ReverseSequence

public final class ReverseSequence

Reverses variable length slices.

This op first slices `input` along the dimension `batch_dim`, and for each slice `i`, reverses the first `seq_lengths[i]` elements along the dimension `seq_dim`.

The elements of `seq_lengths` must obey `seq_lengths[i] <= input.dims[seq_dim]`, and `seq_lengths` must be a vector of length `input.dims[batch_dim]`.

The output slice `i` along dimension `batch_dim` is then given by input slice `i`, with the first `seq_lengths[i]` slices along dimension `seq_dim` reversed.

For example:

# Given this:
 batch_dim = 0
 seq_dim = 1
 input.dims = (4, 8, ...)
 seq_lengths = [7, 2, 3, 5]
 
 # then slices of input are reversed on seq_dim, but only up to seq_lengths:
 output[0, 0:7, :, ...] = input[0, 7:0:-1, :, ...]
 output[1, 0:2, :, ...] = input[1, 2:0:-1, :, ...]
 output[2, 0:3, :, ...] = input[2, 3:0:-1, :, ...]
 output[3, 0:5, :, ...] = input[3, 5:0:-1, :, ...]
 
 # while entries past seq_lens are copied through:
 output[0, 7:, :, ...] = input[0, 7:, :, ...]
 output[1, 2:, :, ...] = input[1, 2:, :, ...]
 output[2, 3:, :, ...] = input[2, 3:, :, ...]
 output[3, 2:, :, ...] = input[3, 2:, :, ...]
 

In contrast, if:

# Given this:
 batch_dim = 2
 seq_dim = 0
 input.dims = (8, ?, 4, ...)
 seq_lengths = [7, 2, 3, 5]
 
 # then slices of input are reversed on seq_dim, but only up to seq_lengths:
 output[0:7, :, 0, :, ...] = input[7:0:-1, :, 0, :, ...]
 output[0:2, :, 1, :, ...] = input[2:0:-1, :, 1, :, ...]
 output[0:3, :, 2, :, ...] = input[3:0:-1, :, 2, :, ...]
 output[0:5, :, 3, :, ...] = input[5:0:-1, :, 3, :, ...]
 
 # while entries past seq_lens are copied through:
 output[7:, :, 0, :, ...] = input[7:, :, 0, :, ...]
 output[2:, :, 1, :, ...] = input[2:, :, 1, :, ...]
 output[3:, :, 2, :, ...] = input[3:, :, 2, :, ...]
 output[2:, :, 3, :, ...] = input[2:, :, 3, :, ...]
 

Nested Classes

class

ReverseSequence.Options

Optional attributes for ReverseSequence

Public Methods

Output<T>	asOutput() Returns the symbolic handle of a tensor.
static ReverseSequence.Options	batchDim(Long batchDim)
static <T, U extends Number> ReverseSequence<T>	create(Scope scope, Operand<T> input, Operand<U> seqLengths, Long seqDim, Options... options) Factory method to create a class wrapping a new ReverseSequence operation.
Output<T>	output() The partially reversed input.

Inherited Methods

From class org.tensorflow.op.PrimitiveOp

final boolean	equals(Object obj)
final int	hashCode()
Operation	op() Returns the underlying Operation
final String	toString()

From class java.lang.Object

boolean	equals(Object arg0)
final Class<?>	getClass()
int	hashCode()
final void	notify()
final void	notifyAll()
String	toString()
final void	wait(long arg0, int arg1)
final void	wait(long arg0)
final void	wait()

From interface org.tensorflow.Operand

abstract Output<T>

asOutput() Returns the symbolic handle of a tensor.

Public Methods

public Output<T> asOutput ()

Returns the symbolic handle of a tensor.

Inputs to TensorFlow operations are outputs of another TensorFlow operation. This method is used to obtain a symbolic handle that represents the computation of the input.

public static ReverseSequence.Options batchDim (Long batchDim)

Parameters

batchDim	The dimension along which reversal is performed.

public static ReverseSequence<T> create (Scope scope, Operand<T> input, Operand<U> seqLengths, Long seqDim, Options... options)

Factory method to create a class wrapping a new ReverseSequence operation.

Parameters

scope	current scope
input	The input to reverse.
seqLengths	1-D with length `input.dims(batch_dim)` and `max(seq_lengths) <= input.dims(seq_dim)`
seqDim	The dimension which is partially reversed.
options	carries optional attributes values

Returns

• a new instance of ReverseSequence

public Output<T> output ()

The partially reversed input. It has the same shape as `input`.