On Wed, Jul 7, 2021 at 9:56 PM Jerry Morrison < jerry.morrison+nu...@gmail.com> wrote:
> Would someone please answer installation questions about NumPy's BLAS on > macOS? I'm not finding the answers in the release notes > <https://github.com/numpy/numpy/releases>, the PR > <https://github.com/numpy/numpy/pull/18874> source, the docs > <https://numpy.org/doc/1.21/>, or Stack Overflow > <https://stackoverflow.com/search?tab=newest&q=%5bnumpy%5d%20openblas>. > > > Q1. The NumPy 1.21.0 release note > <https://github.com/numpy/numpy/releases/tag/v1.21.0> says "This change > enables the Accelerate Framework as an option on macOS." How to set > that option on/off? > It's autodetected at build time. If you have no other BLAS installed, it will be used. Or explicitly select it with NPY_BLAS_ORDER/NPY_LAPACK_ORDER > Q2. How to determine if NumPy uses Accelerate vs. its internal copy of > OpenBLAS? > After installing a wheel, `numpy.show_config()` shows the openblas_info > library_dirs et al as '/usr/local/lib'. Neither '/usr/local/lib/' nor > 'site-packages/numpy/' contains a *blas*.so library (for Python 3.8.* on > macOS 10.14.6) but the doc <https://numpy.org/install/> says "The > OpenBLAS libraries are included in the wheel." > It's a build-time option, you cannot select it at runtime. > Q3. How to pip install NumPy 1.21.0 in a way that ensures it uses its > embedded OpenBLAS on macOS as on Linux? I'm aiming for as portable results > as possible. Or should we link NumPy to an external OpenBLAS via `pip > install numpy --no-binary numpy==1.21.0` with `~/.numpy-site.cfg`? (Ditto > for SciPy.) > If you install a wheel, you will always get the bundled OpenBLAS on every platform for which we have binary wheels. > > Q4. Can the new NPY_* environment variables select specific BLAS & LAPACK > libraries through pip install, and perhaps install faster than building > NumPy, SciPy, etc. from source? How to do that? > This question seems a little bit confused. Those env vars just select the BLAS/LAPACK library. It will not affect build time - we're never building BLAS or LAPACK itself from source. > Q5. Is NumPy's embedded OpenBLAS compiled by gcc or clang? Is that > controllable via `pip install`? > gcc/gfortran. and no, you cannot control it through pip Cheers, Ralf > Thank you! > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@python.org > https://mail.python.org/mailman/listinfo/numpy-discussion >
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