[AstroPy] Proliferating py-astro-libs
perry at stsci.edu
Fri Jun 10 09:48:55 EDT 2011
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
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.
More information about the AstroPy