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tf.contrib.tpu.InfeedQueue

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A helper object to build a device infeed queue.

The InfeedQueue builds the host-side and device-side Ops to enqueue and dequeue elements, respectively, and ensures that their types and shapes match.

number_of_tuple_elements the number of Tensors fed atomically through the queue, must be present unless it can be inferred from other arguments.
tuple_types if not None, a list of types of the elements of the queue.
tuple_shapes if not None, a list of shapes of the elements of the queue.
shard_dimensions if not None, a list of dimensions on which the elements of the queue should be sharded during automatic parallelization.
name the name of the queue.

ValueError if number_of_tuple_elements <= 0; or number_of_tuple_arguments, tuple_types, tuple_shapes, and shard_dimensions are all None; or the length of tuple_types, tuple_shapes, or shard_dimensions is not equal to number_of_tuple_elements; or any element of shard_dimensions can't be converted to a Dimension.
TypeError if any element of tuple_types or tuple_shapes can't be converted to a dtype or TensorShape, respectively.

number_of_shards Gets the number of shards to use for the InfeedQueue.
number_of_tuple_elements Returns the number of InfeedQueue tuple elements.
shard_dimensions Gets the shard dimension of each tuple element.
sharding_policies Returns the sharding policies of the InfeedQueue tuple elements.
tuple_shapes Returns the shapes of the InfeedQueue tuple elements.
tuple_types Returns the types of the InfeedQueue tuple elements.

Methods

freeze

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Freezes the InfeedQueue so it can no longer be modified.

The configuration is implicitly frozen before any host-side or device-side Ops are generated. The configuration cannot be frozen until the types and shapes of the tuple elements have been set.

Raises
ValueError if the types or shapes of the tuple elements have not been set.

generate_dequeue_op

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Generates the device-side Op to dequeue a tuple from the queue.

Implicitly freezes the queue configuration if it is not already frozen, which will raise errors if the shapes and types have not been fully specified.

Args
tpu_device The TPU device ordinal where the infeed instruction should be placed. If None, no explicit placement will be performed, and it is up to the user to call this API from within a proper TPU device scope. The XLA code will fail if the TPU dequeue instruction is not bound to any device.

Returns
A list of Outputs corresponding to a shard of infeed dequeued into XLA, suitable for use within a replicated block.

Raises
ValueError if the types or shapes of the tuple elements have not been set; or if a dequeue op has already been generated.

generate_enqueue_ops

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Generates the host-side Ops to enqueue the shards of a tuple.

sharded_inputs is a list, one for each shard, of lists of Tensors. sharded_inputs[0] is the tuple of Tensors to use to feed shard 0 if the queue. Returns the host-side Ops that must be run to enqueue the sharded tuple. The Op for shard i is colocated with the inputs for shard i.

Implicitly freezes the queue configuration if it is not already frozen. If the configuration has already been frozen, and is not compatible with the types and shapes of sharded_inputs, an error will be raised.

Args
sharded_inputs a list of lists of Tensors. The length of the outer list determines the number of shards. Each inner list indicates the types and shapes of the tuples in the corresponding shard.
tpu_ordinal_function if not None, a function that takes the shard index as input and returns the ordinal of the TPU device the shard's infeed should be placed on. tpu_ordinal_function must be set if the inputs are placed on CPU devices.
placement_function if not None, a function that takes the shard index as input and returns the host device where the enqueue op should be placed on.

Returns
A list of host-side Ops, one for each shard, that when executed together will enqueue a full-size element of infeed.

Raises
ValueError if the queue configuration has previously been frozen and the shapes of the elements of sharded_inputs are not compatible with the frozen configuration; or if the shapes of the elements of sharded_inputs don't form a consistent unsharded tuple; or if the elements of a tuple have different device constraints.
TypeError if the queue configuration has previously been frozen and the types of the elements of sharded_inputs are not compatible with the frozen configuration; or if the types of the elements of sharded_inputs don't form a consistent unsharded tuple.

set_configuration_from_input_tensors

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Sets the shapes and types of the queue tuple elements.

input_tensors is a list of Tensors whose types and shapes are used to set the queue configuration.

