On May 19, 2012, at 10:00 AM, David Cournapeau wrote:

> 
> 
> On Sat, May 19, 2012 at 3:17 PM, Charles R Harris <charlesr.har...@gmail.com> 
> wrote:
> 
> 
> On Fri, May 18, 2012 at 3:47 PM, Travis Oliphant <tra...@continuum.io> wrote:
> Hey all,
> 
> After reading all the discussion around masked arrays and getting input from 
> as many people as possible, it is clear that there is still disagreement 
> about what to do, but there have been some fruitful discussions that ensued.
> 
> This isn't really new as there was significant disagreement about what to do 
> when the masked array code was initially checked in to master.   So, in order 
> to move forward, Mark and I are going to work together with whomever else is 
> willing to help with an effort that is in the spirit of my third proposal but 
> has a few adjustments.
> 
> The idea will be fleshed out in more detail as it progresses, but the basic 
> concept is to create an (experimental) ndmasked object in NumPy 1.7 and leave 
> the actual ndarray object unchanged.   While the details need to be worked 
> out here,  a goal is to have the C-API work with both ndmasked arrays and 
> arrayobjects (possibly by defining a base-class C-level structure that both 
> ndarrays inherit from).     This might also be a good way for Dag to 
> experiment with his ideas as well but that is not an explicit goal.
> 
> One way this could work, for example is to have PyArrayObject * be the 
> base-class array (essentially the same C-structure we have now with a HASMASK 
> flag). Then, the ndmasked object could inherit from PyArrayObject * as well 
> but add more members to the C-structure.     I think this is the easiest 
> thing to do and requires the least amount of code-change.      It is also 
> possible to define an abstract base-class PyArrayObject * that both ndarray 
> and ndmasked inherit from.     That way ndarray and ndmasked are siblings 
> even though the ndarray would essentially *be* the PyArrayObject * --- just 
> with a different type-hierarchy on the python side.
> 
> This work will take some time and, therefore, I don't expect 1.7 to be 
> released prior to SciPy Austin with an end of June target date.   The timing 
> will largely depend on what time is available from people interested in 
> resolving the situation.   Mark and I will have some availability for this 
> work in June but not a great deal (about 2 man-weeks total between us).    If 
> there are others who can step in and help, it will help accelerate the 
> process.
> 
> 
> This will be a difficult thing for others to help with since the concept is 
> vague, the design decisions seem to be in your and Mark's hands, and you say 
> you don't have much time. It looks to me like 1.7 will keep slipping and I 
> don't think that is a good thing. Why not go for option 2, which will get 1.7 
> out there and push the new masked array work in to 1.8? Breaking the flow of 
> development and release has consequences, few of them good.
> 
> Agreed. 1.6.0 was released one year ago already, let's focus on polishing 
> what's in there *now*. I have not followed closely what the decision was for 
> a LTS release, but if 1.7 is supposed to be it, that's another argument about 
> changing anything there for 1.7.

This won't work, because what is in there *now* really shouldn't be there.   
The only way this would work is if we remove the masked array from the ndarray 
object.     I think I saw that Nathaniel has a patch for this, but I have not 
had time to review this patch.  

There has been no agreement on an LTS release.   The best candidate for that is 
1.6.2, but I don't think it makes sense to talk about an LTS release until the 
masked array questions are resolved from what is there in master right now. 

-Travis



> 
> David
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