the sparse gradient to be applied.
grad_shape: Shape of the sparse gradient to be applied.
local_step: Time step at which the gradient was computed.
name: Optional name for the operation.
Returns:
The operation that (conditionally) applies a gradient to the accumulator.
Raises:
InvalidArgumentError: If grad is of the wrong shape
"""
local_step = math_ops.to_int64(ops.convert_to_tensor(local_step))
return gen_data_flow_ops.sparse_accumulator_apply_gradient(
self._accumulator_ref,
local_step=local_step,
gradient_indices=math_ops.to_int64(grad_indices),
gradient_values=grad_values,
gradient_shape=math_ops.to_int64([] if grad_shape is None else
grad_shape),
has_known_shape=(grad_shape is not None),
name=name)
def take_grad(self, num_required, name=None):
"""Attempts to extract the average gradient from the accumulator.
The operation blocks until sufficient number of gradients have been
successfully applied to the accumulator.
Once successful, the following actions are also triggered:
- Counter of accumulated gradients is reset to 0.
- Aggregated gradient is reset to 0 tensor.
- Accumulator's internal time step is incremented by 1.
Args:
num_required: Number of gradients that needs to have been aggregated
name: Optional name for the operation
Returns:
A tuple of indices, values, and shape representing the average gradient.
Raises:
InvalidArgumentError: If num_required < 1
"""
return gen_data_flow_ops.sparse_accumulator_take_gradient(
self._accumulator_ref, num_required, dtype=self._dtype, name=name)
def take_indexed_slices_grad(self, num_required, name=None):
"""Attempts to extract the average gradient from the accumulator.
The operation blocks until sufficient number of gradients have been
successfully applied to the accumulator.
Once successful, the following actions are also triggered:
- Counter of accumulated gradients is reset to 0.
- Aggregated gradient is reset to 0 tensor.
- Accumulator's internal time step is incremented by 1.
Args:
num_required: Number of gradients that needs to have been aggregated
name: Optional name for the operation
Returns:
An IndexedSlices holding the value of the average gradient.
Raises:
InvalidArgumentError: If num_required < 1
"""
return_val = gen_data_flow_ops.sparse_accumulator_take_gradient(
self._accumulator_ref, num_required, dtype=self._dtype, name=name)
return ops.IndexedSlices(
indices=return_val.indices,
values=return_val.values,
dense_shape=return_val.shape)
class StagingArea(object):
"""Class for staging inputs. No ordering guarantees.
A `StagingArea` is a TensorFlow data structure that stores tensors across
multiple steps, and exposes operations that can put and get tensors.
Each `StagingArea` element is a tuple of one or more tensors, where each
tuple component has a static dtype, and may have a static shape.
The capacity of a `StagingArea` is unbounded and supports multiple
concurrent producers and consumers; and provides exactly-once delivery.
Each element of a `StagingArea` is a fixed-length tuple of tensors whose
dtypes are described by `dtypes`, and whose shapes are optionally described
by the `shapes` argument.
If the `shapes` argument is specified, each component of a staging area
element must have the respective fixed shape. If it is
unspecified, different elements may have different shapes,
"""
_identifier = 0
_lock = threading.Lock()
def __init__(self, dtypes, shapes=None, names=None, shared_name=None):
"""Constructs a staging area object.
The two optional lists, `shapes` and `names`, must be of the same length
as `dtypes` if provided. The values at a given index `i` indicate the
shape and name to use for the corresponding queue component in `dtypes`.
The device scope at the time of object creation determines where the
storage for the `StagingArea` will reside. Calls to `put` will incur a copy
to this memory space, if necessary. Tensors returned by `get` will be
placed according to the device scope when `get` is called.
Args:
dtypes: A list of types. The length of dtypes must equal the number
of tensors in each element.
shapes: (Optional.) Constraints on the shapes of tensors in an element.
