[Numpy-discussion] NEP-18 comment

Frederic Bastien fbastien at nvidia.com
Thu Mar 7 13:24:43 EST 2019

I see speed changes vs behavior changes as different category of changes in my mind.

I understand that now importing library can slow down NumPy for small arrays.
But I have the impression you tell this can also give behavior change.

I do not understand why this could happen. A pure numpy script, that you just import dask or other library without using them, would just cause a slowdown. Not a behavior change.

Behavior change's start to happen only when you start to use the new library.

Did I miss something?


-----Original Message-----
From: NumPy-Discussion <numpy-discussion-bounces+fbastien=nvidia.com at python.org> On Behalf Of Stefan van der Walt
Sent: Thursday, March 7, 2019 12:15 PM
To: Discussion of Numerical Python <numpy-discussion at python.org>
Cc: Matthew Rocklin <mrocklin at gmail.com>
Subject: Re: [Numpy-discussion] NEP-18 comment

Hi Sebastian, Frederic,

On Thu, 07 Mar 2019 14:23:10 +0000, Frederic Bastien wrote:
> I like your idea Sebastian. This way it is enabled only when needed and it is invisible to the user at the same time.
> Stefan, does it solve well enough the potential problem you raised?

I don't think so.  This means that NumPy suddenly behaves differently when dask is imported, which again causes the problem mentioned earlier:
that identical NumPy code could behave differently depending on library versions, imports, and the environment.

That said, I think this is a better solution than an environment variable.

Anyway, my opinion is just one of many: I'd like to hear what the other developers think.

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