Urathai

*: My name is Joel Dahne and I am a first year student at the master program in mathematics at Uppsala University, Sweden, where I also did my bachelor in matematics. I am from Sweden, so naturally speak Swedish, but all my current studies are in english so I am used to that as well. Apart from mathematics I have a great intereset in computer science which always is a motivation when taking new courses in mathematics.

*: The nick I will be using is '''Urathai''' and you can find me on other channels with that as well, for example GitHub [[https://github.com/urathai]].

*: I first came accross Matlab in my Scientific Computing courses were I learned the basics. After I have used it several times for calculations and plotting in smaller projects. Since about a year ago I switched from using Matlab to Octave. I am aware of some of the pros and cons with the language, for example that if you want any kind of performance you should use vectorized functions instead of for-loops.

*: Most of my programming have been personal projects so I have little experience from being in a development team, though this is something I really would like to do. On any larger project you are several people working together and I want to learn more about how I function in such situations.

*: The biggest project I have worked on is, as mentioned, my bachelor thesis. It was my first big project and I have learned very much from it. I started on the project last spring and my object was to build a program that could isolate zeros to a system of two analytic functions. Since I am a mathematics student the goal was to have it generate validated results, both on the number of zeros and their locations. It was done using interval methods with the C-XSC package [[http://www2.math.uni-wuppertal.de/~xsc/]]. This was my first project were I used version control in a serious way. I did many mistakes at first, for example keeping track of binary files and making to large commits, but I learned a lot. I learned about optimizing and parallelizing. For some problems the program ran for several days on multiple computers, so performance was very important. At first I wrote the program for myself only, no documentation and weird input and output. Later on I realized I also wanted other people to be able to use the program. This made me rewrite the whole input and output so that it would be easier to understand and use. Now, whenever I start a new project, even if it is just for me at the moment, I think about how I can make using the program easier for other people. The latest version of the project is available at GitHub, https://github.com/Urathai/generateZeros.

*: I think that the one thing that would make the most difference regarding if I stay or not is if people use the code I write. If people make use of it, ask questions and do bug reports I think I will have no problem finding motivation to continue. Also making new new friends and finding people to discuss with would probably get me to stay.

**: The first time I encountered Octave was during a conference last summer, SWIM2016 [[https://swim2016.sciencesconf.org/]], were Oliver Heimlich presented his interval package. Since then I have been using it instead of Matlab but I have not contributed anything before this.

*: I think that the most important part of useful criticism is explaining why they think something should or should not be done in a particular way and what they base that on. If I do not know why I do something I first of all wont remember it and secondly might not like it. When it comes to criticism over mail or other more static channels I think it is extra important to give references when possible. That way I can look up things myself if I need any more information.

*: Sort of. My main interests lies in improving the interval package. The are a couple of listed possible projects, all of which sound interesting. I have have also thought about a different project, implementing Taylor arithmetic in Octave. I think that for the interval package to really shine it needs access to automatic differentiation, which could be done in the form of Taylor arithmetic. I have implemented a proof-of-concept for how this could work [[https://github.com/Urathai/octave-taylor-POC]]. Though I am not sure if it is reasonable to implement a whole new Octave-forge package during GSoC and I am not sure who could mentor such a project, if this is interesting please let me know.