On Thu, Feb 26, 2009 at 5:55 AM, Alex Griffing <argriffi@ncsu.edu> wrote:
I'm another long-time lurker who's been thinking about contributing for a while but who's been a bit uncertain about where to start. These discussions, plus the git branches Pauli has created, are encouraging me greatly to roll up my sleeves and delve in.
Cheers, Gareth.
Hi I'm also mostly a lurker. Here's a story about the time I tried to contribute to scipy.
Maybe a year ago I wanted a procedure to attempt to optimize some aspect of a multidimensional function. I found scipy.optimize, but the procedure that I tried failed by dividing by zero. Undaunted, I started digging in the scipy source code, finding the error in the broyden2 function. The problem was that the algorithm was finding the correct solution in fewer than the default number of iterations and was dividing by an error term that was zero.
I sent an email to a scipy mailing list saying that this function needed some kind of check to see if it was done (error near zero) so that it could stop iterating so that it would not divide by zero. I got a reply saying that I needed to write a patch that included the fix to the function and a new test that used to fail but that now passes. So I simplified my failing code, I changed the broyden2 function in a way that I thought would fix the problem, and I sent the code to the mailing list. I got a reply saying that what they meant by a patch was an svn diff.
So I installed svn and I checked out the scipy code with the idea that I could change my local copy, test my changes, and send the diff to the mailing list. After spending some time trying to get this working, I stopped for the following reasons:
1) Binary format and path problems were causing me grief. 2) I already had a scipy that worked, and I didn't want to break this. 3) Neil's comment: """ If I want to make a change, I have to check out the trunk and then develop my change *completely without the benefit of version control*. I am not allowed to make any intermediate commits while I learn my way through the coding process. I must submit a fully formed patch without ever being able to checkpoint my own progress. This is basically a deal-breaker for me. """
Hi Alex, it was my who was trying to help you with this. The problem was, that people who have svn access to scipy (e.g. I don't) are very busy, and do you must submit your patches in a way so that it is easy for them to apply it. I agree that git is much easier to use for that, but imho it's not difficult to create a patch with svn as well, especially if you have a working scipy on your computer. Just checkout the svn, copy your working scipy files over it, do "svn di" and send us the patch.
I think I still use code that works around this bug by using the iteration keyword argument to specify a fewer-than-default number of iterations so that the error never reaches zero.
If you find time, please do send us the patch with the fix+tests, it will be applied. Thanks a lot, Ondrej