MATLAB

For the region in Bangladesh, see Matlab (Bangladesh).

Not to be confused with MATHLAB.

MATLAB

L-shaped membrane logo
File:MATLAB R2013a Win8 screenshot.png MATLAB R2013a running on Windows 8
Developer(s)	MathWorks
Initial release	1984 (1984)
Stable release	R2014a / March 6, 2014 (2014-03-06)
Preview release	R2014b / June 11, 2014 (2014-06-11)
Written in	C, C++, Java, MATLAB
Operating system	Cross-platform: Microsoft Windows, Linux, and Mac OS X
Platform	IA-32, x86-64
Type	Technical computing
License	Proprietary commercial software
Website	MATLAB product page

MATLAB

Paradigm	multi-paradigm: imperative, procedural, object-oriented, array
Designed by	Cleve Moler
Developer	MathWorks
First appeared	late 1970s
Stable release	8.3 / 2014
Preview release	8.4 / 2014
Typing discipline	dynamic, weak
OS	Cross-platform
Filename extensions	.m
Website	www.mathworks.com/products/matlab.html,%20https://de.mathworks.com/products/matlab.html
MATLAB Programming at Wikibooks

MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programming language. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, and Fortran.

Although MATLAB is intended primarily for numerical computing, an optional toolbox uses the MuPAD symbolic engine, allowing access to symbolic computing capabilities. An additional package, Simulink, adds graphical multi-domain simulation and Model-Based Design for dynamic and embedded systems.

In 2004, MATLAB had around one million users across industry and academia. MATLAB users come from various backgrounds of engineering, science, and economics. MATLAB is widely used in academic and research institutions as well as industrial enterprises.

History

Cleve Moler, the chairman of the computer science department at the University of New Mexico, started developing MATLAB in the late 1970s. He designed it to give his students access to LINPACK and EISPACK without them having to learn Fortran. It soon spread to other universities and found a strong audience within the applied mathematics community. Jack Little, an engineer, was exposed to it during a visit Moler made to Stanford University in 1983. Recognizing its commercial potential, he joined with Moler and Steve Bangert. They rewrote MATLAB in C and founded MathWorks in 1984 to continue its development. These rewritten libraries were known as JACKPAC. In 2000, MATLAB was rewritten to use a newer set of libraries for matrix manipulation, LAPACK.

MATLAB was first adopted by researchers and practitioners in control engineering, Little's specialty, but quickly spread to many other domains. It is now also used in education, in particular the teaching of linear algebra and numerical analysis, and is popular amongst scientists involved in image processing.

Syntax

The MATLAB application is built around the MATLAB language, and most use of MATLAB involves typing MATLAB code into the Command Window (as an interactive mathematical shell), or executing text files containing MATLAB code, including scripts and/or functions.

Variables

Variables are defined using the assignment operator, =. MATLAB is a weakly typed programming language because types are implicitly converted. It is an inferred typed language because variables can be assigned without declaring their type, except if they are to be treated as symbolic objects, and that their type can change. Values can come from constants, from computation involving values of other variables, or from the output of a function. For example:

>> x = 17
x =
 17

>> x = 'hat'
x =
hat

>> y = x + 0
y =
       104        97       116

>> x = [3*4, pi/2]
x =
   12.0000    1.5708

>> y = 3*sin(x)
y =
   -1.6097    3.0000

Vectors/matrices

A simple array is defined using the colon syntax: init:increment:terminator. For instance:

>> array = 1:2:9
array =
 1 3 5 7 9

defines a variable named array (or assigns a new value to an existing variable with the name array) which is an array consisting of the values 1, 3, 5, 7, and 9. That is, the array starts at 1 (the init value), increments with each step from the previous value by 2 (the increment value), and stops once it reaches (or to avoid exceeding) 9 (the terminator value).

>> array = 1:3:9
array =
 1 4 7

the increment value can actually be left out of this syntax (along with one of the colons), to use a default value of 1.

>> ari = 1:5
ari =
 1 2 3 4 5

assigns to the variable named ari an array with the values 1, 2, 3, 4, and 5, since the default value of 1 is used as the incrementer.

Indexing is one-based, which is the usual convention for matrices in mathematics, although not for some programming languages such as C, C++, and Java.

Matrices can be defined by separating the elements of a row with blank space or comma and using a semicolon to terminate each row. The list of elements should be surrounded by square brackets: []. Parentheses: () are used to access elements and subarrays (they are also used to denote a function argument list).

>> A = [16 3 2 13; 5 10 11 8; 9 6 7 12; 4 15 14 1]
A =
 16  3  2 13
  5 10 11  8
  9  6  7 12
  4 15 14  1

>> A(2,3)
ans =
 11

Sets of indices can be specified by expressions such as "2:4", which evaluates to [2, 3, 4]. For example, a submatrix taken from rows 2 through 4 and columns 3 through 4 can be written as:

>> A(2:4,3:4)
ans =
 11 8
 7 12
 14 1

A square identity matrix of size n can be generated using the function eye, and matrices of any size with zeros or ones can be generated with the functions zeros and ones, respectively.

