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.. Copyright (c) 2016, Johan Mabille and Sylvain Corlay
Distributed under the terms of the BSD 3-Clause License.
The full license is in the file LICENSE, distributed with this software.
.. image:: xsimd.svg
:alt: xsimd
C++ wrappers for SIMD intrinsics.
Introduction
------------
`SIMD`_ (Single Instruction, Multiple Data) is a feature of microprocessors that has been available for many years. SIMD instructions perform a single operation
on a batch of values at once, and thus provide a way to significantly accelerate code execution. However, these instructions differ between microprocessor
vendors and compilers.
`xsimd` provides a unified means for using these features for library authors.
The core of the library consist in a parametrized vector type, :ref:`Batch Types`,
and a set of operations to perform :ref:`Arithmetic Operations`,
:ref:`Data Transfer`, and many common mathemtical functions, as for single
values.
There are several ways to use `xsimd` using those :ref:`Batch Types` and
operations:
- one can write a generic, vectorized, algorithm and compile it as part of their
application build, with the right architecture flag;
- one can write a generic, vectorized, algorithm and compile several version of
it by just changing the architecture flags, then pick the best version at
runtime;
- one can write a vectorized algorithm specialized for a given architecture and
still benefit from the high-level abstraction proposed by `xsimd`.
Of course, nothing prevents the combination of several of those approach, but
more about this in section :ref:`Writing vectorized code`.
You can find out more about this implementation of C++ wrappers for SIMD
intrinsics at the `The C++ Scientist`_. The mathematical functions are a
lightweight implementation of the algorithms also used in `boost.SIMD`_.
Compiler and Architecture Support
---------------------------------
The following SIMD instruction set extensions are supported:
+--------------+---------------------------------------------------------+
| Architecture | Instruction set extensions |
+==============+=========================================================+
| x86 | SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, FMA3, AVX2 |
+--------------+---------------------------------------------------------+
| x86 | AVX512 (gcc7 and higher) |
+--------------+---------------------------------------------------------+
| x86 AMD | same as above + FMA4 |
+--------------+---------------------------------------------------------+
| ARM | ARMv7, ARMv8 |
+--------------+---------------------------------------------------------+
| WebAssembly | WASM |
+--------------+---------------------------------------------------------+
| Risc-V | Vector ISA |
+--------------+---------------------------------------------------------+
| PowerPC | VSX |
+--------------+---------------------------------------------------------+
`xsimd` requires a C++11 compliant compiler. The following C++ compilers are supported:
+-------------------------+-------------------------------+
| Compiler | Version |
+=========================+===============================+
| Microsoft Visual Studio | MSVC 2015 update 2 and above |
+-------------------------+-------------------------------+
| g++ | 4.9 and above |
+-------------------------+-------------------------------+
| clang | 3.7 and above |
+-------------------------+-------------------------------+
Licensing
---------
We use a shared copyright model that enables all contributors to maintain the
copyright on their contributions.
This software is licensed under the BSD-3-Clause license. See the LICENSE file for details.
.. toctree::
:caption: INSTALLATION
:maxdepth: 2
installation
.. toctree::
:caption: USAGE
:maxdepth: 2
basic_usage
vectorized_code
integration
.. toctree::
:caption: API REFERENCE
:maxdepth: 1
api/instr_macros
api/batch_index
api/data_transfer
api/arithmetic_index
api/comparison_index
api/bitwise_operators_index
api/math_index
api/reducer_index
api/cast_index
api/type_traits
api/batch_manip
api/misc_index
api/aligned_allocator
api/arch
api/dispatching
.. toctree::
:caption: MIGRATION GUIDE
:maxdepth: 1
migration_guide
.. _SIMD: https://fr.wikipedia.org/wiki/Single_instruction_multiple_data
.. _The C++ Scientist: http://johanmabille.github.io/blog/archives/
.. _boost.SIMD: https://github.com/NumScale/boost.simd
|
