[Numpy-discussion] Numpy wheels, openBLAS and threading

[Max Linke]

os.environ can be used to change environment variables from within
python.

https://docs.python.org/2/library/os.html#os.environ

I do not know when openBLAS is reading the environment variables though.
Changing a value while your python process is running might be to late.

Jean-Christophe Houde writes:

> Hi all,
>
> not sure if this is the best place to ask for this. If not, please advise
> on the correct place.
>
> Since the numpy wheels internally use openBLAS, operations can be
> implicitly multithreaded directly by openBLAS.
>
> This, of course, can clash with multithreading or parallel processing. The
> recommended practice in this case is to set
>
> export OPENBLAS_NUM_THREADS=1
>
> in the environment. However, I would like to be able to adjust this
> directly in my python code.
>
> Is there a way to control this directly through Python, whether through
> numpy or not?
>
> Thanks for your time!