>> eye(3)
ans =
 1 0 0
 0 1 0
 0 0 1

>> zeros(2,3)
ans =
 0 0 0
 0 0 0

>> ones(2,3)
ans =
 1 1 1
 1 1 1

Most MATLAB functions can accept matrices and will apply themselves to each element. For example, mod(2*J,n) will multiply every element in "J" by 2, and then reduce each element modulo "n". MATLAB does include standard "for" and "while" loops, but (as in other similar applications such as R), using the vectorized notation often produces code that is faster to execute. This code, excerpted from the function magic.m, creates a magic square M for odd values of n (MATLAB function meshgrid is used here to generate square matrices I and J containing 1:n).

[J,I] = meshgrid(1:n);
A = mod(I + J - (n + 3) / 2, n);
B = mod(I + 2 * J - 2, n);
M = n * A + B + 1;

Structures

MATLAB has structure data types. Since all variables in MATLAB are arrays, a more adequate name is "structure array", where each element of the array has the same field names. In addition, MATLAB supports dynamic field names (field look-ups by name, field manipulations, etc.). Unfortunately, MATLAB JIT does not support MATLAB structures, therefore just a simple bundling of various variables into a structure will come at a cost.

Function handles

MATLAB supports elements of lambda calculus by introducing function handles, or function references, which are implemented either in .m files or anonymous/nested functions.

Classes

Although MATLAB has classes, the syntax and calling conventions are significantly different from other languages. MATLAB has value classes and reference classes, depending on whether the class has handle as a super-class (for reference classes) or not (for value classes).

Method call behavior is different between value and reference classes. For example, a call to a method

object.method();

can alter any member of object only if object is an instance of a reference class.

Graphics and graphical user interface programming

MATLAB supports developing applications with graphical user interface features. MATLAB includes GUIDE (GUI development environment) for graphically designing GUIs. It also has tightly integrated graph-plotting features. For example the function plot can be used to produce a graph from two vectors x and y. The code:

x = 0:pi/100:2*pi;
y = sin(x);
plot(x,y)

produces the following figure of the sine function:

A MATLAB program can produce three-dimensional graphics using the functions surf, plot3 or mesh.

[X,Y] = meshgrid(-10:0.25:10,-10:0.25:10); f = sinc(sqrt((X/pi).^2+(Y/pi).^2)); mesh(X,Y,f); axis([-10 10 -10 10 -0.3 1]) xlabel('{\bfx}') ylabel('{\bfy}') zlabel('{\bfsinc} ({\bfR})') hidden off		[X,Y] = meshgrid(-10:0.25:10,-10:0.25:10); f = sinc(sqrt((X/pi).^2+(Y/pi).^2)); surf(X,Y,f); axis([-10 10 -10 10 -0.3 1]) xlabel('{\bfx}') ylabel('{\bfy}') zlabel('{\bfsinc} ({\bfR})')
This code produces a wireframe 3D plot of the two-dimensional unnormalized sinc function:		This code produces a surface 3D plot of the two-dimensional unnormalized sinc function:

In MATLAB, graphical user interfaces can be programmed with the GUI design environment (GUIDE) tool.

Object-oriented programming

MATLAB's support for object-oriented programming includes classes, inheritance, virtual dispatch, packages, pass-by-value semantics, and pass-by-reference semantics.

classdef hello
    methods
        function greet(this)
            disp('Hello!')
        end
    end
end

When put into a file named hello.m, this can be executed with the following commands:

>> x = hello;
>> x.greet();
Hello!

Interfacing with other languages

MATLAB can call functions and subroutines written in the C programming language or Fortran. A wrapper function is created allowing MATLAB data types to be passed and returned. The dynamically loadable object files created by compiling such functions are termed "MEX-files" (for MATLAB executable).

Libraries written in Perl, Java, ActiveX or .NET can be directly called from MATLAB, and many MATLAB libraries (for example XML or SQL support) are implemented as wrappers around Java or ActiveX libraries. Calling MATLAB from Java is more complicated, but can be done with a MATLAB toolbox which is sold separately by MathWorks, or using an undocumented mechanism called JMI (Java-to-MATLAB Interface), (which should not be confused with the unrelated Java Metadata Interface that is also called JMI).

As alternatives to the MuPAD based Symbolic Math Toolbox available from MathWorks, MATLAB can be connected to Maple or Mathematica.

Libraries also exist to import and export MathML.

License

MATLAB is a proprietary product of MathWorks, so users are subject to vendor lock-in. Although MATLAB Builder products can deploy MATLAB functions as library files which can be used with .NET or Java application building environment, future development will still be tied to the MATLAB language.

