Tuesday, October 28, 2008

Google Mentor Summit III

On Sunday I checked out from the hotel and enjoyed the breakfast, basically the same as the first picture here. Which is cool, the best way to start a day is with a good breakfast in the morning.

At Google I finally met with Bart Massey, who works at the Portland State University where I was an intern (in 2005) and also he was sponsoring one SymPy GSoC student in 2007.

Then we started to port SymPy to Jython with Philip Jenvey. I first installed openjdk-6, which is in Debian main, then checked out Jython svn, typed "ant" and it just worked. This is so awesome, that we finally have a truly opensource and fully working java implementation in Debian. Philip fixed some bugs already, so SymPy imports just fine. Most of the tests run, but also quite a lot still fail.

We managed to isolate two bugs: issue 1158 and 1159. Then there was an annoying recursion bug, that took us several hours to dig into and I then had to leave at 6pm without a clue. But Philip kept saying, I just need to look more at the java stacktraces that Jython was generating and I'll figure it out. And he did! The next morning he filed an issue 412 in the PyPy tracker, because they seem to have the same problem. There are subtle differences in how to handle __mul__ and __rmul__ methods that are not well documented, so it works in CPython but fails in Jython/PyPy. I think we can fix that in SymPy too in the meantime, so I am very excited, because it seems SymPy will work on top of Jython soon.

There was also a git vs hg session with both hg and git developers. Since I recently switched from hg to git for all stuff where I can choose the vcs, it was very interesting for me. And I must say I am glad I switched. Mercurial works fine enough and with the recent rebase feature I think it is usable, but git just has a bigger momentum at the moment and it just doesn't get in my way.

During the day Steve sent an email to the GSoC list that Dirk forgot his jacket in the hotel room, so I said to myself, haha, that's a pity. And then I realized, oh shit, I left my jacket there as well. They didn't have it in the evening when I stopped there, but fortunately they sent me an email yesterday that they found it, so I'll stop there on my way back.

We also took couple of group pictures, here is just my lame attempt (I am sure people will soon post better ones):

On Monday morning I met with Fernando Perez, the author of ipython, he know works with Jarrod. Then I rented a car and came to visit Brian Granger and his family in San Luis Obispo.

We went to the beach in the evening:

And had a dinner together. Brian showed me his options pricing example he did with SymPy, so I made him create an issue 1175 with the code.
Then we played with the parallel stuff that Brian contributed to ipython and we tried sympy with it and to our disappointment, we found pickling bugs in sympy, it works with protocol 0, but not protocol 2, see the issue 1176 and 1177. This almost smells like a bug in Python itself, but I need to investigate that later more deeply.

Today is Tuesday and we'll work on doing atomic physics calculations with sympy. See also Brian's email to the sympy list about it.
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