ReverseSequence#

Versioned name: ReverseSequence-1

Category: Data movement

Short description: ReverseSequence reverses variable length slices of data.

Detailed description

ReverseSequence slices a given input tensor data along the dimension specified in the batch_axis attribute. For each slice i, it reverses the first seq_lengths[i] elements along the dimension specified in the seq_axis attribute.

Attributes

  • batch_axis

    • Description: batch_axis is the index of the batch dimension along which data input tensor is sliced.

    • Range of values: an integer within the range [-rank(data), rank(data) - 1]

    • Type: int

    • Default value: 0

    • Required: no

  • seq_axis

    • Description: seq_axis is the index of the sequence dimension along which elements of data input tensor are reversed.

    • Range of values: an integer within the range [-rank(data), rank(data) - 1]

    • Type: int

    • Default value: 1

    • Required: no

Inputs

  • 1: data - Input data to reverse. A tensor of type T1 and rank greater or equal to 2. Required.

  • 2: seq_lengths - Sequence lengths to reverse in the input tensor data. A 1D tensor comprising data_shape[batch_axis] elements of type T2. All element values must be integer values within the range [1, data_shape[seq_axis]]. Value 1 means, no elements are reversed. Required.

Outputs

  • 1: The result of slice and reverse data input tensor. A tensor of type T1 and the same shape as data input tensor.

Types

  • T1: any supported type.

  • T2: any supported numerical type.

Example

 <layer ... type="ReverseSequence">
     <data batch_axis="0" seq_axis="1"/>
     <input>
         <port id="0">       <!-- data -->
             <dim>4</dim>    <!-- batch_axis -->
             <dim>10</dim>   <!-- seq_axis -->
             <dim>100</dim>
             <dim>200</dim>
         </port>
         <port id="1">
             <dim>4</dim>    <!-- seq_lengths value: [2, 4, 8, 10] -->
         </port>
     </input>
     <output>
         <port id="2">
             <dim>4</dim>
             <dim>10</dim>
             <dim>100</dim>
             <dim>200</dim>
         </port>
     </output>
 </layer>