Merge

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Product Support Status

Product	Supported
Ascend 950PR&950DT products	√
Atlas A3 products	√
Atlas A2 products	√
Atlas 200I/500 A2 inference products	√
Atlas inference products	√
Atlas training products	√

Function Description

Merge is a basic control flow operator. It forwards the first tensor in the input x that becomes available to the output y, and gives the index of this tensor in the inputs in value_index. Merge usually works with the Switch operator to implement branch convergence: Switch distributes data to different branches based on conditions, and then Merge converges the data of the available branches back to the main flow.

Parameter Description

Parameter Name	Input/Output/Attribute	Description	Data Type	Data Format
x	Dynamic input	Input tensors, one of which becomes available. All input tensors should use the same data type; shape inference merges the dimension information of all inputs.	float16, float32, float64, int8, int16, int32, int64, uint8, uint16, uint32, uint64, bool	ND
y	Output	Available tensor, whose data type is consistent with that of x.	float16, float32, float64, int8, int16, int32, int64, uint8, uint16, uint32, uint64, bool	ND
value_index	Output	Scalar, which is the index of the selected input tensor in the input list.	DT_INT32	ND

Constraint Description

• The number of inputs x must be greater than or equal to 1; otherwise, shape inference fails.
• The data types of all inputs x must be the same; data type inference checks the input types one by one and returns a failure if they are inconsistent. The data type of the output y is the same as that of the inputs, and value_index is DT_INT32.
• If the numbers of dimensions of inputs x are inconsistent or there is an unknown-rank input, the output y is inferred as unknown rank ([-2]), and inference failure is not returned due to inconsistent ranks.
• For a dimension, if the values of the inputs are inconsistent or there is an unknown dimension (-1), the dimension is inferred as -1 (unknown).

Invocation Description

The Merge operator is a basic control flow operator. It is usually used as a branch convergence node in a graph and is not invoked separately.

Invocation Method	Invocation Sample	Description
Graph-mode invocation	test_geir_merge	Invokes the Merge operator by building a graph through the operator IR