openvino/docs/ops/sort/TopK_3.md

TopK

Versioned name: TopK-3

Category: Sorting and maximization

Short description: TopK computes indices and values of the k maximum/minimum values for each slice along specified axis.

Attributes

• axis

  • Description: Specifies the axis along which
  • Range of values: An integer. Negative value means counting dimension from the end.
  • Type: int
  • Default value: None
  • Required: yes

• mode

  • Description: Specifies which operation is used to select the biggest element of two.
  • Range of values: min, max
  • Type: string
  • Default value: None
  • Required: yes

• sort

  • Description: Specifies order of output elements and/or indices.
  • Range of values: value, index, none
  • Type: string
  • Default value: None
  • Required: yes

• index_element_type

  • Description: the type of output tensor with indices
  • Range of values: "i64" or "i32"
  • Type: string
  • Default value: "i32"
  • Required: No

Inputs:

• 1: tensor of arbitrary rank of type T. Required.

• 2: k -- scalar of any integer type specifies how many maximum/minimum elements should be computed. Required

Outputs:

• 1: Output tensor of type T with top k values from the input tensor along specified dimension axis. The shape of the tensor is [input1.shape[0], ..., input1.shape[axis-1], k, input1.shape[axis+1], ...].

• 2: Output tensor with top k indices for each slice along axis dimension of type T_IND. The shape of the tensor is the same as for the 1st output, that is [input1.shape[0], ..., input1.shape[axis-1], k, input1.shape[axis+1], ...]

Types

• T: any numeric type.

• T_IND: int64 or int32.

Detailed Description

Output tensor is populated by values computes in the following way:

output[i1, ..., i(axis-1), j, i(axis+1) ..., iN] = top_k(input[i1, ...., i(axis-1), :, i(axis+1), ..., iN]), k, sort, mode)

So for each slice input[i1, ...., i(axis-1), :, i(axis+1), ..., iN] which represents 1D array, TopK value is computed individually. Sorting and minimum/maximum are controlled by sort and mode attributes.

Example

<layer ... type="TopK" ... >
    <data axis="1" mode="max" sort="value" index_element_type="i64"/>
    <input>
        <port id="0">
            <dim>6</dim>
            <dim>12</dim>
            <dim>10</dim>
            <dim>24</dim>
        </port>
        <port id="1">
            <!-- k = 3 -->
        </port>
    <output>
        <port id="2">
            <dim>6</dim>
            <dim>3</dim>
            <dim>10</dim>
            <dim>24</dim>
        </port>
        <port id="3">
            <dim>6</dim>
            <dim>3</dim>
            <dim>10</dim>
            <dim>24</dim>
        </port>
    </output>
</layer>