Month: July 2014

Nearing the Close

Hello folks.

While admittedly there has not been too much happening on the online front, a lot has been happening on the offline front around here!

There has been talk of introducing some more FrameAttributes to support the HeliographicStonyhurst to Heliocentric and vice-versa transformations. The previous part with the introduction of the new get_hpc_distance() method paid off handsomely – my mentor’s calculations got the HGS to HP transform to work properly. The next step is to fix some buggies and introduce the new FrameAttributes.

I have been learning Flask from Miguel Grinberg’s Mega Tutorial on the advice of my mentor and it has been a very satisfying journey so far. I have created a repo on GitHub to learn while committing. Flask is a microframework for Python based on Werkzeug and Jinja2. It is less complex in comparison with Django, and learning it really is fun. There are also Flask extensions to help one with the job of interfacing with other apps such as SQLAlchemy.

I have appeared for a couple of job interviews for some good startups in these two weeks. The GSoC project definitely has helped me gain some traction. It gets me noticed where I would earlier not have had a chance.

That’s all for now! My apologies if this post is too small, peeps.

Break – Fix – Repeat!

Cadair commented 9 hours ago

@VaticanCameos I broke it

This quote seems to sum up all that we’ve done in the past few weeks. So far, the Coordinates Framework PR has 80 commits. We are to have a meeting on Tuesday to gauge progress and set the path for the rest of the month.

It has been quite an experience. Having complete ownership of a module isn’t easy. One has to think of design and implementation, testing and experimentation, etc. all in quick succession.  On top of that, the repository does not stay the same all the time – one is always on the bleeding-edge of things. Having said that, my mentor has been really supportive. I have migrated to a new laptop, and on his insistence, tried to install ArchLinux but failed due to some problems with the Radeon graphics card. Nevertheless, I am on Linux Mint for the time being!

A summary of things -:

  1. Some coordinate frames have undergone several changes – Heliographic and Helioprojective, more precisely. Helioprojective ‘Cartesian’ is in fact a spherical representation masquerading as Cartesian, so it was decided that it would be better to change the representation to spherical, but keep the attribute names as Tx and Ty.
  2. Astropy have introduced the RepresentationMapping class, which is a useful encapsulation of the mapping of frame representation attributes to the names that the designer wishes to specify, as well as their units. RM objects take a 3-tuple, thus.
  3. Helioprojective frames now have a new property – ‘zeta’ – which was earlier being mapped to the distance attribute. On reviewing the code, we found that distance should actually be ‘d’ (which was a FrameAttribute then) and it is better to have zeta as a property which returns the value of ‘D0 – d’. ‘zeta’ can be used in the constructor to generate a value for ‘d’. This ultimately fixed most of the transformation issues we had from Helioprojective to other class, except for a few corner cases which we are now working on.
  4. A lot has been learned about how to default attributes in the frame constructor. Careful consideration of the various input cases was necessary. Heliographic frames now default ‘rad’ and a FrameAttribute called ‘dateobs’. The empty frame case was the biggest thorn – breaking a lot of things. Since Astropy’s code purposefully generates an empty frame of the same class to check certain things, it was necessary to keep empty frame design clear in mind. Helioprojective frames can default ‘D0’ and ‘d’.
  5. SphericalRepresentation was subclassed to create Spherical180WrapRepresentation. This was done after Stuart noticed that the ‘hlon’ attribute actually spans a range of -180 to +180 degrees. Creating a negative valued longitude was not possible with ordinary Longitude objects. Thus, a new representation had to be created. All frames which were earlier on spherical representations have been shifted to this new frame.
  6. Currently, there are a few corner cases that have to be fixed. These include transformations from Helioprojective to Heliographic when all three attributes are specified as zero and transformation from Heliographic Stonyhurst to Heliographic Carrington which is breaking, presumably because of the dateobs parameter. The dateobs parameter will also be used to generate the Carrington offset for transformation.
  7. Lastly, the coordinates framework has, for the most part, successfully been integrated into the Ginga project! It is now used to model solar coordinates and visualize SunPy maps. This is great news, and it will also push us to work harder on keeping the framework bug free.

In other news, I have started delving into other projects, such as working on an IRC bot, some competitive programming (really lagging on this) and – of course – looking for jobs! The main thing though, is the side project that I have acquired from my mentor to build #sunpy’s irc logs website in Flask. It’s going to take a while as I am completely nil in web dev, but it will be quite worth it!

Oh, and here, have a gif which signifies what Germany have been like this World Cup . Over and out!

Germanic Slaughter