A list of shape tuples or None. This list is the same length
as dtypes. If the shape of any tensors in the element are constrained,
all must be; shapes can be None if the shapes should not be constrained.
names: (Optional.) If provided, the `get()` and
`put()` methods will use dictionaries with these names as keys.
Must be None or a list or tuple of the same length as `dtypes`.
shared_name: (Optional.) A name to be used for the shared object. By
passing the same name to two different python objects they will share
the underlying staging area. Must be a string.
Raises:
ValueError: If one of the arguments is invalid.
"""
if shared_name is None:
self._name = ops.get_default_graph().unique_name("StagingArea")
elif isinstance(shared_name, six.string_types):
self._name = shared_name
else:
raise ValueError("shared_name must be a string")
self._dtypes = dtypes
if shapes is not None:
if len(shapes) != len(dtypes):
raise ValueError("StagingArea shapes must be the same length as dtypes")
self._shapes = [tensor_shape.TensorShape(s) for s in shapes]
else:
self._shapes = [tensor_shape.unknown_shape() for _ in self._dtypes]
if names is not None:
if len(names) != len(dtypes):
raise ValueError("StagingArea names must be the same length as dtypes")
self._names = names
else:
self._names = None
# all get and put ops must colocate with this op
with ops.name_scope("%s_root" % self._name):
self._coloc_op = control_flow_ops.no_op()
@property
def name(self):
"""The name of the staging area."""
return self._name
@property
def dtypes(self):
"""The list of dtypes for each component of a staging area element."""
return self._dtypes
@property
def shapes(self):
"""The list of shapes for each component of a staging area element."""
return self._shapes
@property
def names(self):
"""The list of names for each component of a staging area element."""
return self._names
def _check_put_dtypes(self, vals):
"""Validate and convert `vals` to a list of `Tensor`s.
The `vals` argument can be a Tensor, a list or tuple of tensors, or a
dictionary with tensor values.
If it is a dictionary, the staging area must have been constructed with a
`names` attribute and the dictionary keys must match the staging area names.
If the staging area was constructed with a `names` attribute, `vals` must
be a dictionary.
Args:
vals: A tensor, a list or tuple of tensors, or a dictionary..
Returns:
A list of `Tensor` objects.
Raises:
ValueError: If `vals` is invalid.
"""
if isinstance(vals, dict):
if not self._names:
raise ValueError(
"Staging areas must have names to enqueue a dictionary")
if sorted(self._names) != sorted(vals.keys()):
raise ValueError("Keys in dictionary to put do not match names "
"of staging area. Dictionary: (%s), Queue: (%s)" %
(sorted(vals.keys()), sorted(self._names)))
# The order of values in `self._names` indicates the order in which the
# tensors in the dictionary `vals` must be listed.
vals = [vals[k] for k in self._names]
else:
if self._names:
raise ValueError("You must enqueue a dictionary in a staging area "
"with names")
if not isinstance(vals, (list, tuple)):
vals = [vals]
tensors = []
for i, (val, dtype) in enumerate(zip(vals, self._dtypes)):
tensors.append(
ops.convert_to_tensor(
val, dtype=dtype, name="component_%d" % i))
return tensors
def _scope_vals(self, vals):
"""Return a list of values to pass to `name_scope()`.
Args:
vals: A tensor, a list or tuple of tensors, or a dictionary.
Returns:
The values in vals as a list.
"""
if isinstance(vals, (list, tuple)):
return vals
elif isinstance(vals, dict):
return vals.values()
else:
return [vals]
def put(self, values, name=None):
"""Create an op that places a value into the staging area.
Args:
values: Tensor (or a tuple of Tensors) to place into the staging area.
name: A name for the operation (optional).
Returns:
The created op.
Raises:
ValueError: If the number or type of inputs don't match the staging area.
