[AstroPy] Proliferating py-astro-libs

James Turner jturner at gemini.edu
Mon Jun 13 13:43:53 EDT 2011

Maybe we should hold an AstroPy conference, where we can discuss
co-ordination, get to know each other better and even sit down and
work on libraries together (like at SciPy). That might help generate
a bit of momentum. Some of us have had meetings before that were
full of ideas that didn't go anywhere, but I don't think it has to
be that way if active people on the ground are talking to one another
rather than having institutions present their plans and try to
negotiate at a high level.

On 13/06/11 13:25, James Turner wrote:
> It seems that several of us would really like to improve
> collaboration on Python libraries but have been struggling to pull
> it off. I've raised the same issue on this list in past months, but my
> focus has unavoidably been on other things and since I'm wary of
> shouting a lot without contributing much, I haven't really been able
> to keep the discussion alive...
> I tend to agree with Mark and Stefan about the question of leadership.
> Perry & co. at Space Telescope deserve recognition for getting us this
> far with things like PyFITS and PyRAF. Others have taken the initiative
> with things like astronomical plotting and documentation sprints. We're
> still lacking a bit of coherence though, which (as Mark suggests) is
> likely to involve one or a few dedicated, energetic, knowledgeable,
> hands-on developer(s) who can glue things together. Those people need
> to be employed by someone, though, to ensure stability & continuity
> (fortunately there's already a bit of that going on at STScI, eg. with
> Mike and Matplotlib). Personally, I have the motivation but have not
> had the time/independence (and might not be assertive enough).
> Apparently we do have several energetic authors in the community now
> (like Thomas & Eli), but each with their own project.
> A couple of years ago, a number of us at the observatories submitted a
> white paper to the Decadal Survey, pointing out the need for more
> co-ordinated funding so that we can have people who focus on cross-
> institutional platform development & support. The report from the
> committee did give a nod to our concerns and their importance, but
> stopped short of making any recommendation, which basically means "good
> luck with that". Meanwhile, at Gemini we have had our own problems to
> deal with, which make it very difficult for me to propose something
> internally beyond working with STScI on the distribution of
> dependencies that Perry mentioned. Perhaps someone obtaining a grant
> for this is not out of the question though.
> I would like it if we could get together organically behind Astrolib,
> but sometimes it's difficult to get people away from their immediate
> priorities to focus on that, even within my own institution. If we
> could get people dedicated to it, though, it could become indispensable
> enough to attract and co-ordinate more effort. I'm just not sure how we
> get started at this point and my personal options for tackling the
> problem seem limited given the overarching funding transition at Gemini
> and the intense focus on projects that are needed to make that work...
> Cheers,
> James.
> On 10/06/11 09:48, Perry Greenfield wrote:
>> On Jun 9, 2011, at 11:12 PM, Thomas Robitaille wrote:
>>> I just wanted to also add that (in agreement with Marshall) I'm all
>>> in favor of many small modules that accomplish a particular task
>>> well, rather than packages that aim for a 'do-it-all' approach and
>>> fall short. It's always possible to bundle small packages together
>>> afterwards, and I don't mean merge development, but instead just
>>> bundling the packages for installation (kind of like EPD). I think
>>> that is the easiest approach for all of us.
>>> Maybe in the long run, a specific set of core packages will emerge
>>> as essential and we can then talk about truly merging them into a
>>> scipy-like package, but for now, I think the race is still on. And
>>> after all, there's nothing to say we *have* to achieve the same
>>> setup as in IDL.
>> It sure seems to me that the time is ripe to start trying to coalesce
>> some of the ongoing efforts.
>> Mind you, I don't think it is necessarily good to start with only one
>> version. Allowing a few different approaches initially has its
>> benefits. You get to see more approaches and ideas in play and having
>> experience with them is very helpful in deciding which one is more
>> productive. And sometimes there is room for more than one in the long
>> run. The different approaches may have their own niches. But it is
>> hard to imagine any long-term need for more than two or three
>> different approaches.
>> Early on there are some pragmatic needs for different approaches. For
>> example, having a fairly "literal" translation of IDL tools into
>> Python has its benefit. It is very useful for those that would like to
>> migrate IDL code, and given the existing IDL versions, make it much
>> easier to test their correctness. But I don't see this as a substitute
>> for a good set of modular tools that have a better object design and
>> consistent interfaces with other modules. Doing this is more work and
>> will take more time. So a need for both approaches is likely. Some
>> could argue the same for replacing IRAF tasks.
>> All this is much easier said than done of course.
>> I wish STScI had more resources to devote to this than we've actually
>> had. We've been planning to do more on this front than we've actually
>> done. Things come up repeatedly that ruin these plans. But it may be
>> worth saying where some of our current efforts are going that may
>> overlap some of these other efforts.
>> 1) We've been planning (along with Gemini, and particularly James
>> Turner), to try to develop some Sage-like installation package that
>> would make it easy to install all the basic tools for most
>> astronomers. We had hoped to have a beta version out, but one of the
>> people working on this left at the end of last year, and we've not
>> been able to replace that person. We are going to continue this effort
>> with existing staff though. Hopefully in a few months we'll have
>> something to try out.
>> 2) There is a recognition that a more serious effort needs to be made
>> to replace IRAF functionality. Perhaps one of the benefits of a JWST
>> delay is that it will allow us to do some of that work more
>> explicitly. But we would not do it by replacing IRAF tasks one-for-one
>> but coming up with an entirely different approach which has to start
>> from the bottom up (the end result could have applications that mostly
>> emulate IRAF tasks, but also provide much more modular tools).
>> 3) More specifically, we are currently focussing on how to handle WCS
>> issues in a more general way than they are handled in FITS. If there
>> is interest, perhaps we should say more about the intended approach.
>> This is particularly important for replacing spectrographic tools in
>> IRAF, and this is where we are starting our effort.
>> 4) We need a way of saving these WCS models, and FITS is not the way.
>> We are looking at an alternate data format, not just for WCS models,
>> but for data in general [gasp!]. Work has begun on this too.
>> 5) A lot of our recent work has been on pysynphot and ETCs. We plan on
>> making the computational part of our ETCs a released tool. But I'm
>> also wondering if we can generalize the pysynphot spectral models for
>> more general use in spectral tools.
>> 6) We have been working on a framework for making pipelines easier to
>> build and configure. That won't be ready for at least a few months,
>> but could well be of general interest and use.
>> But besides these things, I would like to see if we can't begin the
>> effort of narrowing some of the underlying libraries being used. FITS
>> WCS is one obvious area that seems ripe for that.
>> But the community ought to identify one or two areas that are of the
>> most interest in consolidating (let's start small). What should we
>> start with? Focus is important in making any progress in this area.
>> Perry
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James E.H. Turner
Gemini Observatory Southern Operations Centre,
Casilla 603,		Tel. (+56) 51 205609
La Serena, Chile.	Fax. (+56) 51 205650

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