.. _op_ai_onnx_Sigmoid:

Sigmoid
=======

- **Domain**: ``ai.onnx``
- **Since version**: 13

Sigmoid takes one input data (Tensor ) and produces one output data
(Tensor ) where the sigmoid function, y = 1 / (1 + exp(-x)), is applied
to the tensor element-wise.

**Inputs**

- **X** (*T*): Input tensor

**Outputs**

- **Y** (*T*): Output tensor

**Type Constraints**

- **T**: Constrain input and output types to float tensors.
  Allowed types: tensor(bfloat16), tensor(double), tensor(float), tensor(float16).

Examples
--------

**test_cc_sigmoid**

.. code-block:: text

    Node:
      Sigmoid(X) -> (Y)

.. code-block:: text

    Inputs:
      X: shape=(2, 3), dtype=float32
        [[-4., -1.,  0.],
         [ 1.,  2.,  4.]]

    Outputs:
      Y: shape=(2, 3), dtype=float32
        [[0.01798621, 0.26894143, 0.5       ],
         [0.7310586 , 0.880797  , 0.98201376]]

**test_cc_sigmoid_bfloat16**

.. code-block:: text

    Node:
      Sigmoid(x) -> (y)

.. code-block:: text

    Inputs:
      x: shape=(2, 3), dtype=bfloat16
        [[-2, -1, 0],
         [0.5, 1, 2]]

    Outputs:
      y: shape=(2, 3), dtype=bfloat16
        [[0.119141, 0.269531, 0.5],
         [0.621094, 0.730469, 0.878906]]

**test_cc_sigmoid_double**

.. code-block:: text

    Node:
      Sigmoid(x) -> (y)

.. code-block:: text

    Inputs:
      x: shape=(2, 3), dtype=float64
        [[-2. , -1. ,  0. ],
         [ 0.5,  1. ,  2. ]]

    Outputs:
      y: shape=(2, 3), dtype=float64
        [[0.11920292, 0.26894142, 0.5       ],
         [0.62245933, 0.73105858, 0.88079708]]

**test_cc_sigmoid_float16**

.. code-block:: text

    Node:
      Sigmoid(x) -> (y)

.. code-block:: text

    Inputs:
      x: shape=(2, 3), dtype=float16
        [[-2. , -1. ,  0. ],
         [ 0.5,  1. ,  2. ]]

    Outputs:
      y: shape=(2, 3), dtype=float16
        [[0.1192, 0.269 , 0.5   ],
         [0.6226, 0.731 , 0.881 ]]

Differences with previous version (6)
-------------------------------------

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

* old version: 6
* new version: 13
* breaking: no

**Type constraints:**

* changed 'T': added types: ['tensor(bfloat16)']

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

- :doc:`Version 6 <Sigmoid-6>`
- :doc:`Version 1 <Sigmoid-1>`