GSoC Week 5

24 Jun 2016

Well I started this week off by getting sick and as such productivity took a little bit of a hit. The majority of this week was spent reading Featherstone’s text book. The example documentation showcasing the base class API still hasn’t been reviewed and so that part of the project will just have to be set aside until later. Overall the project will not suffer, however, because of my progress in learning Featherstone’s method.

I’ve done a couple of other things this week as well. In a discussion with Jason it was determined that the LagrangesMethod class must have access to the dynamic system’s bodies through the Lagrangian input. Upon research the Lagrangain turned out to not be an object instance but rather a function that simply returned the Lagrangian for input bodies. This meant that LagrangesMethod did not in fact have access to the dynamic system’s bodies. Due to this I decided that an easy way to get LagrangesMethod to have body information would be to add an optional keyword argument for it. This was LagrangesMethod can have a more similar API to KanesMethod. This change can be found in PR #11263.

This week I reviewed PR #10856 which claimed to fix Issue #10855. Upon review it seemed that the “fix” was to just not run tests that were failing. When researched it looks like a whole module has not been updated for Python 3.X and is failing its relative imports. When run in Python 2.X it’s still not working either but rather is throwing up many KeyError flags. I think this has not been caught sooner due to the module being a component directly dealing with another project (pyglet) thus the tests are not run by TravisCI.

Lastly there were some test errors in the example documentation for the base class on PyDy. I was not too worried about these because the PR is not currently awaiting merging and is simply a discussion PR. The failing tests, however, were not related to the changes in the PR and so a PyDy member submitted a PR that fixed the tests and asked me to review it. After I looked it over and determined that the fix addressed the issue correctly he merged the PR.

Future Directions

Next week I plan to continue forward with reading Featherstone’s book and, if possible, begin implementing one of the methods outlined in the book. Also I plan on beginning work on mirroring Jason’s overhaul of KanesMethod on LagrangesMethod.

PR’s and Issues

  • (Open) Added support for a bodies attribute to LagrangesMethod PR #11263
  • (Open) Added a depencency on older version of ipywidgets PR #100
  • (Open) Blacklisted pygletplot from doctests when pyglet is installed PR #10856
  • (Open) sympy.doctest(“plotting”) fails in python 3.5 Issue #10855
  • (Merged) Fix multiarray import error on appveyor PR #354


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