Summer of Code - Getting Started: Difference between revisions

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→‎Chebfun in Octave: Overhaul item.
(→‎Chebfun in Octave: Overhaul item.)
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[https://www.chebfun.org/ Chebfun] is a mathematics and software project for "numerical computing with functions".  Basically it approximates functions to machine precision accuracy (10<sup>-15</sup>) using piecewise Chebyshev polynomial interpolants.  Operations on those functions (arithmetic, derivatives, root-finding, etc) are then overloaded and return new interpolating polynomials, which are themselves proxies for the actual solution.
[https://www.chebfun.org/ Chebfun] is a mathematics and software project for "numerical computing with functions".  Basically it approximates functions to machine precision accuracy (10<sup>-15</sup>) using piecewise Chebyshev polynomial interpolants.  Operations on those functions (arithmetic, derivatives, root-finding, etc) are then overloaded and return new interpolating polynomials, which are themselves proxies for the actual solution.


Chebfun makes extensive use of classdef classes, and is one of the largest Free Software projects to do so.  Unfortunately it currently only works in Matlab.  This project seeks to (1) improve Octave's classdef support and (2) tweak Chebfun to work under Octave, for example, removing undocumented classdef features.  The final goal is to have at least basic Chebfun features working on Octave.  An additional goal would be making "pkg install chebfun.zip" work in Octave.
Chebfun makes extensive use of classdef classes, and is one of the largest Free Software projects to do so.  Unfortunately it currently only works in Matlab.  This project seeks to (1) improve Octave's classdef support and (2) tweak Chebfun to work under Octave, for example, removing undocumented classdef features.  The final goal is to have at least basic Chebfun features working on Octave.  An additional goal would be making <code>pkg install chebfun.zip</code> work in Octave.


The impact of this project is improving Octave and allowing Chebfun to be used without proprietary software.
The impact of this project is improving Octave and allowing Chebfun to be used without proprietary software.
How to get started:
* Learn about [https://www.chebfun.org/ Chebfun]
* Browse [https://savannah.gnu.org/bugs/?group=octave Octave's bug list] for "classdef"-related bugs.
* Clone this Chebfun [https://github.com/cbm755/chebfun/tree/octave_dev octave_dev branch].
** On that, <code>f = chebfun(@(x) sin(x), [-2 6])</code> should work with Octave 4.3.0+ and maybe even with 4.2.1.  Check that <code>f(pi)</code> and <code>g = f + 1</code> work.
** A good first task would be to study [https://github.com/cbm755/chebfun/commit/e20b0ad2dc89cfe8e50ba461b864eff7d5bbef17 this commit], a workaround for <code>f.funs{1}</code> using <code>temp = f.funs; temp{1}</code>.  <code>2*f</code> is failing, can you fix it, perhaps with this workaround?  Or can you make <code>f.funs{1}</code> work by changing something in <code>@chebfun/subsref.m</code>?


* '''Required skills'''
* '''Required skills'''
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* '''Potential mentors'''
* '''Potential mentors'''
: Colin B. Macdonald, [[User:KaKiLa|KaKiLa]], Mike Miller (?), Carnë Draug (?), someone from Chebfun team (?).
: Colin B. Macdonald, [[User:KaKiLa|KaKiLa]], Mike Miller (?), Carnë Draug (?), someone from Chebfun team (?).
How to get started: learn about Chebfun, browse Octave's bug list for classdef-related bugs.
First steps: clone this Chebfun [https://github.com/cbm755/chebfun/tree/octave_dev octave_dev branch].  On that, "f = chebfun(@(x) sin(x), [-2 6])" should work with Octave 4.3.0+ and maybe even with 4.2.1.  Check that "f(pi)" and "g = f + 1" work.  A good first task would be to study [https://github.com/cbm755/chebfun/commit/e20b0ad2dc89cfe8e50ba461b864eff7d5bbef17 this commit], a workaround for "f.funs{1}" using "temp = f.funs; temp{1}".  "2*f" is failing, can you fix it, perhaps with this workaround?  Or can you make "f.funs{1}" work by changing something in "@chebfun/subsref.m"?


== Adding functionality to Forge packages ==
== Adding functionality to Forge packages ==

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