OpenBLAS

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Introduction

OpenBLAS is an optimized BLAS library based on GotoBLAS2 1.13 BSD version.

Please read the documents on OpenBLAS wiki pages http://github.com/xianyi/OpenBLAS/wiki.

Binary Packages

We provide binary packages for the following platform.

Windows x86/x86_64

You can download them from file hosting on sourceforge.net.

Installation from Source

Download from project homepage. http://xianyi.github.com/OpenBLAS/

Or, check out codes from git://github.com/xianyi/OpenBLAS.git

Normal compile

type "make" to detect the CPU automatically. or
type "make TARGET=xxx" to set target CPU, e.g. "make TARGET=NEHALEM". The full target list is in file TargetList.txt.

Cross compile

Please set CC and FC with the cross toolchains. Then, set HOSTCC with your host C compiler. At last, set TARGET explicitly.

Examples:

On X86 box, compile this library for loongson3a CPU.

make BINARY=64 CC=mips64el-unknown-linux-gnu-gcc FC=mips64el-unknown-linux-gnu-gfortran HOSTCC=gcc TARGET=LOONGSON3A

On X86 box, compile this library for loongson3a CPU with loongcc (based on Open64) compiler.

make CC=loongcc FC=loongf95 HOSTCC=gcc TARGET=LOONGSON3A CROSS=1 CROSS_SUFFIX=mips64el-st-linux-gnu-   NO_LAPACKE=1 NO_SHARED=1 BINARY=32

Debug version

make DEBUG=1

Install to the directory (optional)

Example:

make install PREFIX=your_installation_directory

The default directory is /opt/OpenBLAS

Support CPU & OS

Please read GotoBLAS_01Readme.txt

Additional support CPU:

x86/x86-64:

Intel Xeon 56xx (Westmere): Used GotoBLAS2 Nehalem codes.
Intel Sandy Bridge: Optimized Level-3 and Level-2 BLAS with AVX on x86-64.
Intel Haswell: Optimized Level-3 and Level-2 BLAS with AVX2 and FMA on x86-64.
AMD Bobcat: Used GotoBLAS2 Barcelona codes.
AMD Bulldozer: x86-64 ?GEMM FMA4 kernels. (Thank Werner Saar)
AMD PILEDRIVER: Uses Bulldozer codes with some optimizations.
AMD STEAMROLLER: Uses Bulldozer codes with some optimizations.

MIPS64:

ICT Loongson 3A: Optimized Level-3 BLAS and the part of Level-1,2.
ICT Loongson 3B: Experimental

ARM:

ARMV6: Optimized BLAS for vfpv2 and vfpv3-d16 ( e.g. BCM2835, Cortex M0+ )
ARMV7: Optimized BLAS for vfpv3-d32 ( e.g. Cortex A8, A9 and A15 )

ARM64:

ARMV8: Experimental
ARM Cortex-A57: Experimental

Support OS:

GNU/Linux
MingWin or Visual Studio(CMake)/Windows: Please read https://github.com/xianyi/OpenBLAS/wiki/How-to-use-OpenBLAS-in-Microsoft-Visual-Studio.
Darwin/Mac OS X: Experimental. Although GotoBLAS2 supports Darwin, we are the beginner on Mac OS X.
FreeBSD: Supported by community. We didn't test the library on this OS.
Android: Supported by community. Please read https://github.com/xianyi/OpenBLAS/wiki/How-to-build-OpenBLAS-for-Android.

Usages

Link with libopenblas.a or -lopenblas for shared library.

Set the number of threads with environment variables.

Examples:

export OPENBLAS_NUM_THREADS=4

export GOTO_NUM_THREADS=4

export OMP_NUM_THREADS=4

The priorities are OPENBLAS_NUM_THREADS > GOTO_NUM_THREADS > OMP_NUM_THREADS.

If you compile this lib with USE_OPENMP=1, you should set OMP_NUM_THREADS environment variable. OpenBLAS ignores OPENBLAS_NUM_THREADS and GOTO_NUM_THREADS with USE_OPENMP=1.

Set the number of threads on runtime.

We provided the below functions to control the number of threads on runtime.

void goto_set_num_threads(int num_threads);

void openblas_set_num_threads(int num_threads);

If you compile this lib with USE_OPENMP=1, you should use the above functions, too.

Report Bugs

Please add a issue in https://github.com/xianyi/OpenBLAS/issues

Contact

OpenBLAS users mailing list: https://groups.google.com/forum/#!forum/openblas-users
OpenBLAS developers mailing list: https://groups.google.com/forum/#!forum/openblas-dev

ChangeLog

Please see Changelog.txt to obtain the differences between GotoBLAS2 1.13 BSD version.

Troubleshooting

Please read Faq at first.
Please use gcc version 4.6 and above to compile Sandy Bridge AVX kernels on Linux/MingW/BSD.
Please use Clang version 3.1 and above to compile the library on Sandy Bridge microarchitecture. The Clang 3.0 will generate the wrong AVX binary code.
The number of CPUs/Cores should less than or equal to 256. On Linux x86_64(amd64), there is experimental support for up to 1024 CPUs/Cores and 128 numa nodes if you build the library with BIGNUMA=1.
OpenBLAS does not set processor affinity by default. On Linux, you can enable processor affinity by commenting the line NO_AFFINITY=1 in Makefile.rule. But this may cause the conflict with R parallel.
On Loongson 3A. make test would be failed because of pthread_create error. The error code is EAGAIN. However, it will be OK when you run the same testcase on shell.

Contributing

Check for open issues or open a fresh issue to start a discussion around a feature idea or a bug.
Fork the OpenBLAS repository to start making your changes.
Write a test which shows that the bug was fixed or that the feature works as expected.
Send a pull request. Make sure to add yourself to CONTRIBUTORS.md.

Donation

Please read this wiki page.

dpfoose/OpenBLAS