Args
input_tensors list of Tensors of the same types and shapes as the desired queue Tuple.

Raises
ValueError if input_tensors is not a list of length self.number_of_tuple_elements

set_configuration_from_sharded_input_tensors

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Sets the shapes and types of the queue tuple elements.

input_tensors is a list of lists of Tensors whose types and shapes are used to set the queue configuration. The length of the outer list is the number of shards required, and each inner list is the tuple of Tensors to use to determine the types and shapes of the corresponding shard. This method depends on the shard dimension, and calling it freezes the shard policy.

Args
input_tensors list of lists of Tensors. The outer list length corresponds to the desired number of shards, and each inner list is the size and shape of the desired configuration of the corresponding shard.

Raises
ValueError if any inner list is not a list of length self.number_of_tuple_elements; or the inner lists do not combine to form a consistent unsharded shape.
TypeError if the types of the Tensors in the inner lists do not match.

set_number_of_shards

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Sets the number of shards to use for the InfeedQueue.

Args
number_of_shards number of ways to shard the InfeedQueue.

Raises
ValueError if number_of_shards is not > 0; or the policies have been frozen and number_of_shards was already set to something else.

set_shard_dimensions

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Sets the shard_dimension of each element of the queue.

shard_dimensions must be a list of length self.number_of_tuple_elements, and each element must be convertible to a Dimension compatible with self.tuple_shapes.

Args
shard_dimensions the dimensions of each queue element.

Raises
ValueError if shard_dimensions is not of length self.number_of_tuple_elements; or an element of shard_dimensions cannot be converted to a Dimension; or an element of shard_dimensions is a Dimension that is out of range for the corresponding tuple element shape.

set_tuple_shapes

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Sets the shape of each element of the queue.

tuple_shapes must be a list of length self.number_of_tuple_elements, and each element must be convertible to a TensorShape.

Args
tuple_shapes the shapes of each queue element.

Raises
ValueError if tuple_shapes is not of length self.number_of_tuple_elements.
TypeError if an element of tuple_shapes cannot be converted to a TensorShape.

set_tuple_types

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Sets the type of each element of the queue.

tuple_types must be a list of length self.number_of_tuple_elements, and each element must be convertible to a dtype.

Args
tuple_types the types of each queue element.

Raises
ValueError if tuple_types is not of length self.number_of_tuple_elements.
TypeError if an element of tuple_types cannot be converted to a dtype.

split_inputs_and_generate_enqueue_ops

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POORLY-PERFORMING ON MULTI-HOST SYSTEMS.

Generates the host-side Ops to enqueue a tuple.

This method performs poorly because it takes an entire input on a single host, splits it, and distributes it to all of the cores. It is present only to simplify tutorial examples.

inputs is a list of Tensors to use to feed the queue. Each input is split into self.number_of_shards shards. Returns an Op for each shard to enqueue the shard. The Op for shard i is placed on device placement_function(i).

Implicitly freezes the queue configuration if it is not already frozen. If the configuration has already been frozen, and is not compatible with the types and shapes of inputs, an error will be raised.

Args
inputs: a list of Tensors which indicates the types and shapes of the queue tuple.
device_assignment if not None, a TPU DeviceAssignment. If device_assignment is not None, but placement_function and ordinal_function are None, then device_assignment will be used to place infeeds on the first k TPU shards, where k is the number of shards in the queue. If all three are None, then default placement and ordinal functions are used. placement_function: if not None, a function that takes the shard index as input and returns a device string indicating which device the shard's infeed should be placed on. If placement_function and tpu_ordinal_function are None, inputs are sharded round-robin across the devices in the system. tpu_ordinal_function: if not None, a function that takes the shard index as input and returns the ordinal of the TPU device the shard's infeed should be placed on. If placement_function and tpu_ordinal_function are None, inputs are sharded round-robin across the devices in the system.

Returns
A list of host-side Ops, one for each shard, that when executed together will enqueue a full-size element of infeed.

Raises
ValueError if the queue configuration has previously been frozen and the shapes of the elements of inputs are not compatible with the frozen configuration.
TypeError if the queue configuration has previously been frozen and the types of the elements of inputs are not compatible with the frozen configuration.