[pypy-dev] Questions on the pypy+numpy project

Christopher Felton chris.felton at gmail.com
Wed Oct 19 15:49:57 CEST 2011

On 10/19/2011 8:32 AM, Wes McKinney wrote:
> On Wed, Oct 19, 2011 at 6:35 AM, Gary Robinson<garyrob at me.com>  wrote:
>>> Jacob Hall?n, 18.10.2011 18:41:
>>>> I'd just like to note that the compelling reason for PyPy to develop numpy
>>>> support is popular demand. We did a survey last spring, in which an
>>>> overwhelming number of people asked for numpy support. This indicates that
>>>> there is a large group of people who will be reap benefits from using PyPy
>>>> plus Numpy, without specific support for scipy packages.
>>> Depends on what the question was. Many people say "NumPy", and when you ask
>>> back, you find out that they actually meant "SciPy" or at least "NumPy and
>>> parts x, y and z of its ecosystem that I commonly use…
>> I was one of the people who responded to that poll, and I have to say that I fall into the category "they actually meant 'SciPy'…".  I assumed that there would be an interface to numpy that would also support scipy. SciPy has a lot of packages that run various things like SVD very, efficiently because it does them in C. I need access to those packages. I also write my own algorithms. For those, I want to benefit from PyPy's speed and don't necessarily want to make the algorithms fit into numpy's array-processing approach.
> I suspect most of the poll respondents see NumPy as representing a lot
> more than just a fast ndarray-- i.e. that being able to type
> import numpy

Or a misunderstanding how much the other packages rely on low-level 
functions.  There might have been a perception that for a good chunk of 
the supporting libraries required only the numpy API (Python side API).

My guess, there has to be some packages that only require numpy on the 
Python side and none of the foreign interfaces.  I am surprised that MPL 
is mentioned requiring the low-level interfaces and not simply the num 
arrays API.

If the pypy team is successful with numpypy, I would guess some packages 
would work (naive guess?) with minimal modification?

My preference would be to have full support (numpy/scipy/matplotlib) but 
because of the success of pypy on MyHDL I would be happy (extremely 
happy) with fast running numpy without scipy.


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