:nosearch:

.. _op_ai_onnx_NonZero-9:

NonZero - version 9
===================

This page documents version **9** of operator **NonZero**. See :doc:`NonZero` for the latest version (since version 13).

- **Domain**: ``ai.onnx``
- **Since version**: 9

Returns the indices of the elements that are non-zero
(in row-major order - by dimension).
NonZero behaves similar to numpy.nonzero:
https://docs.scipy.org/doc/numpy/reference/generated/numpy.nonzero.html,
but for scalar input, NonZero produces output shape (0, N) instead of (1, N), which is different from Numpy's behavior.

**Inputs**

- **X** (*T*): input

**Outputs**

- **Y** (*tensor(int64)*): output

**Type Constraints**

- **T**: Constrain to all tensor types.
  Allowed types: tensor(bool), tensor(complex128), tensor(complex64), tensor(double), tensor(float), tensor(float16), tensor(int16), tensor(int32), tensor(int64), tensor(int8), tensor(string), tensor(uint16), tensor(uint32), tensor(uint64), tensor(uint8).