Each toolbox is purchased separately. If an evaluation license is requested, the MathWorks sales department requires detailed information about the project for which MATLAB is to be evaluated. If granted (which it often is), the evaluation license is valid for two to four weeks. A student version of MATLAB is also available.

It has been reported that EU competition regulators are investigating whether MathWorks refused to sell licenses to a competitor.

Alternatives

See also: list of numerical analysis software and comparison of numerical analysis software

MATLAB has a number of competitors. Commercial competitors include Mathematica, TK Solver, Maple, and IDL. There are also free open source alternatives to MATLAB, in particular GNU Octave, Scilab, FreeMat, Julia, and Sage which are intended to be mostly compatible with the MATLAB language. Among other languages that treat arrays as basic entities (array programming languages) are APL, Fortran 90 and higher, S-Lang, as well as the statistical languages R and S. There are also libraries to add similar functionality to existing languages, such as IT++ for C++, Perl Data Language for Perl, ILNumerics for .NET, NumPy/SciPy for Python, and Numeric.js for JavaScript.

GNU Octave stands out as it treats incompatibility with MATLAB as a bug (see GNU Octave#Matlab), therefore it aims to provide a software clone.

Release history

Version	Release name	Number	Bundled JVM	Year	Release Date	Notes
MATLAB 1.0				1984
MATLAB 2				1986
MATLAB 3				1987
MATLAB 3.5				1990		Ran on MS-DOS but required at least a 386 processor. Version 3.5m required math coprocessor
MATLAB 4				1992
MATLAB 4.2c				1994		Ran on Windows 3.1. Required a math coprocessor.
MATLAB 5.0	Volume 8			1996	December, 1996	Unified releases across all platforms.
MATLAB 5.1	Volume 9			1997	May, 1997
MATLAB 5.1.1	R9.1
MATLAB 5.2	R10			1998	March, 1998
MATLAB 5.2.1	R10.1
MATLAB 5.3	R11			1999	January, 1999
MATLAB 5.3.1	R11.1				November, 1999
MATLAB 6.0	R12	12	1.1.8	2000	November, 2000	First release with bundled Java Virtual Machine (JVM).
MATLAB 6.1	R12.1		1.3.0	2001	June, 2001
MATLAB 6.5	R13	13	1.3.1	2002	July, 2002
MATLAB 6.5.1	R13SP1			2003
MATLAB 6.5.2	R13SP2
MATLAB 7	R14	14	1.4.2	2004	June, 2004
MATLAB 7.0.1	R14SP1				October, 2004
MATLAB 7.0.4	R14SP2		1.5.0	2005	March 7, 2005	Support for memory-mapped files.
MATLAB 7.1	R14SP3		1.5.0		September 1, 2005
MATLAB 7.2	R2006a	15	1.5.0	2006	March 1, 2006
MATLAB 7.3	R2006b	16	1.5.0		September 1, 2006	HDF5-based MAT-file support
MATLAB 7.4	R2007a	17	1.5.0_07	2007	March 1, 2007	New bsxfun function to apply element-by-element binary operation with singleton expansion enabled.
MATLAB 7.5	R2007b	18	1.6.0		September 1, 2007	Last release for Windows 2000 and PowerPC Mac. License Server support for Windows Vista. New internal format for P-code.
MATLAB 7.6	R2008a	19	1.6.0	2008	March 1, 2008	Major enhancements to object-oriented programming capabilities with a new class definition syntax, and ability to manage namespaces with packages.
MATLAB 7.7	R2008b	20	1.6.0_04		October 9, 2008	New Map data structure. Upgrades to random number generators.
MATLAB 7.8	R2009a	21	1.6.0_04	2009	March 6, 2009	First release for 32-bit & 64-bit Microsoft Windows 7. New external interface to Microsoft .NET Framework.
MATLAB 7.9	R2009b	22	1.6.0_12		September 4, 2009	First release for Intel 64-bit Mac, and last for Solaris SPARC. New usage for the tilde operator (~) to ignore arguments in function calls.
MATLAB 7.9.1	R2009bSP1		1.6.0_12	2010	April 1, 2010	bug fixes.
MATLAB 7.10	R2010a	23	1.6.0_12		March 5, 2010	Last release for Intel 32-bit Mac.
MATLAB 7.11	R2010b	24	1.6.0_17		September 3, 2010	Support for enumerations added.
MATLAB 7.11.1	R2010bSP1		1.6.0_17	2011	March 17, 2011	bug fixes and updates.
MATLAB 7.11.2	R2010bSP2		1.6.0_17		April 5, 2012	bug fixes.
MATLAB 7.12	R2011a	25	1.6.0_17		April 8, 2011	New rng function to control random number generation.
MATLAB 7.13	R2011b	26	1.6.0_17		September 1, 2011	Access/change parts of variables directly in MAT-files, without loading into memory. Increased maximum local workers with Parallel Computing Toolbox from 8 to 12.
MATLAB 7.14	R2012a	27	1.6.0_17	2012	March 1, 2012
MATLAB 8	R2012b	28	1.6.0_17		September 11, 2012	First release with Toolstrip interface. MATLAB Apps. Redesigned documentation system.
MATLAB 8.1	R2013a	29	1.6.0_17	2013	March 7, 2013	New unit testing framework.
MATLAB 8.2	R2013b	30	1.7.0_11		September 6, 2013	New table data type.
MATLAB 8.3	R2014a	31	1.7.0_11	2014	March 7, 2014	Simplified compiler setup for building MEX-files. USB Webcams support in core MATLAB. Number of local workers no longer limited to 12 with Parallel Computing Toolbox.
MATLAB 8.4	R2014b	32	1.7.0_11	2014	October 3, 2014	New class-based graphics engine (a.k.a. HG2). Tabbing functionality in GUI. Improved user toolbox packaging and help files. New objects for date/time manipulations.

