[Python-Dev] Microsoft Visual C++ Compiler for Python 2.7 (original) (raw)

Sturla Molden sturla.molden at gmail.com
Sat Sep 27 18:28:00 CEST 2014

Steve Dower <Steve.Dower at microsoft.com> wrote:

It'll help with the numerical stack, but only a little. The devs involved have largely figured it out already and I can't provide a good Fortran compiler or BLAS library, which is what they need.

We finally have a MinGW based toolchain that can be used. Making sure it was compatible with VC9 is actually worse than most would expect, as there are subtile incompatibilities between vanilla MinGW and VC9, beyond just linking the same C runtime DLL. But it was worked out:

https://github.com/numpy/numpy/wiki/Mingw-static-toolchain

As for BLAS, the NumPy/SciPy devs have procured a permission from Intel to use MKL in binary wheels. But still there will be official binaries linked with a free BLAS library available. Currently we use ATLAS, but the plan is to use OpenBLAS (successor to GotoBLAS2) when it matures.

OpenBLAS is currently the fastest abd most scalable BLAS library available, actually better than MKL, but it is severely underfunded. It is not a good situation for the industry that the only open BLAS library with the performance of MKL is a Chinese student project in HPC. ATLAS is unfortunately far less performant and scalable.

Apple and Cray solved the problem on their platforms by building high-performance BLAS and LAPACK libraries into their operating systems (Apple Accelerate Framework and Cray libsci). But AFAIK, Windows does not have a BLAS library from Microsoft.

Sturla Molden

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