# Changes

## Projects

, 09:55, 19 September 2019
m
The list below summarizes features or bug fixes we would like to see in Octave. if you start working steadily on a project, please let octave-maintainers@octave.org know. We might have information that could help you. You should also read the [http://www.gnu.org/software/octave/doc/interpreter/Contributing-Guidelines.html#Contributing-Guidelines [Contribution guidelines |Contributing Guidelines chapter] in the [http://www.gnu.org/software/octave/docs.html Octave manual].
This list is not exclusive -- there are many other things that might be good projects, but it might instead be something we already have. Also, some of the following items may not actually be considered good ideas now. So please check with octave-maintainers@octave.org before you start working on some large project.
GSoC Summer of Code students, please also see [[GSoC SoC Project Ideas]]. If you're looking for small project, something more suited to start getting involved with Octave development or to fill a boring evening, see [[short projects]]
=Numerical=
*Improve logm, and sqrtm (see this thread: http://octave.1599824.n4.nabble.com/matrix-functions-td3137935.html)

*Use pairwise addition in sum() to mitigate against numerical errors without substantial performance penalty (https://en.wikipedia.org/wiki/Pairwise_summation).

*Review implementing algorithm in this 2009 paper (https://epubs.siam.org/doi/pdf/10.1137/080738490) for xsum (sum with extra accuracy). The existing implementation uses a 2005 paper.
*Improve complex mapper functions. See W. Kahan, Branch Cuts for Complex Elementary Functions, or Much Ado About Nothing's Sign Bit (in The State of the Art in Numerical Analysis, eds. Iserles and Powell, Clarendon Press, Oxford, 1987) for explicit trigonometric formulae.
*Add optional arguments to colloc so that it's not restricted to Legendre polynomials.

*Fix eig to also be able to solve the generalized eigenvalue problem, and to solve for eigenvalues and eigenvectors without performing a balancing step first.
*Move rand, eye, xpow, xdiv, etc., functions to the matrix classes.

*Use octave_allocator for memory management in Array classes once g++ supports static member templates.
*Improve design of ODE, DAE, classes.
*Make QR more memory efficient for large matrices when not all the columns of Q are required (apparently this is not handled by the lapack code yet).
=GUI/IDE=
*Søren Hauberg has suggested that we need C++ code that can:
**Determine if a line of code could be fully parsed, i.e. it would return true for "plot (x, y);", but false for "while (true)".
**Evaluate a line of code and return the output as a string (it would be best if it could provide three strings: output, warnings and errors).
**Query defined variables, i.e. get a list of currently defined variables. Bonus points if it could tell you if anything had changed since the last time you checked the variables (could also be done with signals).
*There is currently Create a GUI being developedbetter (G)UI for the {{manual|profile|profiler}}. This may be done with Qt, it's in [https://savannahbut not necessarily.gnu == Sisotool.org/projects/octave/ savannahCreate a graphical design tool for tuning closed loop control system ([[Control package]])== 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. Further info can As they are moving the software must update all the plotted lines. There should be found on 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.Recently, some implementation was done during [http[Summer_of_Code#GSoC_2018|GSoC 2018]], see https://octave-gsoc2012eriveltongualter.blogspotgithub.io/GSoC2018/final.com GSoC 2012 GNU Octave GUI Development blog]html for details.
=Sparse Matrices=

The paper by [http://arxiv.org/abs/cs.MS/0604006 Bateman & Adler] is good reading for understanding the sparse matrix implementation.
*Improve QR factorization functions, using idea based on CSPARSE cs_dmsol.m
*Improve QR fqctorization factorization by replace replacing CXSPARSE code with SPQR code, and make the linear solve return 2-norm solutions for ill-conditioned matrices based on this new code
*Implement fourth argument to the sprand and sprandn, and addition arguments to Improve Matlab compatibility for {{manual|sprandsym that the leading brand implements}}.
*Sparse logical indexing in idx_vector class so that something like '<code>a=sprandn(1e6,1e6,1e-6); a(a<1) = 0' ;</code> won't cause a memory overflow.
*Other missing Functions
**<strike>symmmd</strike> (Superseded by symamd)
**<strike>colmmd</strike> (Superseded by colamd)
**cholinc (or ichol)
**<strike>bicg</strike> Moved into octave-core
**<strike>gmres</strike>Moved into octave-core
**lsqr
**minres
**qmr
**symmlq
=Strings=

*Improve performance of string functions, particularly for searching and replacing.

