# GSoC Week 9: Docs!

Posted on July 18, 2014

This week I spent time on all sorts of little things:

• Finished up the refactoring of KanesMethod
• Little fixes to my current PR. Just waiting on my mentors to review this, I want to get it merged soon-ish.
• Documentation.

Writing documentation is the worst1. After taking time to implement all sorts of new interesting things, the last thing I want to do is go back and write about them in detail. Which is why it's so important to do early on. Good documentation needs to accomplish three things:

1. Provide motivation for why your software is necessary/better/useful.
2. Describe the user interface, showing how to use each function or class.
3. Provide real world examples showing how to tie everything together.

Python's documentation is interesting in that there are varying ways to do it. Some of Sympy's documentation is just a nicely rendered form of the docstrings for all the methods. Other modules have a more prose-y explanation of their functionality. mechanics is one of those modules.

In my opinion the prose documentation approach is the better way. Having good docstrings is important, but they aren't the end-all of documentation2. Of course, if I have a question the first thing I'm going to do is read the docstrings (IPython makes this trivially easy). Only if I still have questions afterwards will I turn to the online documentation. However, it'd be extremely off-putting if the online documentation was just the docstrings again.

With the various changes I've made so far I needed to:

1. Update the LagrangesMethod documentation to reflect the interface change.
2. Create a documentation page all about the linearization methods.
3. Update all the examples to reflect the new functionality.

All of these are "done". I still need to go through and proofread, but overall I'd say that the current state of the documentation is acceptable. I would like to take some time to reorganize the layout of the whole mechanics documentation at some point. The current layout isn't the easiest to navigate for what you're looking for.

With this out of the way, the linearization portion of my project is tentatively done. I say tentatively because I'm still waiting on my PRs to get merged, and am also still playing around with solving the nan issue that I've been writing about these last couple weeks.

With that done, I hope to move on to code generation. I've read the current code generation code and documentation, as well as this pydy wiki page on Jason's ideas about code generation. I'm still a little iffy about the intention of this functionality, so I'm waiting until we can all meet to discuss what needs to be done. That was supposed to have happened this week, but fell through. Hopefully we can set some time aside next week, and I can finally get to work on it.

1. Not actually the worst.