Summer of Code - Getting Started

Since 2011 the GNU Octave project has mentored 38 students in Summer of Code (SoC) programs by Google and ESA. Those programs aim to populate open-source software development and to attract potential new Octave developers.

Steps toward a successful application

1. 😉💬 We want to get to know you. Communicate with us.
   • Join Octave Discourse or our IRC channel.
   • We are interested in you as motivated developer 💻 There is no need to present an overwhelming CV with prestigious universities 🏰 and programming contest awards 🏆 in it. We are very fine if you just communicate using a nickname with us.
   • If your first question is "Hi I'm new to Octave. What should I do?" you are out 🤦
   • Remember, we are mentors and not your boss 🙂
2. 📝💡 Tell us what you are going to do.
   • When you contact us for the first time, do not write just to say in what project you're interested in. Be specific about what you are going to do, post many links 🔗, show us you know what you are talking about 💡, and ask many smart questions 🤓
3. 👩‍🔬 Get your hands dirty.
   • We are curious about your programming skills ⌨️
     • Try to fix Octave bugs or submit patches before the end of the application deadline.
     • Take a look at the Short projects for simple bugs to start with.
   • Use Octave!
     • If you come across something that does not work the way you like ➡️ try to fix that 🔧
     • Or you come across a missing function ➡️ try to implement it.
4. 📔 Prepare your proposal with us.
   • GSoC, for example, requires to submit a proposal.
   • If we see your proposal for the first time after the application deadline, you can easily imagine that it might contain ambiguities or some paragraphs are not fully clear to us. We easily get doubts if you are capable of working on your project 😓
   • Try to show us as early as possible a draft of your proposal 👍

How do we judge your application?

Depending on the mentors and SoC program there are varieties, but typically the main factors considered would be:

• You have demonstrated interest in Octave and an ability to make substantial modifications to Octave

  The most important thing is that you've contributed some interesting code samples to judge your skills. It's OK during the application period to ask for help on how to format these code samples, which normally are Mercurial patches.

• You showed understanding of your topic

  Your proposal should make it clear that you're reasonably well versed in the subject area and won't need all summer just to read up on it.

• Well thought out, adequately detailed, realistic project plan

  "I'm good at this, so trust me" isn't enough. In your proposal, you should describe which algorithms you'll use and how you'll integrate with existing Octave code. You should also prepare a project timeline and goals for the midterm and final evaluations.

What you should know about Octave

GNU Octave is mostly written in C++ and its own scripting language that is mostly compatible with Matlab. There are bits and pieces of Fortran, Perl, C, awk, and Unix shell scripts here and there. In addition to being familiar with C++ and Octave's scripting language, you as successful applicant will be familiar with or able to quickly learn about Octave's infrastructure. You can't spend the whole summer learning how to build Octave or prepare a changeset and still successfully complete your project 😇

• The Build System

  The GNU build system is used to build Octave.

  While you generally don't need to understand too much unless you actually want to change how Octave is built, you should be able to understand enough to get a general idea of how to build Octave.

  If you've ever done a ./configure && make && make install series of commands, you have already used the GNU build system.

  You must demonstrate that you are able to build the development version of Octave from sources before the application deadline. Linux is arguably the easiest system to work on. Instructions:

  • Building
  • Octave Manual on Installing Octave

• The Version Control System

  We use Mercurial (abbreviated hg).

  Mercurial is the distributed version control system (DVCS) we use for managing our source code. You should have some basic understanding of how a DVCS works, but hg is pretty easy to pick up, especially if you already know a VCS like git or svn.

• The Procedure for Contributing Changesets

  You will be expected to follow the same procedures as other contributors and core developers.

  You will be helping current and future Octave developers by using our standard style for changes, commit messages, and so on. You should also read the same contribution guidelines we have for everyone.

  This page describes the procedures students are expected to use to publicly display their progress in a public mercurial repo during their work.

Suggested projects

The following suggested projects are distilled from the Projects page for the benefit of potential SoC students. You can also look at our completed past projects for more inspiration.

Do you use Octave at your university or do you have some numerical project in mind? You are always welcome to propose your own projects. If you are passionate about your project, it will be easy to find an Octave developer to mentor and guide you.

ode15{i,s} : Matlab Compatible DAE solvers

An initial implementation of a Matlab compatible ode15{i,s} solver, based on SUNDIALS, was done by Francesco Faccio during GSOC 2016. The blog describing the work is here. The resulting code has been pushed into the main Octave repository in the development branch and consists mainly of the following three files __ode15__.cc, ode15i.m and ode15s.m. The list of outstanding tracker tickets concerning this implementation can be found here

Possible useful improvements that could be done in a new project include:

• Implement a better function for selecting consistent initial conditions compatible with Matlab's decic.m. The algorithm to use is described here

• make ode15{i,s} work with datatypes other than double

• improve interpolation at intermediate time steps.

• general code profiling and optimization

Other tasks, not strictly connected to ode15{i,s} but closely related, that could be added to a possible project plan would be improving documentation and tests in odepkg and removing overlaps with the documentation in core Octave.