The number (or Release number) is the version reported by Concurrent License Manager program FLEXlm.

For a complete list of changes of both MATLAB and official toolboxes, consult the MATLAB release notes.

File extensions

MATLAB

.fig

MATLAB figure

.m

MATLAB code (function, script, or class)

.mat

MATLAB data (binary file for storing variables)

.mex... (.mexw32, .mexw64, .mexglx, ...)

MATLAB executable MEX-files (platform specific, e.g. ".mexmac" for the Mac, ".mexglx" for Linux, etc.)

.p

MATLAB content-obscured .m file (P-code)

.mlappinstall

MATLAB packaged App Installer

Simulink

.mdl

Simulink Model

.mdlp

Simulink Protected Model

.slx

Simulink Model (SLX format)

.slxp

Simulink Protected Model (SLX format)

Simscape

.ssc

Simscape Model

MuPAD

.mn

MuPAD Notebook

.mu

MuPAD Code

.xvc, .xvz

MuPAD Graphics

Third-party

.jkt

GPU Cache file generated by Jacket for MATLAB (AccelerEyes)

.mum

MATLAB CAPE-OPEN Unit Operation Model File (AmsterCHEM)

Easter eggs

Several easter eggs exist in MATLAB. These include hidden pictures, and jokes. For example, typing in "spy" will generate a picture of the spies from Spy vs Spy. "Spy" was changed to an image of a dog in recent releases (R2011B). Typing in "why" randomly outputs a philosophical answer. Other commands include "penny", "toilet", "image", and "life". Not every Easter egg appears in every version of MATLAB.

Screen capture of two easter eggs in MATLAB 3.5.

See also

• List of numerical analysis software
• Comparison of numerical analysis software

References

• Gilat, Amos (2004). MATLAB: An Introduction with Applications 2nd Edition. John Wiley & Sons. ISBN 978-0-471-69420-5.
• Quarteroni, Alfio; Saleri, Fausto (2006). Scientific Computing with MATLAB and Octave. Springer. ISBN 978-3-540-32612-0.
• Ferreira, A.J.M. (2009). MATLAB Codes for Finite Element Analysis. Springer. ISBN 978-1-4020-9199-5.
• Lynch, Stephen (2004). Dynamical Systems with Applications using MATLAB. Birkhäuser. ISBN 978-0-8176-4321-8.

External links

• "Linear algebra software packages", Encyclopedia of Mathematics, EMS Press, 2001 [1994]
• MATLAB overview, at the MathWorks website
• Platform Road Map, at the MathWorks website.
• System Requirements, at the MathWorks website.
• MATLAB Central File Exchange – Library of over 18,000 user-contributed MATLAB files and toolboxes, mostly distributed under BSD License.
• Template:Dmoz
• MATLAB Central Newsreader – a web-based newsgroups reader hosted by MathWorks for comp.soft-sys.matlab
• LiteratePrograms (MATLAB)
• MATLAB Central Blogs
• Physical Modeling in MATLAB by Allen B. Downey, Green Tea Press, PDF, ISBN 978-0-615-18550-7. An introduction to MATLAB.
• Writing Fast MATLAB Code by Pascal Getreuer
• Calling MATLAB from Java: MatlabControl JMI Wrapper, The MatlabJava Server, MatlabControl
• International Online Workshop on MATLAB and Simulink by WorldServe Education
• MATLAB tag on Stack Overflow.
• MATLAB Answers – a collaborative environment for finding the best answers to your questions about MATLAB, Simulink, and related products.
• Cody – a MATLAB Central game that challenges and expands your knowledge of MATLAB.
• MATLAB Online Programming Contest
• Trendy – a MATLAB based web service for tracking and plotting trends.