*Make find work for strings.
*Consider making octave_print_internal() print some sort of text representation for unprintable characters instead of sending them directly to the terminal. (But don't do this for fprintf!)
*Make it possible to tie arbitrary input and output streams together, similar to the way iostreams can be tied together.

*Expand {{codeline|imwrite}} options. This shouldn't be too hard to implement, since it's wrapped around GraphicsMagick.

*Extend Octave functions to work on stored arrays that are too big to fit in RAM, similar to available R [http://www.bigmemory.org/ packages.]

* write {{codeline|xmlread}} and {{codeline|xmlwrite}}. This could be done using [http://xerces.apache.org/xerces-c/ Xerces C++ interface] which apparently is what [http://octave.1599824.n4.nabble.com/xml-in-octave-td4663034.html Matlab uses].

=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 [http://en.wikipedia.org/wiki/Gnu_bison GNU bison] and [http://en.wikipedia.org/wiki/Flex_lexical_analyser 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.
*Allow customization of the debug prompt.
if (expr) 'this is a string' end
is parsed as IF expr STRING END.''(see [https://lists.gnu.org/archive/html/octave-maintainers/2014-03/msg00087.html this] post on the mailing list)''
*Clean up functions in input.cc that handle user input (there currently seems to be some unnecessary duplication of code and it seems overly complex).
*Too much time is spent allocating and freeing memory. What can be done to improve performance?

