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OpenACC (for Open Accelerators) is a programming standard for parallel computing developed by Cray, CAPS, Nvidia and PGI. The standard is designed to simplify parallel programming of heterogeneous CPU/GPU systems.〔(【引用サイトリンク】title=Nvidia, Cray, PGI, and CAPS launch ‘OpenACC’ programming standard for parallel computing )〕 Like in OpenMP, the programmer can annotate C, C++ and Fortran source code to identify the areas that should be accelerated using compiler directives and additional functions.〔(【引用サイトリンク】title=OpenACC standard version 2.0 )〕 Like OpenMP 4.0 and newer, code can be started on both the CPU and GPU. OpenACC members have worked as members of the OpenMP standard group to merge into OpenMP specification to create a common specification which extends OpenMP to support accelerators in a future release of OpenMP.〔(【引用サイトリンク】title=How does the OpenACC API relate to the OpenMP API? )〕〔(【引用サイトリンク】title=How did the OpenACC specifications originate? )〕 These efforts resulted in a technical report for comment and discussion timed to include the annual Supercomputing Conference (November 2012, Salt Lake City) and to address non-Nvidia accelerator support with input from hardware vendors who participate in OpenMP. At ISC’12 OpenACC was demonstrated to work on Nvidia, AMD and Intel accelerators, without performance data. In November 12, 2012, at the SC12 conference, a draft of the OpenACC version 2.0 specification was presented. New suggested capabilities include new controls over data movement (such as better handling of unstructured data and improvements in support for non-contiguous memory), and support for explicit function calls and separate compilation (allowing the creation and reuse of libraries of accelerated code). == Compiler support == Support of OpenACC is available in commercial compilers from PGI (from version 12.6), Cray, and CAPS.〔 OpenUH〔(【引用サイトリンク】title=OpenUH Compiler )}〕 is an Open64 based open source OpenACC compiler supporting C and FORTRAN, developed by HPCTools group from University of Houston. The OpenARC compiler〔(【引用サイトリンク】title=OpenARC Compiler )〕 is an open source, C language compiler developed over the past several years at Oak Ridge National Laboratory to fully support all features in the OpenACC 1.0 specification. An experimental open source compiler, accULL, is developed by the University of La Laguna (C language only).〔(【引用サイトリンク】title=accULL The OpenACC research implementation )〕 GCC support for OpenACC was slow in coming. A GPU-targeting implementation from Samsung was announced in September 2013; this translated OpenACC 1.1-annotated code to OpenCL. The announcement of a "real" implementation followed two months later, this time from NVIDIA and based on OpenACC 2.0. This sparked some controversy, as the implementation would only target NVIDIA's own PTX assembly language, for which no open source assembler or runtime was available. Experimental support for OpenACC/PTX did end up in GCC as of version 5.1.〔https://gcc.gnu.org/wiki/OpenACC〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「OpenACC」の詳細全文を読む スポンサード リンク
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