GNU Octave

Last updated
GNU Octave
Developer(s) John W. Eaton and many others [1]
Initial release4 January 1993;31 years ago (4 January 1993) (first alpha release)
17 February 1994;30 years ago (17 February 1994) (version 1.0) [2]
Stable release
9.2.0 [3]   OOjs UI icon edit-ltr-progressive.svg / 7 June 2024;3 months ago (7 June 2024)
Repository
Written in C++ (main), Octave itself (scripts), C (wrapper code), Fortran (linear algebra wrapper code) [4]
Operating system Windows, macOS, Linux, BSD
Available in18 languages [5]
Type Scientific computing
License 2007: GPL-3.0-or-later [lower-alpha 1]
1992: GPL-2.0-or-later [lower-alpha 2]
Website octave.org

GNU Octave is a scientific programming language for scientific computing and numerical computation. Octave helps in solving linear and nonlinear problems numerically, and for performing other numerical experiments using a language that is mostly compatible with MATLAB. It may also be used as a batch-oriented language. As part of the GNU Project, it is free software under the terms of the GNU General Public License.

Contents

History

The project was conceived around 1988. [6] At first it was intended to be a companion to a chemical reactor design course. Full development was started by John W. Eaton in 1992. The first alpha release dates back to 4 January 1993 and on 17 February 1994 version 1.0 was released. Version 8.4.0 was released on 5 November 2023. [7]

The program is named after Octave Levenspiel, a former professor of the principal author. Levenspiel was known for his ability to perform quick back-of-the-envelope calculations. [8]

Development history

TimeAction
1988/19891st discussions (Book and Software)
February 1992Start of Development
January 1993News in Web (Version 0.60)
February 19941st Publication (Version 1.0.0 to 1.1.1) [9]
December 19962nd Publication (Version 2.0.x) with Windows Port (Cygwin) [10]
December 2007Publication of Version 3.0 (Milestone) [11]
29 May 2015Version 4.0.0 (stable GUI and new Syntax for OOP) [12] [13] [14] [15]
1 March 2019Publication of Octave 5.1.0 (QT5 preferred, Qt 4.8 minimum), hiDpi support [16]
26 November 2020Publication of Octave 6.1.0 (QT5 preferred, Qt 4.x deprecated for remove in 7) [17]
6 April 2022Publication of Octave 7.1.0 (QT5 preferred), improved graphics backend and matlab compatibility [18]
7 March 2023Publication of Octave 8.1.0, improved graphics backend and matlab compatibility [19]
14 March 2024Publication of Octave 9.1.0, general, matlab compatibility, and graphics improvements. [20]

Developments

In addition to use on desktops for personal scientific computing, Octave is used in academia and industry. For example, Octave was used on a massive parallel computer at Pittsburgh Supercomputing Center to find vulnerabilities related to guessing social security numbers. [21]

Acceleration with OpenCL or CUDA is also possible with use of GPUs. [22]

Technical details

Octave, the language

The Octave language is an interpreted programming language. It is a structured programming language (similar to C) and supports many common C standard library functions, and also certain UNIX system calls and functions. [23] However, it does not support passing arguments by reference [24] although function arguments are copy-on-write to avoid unnecessary duplication.

Octave programs consist of a list of function calls or a script. The syntax is matrix-based and provides various functions for matrix operations. It supports various data structures and allows object-oriented programming. [25]

Its syntax is very similar to MATLAB, and careful programming of a script will allow it to run on both Octave and MATLAB. [26]

Because Octave is made available under the GNU General Public License, it may be freely changed, copied and used. [8] The program runs on Microsoft Windows and most Unix and Unix-like operating systems, including Linux, Android, and macOS. [27] [28] [29]

Notable features

Command and variable name completion

Typing a TAB character on the command line causes Octave to attempt to complete variable, function, and file names (similar to Bash's tab completion). Octave uses the text before the cursor as the initial portion of the name to complete. [30]

Command history

When running interactively, Octave saves the commands typed in an internal buffer so that they can be recalled and edited.