Use move constructors rather than copy constructors for things like dim_vectors which are repeatedly created just to initialize Array or Matrix objects.
*Error output from Fortran code is ugly. Something should be done to make it look better.
*<strike>Per the following discussion, allow bsxfun style singleton dimension expansion as the default behavior for the builtin element-wise operators: http://octave.1599824.n4.nabble.com/Vector-approach-to-row-margin-frequencies-tp1636361p1636367.html</strike> This is done. <strike>Now [[User:JordiGH|I]] just have to document it.</strike> This is done too!
* Start == Improve JIT compiling == Octave's interpreter is ''very'' slow on some loops. Recently, thanks to Max Brister's work, an initial implementation of a just-in-time compiler (JITC) in [http://llvm.org LLVM] for GSoC 2012. This project consists in understanding Max's current implementation and extending it so that functions and exponents (e.g. 2^z) compile with the JITC. This requires knowledge of compilers, C++, LLVM, and the Octave or Matlab languages. A capable student who demonstrates the ability to acquire this knowledge quickly may also be considered. Max himself will mentor this project. [http://planet.octave.org/octconf2012/jit.pdf Here] is Max's OctConf 2012 presentation about his current implementation. See also [[JIT]]. == 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 fully implemented the old style. There is partial support for classdef classes in version 4.0, refer to the development [[Classdef|classdef status page]] for what is not yet implemented. There is irregular work here, and classdef is [http://www.mathworks.com/help/matlab/matlab_oop/method-attributes.html a very] [http://www.mathworks.com/help/matlab/events-sending-and-responding-to-messages.html complicated] [http://www.mathworks.com/help/matlab/enumeration-classes.html thing] to fully implement. A successful project would be to implement enough of classdef for most basic usages. Familiarity with Matlab's current classdef support would be a huge plus. Michael Goffioul and jwe can mentor this. Although there's already a substantial classdef support in current octave code base, there are still many areas that are unimplemented or need improvements. The main ones that come to my mind are:* support for events* support for enums* support for "import" (this requires good understanding of octave internals, especially the symbol table)* improving multiple inheritance and method resolution* honoring and computing "Sealed" attribute* support for function handle to methods == Improve MPI package == Octave Forge's [http://octave.sourceforge.net/mpi/index.html MPI package] is a wrapper for basic MPI functions for parallel computing. It is implemented by wrapping MPI function calls in simple DLD functions that map Octave's Datataypes to MPI Derived Datatypes. The proposed project deals with improving and extending the Octave MPI package, for example:* Octave MPI applications can currently be only run in batch mode, add the ability to launch parallel jobs and collect their output in an interactive Octave session.* Implement functions for non-blocking communication (already underwayMPI_Isend, MPI_Irecv)* Implement one-to-many (Broadcast, Scatter), many-to-one (Reduce, Gather), and many-to-many (All Reduce, Allgather)communication routines
=Graphics=
* On 'imagesc' plots, report the matrix values also based on the mouse position, updating on mouse moving.
* Create Add map-creating capabilities similar to the Matlab [http://www.mathworks.com/help/map/functionlist.html Mapping toolbox] for inclusion in the Octave Forge [https://sourceforge.net/p/octave/mapping mapping package]. * Add data cursor to trace data values in figure. == Lighting == Implement transparency and lighting in OpenGL backend(s). A basic implementation is available in [http://octave.svn.sourceforge.net/viewvc/octave/trunk/octave-forge/extra/jhandles/ JHandles]. This needs to be ported/re-implement/re-engineered/optimized in the C++ OpenGL renderer of Octave. == Object selection in OpenGL renderer == This project is about the implementation of a "getframe" function selection method of graphics elements within the OpenGL renderer [http://glprogramming.com/red/chapter13.html] == Non-OpenGL renderer == Besides the original gnuplot backend, Octave also contains an OpenGL-based renderer for advanced and more powerful 3D plots. However, OpenGL is not perfectly suited for 2D-only plots where other methods could result in better graphics. The purpose of this project is to implement an alternate graphics renderer for 2D only plots (although 3D is definitely not the focus, extending the new graphics renderer to support basic 3D features should also be taken into account). There is no particular toolkit/library that receives must be used, but natural candidates are:* [http://qt.nokia.com Qt]: the GUI is currently written in Qt and work is also in progress to provide a Qt/OpenGL based backend [https://github.com/goffioul/QtHandles]* [http://en.wikipedia.org/wiki/Cairo_%28software%29 Cairo]: this library is widely used and known to provides high-quality graphics with support for PS/PDF/SVG output. == TeX/LaTeX markup == Text objects in plots (like titles, labels, texts...) in the OpenGL renderer only support plain text mode without any formatting possibility. Support for TeX and/or LaTeX formatting needs to be added. * The TeX formatting support actually only consists of a very limited subset of the TeX language. This can be implemented directly in C++ into Octave by extending the existing text engine, avoiding to add a dependency on a full TeX system. Essentially, support for Greek letters, super/sub-scripts, and several mathematical symbols needs to be supported. For example, :<pre>\alpha \approx \beta_0 + \gamma^\chi</pre> :Would be rendered as, :&alpha; &asymp; &beta;<sub>0</sub> + &gamma;<sup>&chi;</sup> :This is analogous to how special characters may be included in a graphics handle wiki using html. :<pre>&amp;alpha; &amp;asymp; &amp;beta;<sub>0</sub> + &amp;gamma;<sup>&amp;chi;</sup></pre> :The text object's {{Codeline|extent}} for the rendered result needs to be calculated and returns the text placed the location specified by the text object's {{Codeline|position}} property. An itemized list of a 3D matrix from text objects properties can be found [http://www.gnu.org/software/octave/doc/interpreter/Text-Properties.html here]. * On the other hand, the LaTeX formatting support is expected to provide full LaTeX capabilities. This will require to use an external LaTeX system to produce text graphics window associated with in some format (to be specified) that handleis then integrated into Octave plots. :The matplotlib project [http://matplotlib.sourceforge.net/users/usetex.html has already done this in Python] and might be used as an example of how to do this in Octave. Mediawiki has also also done [http://en.wikipedia.org/wiki/Wikipedia:Texvc something similar]. There is also [http://forge.scilab.org/index.php/p/jlatexmath/ JLaTeXMath], a Java API to display LaTeX code in mathematical mode.
=History=
=Configuration and Installation=

*Split config.h into a part for Octave-specific configuration things (this part can be installed) and the generic HAVE_X type of configure information that should not be installed.
*Makefile changes:
**define shell commands or eliminate them
**consolidate targets

