As of 2020[update], MATLAB has more than four million users worldwide.[19] They come from various backgrounds ofengineering,science, andeconomics. As of 2017[update], more than 5000 global colleges and universities use MATLAB to support instruction and research.[20]
Before version 1.0, MATLAB "was not a programming language; it was a simple interactivematrix calculator. There were no programs, no toolboxes, no graphics. And noODEs orFFTs."[23]
The first early version of MATLAB was completed in the late 1970s.[21] The software was disclosed to the public for the first time in February 1979 at theNaval Postgraduate School in California.[22] Early versions of MATLAB were simplematrix calculators with 71 pre-built functions.[24] At the time, MATLAB was distributed for free[25][26] to universities.[27] Moler would leave copies at universities he visited and the software developed a strong following in the math departments of university campuses.[28]: 5
In the 1980s, Cleve Moler metJohn N. Little. They decided to reprogram MATLAB inC and market it for theIBMdesktops that were replacingmainframe computers at the time.[21] John Little and programmer Steve Bangert re-programmed MATLAB in C, created the MATLAB programming language, and developed features for toolboxes.[22]
By the end of the 1980s, several hundred copies of MATLAB had been sold to universities for student use.[22] The software was popularized largely thanks to toolboxes created by experts in various fields for performing specialized mathematical tasks.[25] Many of the toolboxes were developed as a result ofStanford students that used MATLAB in academia, then brought the software with them to the private sector.[22]
In 2000, MathWorks added a Fortran-based library for linear algebra in MATLAB 6, replacing the software's original LINPACK and EISPACK subroutines that were in C.[24] MATLAB's Parallel Computing Toolbox was released at the 2004 Supercomputing Conference and support for graphics processing units (GPUs) was added to it in 2010.[24]
The MATLAB application is built around the MATLAB programming language.
Common usage of the MATLAB application involves using the "Command Window" as an interactive mathematicalshell or executingtext files containing MATLAB code.[34]
MATLAB is aweakly typed programming language becausetypes are implicitly converted.[35] It is aninferredtyped language because variables can be assigned without declaring their type, except if they are to be treated as symbolic objects,[36] and that their type can change.
Values can come fromconstants, from computation involving values of other variables, or from the output of afunction.
A simple array is defined using the colon syntax:initial:increment:terminator. For instance:
>>array=1:2:9array = 1 3 5 7 9
defines a variable namedarray (or assigns a new value to an existing variable with the namearray) which is an array consisting of the values 1, 3, 5, 7, and 9. That is, the array starts at 1 (theinitial value), increments with each step from the previous value by 2 (theincrement value), and stops once it reaches (or is about to exceed) 9 (theterminator value).
Theincrement value can actually be left out of this syntax (along with one of the colons), to use a default value of 1.
>>ari=1:5ari = 1 2 3 4 5
assigns to the variable namedari an array with the values 1, 2, 3, 4, and 5, since the default value of 1 is used as the increment.
Indexing is one-based,[37] which is the usual convention formatrices in mathematics, unlike zero-based indexing commonly used in other programming languages such as C,C++, andJava.
Matrices can be defined by separating the elements of a row with blank space or comma and using a semicolon to separate the rows. 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).
Sets of indices can be specified by expressions such as2:4, 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 squareidentity matrix of sizen can be generated using the functioneye, and matrices of any size with zeros or ones can be generated with the functionszeros andones, respectively.
Transposing a vector or a matrix is done either by the functiontranspose or by adding dot-prime after the matrix (without the dot, prime will performconjugate transpose for complex arrays):
Most functions accept arrays as input and operate element-wise on each element. For example,mod(2*J,n) will multiply every element inJ by 2, and then reduce each element modulon. MATLAB does include standardfor andwhile loops, but (as in other similar applications such asAPL andR), using thevectorized notation is encouraged and is often faster to execute. The following code, excerpted from the functionmagic.m, creates amagic squareM for odd values ofn (MATLAB functionmeshgrid is used here to generate square matricesI andJ containing):
MATLAB supports structure data types.[38] 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[39] (field look-ups by name, field manipulations, etc.).
