.. _op_ai_onnx_Size:

Size
====

- **Domain**: ``ai.onnx``
- **Since version**: 25

Takes a tensor as input and outputs a int64 scalar that equals to the total number of elements of the input tensor.

**Inputs**

- **data** (*T*): An input tensor.

**Outputs**

- **size** (*T1*): Total number of elements of the input tensor

**Type Constraints**

- **T**: Input tensor can be of arbitrary type.
  Allowed types: tensor(bfloat16), tensor(bool), tensor(complex128), tensor(complex64), tensor(double), tensor(float), tensor(float16), tensor(float4e2m1), tensor(float8e4m3fn), tensor(float8e4m3fnuz), tensor(float8e5m2), tensor(float8e5m2fnuz), tensor(float8e8m0), tensor(int16), tensor(int2), tensor(int32), tensor(int4), tensor(int64), tensor(int8), tensor(string), tensor(uint16), tensor(uint2), tensor(uint32), tensor(uint4), tensor(uint64), tensor(uint8).
- **T1**: Constrain output to int64 tensor, which should be a scalar though.
  Allowed types: tensor(int64).

Differences with previous version (24)
--------------------------------------

**SchemaDiff**: ``Size`` (domain ``'ai.onnx'``)

* old version: 24
* new version: 25
* breaking: no

**Type constraints:**

* changed 'T': added types: ['tensor(int2)', 'tensor(uint2)']

Version History
---------------

- :doc:`Version 24 <Size-24>`
- :doc:`Version 23 <Size-23>`
- :doc:`Version 21 <Size-21>`
- :doc:`Version 19 <Size-19>`
- :doc:`Version 13 <Size-13>`
- :doc:`Version 1 <Size-1>`