"""
with ops.name_scope(name, "%s_put" % self._name,
self._scope_vals(values)) as scope:
vals = self._check_put_dtypes(values)
if len(values) != len(self._dtypes):
raise ValueError("Unexpected number of inputs " + str(len(values)) +
"vs " + str(len(self._dtypes)))
for val, dtype in zip(vals, self._dtypes):
if val.dtype != dtype:
raise ValueError("Datatypes do not match. " + str(val.dtype) + " != "
+ str(dtype))
for val, shape in zip(vals, self._shapes):
val.get_shape().assert_is_compatible_with(shape)
with ops.colocate_with(self._coloc_op):
op = gen_data_flow_ops.stage(values=vals, shared_name=self._name,
name=scope)
return op
def _get_return_value(self, tensors):
"""Return the value to return from a get op.
If the staging area has names, return a dictionary with the
names as keys. Otherwise return either a single tensor
or a list of tensors depending on the length of `tensors`.
Args:
tensors: List of tensors from the get op.
Returns:
A single tensor, a list of tensors, or a dictionary
of tensors.
"""
if self._names:
# The returned values in `tensors` are in the same order as
# the names in `self._names`.
return {n: tensors[i] for i, n in enumerate(self._names)}
elif len(tensors) == 1:
return tensors[0]
else:
return tensors
def get(self, name=None):
"""Gets one element from this staging area.
If the staging area is empty when this operation executes, it will block
until there is an element to dequeue.
Note that unlike others ops that can block, like the queue Dequeue
operations, this can stop other work from happening. To avoid this, the
intended use is for this to be called only when there will be an element
already available. One method for doing this in a training loop would be to
run a `put()` call during a warmup session.run call, and then call both
`get()` and `put()` in each subsequent step.
The placement of the returned tensor will be determined by the current
device scope when this function is called.
Args:
name: A name for the operation (optional).
Returns:
The tuple of tensors that was gotten.
"""
if name is None:
name = "%s_get" % self._name
with ops.colocate_with(self._coloc_op):
ret = gen_data_flow_ops.unstage(dtypes=self._dtypes,
shared_name=self._name, name=name)
curr_device_scope = control_flow_ops.no_op().device
if curr_device_scope != self._coloc_op.device:
for i in range(len(ret)):
ret[i] = array_ops.identity(ret[i])
for output, shape in zip(ret, self._shapes):
output.set_shape(shape)
return self._get_return_value(ret)
class RecordInput(object):
"""RecordInput asynchronously reads and randomly yields TFRecords.
A RecordInput Op will continuously read a batch of records asynchronously
into a buffer of some fixed capacity. It can also asynchronously yield
random records from this buffer.
It will not start yielding until at least `buffer_size / 2` elements have been
placed into the buffer so that sufficient randomization can take place.
The order the files are read will be shifted each epoch by `shift_amount` so
that the data is presented in a different order every epoch.
"""
def __init__(self,
file_pattern,
batch_size=1,
buffer_size=1,
parallelism=1,
shift_ratio=0,
seed=0,
name=None):
"""Constructs a RecordInput Op.
Args:
file_pattern: File path to the dataset, possibly containing wildcards.
All matching files will be iterated over each epoch.
batch_size: How many records to return at a time.
buffer_size: The maximum number of records the buffer will contain. This
_must_ be smaller than the total number of records in an epoch or
deadlock can occur.
parallelism: How many reader threads to use for reading from files.
shift_ratio: What percentage of the total number files to move the start
file forward by each epoch.
seed: Specify the random number seed used by generator that randomizes
records.
name: Optional name for the operation.
Raises:
ValueError: If one of the arguments is invalid.
"""
self._batch_size = batch_size
self._file_pattern = file_pattern
self._buffer_size = buffer_size
self._parallelism = parallelism
self._shift_ratio = shift_ratio
self._seed = seed
self._name = name
def get_yield_op(self):
"""Add a node that yields a minibatch every time it is executed."""
return gen_data_flow_ops.record_input(
file_pattern=self._file_pattern,
file_buffer_size=self._buffer_size,
file_parallelism=self._parallelism,
file_shuffle_shift_ratio=self._shift_ratio,
batch_size=self._batch_size,
file_random_seed=self._seed,
name=self._name)
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