The all-important Community Bonding Period ends!! During these three weeks, I have come to learn a lot more things about SymPy, and especially its Series module, the module I would be improving this summer. The first week of the CBP was wasted since I had college exams going on, and couldn’t focus. After they ended, I set my blog, and had a meeting over Hangouts with Sartaj.

The meeting ended with the following plan of action to be done in the CBP :-

• Currently, I will try to understand about the inheritance methodology of Formal Power Series, the algorithm behind computing Formal Power Series, and the logic behind improving the XFAIL tests.
• I will also try to deduce means to include composition, and coefficient sequence of power of fps as operations on fps.
• Get familiarized with the documentation style of SymPy.
• Gitter will be the primary channel of communication. I will soon add my blog to planet-sympy as well.

I started by thinking about the XFAIL tests which were about functions having symbolic terms in test_formal.py. Previously,

fps(x**n*sin(x**2),x).truncate() gave rise to a Value Error.

So, I thought of splitting the x**n term from the function itself, use the rest of the portion to compute the fps accordingly, and then multiply the symbolic term in the xk (powers of x) and ind (independent term) respectively.

• I made a PR #16869 incorporating those changes. It’s a WIP Pull request, since the code was too nested and heuristic changes had to be modified.
• I also read Wikipedia articles for implementation of convolution, composition and coeff. of power sequence of fps. I will try to implement this the following coding week.
• I read the official SymPy documentation of the series module.

All in all, this was a great phase. Had some constructive discussions with Sartaj as well. Looking forward to the next enchanting phase, the Coding Period (Phase 1). Till then, adios !!