# Part 3: The Debugging#

This is part 3 of the ongoing series of my blog posts describing my journey as a Google Summer Of Code student working with Sunpy to develop Sunkit-image, an image processing toolbox for solar images.

This particular part describes the work that has been done from 10th June to date. This part of the project was especially tricky involving lots of debugging. But, first I would like to begin on a positive note. My both the initial pull requests — one on the Fourier Normalizing Radial Gradient Filter and the other on Multiscale Gaussian Normalization were finally merged. It was such a delightful moment when your code gets accepted, I am sure all the coders reading this understand how I feel!! You can have a look at my pull requests here —

Now coming to the tricky part of the affairs. I spent these two weeks almost entirely on implementing the Oriented Coronal CUrved Loop Tracing (OCCULT-2) algorithm, which is aimed at automatic tracing of coronal loops. The initial implementation of the algorithm was relatively easy but then the complications started to manifest themselves. The major issue was the paper describing the algorithm and the code written by the author in IDL had some differences. So figuring out why those changes were made was a very tiring job.

Those modifications were finally incorporated in the python code but still, my implementation is not performing the way it should. So it is clear that there are some bugs still present. So began the process of bug hunting. Being such a complex algorithm find those hidden bugs was a challenge. I had many of “Eureka” moments which later turned out to be false alarms. There were a few moments when I actually got frustrated and thought of moving to something else. But I stuck to it, hoping I will find it soon.

The hunt for the culprit is still on though. I was able to fix many other minor bugs in this entire endeavour but the mighty one is still elusive. I am still working on it and hope to locate it soon enough.

The left image is an image of the solar surface showing some very prominent loops. The right image shows the output of my code. My code is being able to trace the loops but the loops are not being traced continuously rather there are traced in parts having breaks in between them. This is the major bug in the code which I am unable to find out till now.

I am still on my schedule and have some more days to tackle this issue and I am confident that I can make it work.

Hope you enjoyed this. Join me again in the coming weeks to see what comes out of this algorithm and all the other cool things I would be working on.