Data structures

Octave includes a limited amount of support for organizing data in structures. In this example, we see a structure x with elements a, b, and c, (an integer, an array, and a string, respectively):

octave:1>x.a=1;x.b=[1,2;3,4];x.c="string";octave:2>x.aans=1octave:3>x.bans=1234octave:4>x.cans=stringoctave:5>xx=scalarstructurecontainingthefields:a=1b=1234c=string

Short-circuit Boolean operators

Octave's && and || logical operators are evaluated in a short-circuit fashion (like the corresponding operators in the C language), in contrast to the element-by-element operators & and |.

Increment and decrement operators

Octave includes the C-like increment and decrement operators ++ and -- in both their prefix and postfix forms. Octave also does augmented assignment, e.g. x += 5.

Unwind-protect

Octave supports a limited form of exception handling modelled after the unwind_protect of Lisp. The general form of an unwind_protect block looks like this:

unwind_protectbodyunwind_protect_cleanupcleanupend_unwind_protect

As a general rule, GNU Octave recognizes as termination of a given block either the keyword end (which is compatible with the MATLAB language) or a more specific keyword endblock or, in some cases, end_block. As a consequence, an unwind_protect block can be terminated either with the keyword end_unwind_protect as in the example, or with the more portable keyword end.

The cleanup part of the block is always executed. In case an exception is raised by the body part, cleanup is executed immediately before propagating the exception outside the block unwind_protect.

GNU Octave also supports another form of exception handling (compatible with the MATLAB language):

trybodycatchexception_handlingend

This latter form differs from an unwind_protect block in two ways. First, exception_handling is only executed when an exception is raised by body. Second, after the execution of exception_handling the exception is not propagated outside the block (unless a rethrow( lasterror ) statement is explicitly inserted within the exception_handling code).

Variable-length argument lists

Octave has a mechanism for handling functions that take an unspecified number of arguments without explicit upper limit. To specify a list of zero or more arguments, use the special argument varargin as the last (or only) argument in the list. varargin is a cell array containing all the input arguments.

functions=plus (varargin)if(nargin==0)s=0;elses=varargin{1}+plus(varargin{2:nargin});endend

Variable-length return lists

A function can be set up to return any number of values by using the special return value varargout. For example:

functionvarargout=multiassign (data)fork=1:nargoutvarargout{k}=data(:,k);endend

C++ integration

It is also possible to execute Octave code directly in a C++ program. For example, here is a code snippet for calling rand([10,1]):

#include<octave/oct.h>...ColumnVectorNumRands(2);NumRands(0)=10;NumRands(1)=1;octave_value_listf_arg,f_ret;f_arg(0)=octave_value(NumRands);f_ret=feval("rand",f_arg,1);Matrixunis(f_ret(0).matrix_value());

C and C++ code can be integrated into GNU Octave by creating oct files, or using the MATLAB compatible MEX files.

MATLAB compatibility

Octave has been built with MATLAB compatibility in mind, and shares many features with MATLAB:

  1. Matrices as fundamental data type.
  2. Built-in support for complex numbers.
  3. Powerful built-in math functions and extensive function libraries.
  4. Extensibility in the form of user-defined functions.

Octave treats incompatibility with MATLAB as a bug; therefore, it could be considered a software clone, which does not infringe software copyright as per Lotus v. Borland court case.

MATLAB scripts from the MathWorks' FileExchange repository in principle are compatible with Octave. However, while they are often provided and uploaded by users under an Octave compatible and proper open source BSD license, the FileExchange Terms of use prohibit any usage beside MathWorks' proprietary MATLAB. [31] [32] [33]

Syntax compatibility

There are a few purposeful, albeit minor, syntax additions Archived 2012-04-26 at the Wayback Machine :

  1. Comment lines can be prefixed with the # character as well as the % character;
  2. Various C-based operators ++, --, +=, *=, /= are supported;
  3. Elements can be referenced without creating a new variable by cascaded indexing, e.g. [1:10](3);
  4. Strings can be defined with the double-quote " character as well as the single-quote ' character;
  5. When the variable type is single (a single-precision floating-point number), Octave calculates the "mean" in the single-domain (MATLAB in double-domain) which is faster but gives less accurate results;
  6. Blocks can also be terminated with more specific Control structure keywords, i.e., endif, endfor, endwhile, etc.;
  7. Functions can be defined within scripts and at the Octave prompt;
  8. Presence of a do-until loop (similar to do-while in C).

