The package provides a source of BLAS and LAPACK via OpenBLAS.
The following Cargo features are supported:
cacheto build in a shared directory instead oftarget(see below),cblasto build CBLAS (enabled by default),lapacketo build LAPACKE (enabled by default),staticto link to OpenBLAS statically,systemto skip building the bundled OpenBLAS.
Note: On Windows, OpenBLAS can not be built from source. The system feature is
supposed to be used.
If you want to build OpenBLAS from source, you need to have the following dependencies installed:
- HOSTCC compiler (e.g.,
gcc,clang, oricc), make,- CC compiler of the target architecture (e.g.,
aarch64-linux-gnu-gccforaarch64), - Fortran compiler of the target architecture(e.g.,
gfortran,flang, orifort), if there is no Fortran compiler detected, the flagNOFORTRANshould be set to1andOpenBLASwill only compile BLAS and f2c-converted LAPACK. For more information, please refer to the Use f2c translations of LAPACK when no Fortran compiler is available.
The cache feature allows the OpenBLAS build products to be reused between
crates that have different target directories. This avoids rebuilding OpenBLAS
unnecessarily. However, this also prevents cargo clean from working properly,
since the aforementioned build products will not be removed by the command.
The OpenBLAS binary will be placed at ${XDG_DATA_HOME}/openblas_build/[hash of build configure object]. For example, build with LAPACK and build without
LAPACK will be placed on different directories. If you build OpenBLAS as a
shared library, you need to add the above directory to LD_LIBRARY_PATH (for
Linux) or DYLD_LIBRARY_PATH (for macOS). Since build from source is not
supported on Windows (see next section), this feature is also not supported.
On Windows, openblas-src relies on vcpkg to find OpenBLAS. Before building,
you must have the correct OpenBLAS installed for your target triplet and kind of
linking. For instance, to link dynamically for the x86_64-pc-windows-msvc
toolchain, install openblas for the x64-windows triplet:
vcpkg install openblas --triplet x64-windowsTo link OpenBLAS statically, install openblas for the x64-windows-static-md triplet:
vcpkg install openblas --triplet x64-windows-static-mdTo link OpenBLAS and C Runtime (CRT) statically, install openblas for the
x64-windows-static triplet:
vcpkg install openblas --triplet x64-windows-staticand build with +crt-static option
RUSTFLAGS='-C target-feature=+crt-static' cargo build --target x86_64-pc-windows-msvcPlease see the "Static and dynamic C runtimes" in The Rust reference for detail.
The openblas-src crate will detect and use proxy settings from your environment
variables, such as http_proxy and https_proxy to download necessary dependencies.
According to the OpenbLAS build system, the variables used by OpenBLAS could be
passed through environment, such as DYNAMIC_LIST, NUM_THREADS.
HOWEVER, for some of the variables, the openblas-src crate rename them to
others to avoid conflicts with the existing envs. The following is the list of
the variables that are renamed:
| OpenBLAS variable | openblas-src variable |
|---|---|
| TARGET | OPENBLAS_TARGET |
| CC | OPENBLAS_CC |
| FC | OPENBLAS_FC |
| HOSTCC | OPENBLAS_HOSTCC |
| RANLIB | OPENBLAS_RANLIB |
Apart from providing the --target option to cargo build, one also has to
specify the cross-compilation variables of OpenBLAS.
They can be set as environment variables for cargo build using the OPENBLAS_
prefix as follows: OPENBLAS_CC, OPENBLAS_FC, OPENBLAS_HOSTCC, and
OPENBLAS_TARGET.
If you do not set these variables, the openblas-build will try to detect them.
For OPENBLAS_TARGET, the basic target that corresponds to the arch of --target
will be used.
| Rust target | OpenBLAS target |
|---|---|
| aarch64 | ARMV8 |
| arm | ARMV6 |
| armv5te | ARMV5 |
| armv6 | ARMV6 |
| armv7 | ARMV7 |
| loongarch64 | LOONGSONGENERIC |
| mips64 | MIPS64_GENERIC |
| mips64el | MIPS64_GENERIC |
| riscv64 | RISCV64_GENERIC |
| csky | CK860FV |
| sparc | SPARCV7 |
For OPENBLAS_CC and OPENBLAS_HOSTCC, the cc crate will be used to detect
the compiler. Please refer to the cc documentation
for more information.
For OPENBLAS_FC, openblas-build will try to detect the compiler through the
OPENBLAS_CC set above. It will replace the gcc with gfortran, clang with
flang, and icc with ifort and then test if the Fortran compiler exists.
Note: If there is no Fortran compiler detected, the build flag NOFORTRAN will
be set to 1 and OpenBLAS will only compile BLAS and f2c-converted LAPACK.
For more information, please refer to the
Use f2c translations of LAPACK when no Fortran compiler is available.
Your contribution is highly appreciated. Do not hesitate to open an issue or a pull request. Note that any contribution submitted for inclusion in the project will be licensed according to the terms given in LICENSE.md.