[SciPy-dev] [Numpy-discussion] Thoughts on making it easier for numarray users to transition to scipy_core

Peter Verveer verveer at embl-heidelberg.de
Wed Dec 14 01:29:04 EST 2005

On 13 Dec, 2005, at 23:39, Travis Oliphant wrote:

>> However, even though I am the author, I am  most likely not going  
>> to support it outside numarray. I do realize  that at some point  
>> numarray may be retired, but I  have not decided  yet if I will be  
>> using/supporting nd_image beyond that point. It  would be nice to  
>> have a common code-base with the numarray version so  that all can  
>> profit from any bug-fixes that I am still doing in the  numarray  
>> version.
> So, do I take this to mean that you are not enthusiastic about a  
> merger between the Numeric and numarray communities?  I would love  
> to hear why you feel this way.
> From my perspective, it just makes unification that much harder to  
> have important third-party authors make these kinds of statements,  
> so I'm curious as to why you don't want to convert to a common code- 
> base.  Because others may have the same feelings, it would help all  
> of us if we could address them.   Don't worry about offending me or  
> others in the scipy world.  We have pretty thick skins by this point.

I think I should clarify what I intent to do with nd_image in the  
future. It affects current nd_image users and the numarray package  
also, so I am also sending this to the numpy list.

First of all, I should stress that I am quite  happy about a possible  
merger. It is quite likely that I will be using python for numerical  
work in the future, and a merger of numarray and Numeric into a  
package of equal or better quality will only make my life easier.

Currently I am the only software developer within a scientific  
laboratory, but software development is not my main focus. I used  
python with numarray for virtual all of my numerical work, and  
nd_image was sort of a side effect of that. Right now I do not have  
the time to make a switch to a new package, nor can I really further  
expand nd_image. It would be nice to try moving to scipy_core now,  
which would help the community too I guess, but I just cannot affort  
it at the moment, so I am sticking with numarray for the time being.

My situation will most likely change next year, since our group will  
move and expand a lot, and I will hopefully be able to have other  
people working on software development. I guess around that time we  
will see scipy_core mature, so that would be a good time to switch. I  
understand the numarray people take a wait-and-see approach, but  
intent to switch when scipy_core matures and fulfills their  
requirements. I guess I am following their example.

So next year I will might be in the position of having more resources  
and I then will start thinking about developing some open-source  
scientific software. An imaging package like nd_image would be one of  
them. However, in contrast to the current design, I would like to  
move to a package that is fully written in C, with a thin interface  
layer to numarray/scipy_core for use with python. That would allow   
me to use the routines in other environments than python,.

Sofar I have been very comfortable to make my package available under  
the license that is used by numarray. The same would be true for a  
scipy_core/scipy version. However, for a general C package that could  
have a much broader audience in the same way, I feel different. I  
would most likely release such a package using the GPL. In addition,  
that would allow me to  use other GPL licensed software such as GSL  
with it. However, that would mean that a python package based on it  
would also be released with that license. I am not complete sure what  
the implications for distribution with a package like scipy would be,  
this may not be possible. But it would be freely available as a  
separate module which we would maintain ourself.

If it pans out this way, it means that nd_image will not be further  
developed at some point. I am currently doing bug-fixes in the  
numarray version, and I certainly would not  mind if there would be a  
common code-base allowing it to work with scipy_core. But if I am  
going to developer package as described above, I will to focus on  
that and recommend nd_image users to switch at some point.

> Even if your statement is made from the perspective of someone who  
> is moving away from Python altogether, I would still very-much  
> appreciate hearing your reasons.  Now, perhaps, your  just going to  
> experience a career-change altogether in which case, best wishes,  
> and thanks for all you've contributed.

I will certainly stick with Python :-)

> Regardless of whether or not you have time to respond, I do  
> appreciate all your efforts.  The nd_image package is very nice as  
> I've told you before.   Thank you!

Thanks! nd_image seems to find some users, and I would like to  
continue to provide something like nd_image. It might be a while  
though until nd_image or a replacement will start moving again and  
further developing. Meanwhile I am committed to keep nd_image working  
with numarray and doing minor bug-fixes. If we can at some point find  
a solution for a single code-base which would work with scipy_core, I  
am  happy to expand this commitment to scipy_core. I cannot promise  
indefinite support, but  as long as I am in the field and as long as  
I do not release a 'successor' package, I will try...

Cheers, Peter

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