[Numpy-discussion] OS X wheels: speed versus multiprocessing

[Matthew Brett]

Hi,

On Mon, Apr 6, 2015 at 5:13 PM, Sturla Molden <sturla.molden at gmail.com> wrote:
> On 07/04/15 01:49, Nathaniel Smith wrote:
>
>> Any opinions, objections?
>
> Accelerate does not break multiprocessing, quite the opposite. The bug
> is in multiprocessing and has been fixed in Python 3.4.
>
> My vote would nevertheless be for OpenBLAS if we can use it without
> producing test failures in NumPy and SciPy.
>
> Most of the test failures with OpenBLAS and Carl Kleffner's toolchain on
> Windows are due to differences between Microsoft and MinGW runtime
> libraries and not due to OpenBLAS itself. These test failures are not
> relevant on Mac.
>
> ATLAS can easily reduce the speed of a matrix product or a linear
> algebra call with a factor of 20 compared to Accelerate, MKL or
> OpenBLAS. It would give us bad karma.

ATLAS compiled with gcc also gives us some more license complication:

http://numpy-discussion.10968.n7.nabble.com/Copyright-status-of-NumPy-binaries-on-Windows-OS-X-tp38793p38824.html

I agree that big slowdowns would be dangerous for numpy's reputation.

Sturla - do you have a citable source for your factor of 20 figure?

Cheers,

Matthew