:nosearch:

.. _op_ai_onnx_Size-23:

Size - version 23
=================

This page documents version **23** of operator **Size**. See :doc:`Size` for the latest version (since version 25).

- **Domain**: ``ai.onnx``
- **Since version**: 23

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(int16), tensor(int32), tensor(int4), tensor(int64), tensor(int8), tensor(string), tensor(uint16), 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 (21)
--------------------------------------

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

* old version: 21
* new version: 23
* breaking: no

**Type constraints:**

* changed 'T': added types: ['tensor(float4e2m1)']