*Make it possible to configure so that installed binaries and shared libraries are stripped.
*Create a docs-only distribution?
*Better binary packaging and distribution<strike> Convert build system to a non-recursive Automake setup. See how Makefile.am files currently include module.mk files in subdirectories, extend this concept to the entire project so there is only one top-level Makefile.am. </strike> Done, especially on Windowsexcept for special dir libgnu which is the only SUBDIRS listed in configure*Octave Emacs mode needs maintenanceac.
=Documentation and On-Line Help=

*Document new features.
*Improve the Texinfo Documentation for the interpreter. It would be useful to have lots more examples, to not have so many forward references, and to not have very many simple lists of functions.
*The docs should mention something about efficiency and that using array operations is almost always a good idea for speed. *[[Doxygen ]] documentation for the C++ classes. *Make index entries more consistent to improve behavior of help -i'. *Make help -i' try to find a whole word match first.
*Clean up Make index entries more consistent to improve behavior of <code>help stuff-i</code>.
*Demo filesMake <code>help -i</code> try to find a whole word match first.
*Document C++ sources, to make it easier for newcomers to get into writing codeAdd more demo files.
*Flesh out this wiki
=Tests=
*Improved set of tests:[http://octave.1599824.n4.nabble.com/template/NamlServlet.jtp?macro=user_nodes&user=370633]**Tests for various functions. Would be nice to have a test file corresponding to every function.(see below)
**Tests for element by element operators: + - .* ./ .\ .^ | & < <= == >= > != !
**Tests for boolean operators: && ||
**Tests for all internal functions.
=Programming=* Implement a coverage tool for collecting coverage data and generating code coverage reports on m-file functions and scripts. This would be very useful for Octave development as well as for users who want a code coverage report for their own functions and scripts. We are far from even having one test for every function, so focus should be on getting the breadth of coverage first before trying to get the depth of 100% statement coverage. As of Dec 2015, 202 of 1020 m-files have no tests. Some of these will be plotting functions which have demos instead, but that leaves enough functions to be an interesting project. As of Dec 2015, there are 485 instances of C++ functions which need tests. After Octave is compiled, running the {{Codeline|make check}} build target will run the full test suite and generate a file called test/fntests.log in the build directory with a summary of the results. At the end of the file is a list of all functions for which no tests were found. An extract is posted in the [[files missing tests]] page. If you are not building Octave yourself, the test suite can be run on an installed binary copy by executing the {{Codeline|__run_test_suite__}} command at the Octave prompt. The fntests.log file will be written in the current directory in this case. There also need to be tests for functions written in the C++ files. See [[Add_BIST_tests_for_octave_functions_written_in_C%2B%2B]] for instructions and a list of instances.
*C++ namespace for Octave library functions.=Programming=
*Better error messages for missing operators?
*Share more code among the various _options functions.

*Use non-empty identifiers in all warnings and errors issued by Octave, see [[Easy projects#Miscellaneous]].

