# Difference between revisions of "Summer of Code - Getting Started"

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=== Implement solver for initial-boundary value problems for parabolic-elliptic PDEs in 1D === | === Implement solver for initial-boundary value problems for parabolic-elliptic PDEs in 1D === | ||

− | The project will deliver a solver for initial-boundary value problems for parabolic-elliptic PDEs in 1D similar to Matlab's function <tt>pdepe</tt>. A good starting point is the [http://en.wikipedia.org/wiki/Method_of_lines method of lines] for which you can find more details [http://en.wikibooks.org/wiki/Partial_Differential_Equations/Method_of_Lines here] and [http://www.scholarpedia.org/article/Method_of_lines here], whereas an example implementation can be found [http://www.scholarpedia.org/article/Method_of_Lines/Example_Implementation here]. | + | The project will deliver a solver for initial-boundary value problems for parabolic-elliptic PDEs in 1D similar to Matlab's function <tt>pdepe</tt>. A good starting point is the [http://en.wikipedia.org/wiki/Method_of_lines method of lines] for which you can find more details [http://en.wikibooks.org/wiki/Partial_Differential_Equations/Method_of_Lines here] and [http://www.scholarpedia.org/article/Method_of_lines here], whereas an example implementation can be found [http://www.scholarpedia.org/article/Method_of_Lines/Example_Implementation here]. In addition, [http://www.pdecomp.net/ this page] provides some useful material. |

== GUI == | == GUI == |

## Revision as of 12:48, 16 February 2012

The following is distilled from the Projects page for the benefit of potential Summer of Code students. Although students are welcome to attempt any of the projects in that page or any of their own choosing, here we offer some suggestions on what good student projects might be.

# General Guidelines

Octave is mostly written in (sadly, mostly undocumented) C++ and its own scripting language (m-scripts), which includes (or should include) most of the Matlab language as a subset. We generally prefer a different Octave house style to the usual Matlab style for m-scripts, but it's primarily a superficial stylistic difference. Additionally, 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/or Octave or Matlab's scripting languages, you should probably be familiar or learn about Octave's infrastructure:

- 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. - Mercurial (abbreviated hg) 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.
- You should also read the same contributing guidelines we have for everyone.
- We primarily use mailing lists for communication. You should follow basic mailing list etiquette. For us, this mostly means "do not top post".
- We also have an IRC channel. The atmosphere is more relaxed, and we may talk about things that are not at all related to Octave.
- In addition, you probably should know
**some**mathematics, engineering, or experimental science or something of the sort. If you've used Matlab before, you probably have already been exposed to the kinds of problems that Octave is used for.

# Suggested projects

The following projects are broadly grouped by category and probable skills required to tackle each. Remember to check Projects for more ideas if none of these suit you, and your own ideas are always welcome.

## Numerical

These projects involve implementing certain mathematical functions in Octave.

**Required skills**: You should understand quite a bit of mathematics. Words like "eigenvalue", "analytic", and "Taylor series" shouldn't scare you at all. There is probably little C++ experience required, and probably many of these problems can be solved with m-scripts.

**Difficulty**: Mid-to-hard depending how much mathematics you know and how well you can read numerical analysis journal articles.

**Potential mentor**: Carlo de Falco, Nir Krakauer, Fotios Kasolis

### Improve logm, sqrtm, funm

The goal here is to implement some missing Matlab functions related to matrix functions like the matrix exponential. There is a general discussion of the problem.

### Generalised eigenvalue problem

Certain calling forms of the `eig` function are missing. The problem is to understand what those missing forms are and implement them.

### Various sparse matrix improvements

The implementation of sparse matrices in Octave needs several improvements. Any of these would be good. The paper by Bateman & Adler is good reading for understanding the sparse matrix implementation.

### Least-squares spectral analysis

Develop and test as an Octave-Forge package functionality for fast evaluation of harmonics and cross-correlations of unevenly sampled and nonstationary time series, possibly building on this paper (which has C code with interface to R).

### Implement solver for initial-boundary value problems for parabolic-elliptic PDEs in 1D

The project will deliver a solver for initial-boundary value problems for parabolic-elliptic PDEs in 1D similar to Matlab's function `pdepe`. A good starting point is the method of lines for which you can find more details here and here, whereas an example implementation can be found here. In addition, this page provides some useful material.

## GUI

Octave is currently working on a new native GUI. It is written in Qt, but it is still not ready for production. There are various ways in which it could be improved.

**Required skills**: C++ and Qt. Whatever tools you want to use to write Qt code are fine, but Qt Creator is a popular choice nowadays.

**Difficulty**: Mostly medium, depending if you've had Qt or GUI development experience before.

**Potential mentor**: Jordi Gutiérrez Hermoso

### Finish the Octave GUI

The GUI is currently on its own branch in hg. It is not stable enough and its design is still in flux. It needs to be finished.