• Required skills

C++; C; familiarity with numerical methods for DAEs; Basic knowledge of makefiles and/or autotools.

• Difficulty

Medium.

• Potential mentors

Francesco Faccio, Carlo de Falco, Marco Caliari, Jacopo Corno, Sebastian Schöps

Using Python within Octave

Pythonic allows one to call Python functions and interact with Python objects from within Octave .m file code and from the Octave command line interface. Pythonic may eventually not be a separate package, but rather a core feature of Octave. This project aims to improve Pythonic with the goal of making the package more stable, maintainable, and full-featured.

Based on a previous summer project related to Pythonic, this work will consist of fast-paced collaborative software development based on tackling the Pythonic issue list. You would also be expected to participate in software design decisions and discussion, as well as improve documentation, doctests, and unit tests. As an example of the sorts of decisions being made, note that Octave indexes from 1 whereas Python typically indexes from 0; in which cases is it appropriate to make this transparent to the user?

• Mentors

Mike Miller, Colin B. Macdonald, Abhinav Tripathi, others?

Improve TIFF image support

Tag Image File Format (TIFF) is the de facto standard for scientific images. Octave uses the GraphicsMagic (GM) C++ library to handle TIFF and many others image formats. However, GM still has several limitations:

• GM has build option quantum which defines the bitdepth to use when reading an image:
  • Building GM with high quantum means that images of smaller bitdepth will take a lot more memory when reading.
  • Building GM with low quantum will make it impossible to read images of higher bitdepth. It also means that the image needs to always be rescaled to the correct range.
• GM supports unsigned integers only, thus incorrectly reading files such as TIFF with floating-point data.
• GM hides details of the image such as whether the image file is indexed. This makes it hard to access the real data stored on file.

This project aims to implement better TIFF image support using libtiff, while leaving GM handle all other image formats. After writing a classdef interface to libtiff, improve the Octave functions imread, imwrite, and imfinfo to make use of it.

• Required skills

Knowledge of Octave, C++ and C.

• Difficulty

Medium.

• Potential mentor

Carnë Draug

PolarAxes and Plotting Improvements

Octave currently provides supports for polar axes by using a Cartesian 2-D axes and adding a significant number of properties and callback listeners to get things to work. What is needed is the implementation of a dedicated "polaraxes" object in C++. This will require creating a new fundamental graphics object type, and programming in C++/OpenGL to render the object. When "polaraxes" exists as an object type, then m-files will be written to access them, including polaraxes.m, polarplot.m, rticks.m, rticklabels.m, thetaticks, thetaticklabels.m, rlim.m, thetalim.m. This relates to bug #49804.

• Minimum requirements

Ability to read and write C++ code. Ability to read and write Octave code. Experience with OpenGL programming is optional.

• Difficulty

Medium.

• Mentor

Rik

Adding functionality to packages

TISEAN package

TISEAN is a suite of code for nonlinear time series analysis. It has been partially re-implemented as libre software. The objective is to integrate TISEAN as an Octave Forge package, as was done for the Control package. A lot has been completed but there is still work left to do.

There are missing functions to do computations on spike trains, to simulate autoregresive models, to create specialized plots, etc. Do check the progress of the project to see if you are interested.

• Package help at source forge.
• Package repository at source forge.

• Required skills

m-file scripting, C, C++, and FORTRAN API knowledge.

• Difficulty

easy/medium

• Mentor

KaKiLa

Symbolic package

Octave's Symbolic package provides symbolic computing and other computer algebra system tools. The main component of Symbolic is a pure m-file class "@sym" which uses the Python package SymPy to do (most of) the actual computations. The package aims to expose the full functionality of SymPy while also providing a high level of compatibility with the Matlab Symbolic Math Toolbox. The Symbolic package requires communication between Octave and Python. A GSoC2016 project successfully re-implemented this communication using the new Pythonic package.

This project proposes to go further: instead of using Pythonic only for the communication layer, we'll use it throughout the Symbolic project. For example, we might make "@sym" a subclass of "@pyobject". We also could stop using the "python_cmd" interface and use Pythonic directly from methods. The main goal was already mentioned: to expose the *full functionality* of SymPy. For example, we would allow OO-style method calls such as "f.diff(x)" instead of "diff(f, x)".

• Required skills

OO-programming with m-files, Python, and possibly C/C++ for improving Pythonic (if needed).

• Difficulty

easy/medium

• Mentors and/or other team members

Colin B. Macdonald, Mike Miller, Abhinav Tripathi

OCS

OCS is a circuit simulator for Octave. The objective of this project is to update the code to use modern features of Octave (e.g. classdef), fix open bugs, increase compatibility with SPICE and improve compatibility with other Octave packages (odepkg, control etc).

• Package help at source forge.

• Required skills

m-file scripting, C, C++, and FORTRAN API knowledge.

• Difficulty

easy/medium

• Mentor

Sebastian Schöps, Carlo de Falco