Editing Summer of Code - Getting Started

{{Note|GNU Octave is a [https://summerofcode.withgoogle.com/programs/2023/organizations/gnu-octave mentoring organization for GSoC 2023].}}

Since 2011 the GNU Octave project has successfully mentored:
* [[Summer of Code | '''37 participants''' 🙂]]
* [[Summer of Code | '''39 projects''' 📝]]
in [[Summer of Code]] (SoC) programs by [https://summerofcode.withgoogle.com/ Google] and [https://esa.int/ ESA].

Those SoC programs aim to advertise open-source software development and to attract potential new Octave developers.

= Steps toward a successful application =

# 😉💬 '''We want to get to know you (before the deadline).  Communicate with us.'''
#* Join [https://octave.discourse.group/ '''Octave Discourse'''] or [[IRC]]. Using a nickname is fine.
#* Show us that you're motivated to work on Octave 💻.  There is no need to present an overwhelming CV 🏆; evidence of involvement with Octave is more important.
#* '''<span style="color:darkblue;">If you never talked to us, we will likely reject your proposal</span>''', even it looks good 🚮
# 👩‍🔬 '''Get your hands dirty.'''
#* We are curious about your programming skills 🚀
#** Your application will be much stronger if you [https://savannah.gnu.org/bugs/?group=octave fix Octave bugs] or [https://savannah.gnu.org/patch/?group=octave submit patches] before or during the application period.
#** You can take a look at the [[short projects]] for some 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 if you find a missing function ➡️ try to implement it.
# 📝💡 '''Tell us what you are going to do.'''
#* Do not write just to say what project you're interested in.  Be specific about what you are going to do, include links 🔗, show us you know what you are talking about 💡, and ask many [http://www.catb.org/esr/faqs/smart-questions.html smart questions] 🤓
#* Remember, '''we are volunteer developers and not your boss''' 🙂
# 📔 '''Prepare your proposal with us.'''
#* Try to show us as early as possible a draft of your proposal 📑
#* If we see your proposal for the first time after the application deadline, it might easily contain some paragraphs not fully clear to us.  Ongoing interaction will give us more confidence that you are capable of working on your project 🙂👍
#* Then submit the proposal following the applicable rules, e.g. for [https://google.github.io/gsocguides/student/writing-a-proposal GSoC]. 📨

= 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 😇

You should know:
# How to build Octave from its source code using [http://en.wikipedia.org/wiki/GNU_build_system the GNU build system].
#* Read in this wiki: [[Developer FAQ]], [[Building]]
#* Tools to know: [https://en.wikipedia.org/wiki/GNU_Compiler_Collection gcc], [https://en.wikipedia.org/wiki/Make_(software) make]
# How to submit patches (changesets).
#* Read in this wiki: [[Contribution guidelines]], [[Mercurial]]
#* Tools to know: [https://en.wikipedia.org/wiki/Mercurial Mercurial (hg)], [https://en.wikipedia.org/wiki/Git git]

= Suggested projects =

The following suggested projects are distilled from the [[Projects]] page for the benefit of potential SoC participants.  You can also look at our [[Summer of Code|completed past projects]] for more inspiration.

{{Note|Do you use Octave at your working place or university? 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 Matlab compatible Differential Algebraic Equations (DAE) solvers, {{manual|ode15i}} and {{manual|ode15s}}, based on [https://computing.llnl.gov/projects/sundials SUNDIALS], 
was done by [https://gsoc2016ode15s.blogspot.com/ Francesco Faccio during GSoC 2016].  The code is maintained in the main Octave repository and consists mainly of the following three files: [https://hg.savannah.gnu.org/hgweb/octave/file/tip/libinterp/dldfcn/__ode15__.cc {{path|libinterp/dldfcn/__ode15__.cc}}], [https://hg.savannah.gnu.org/hgweb/octave/file/tip/scripts/ode/ode15i.m {{path|scripts/ode/ode15i.m}}] and [https://hg.savannah.gnu.org/hgweb/octave/file/tip/scripts/ode/ode15s.m {{path|scripts/ode/ode15s.m}}].

The {{manual|decic}} function for selecting consistent initial conditions for ode15i can be made more Matlab compatible by using [http://dx.doi.org/10.1515/JNMA.2002.291 another algorithm].  Another useful extension is to make ode15{i,s} work with datatypes other than double and to improve interpolation at intermediate time steps.

* '''Project size''' [[#Project sizes | [?]]] and '''Difficulty'''
: ~350 hours (medium)
* '''Required skills'''
: Octave, C/C++; familiarity with numerical methods for DAEs
* '''Potential mentors'''
: Francesco Faccio, [https://octave.discourse.group/u/cdf Carlo de Falco], [https://octave.discourse.group/u/marco_caliari Marco Caliari], Jacopo Corno, [https://octave.discourse.group/u/schoeps Sebastian Schöps]

== Symbolic package ==

The [[Symbolic package]] provides symbolic computing and other [https://en.wikipedia.org/wiki/Computer_algebra_system computer algebra system] tools.  GSoC projects in 2016 and 2022 improved the package.

