.. index:: pair: page; Deterministic Mode
.. _doxid-dev_guide_attributes_deterministic:

Deterministic Mode
==================

To support debugging, validation and certification of some applications, oneDNN provides a deterministic mode. This mode guarantees that multiple executions of the same primitive on a given platform return the exact same result bitwise.

For most primitives, oneDNN provides a run-to-run deterministic execution for a fixed environment. In particular, if the hardware platform and software environment (library/runtime versions, environment variables, etc.) are identical between multiple runs, the produced results should be bit-wise identical.

However, some implementations rely on non-deterministic constructs such as atomic operations. In order to guarantee deterministic execution, a deterministic attribute can be set (default false) with the :ref:`dnnl_primitive_attr_set_deterministic <doxid-group__dnnl__api__attributes_1ga69af4e29cba07fdb95672c070ac26511>` (C API) or the :ref:`dnnl::primitive_attr::set_deterministic <doxid-structdnnl_1_1primitive__attr_1ad4c1ea7156ce31cd231a00d4e3399add>` (C++ API) functions.

The deterministic primitive attribute accepts:

* ``false`` (default): Permits the library to use non-deterministic constructs resulting in non-identical run-to-run outputs.

* ``true`` : Enforces dispatching of implementations with deterministic execution.

Enforcing deterministic execution might impact the performance of Convolution, Matmul, and normalization primitives, especially on some GPU devices.