Function compatibility

Many, but not all, of the numerous MATLAB functions are available in GNU Octave, some of them accessible through packages in Octave Forge. The functions available as part of either core Octave or Forge packages are listed online Archived 2024-03-14 at the Wayback Machine .

A list of unavailable functions is included in the Octave function __unimplemented.m__. Unimplemented functions are also listed under many Octave Forge packages in the Octave Wiki.

When an unimplemented function is called the following error message is shown:

octave:1>guidewarning:the'guide'functionisnotyetimplementedinOctavePleaseread<http://www.octave.org/missing.html>tolearnhowyoucancontributemissingfunctionality.error:'guide'undefinednearline1column1

User interfaces

Octave comes with an official graphical user interface (GUI) and an integrated development environment (IDE) based on Qt. It has been available since Octave 3.8, [34] and has become the default interface (over the command-line interface) with the release of Octave 4.0. [12] It was well-received by an EDN contributor, who wrote "[Octave] now has a very workable GUI" in reviewing the then-new GUI in 2014. [35]

Several 3rd-party graphical front-ends have also been developed, like ToolboX for coding education.

GUI applications

With Octave code, the user can create GUI applications. See GUI Development (GNU Octave (version 7.1.0)). Below are some examples:

Button, edit control, checkbox

# create figure and panel on itf=figure;# create a button (default style)b1=uicontrol(f,"string","A Button","position",[101015040]);# create an edit controle1=uicontrol(f,"style","edit","string","editable text","position",[106030040]);# create a checkboxc1=uicontrol(f,"style","checkbox","string","a checkbox","position",[1012015040]);

Textbox

prompt={"Width","Height","Depth"};defaults={"1.10","2.20","3.30"};rowscols=[1,10;2,20;3,30];dims=inputdlg(prompt,"Enter Box Dimensions",rowscols,defaults);

Listbox with message boxes.

my_options={"An item","another","yet another"};[sel,ok]=listdlg("ListString",my_options,"SelectionMode","Multiple");if(ok==1)msgbox("You selected:");fori=1:numel(sel)msgbox(sprintf("\t%s",my_options{sel(i)}));endforelsemsgbox("You cancelled.");endif

Radiobuttons

# create figure and panel on itf=figure;# create a button groupgp=uibuttongroup(f,"Position",[00.511])# create a buttons in the groupb1=uicontrol(gp,"style","radiobutton","string","Choice 1","Position",[1015010050]);b2=uicontrol(gp,"style","radiobutton","string","Choice 2","Position",[105010030]);# create a button not in the groupb3=uicontrol(f,"style","radiobutton","string","Not in the group","Position",[105010050]);

Packages

Octave also has many packages available. Those packages are located at Octave-Forge Octave Forge - Packages, or Github Octave Packages. It is also possible for anyone to create and maintain packages.

Comparison with other similar software

Alternatives to GNU Octave under an open source license, other than the aforementioned MATLAB, include Scilab and FreeMat. [36] [37] [38] [39] Octave is more compatible with MATLAB than Scilab is, [36] [40] [41] and FreeMat has not been updated since June 2013. [42]

Also the Julia programming language and its plotting capabilities has similarities with GNU Octave.

See also

Notes

  1. ↑ GPL-3.0-or-later since 2007-10-12.
  2. ↑ GPL-2.0-or-later from 1992-02-19 until 2007-10-11.