*Reduce the amount of datatypes in liboctave.
=Miscellaneous=
*:If possible, I would like to have the virtual memory system in Octave i.e., the all big files, the user see as one big array or such. There could be several user selectable models to do the virtual memory depending on what kind of data the user have (1d, 2d) and in what order they are processed (stream or random access).
Perhaps this can *An interface to gdb. Michael Smolsky <fnsiguc@weizmann.weizmann.ac.il> wrote:*:I was thinking about a tool, which could be very useful for me in my numerical simulation work. It is an interconnection between gdb and octave. We are often managing very large arrays of data in our fortran or c codes, which might be done entirely studied with the help of octave at the algorithm development stages. Assume you're coding, say, wave equation. And want to debug the code. It would be great to pick some array from the memory of the code you're developing, fft it and see the image as a library log-log plot of Mthe spectral density. I'm facing similar problems now. To avoid high c-development cost, I develop in matlab/octave, and then rewrite into c. It might be so much easier, if I could off-filesload a c array right from the debugger into octave, study it, and, perhaps, change some [many] values with a convenient matlab/octave syntax, similar to <code>a(:,51:250)=zeros(100,200)</code>, and then store it back into the memory of my c code.
*An interface to Implement gdbextensions for Octave types. Michael Smolsky Octave has the <fnsiguc@weizmann.weizmann.ac.ilcode>etc/gdbinit</code> wrote:*:I was thinking about a toolfile, which could be very useful has some basic support for me in my numerical simulation work. It is an interconnection between gdb and octave. We are often managing very large arrays of data in our fortran or c codes, which might be studied with displaying the help contents of octave at the algorithm development stages. Assume you're coding, say, wave equation. And want to debug the codeOctave types. It would be great Add more extensions to pick some array from the memory of the code you're developing, fft make it and see the image as a log-log plot of the spectral density. I'm facing similar problems now. To avoid high c-development cost, I develop in matlab/octave, and then rewrite into c. It might be so much easier, if I could off-load a c array right from the debugger into octave, study it, and, perhaps, change some [many] values with a convenient matlab/octave syntax, similar to <code>a(:,50:250)=zeros(100,200)</code>, debug octave_values and then store it back into the memory of my c codeother Octave types.
*Spatial statistics, including covariogram estimation and kriging -- perhaps via an interface to [http://www.gstat.org/ gstat]? * the [http://octave.sourceforge.net/miscellaneous/function/units.html units] function from the miscellaneous package works by parsing the output of from a call to GNU units. This can be made much more robust by writing it in C++ and including its library "units.h" =Marketing and Community= *Make the Octave website prettier/[[Project Infrastructure]] easier to maintain. * Make it easier for newcomers to contribute. * For marketing ideas, see the [https://openoffice.apache.org/orientation/intro-marketing. Maybe html Apache Open Office Introduction to Marketing] * Help design a new design, maybe user or a more [https://www.openoffice.org/marketing/ooocon2006/presentations/wednesday_c10.pdf developer survey] * Help prepare and deliver presentations about Octave at colleges and universities.** [https://indico.cern.ch/event/626097/contributions/2902420/attachments/1615292/2566811/2018-03-12-octave.pdf Octave talk] at [[OctConf 2018]].** "corporateWhat is Octave?" design [[File:Slides_octconf_gdf_jgh.pdf]] (if we[http://inversethought.com/hg/what-is-octave/ source]). == Improve Windows binary packaging == We are currently able to build and provide a [[Windows Installer|installer for Windows]]. The build process involves cross-compiling on a Linux system using a fork of the [http://mxe.cc/ MXE] project to build Octave and all of its dependencies. Any ideas for improving this process to make it easier or faster, or to improve the installer itself or the installation experience for Windows users would be appreciated. '''Skills Required'''re heading down : Knowledge of GNU build systems, Makefiles, configure files, chasing library dependencies, how to use a compiler. No m-scripting or C++ necessary, beyond understanding [http://david.rothlis.net/c/compilation_model/ the "paid support for Octave" pathC++ compilation model].
*Agora -- website for rapid collaboration related to GNU Octave. Talk to [[User:JordiGH|Jordi]]== Improve macOS binary packaging ==
*Move We would like to be able to easily generate binary packages for macOS. Right now, it's difficult and tedious to do so. Most OS X users install Octave using one of the source-based package managers such as Homebrew or MacPorts. Any way to help us build a binary package would be appreciated. Required knowledge is understanding how building binaries in macOS works. Our current approach to building binaries for Windows is to cross-compile from a GNU system using [http://octavemxe.sourceforgecc/ MXE], something similar may be possible for OS X ([http://lilypond.netorg/gub/ Octave-ForgeGUB] ?). '''Skills Required''': Knowledge of GNU build systems, Makefiles, configure files, chasing library dependencies, how to use a compiler. If you choose to work on GUB, Python will be required. No m-scripting or C++ necessary, beyond understanding [http://savannahdavid.gnurothlis.orgnet/projectsc/octavecompilation_model/ Savannahthe C++ compilation model] so everything is hosted in the same place.
=Performance=
*A profiler for Octave would be a very useful tool. And now we have one! But it really needs a better interface.
*Having {{Codeline|parfor}} functioning would speed code development and execution now that multicore architectures are widespread. See [http://octave.1599824.n4.nabble.com/Parfor-td4630575.html here] and [http://stackoverflow.com/questions/24970519/how-to-use-parallel-for-loop-in-octave-or-scilab here]. Existing code from the [[Parallel package | parallel]] and [http://octave.sourceforge.net/mpi/index.html mpi] packages could perhaps be adapted for this.
=Packaging=