Select

Versioned name: Select-1

Category: Conditions

Short description: Select returns a tensor filled with the elements from the second or the third inputs, depending on the condition (the first input) value.

Detailed description

Select takes elements from then input tensor or the else input tensor based on a condition mask provided in the first input cond. Before performing selection, input tensors then and else are broadcasted to each other if their shapes are different and auto_broadcast attributes is not none. Then the cond tensor is one-way broadcasted to the resulting shape of broadcasted then and else. Broadcasting is performed according to auto_broadcast value.

Attributes

• auto_broadcast
  • Description: specifies rules used for auto-broadcasting of input tensors.
  • Range of values:
    • none - no auto-broadcasting is allowed, all input shapes should match
    • numpy - numpy broadcasting rules, aligned with ONNX Broadcasting. Description is available in ONNX docs.
  • Type: string
  • Default value: "numpy"
  • Required: no

Inputs:

• 1: cond tensor with selection mask of type boolean. The tensor can be 0D.
• 2: then the tensor with elements to take where the corresponding element in cond is true. Arbitrary type that should match type of else input tensor.
• 3: else the tensor with elements to take where the corresponding element in cond is false. Arbitrary type that should match type of then input tensor.

Outputs:

• 1: blended output tensor that is tailored from values of inputs tensors then and else based on cond and broadcasting rules. It has the same type of elements as then and else.

Example

<layer ... type="Select">
    <input>
        <port id="0">     <!-- cond value is: [[false, false], [true, false], [true, true]] -->
            <dim>3</dim>
            <dim>2</dim>
        </port>
        <port id="1">     <!-- then value is: [[-1, 0], [1, 2], [3, 4]] -->
            <dim>3</dim>
            <dim>2</dim>
        </port>
        <port id="2">     <!-- else value is: [[11, 10], [9, 8], [7, 6]] -->
            <dim>3</dim>
            <dim>2</dim>
        </port>
    </input>
    <output>
        <port id="1">     <!-- output value is: [[11, 10], [1, 8], [3, 4]] -->
            <dim>3</dim>
            <dim>2</dim>
        </port>
    </output>
</layer>