Crate rstsr_openblas 

RSTSR OpenBLAS device

This crate enables OpenBLAS device.

For more information of OpenBLAS and its usage, we refer to document of rstsr-openblas-ffi.

Usage

use rstsr_core::prelude::*;
use rstsr_openblas::DeviceOpenBLAS;

// specify the number of threads of 16
let device = DeviceOpenBLAS::new(16);
// if you want to use the default number of threads, use the following line
// let device = DeviceOpenBLAS::default();

let a = rt::linspace((0.0, 1.0, 1048576, &device)).into_shape([16, 256, 256]);
let b = rt::linspace((1.0, 2.0, 1048576, &device)).into_shape([16, 256, 256]);

// by optimized BLAS, the following operation is very fast
let c = &a % &b;

// mean of all elements is also performed in parallel
let c_mean = c.mean_all();

println!("{:?}", c_mean);
assert!((c_mean - 213.2503660477036) < 1e-6);

Important Notes

• We do not provide automatic linkage:

  • Please add -l openblas in RUSTFLAGS, or cargo:rustc-link-lib=openblas in build.rs, or something similar, to your project. We do not use external FFI crates blas or blas-sys, and do not automatically search OpenBLAS library for linking.
  • The openmp feature is a default feature (since 0.8.0), so an OpenMP runtime must also be linked: gomp on Linux (GNU toolchain), omp on macOS (LLVM), vcomp on Windows (MSVC). Please add -l gomp or -l omp in RUSTFLAGS, or cargo:rustc-link-lib=gomp or cargo:rustc-link-lib=omp in build.rs, or something similar, to your project. We do not use external FFI crate openmp-sys, and do not automatically search for OpenMP library for linking.

• Why openmp by default, and what it costs you:

  • In our testing, OpenBLAS compiled with OpenMP is generally more efficient than the pthread build, and OpenBLAS binaries built either way are common in the wild; with openmp enabled the crate handles both at runtime.

  • The feature is compatible with a pthread-built OpenBLAS: the runtime reports OPENBLAS_THREAD and the pthread API (openblas_set_num_threads) is used; the linked OpenMP runtime simply stays unused.

  • The only cost is the link requirement above. If you do not want it, disable default features and re-enable what you need:

    rstsr-openblas = { version = "0.8", default-features = false, features = ["linalg"] }

    Note that cargo feature unification is graph-global: if any other crate in your build enables rstsr-openblas default features, openmp is on for the whole build, and your opt-out alone will not remove the link requirement.

  • With openmp (and dynamic_loading) disabled, an OpenMP-built OpenBLAS makes the threading API panic with migration guidance. If you cannot link an OpenMP runtime at all, either use a pthread-built OpenBLAS, or enable dynamic_loading and resolve everything at runtime.

• Compatibility matrix (verified against OpenBLAS 0.3.34 built both ways, Linux/GNU toolchain):

OpenBLAS build	openmp feature	OpenMP runtime linked	result
OpenMP	on (default)	yes	works; threading via omp_*
OpenMP	on	no	link error (omp_* undefined; OpenBLAS’s own dependency on libgomp does not resolve them for you)
OpenMP	off	no	links; threading API panics with guidance
pthread	on (default)	yes	works; threading via openblas_*, OpenMP runtime unused
pthread	on	no	link error (omp_* undefined)
pthread	off	no	works; no OpenMP runtime needed

Modules

conversion

device

driver_impl

linalg_auto_impl

matmul

matmul_impl

prelude_dev

rayon_auto_impl

threading

openblas threading

Structs

DeviceOpenBLAS