When creating a MATLAB function, the name of the file should match the name of the first function in the file. Valid function names begin with an alphabetic character, and can contain letters, numbers, or underscores. Variables and functions are case sensitive.[40]
rgbImage=imread('ecg.png');grayImage=rgb2gray(rgbImage);% for non-indexed imageslevel=graythresh(grayImage);% threshold for converting image to binary,binaryImage=im2bw(grayImage,level);% Extract the individual red, green, and blue color channels.redChannel=rgbImage(:,:,1);greenChannel=rgbImage(:,:,2);blueChannel=rgbImage(:,:,3);% Make the black parts pure red.redChannel(~binaryImage)=255;greenChannel(~binaryImage)=0;blueChannel(~binaryImage)=0;% Now recombine to form the output image.rgbImageOut=cat(3,redChannel,greenChannel,blueChannel);imshow(rgbImageOut);
MATLAB supports elements oflambda calculus by introducing function handles,[41] or function references, which are implemented either in .m files or anonymous[42]/nested functions.[43]
MATLAB supportsobject-oriented programming including classes,inheritance, virtual dispatch, packages,pass-by-value semantics, andpass-by-reference semantics.[44] However, the syntax and calling conventions are significantly different from other languages. MATLAB has value classes and reference classes, depending on whether the class hashandle as a super-class (for reference classes) or not (for value classes).[45]
Method call behavior is different between value and reference classes. For example, a call to a method:
object.method();
can alter any member ofobject only ifobject is an instance of a reference class, otherwise value class methods must return a new instance if it needs to modify the object.
Graphs are unavailable due to technical issues. Updates on reimplementing the Graph extension, which will be known as the Chart extension, can be found onPhabricator and onMediaWiki.org.
MATLAB has tightly integrated graph-plotting features. For example, the functionplot can be used to produce a graph from two vectorsx andy. The code:
This code produces asurface 3D plot of the two-dimensional unnormalizedsinc function:
MATLAB supports developinggraphical user interface (GUI) applications.[46] UIs can be generated either programmatically or using visual design environments such asGUIDE andApp Designer.[47][48]
MATLAB can call functions and subroutines written in the programming languagesC orFortran.[49] A wrapper function is created allowing MATLAB data types to be passed and returned.MEX files (MATLAB executables) are the dynamically loadable object files created by compiling such functions.[50][51] Since 2014 increasing two-way interfacing withPython was being added.[52][53]
Libraries written inPerl,Java,ActiveX or.NET can be directly called from MATLAB,[54][55] and many MATLAB libraries (for exampleXML orSQL 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[56] which is sold separately byMathWorks, or using an undocumented mechanism called JMI (Java-to-MATLAB Interface),[57][58] (which should not be confused with the unrelatedJava Metadata Interface that is also called JMI). Official MATLAB API for Java was added in 2016.[59]
As alternatives to theMuPAD based Symbolic Math Toolbox available from MathWorks, MATLAB can be connected toMaple orMathematica.[60][61]
Libraries also exist to import and exportMathML.[62]
In 2020, MATLAB withdrew services from two Chinese universities as a result of US sanctions. The universities said this will be responded to by increased use of open-source alternatives and by developing domestic alternatives.[63]
^Bezanson, Jeff; Karpinski, Stefan; Shah, Viral; Edelman, Alan (February 14, 2012)."Why We Created Julia". Julia Language. RetrievedDecember 1, 2016.
^Eaton, John W. (May 21, 2001)."Octave: Past, Present, and Future"(PDF).Texas-Wisconsin Modeling and Control Consortium. Archived fromthe original(PDF) on August 9, 2017. RetrievedDecember 1, 2016.
^"History". Scilab. Archived fromthe original on December 1, 2016. RetrievedDecember 1, 2016.
^Weitzel, Michael (September 1, 2006)."MathML import/export". MathWorks - File Exchange. Archived fromthe original on February 25, 2011. RetrievedAugust 14, 2013.