There are no specific plans for Symbolic in GSoC 2023, but improvements elsewhere that would help Symbolic include:
* Developing the Octave-Pythonic package.
* Fix the storage of non-expressions by working with upstream SymPy: currently we rely on deprecated functionality in SymPy.
* Improvements and fixes to classdef-related issues in Octave itself.
* Developing the Octave Jupyter kernel.

== 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 {{bug|49804}}.

* '''Project size''' [[#Project sizes | [?]]] and '''Difficulty'''
: ~350 hours (medium)
* '''Required skills'''
: Octave, C/C++; optional experience with OpenGL programming
* '''Potential mentors'''
: [https://octave.discourse.group/u/rik Rik]

== Table datatype ==

In 2013, Matlab introduced a [https://www.mathworks.com/help/matlab/tables.html new table datatype] to conveniently organize and access data in tabular form.  This datatype has not been introduced to Octave yet (see bug {{bug|44571}}).  However, there are two initial implementation approaches https://github.com/apjanke/octave-tablicious and https://github.com/gnu-octave/table.

Based upon the existing approaches, the goal of this project is to define an initial subset of [https://www.mathworks.com/help/matlab/tables.htmlMatlab's table functions], which involve sorting, splitting, merging, and file I/O and implement it within the given time frame.

* '''Project size''' [[#Project sizes | [?]]] and '''Difficulty'''
: ~350 hours (hard)
* '''Required skills'''
: Octave, C/C++

== TISEAN package ==

The [[TISEAN package]] provides an Octave interface to [https://www.pks.mpg.de/~tisean/Tisean_3.0.1/index.html TISEAN] is a suite of code for nonlinear time series analysis.  In 2015, another GSoC project started with the work to create interfaces to many TISEAN functions, but [[TISEAN_package:Procedure | 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.  These are of importance for many scientific disciplines involving statistical computations and signal processing.

* '''Project size''' [[#Project sizes | [?]]] and '''Difficulty'''
: ~350 hours (medium)
* '''Required skills'''
: Octave, C/C++; FORTRAN API knowledge
* '''Potential mentors'''
: [https://octave.discourse.group/u/kakila KaKiLa]

== Better tab completion ==

Links: [https://savannah.gnu.org/bugs/index.php?62492 https://savannah.gnu.org/bugs/index.php?62492] and [https://savannah.gnu.org/bugs/?53384 https://savannah.gnu.org/bugs/?53384]

Description: currently pressing Tab at the Octave command prompt attempts autocompletion of all identifiers in scope (variables, functions, classdefs etc) as well as files and directories in the path. It is not context sensitive.

Project: Improve tab completion. For example,

* Typing
: load x
and then pressing tab should ideally give all loadable files and directories starting with x, not unrelated results like variables or functions. 

* Typing
:cd
and tab should only give directories.

* Any file and directory names that are included in the results should include those with spaces and special characters including those that would be interpreted as operators by Octave.

* Typing commands like
: axis
or
: format
and pressing tab should give only those options relevant to that command. E.g. format can be followed by short / long / loose / compact etc but not by a file or variable. Similarly axis can be followed by ij / xy / tight / equal / actual limits etc but not by files or directories. And so on for other commands. This should be made possible for both preexisting commands and for yet-to-be-written commands without any rewriting of existing function code or documentation.

To get more examples, see how bash completion works. You can type git or hg and then tab and it will give the list of available commands. If you type "sort --r" and then tab, it gives the list of options to sort starting with "--r", etc.

== Graphics rendering back to front sorting ==
Several incompatibilities have been identified in how Octave plots transparent objects in 3D, causing certain transparent objects to hide opaque objects behind them even though they're not supposed to. The vast majority of them were isolated to one problem: if the objects to be drawn are rendered such that the one farthest away from the viewer is rendered first and nearer objects are rendered on top of that, then transparency would be automatically achieved, but this needs very careful coding to stay performant and to avoid rendering objects that will be overwritten fully by others. See [https://savannah.gnu.org/bugs/?57980] for a summary.

This project can be a GSoC for a student who understands 3D graphics rendering.

= Project sizes =

Since GSoC 2022 there exist two project sizes<ref>https://groups.google.com/g/google-summer-of-code-announce/c/_ekorpcglB8</ref><ref>https://google.github.io/gsocguides/mentor/defining-a-project-ideas-list</ref>:
* '''~175 hours''' (~12 weeks, Jun 13 - Sept 12)
* '''~350 hours''' (~22 weeks, Jun 13 - Nov 21)

= Footnotes =

<references />

= See also =

* https://summerofcode.withgoogle.com/
* [https://google.github.io/gsocguides/student/ GSoC Student Guide]
* [https://google.github.io/gsocguides/mentor/ GSoC Mentor Guide]
* [https://developers.google.com/open-source/gsoc/timeline GSoC Timeline]

[[Category:Summer of Code]]
[[Category:Project Ideas]]