# OpenBLAS
[](https://travis-ci.org/xianyi/OpenBLAS)
## 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](https://sourceforge.net/projects/openblas/files/).
## 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
### Support OS:
- **GNU/Linux**
- **MingWin/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.
## Usages
Link with libopenblas.a or -lopenblas for shared library.
### Set the number of threads with environment variables.
Examples:
export OPENBLAS_NUM_THREADS=4
or
export GOTO_NUM_THREADS=4
or
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](https://github.com/xianyi/OpenBLAS/wiki/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](https://stat.ethz.ch/pipermail/r-sig-hpc/2012-April/001348.html).
* 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
1. [Check for open issues](https://github.com/xianyi/OpenBLAS/issues) or open a fresh issue to start a discussion around a feature idea or a bug.
1. Fork the [OpenBLAS](https://github.com/xianyi/OpenBLAS) repository to start making your changes.
1. Write a test which shows that the bug was fixed or that the feature works as expected.
1. Send a pull request. Make sure to add yourself to `CONTRIBUTORS.md`.
## Donation
Please read [this wiki page](https://github.com/xianyi/OpenBLAS/wiki/Donation).