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References

  1. ↑ Rik (10 June 2015). "contributors.in" . Retrieved 14 June 2015.
  2. ↑ ""Full-time development began in the Spring of 1992. The first alpha release was January 4, 1993, and version 1.0 was released February 17, 1994."".
  3. ↑ "GNU Octave 9.2.0 Released". 7 June 2024. Retrieved 10 July 2024.
  4. ↑ "Building - Octave". wiki.octave.org. GNU. Retrieved 1 May 2018.
  5. ↑ "Basque, Belarusian, Catalan, Chinese, Dutch, English, French, German, Hungarian, Italian, Japanese, Latvian, Portuguese (Brazil), Portuguese (Portugal), Russian, Spanish, Turkish, Ukrainian". hg.savannah.gnu.org.
  6. ↑ "About GNU Octave". www.gnu.org. GNU. Retrieved 1 May 2018.
  7. ↑ "GNU Octave 8.4.0 Released". octave.org. 2023-11-05. Retrieved 2023-11-20.
  8. 1 2 Eaton, John W. "About Octave" . Retrieved 2009-06-28.
  9. ↑ "GNU Octave Version 1". www.gnu.org.
  10. ↑ "GNU Octave Version 2". www.gnu.org.
  11. ↑ "GNU Octave Version 3". www.gnu.org.
  12. 1 2 "GNU Octave Version 4.0". www.gnu.org.
  13. ↑ "GNU Octave 4.0.0 Released". www.gnu.org. 29 May 2015.
  14. ↑ "GNU Octave 4.0.1 Released". www.gnu.org. 23 March 2016.
  15. ↑ "GNU Octave 4.0.3 Released". www.gnu.org. 2 July 2016.
  16. ↑ "GNU Octave Version 5". www.gnu.org.
  17. ↑ "GNU Octave 6.1.0 Released". www.gnu.org. 26 November 2020.
  18. ↑ "GNU Octave 7.1.0 Released". www.gnu.org. 6 April 2022.
  19. ↑ "GNU Octave 8.1.0 Released". octave.org. 7 March 2023.
  20. ↑ "GNU Octave Version 9". octave.org. Retrieved 2024-03-25.
  21. ↑ "Social Security Number Vulnerability Findings Relied on Supercomputing". 8 July 2009. Archived from the original on 29 February 2012.
  22. ↑ "Drop-in Acceleration of GNU Octave". NVIDIA Developer Blog. June 5, 2014.
  23. ↑ "GNU Octave - Controlling subprocesses". 14 November 2008. Archived from the original on 7 January 2009. Retrieved 2009-01-28.
  24. ↑ "GNU Octave" . Retrieved 2009-01-28.
  25. ↑ "Summary of important user-visible changes for version 3.2" . Retrieved 2012-01-05.
  26. ↑ "FAQ: MATLAB compatibility". Archived from the original on 2011-11-21. Retrieved 2009-04-04.
  27. ↑ "FAQ: Getting Octave". Archived from the original on 2011-11-21. Retrieved 2009-04-04.
  28. ↑ "Top (GNU Octave (version 6.3.0))". octave.org.
  29. ↑ "Octave for Android - Octave". wiki.octave.org. Retrieved 2021-08-23.
  30. ↑ Eaton, John W. "Letting Readline Type For You". GNU Octave Reference Manual. Archived from the original on 2018-02-12. Retrieved 2016-07-29.
  31. ↑ "FAQ - Octave". wiki.octave.org. Retrieved 2022-12-05.
  32. ↑ "MATLAB Central Terms of Use". www.mathworks.com. Retrieved 2022-12-05.
  33. ↑ "File Exchange Licensing FAQ". www.mathworks.com. Retrieved 2022-12-05.
  34. ↑ "GNU Octave Version 3.8". www.gnu.org.
  35. ↑ Hageman, Steve (7 February 2014). "GNU Octave hits a high note". EDN .
  36. 1 2 Trappenberg, Thomas (2010). Fundamentals of Computational Neuroscience. Oxford University Press. p. 361. ISBN   978-0-19-956841-3.
  37. ↑ Muhammad, A; Zalizniak, V (2011). Practical Scientific Computing . Woodhead Publishing. p.  3. ISBN   978-0-85709-226-7.
  38. ↑ Megrey, Bernard A.; Moksness, Erlend (2008). Computers in Fisheries Research . Springer Science & Business Media. p.  345. ISBN   978-1-4020-8636-6.
  39. ↑ Kapuno, Raul Raymond (2008). Programming for Chemical Engineers Using C, C++, and MATLAB. Jones & Bartlett Publishers. p. 365. ISBN   978-1-934015-09-4.
  40. ↑ Herman, Russell L. (2013). A Course in Mathematical Methods for Physicists. CRC Press. p. 42. ISBN   978-1-4665-8467-9.
  41. ↑ Wouwer, Alain Vande; Saucez, Philippe; Vilas, Carlos (2014). Simulation of ODE/PDE Models with MATLAB, Octave and Scilab: Scientific and Engineering Applications. Springer. pp. 114–115. ISBN   978-3-319-06790-2.
  42. ↑ "FreeMat". freemat.sourceforge.net. Retrieved 22 February 2020.

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