### Integrate the GUI with the Octave build system

The current GUI build system is independent of Octave. First one builds and installs Octave, and then the GUI. The goal of this project is to integrate the GUI and make it all build together. Good understanding of both the GNU build system and Qt's (qmake and the meta-object compiler) will be necessary here.

### Implement a Qt widget for manipulating plots

Octave has had for some time a native OpenGL plotter. The plotter requires some user interaction for manipulating the plots, and it's been using fltk for quite some time. We want to replace this with Qt, so it fits better with the overall GUI look-and-feel and is easier to extend in the future.

### Create a better (G)UI for the profiler

During GSoC 2011, Daniel Kraft successfully implemented a profiler for Octave. It needs a better interface and a way to generate reports. This may be done with Qt, but not necessarily, and HTML reports might also be good.

### Create a graphical design tool for tuning closed loop control system (control pkg)

When tuning a SISO feedback system it is very helpful to be able to grab a pole or a zero and move them by dragging them with the mouse. As they are moving the software must update all the plotted lines. There should be the ability to display various graphs rlocuse, bode, step, impulse etc. and have them all change dynamically as the mouse is moving. The parameters of the compensator must be displayed and updated. Potential mentor: Doug Stewart

## Graphics

Octave has a new native OpenGL plotter (currently via fltk, but we want to move away from that). There are several possible projects involved with it. Michael Goffioul has expressed interest in mentoring these projects.

**Required skills**: C++ and OpenGL. General understanding of computer graphics.

**Difficulty**: Medium, depending on your previous understanding of the topic.

**Potential mentor**: Michael Goffioul

### Lighting

Implement transparency and lighting in OpenGL backend(s). A basic implementation was available in JHandles. This needs to be ported/re-implement/re-engineered/optimized in the C++ OpenGL renderer of Octave.

### Cairo renderer

Implement a Cairo-based renderer for 2D-only graphics, with support for PS/PDF/SVG output (for printing). Naturally this requires understanding or learning how Cairo works.

## Interpreter

The interpreter is written in C++, undocumented. There are many possible projects associated with it.

**Required skills**: *Very good* C and C++ knowledge, possibly also understanding of GNU bison and flex. Understanding how compilers and interpreters are made plus being able to understand how to use a profiler and a debugger will probably be essential skills.

**Difficulty**: Mid hard to very hard. Some of the biggest problems will probably be the interpreter.

**Potential mentors**: John W. Eaton, Jordi Gutiérrez Hermoso

### Implement (or improve?) JIT compiling

Octave's interpreter is *very* slow on loops. Implementing JIT compiling would dramatically speed up execution of these loops. This is a very big project, but a dedicated student might make a good attempt of doing this over a summer. There may be some work already in place by the time the summer comes along. The idea is to probably use LLVM to aid with the JIT compilation.

### Improve memory management

From profiling the interpreter, it appears that a lot of time is spending allocating and deallocating memory. A better memory management algorithm might provide some improvement.

### Implement classdef classes

Matlab has two kinds of classes: old style @classes and new style classdef. Octave has only implemented the old style. Although the lexer and parser have been updated to recognise the syntax for the new style classdef declarations, they currently do nothing with it. A successful project would design and implement the necessary functionality for these classes. This project is somewhat simpler than others in the interpreter group.

## Infrastructure

There are several projects closely related to Octave but not exactly core Octave that could be worked on. They are mostly infrastructure around Octave, stuff that would help a lot.

**Required skills**: Various. See below.

**Difficulty**: Various. See below.

**Potential mentor**: Jordi Gutiérrez Hermoso, Carlo de Falco

### Finish the Agora website

In 2009, the Mathworks decided to restrict the terms of use Matlab Central, a place dedicated to Matlab collaboration. The Mathworks forbade copyleft licenses and using the "free" code found in Matlab central on anything other than Mathworks products (e.g. forbidding from using it on Octave, even if the authors of the code wanted to allow this). Thus Octave users have no place to centrally, quickly, and conveniently share Octave code. In response to this, a website started to form, Agora Octave.

This should be relatively easy webdev in Python using Django.

### Give maintenance to the Emacs octave mode

Emacs has an octave-mode that requires a lot of maintenance. This should also be an easy project if you already use Emacs and elisp.

### Improve binary packaging

We would like to be able to easily generate binary packages for Windows and Mac OS X. Right now, it's difficult and tedious to do so. Any way to help us do this in a faster way would be appreciated. Required knowledge is understanding how building binaries in Windows and Mac OS X works. Medium difficulty.

### Installation of packages

We would like to enhance the management of Octave-forge packages from within Octave environment. Currently there is a working (but rather monolithic) function that is used to do the job. The work would be to improve the way Octave interacts with the package server. Since the functionality is already sketched by the current function, the most important skill is software design.

**Minimum requirements**: Ability to read and write Octave code. Minimal FTP/HTTP knowledge.

**Difficulty**: Easy