.. index:: pair: page; Binary Fusion Patterns
.. _doxid-dev_guide_graph_binary_fusion_patterns:

Binary Fusion Patterns
======================

Overview
~~~~~~~~

The Binary category includes operations such as: Add, Subtract, Maximum, Minimum, Multiply, Divide.

oneDNN supports various binary fusion patterns to optimize performance and reduce memory bandwidth requirements. This document describes the supported fusion patterns for Binary operations.

Pattern Structure
~~~~~~~~~~~~~~~~~

oneDNN defines floating-point Binary fusion patterns as follows. The blue nodes are required when defining a Binary fusion pattern while the brown nodes are optional.

.. image:: binary_pattern.png
	:alt: Binary pattern



#. Binary Operation : Performs the corresponding binary operation between the ``src_0`` and ``src_1`` tensors. Refer to the Note in `Fusion Patterns <graph_fusion_patterns.html>`__.

#. Epilogue Subgraph : Optional and can include the following operations:
   
   * Binary Operations.
   
   * Unary Operations : Refer to the Note in `Fusion Patterns <graph_fusion_patterns.html>`__.
   
   Combination Rules:
   
   .. image:: epilogue_subgraph_general_1.png
   	:alt: epilogue subgraph
   
   
   
   * N=20, 0 to 20 Binary or Unary operations are supported in the epilogue subgraph.

Data Types
~~~~~~~~~~

oneDNN supports the following combinations of data types for src0, src1 and dst:

=============  =============  =============  
src_0          src_1          dst            
=============  =============  =============  
f32,bf16,f16   f32,bf16,f16   f32,bf16,f16   
=============  =============  =============

The definition of the data types and support status on different CPU and GPU platforms follow the general description in the :ref:`Data Types Guide <doxid-dev_guide_data_types>`.

Implementation Notes
~~~~~~~~~~~~~~~~~~~~

Post-binary Add operations in the epilogue subgraph support in-place operations when the post-binary Add is the last operation in the epilogue subgraph and the ``dst`` output shape is identical and data type size is the same as the binary Add input. In case of an in-place operation, the original input data will be overwritten. Use in-place operations whenever possible for performance.