MatlabJS

A Javascript library for Matlab/Octave users

Description

MatlabJS is a lightweight and easy-to-use library with essential functions for Matlab® / GNU Octave users who are new to Javascript. It is meant for rapid prototyping of projects or code conversion from Matlab/Octave. This free and open source utility is currently at version loading...

Examples:

The library is already loaded in this webpage.
To try it out, open the browser console using rightclick + inspect and test these lines of code: 
                
    tic() 
    a=linspace(0,1) 
    disp(a)
    b=eye(8) 
    c=rand(8) 
    d=mul(b,c) 
    toc()

How to use this in your project:

Method 1 - CDN (recommended - to get the latest updates and bug fixes):

Include the following script tag within your html head. 
     <script src="https://cdn.jsdelivr.net/gh/VivekTRamamoorthy/MatlabJS/Matlab.js"></script>
This would only give the standard functions.
To use plotting tools, additionally include plotlib.js file. 
     <script src="https://cdn.jsdelivr.net/gh/VivekTRamamoorthy/MatlabJS/plotlib.js"></script>

Method 2 - File inclusion (robust - to include a non-breaking local version):

Download Matlab.js file from the MatlabJS repository to your project and and include it using a script tag as below. 
                     <script src="Matlab.js"></script>

Method 3 - Using NodeJS:

MatlabJS is also available as an npm package. To use this method, it is presumed that Node is installed on your machine. If not, do this first. Use the following command from a terminal within your project folder. 
                  npm install matlabjs
Use const MatlabJS = require("matlabjs") to include the namespace in your js modules.
Then use the functions like below: 
                let A = MatlabJS.linspace(0,1)

Limitations:

  • Unfortunately, operator overloading is not permitted in JavaScript, and we cannot yet write c=A*b for matrices and arrays. Instead we have to resort to using universal functions c=mul(A,b) that perform actions based on the input datatypes.

  • The code is not necessarily optimised for efficiency. For intensive computations, users can manually optimise the code for their use case if performance becomes an issue.

  • This project is in its priliminary stage and many functions are not implemented. Additional functionalities will be included as time permits.

    • Full list of functions:

    Use left or right arrow keys to scroll if the the table is not fully visible.
    Matlab function MatlabJS equivalent Example usage Description
    tic tic() Starts recording time
    toc toc() tic();
    t=toc();     		Prints elapsed time since start
    clc clc() clc() Clears console
    linspace linspace A=linspace(0,1)
    // [0 .1010.. 1]
    B=linspace(10,20,3)
    // [10,15,20]     		Produces linearly spaced array.
    logspace logspace A=logspace(1,1000,4)
    // [1 10 100 1000]
    B=logspace(1,25,3)
    // [1,5,25]     		Produces logarithmically spaced arrays.
    disp, display disp, display A=linspace(0,1)
    B=linspace(10,20,3)
    disp(A)
    display(B)
    		 Displays matrices and arrays in console
    isfield isfield(struc,fieldname) struc={x:10,y:100}
    isfield(struc,'x') // true
    isfield(struc,'a') // false
    		Checks the presence of
    fieldnames in a structure
    size size(A) A=[[1,2,3],[3,4,5]]
    size(A) // [2,3]     		Dimensions of a matrix or array
    length A.length
    length(A)     		A=[1,2,3,3,4,5]
    A.length // 6
    length(A) // 6     		Length of an array
    find find A=[1,2,0,0,4,5]
    find(A) // [1, 2, 5, 6]     		Find nonzero elements
    sort sort() A=[3,2,1,5,7];
    [sortedA,indices]=sort(A);
    disp(sortedA); // [1,2,3,5,7]
    disp(indices); // [3,2,1,4,5]     		Sorts numbers ascending
    sum sum A=[1,2,3]
    sum(A) // 6
    B=[[1,2,3],[4,5,6],[7,8,9]]
    disp(sum(B,1))
    // column sum [12,15,18]
    disp(sum(B,2))
    // row sum [[6],[15],[24]]
    Sum of an array

    Column sum of a matrix
    Row sum of a matrix
    abs abs A=[1,-2,3]
    abs(A) // [1,2,3]
    B=[[1,-2,3],[-4,5,6],[-7,8,-9]]
    disp(abs(B))
    //[1,2,3],[4,5,6],[7,8,9]     		Absolute value of
    num, array or matrix
    sqrt sqrt A=[1,4,2]
    disp(sqrt(A))
    // [1,2,1.414] A=rand(4)
    disp(A)
    disp(sqrt(A))     		Square root of
    num, array or matrix
    setdiff setdiff A=[4,3,1,5]
    B=[5,3,7,8]
    setdiff(A,B) // [1,4]     		Set difference (sorted)
    min min A=[1,3,-5,9]
    disp(min(A)) // -5
    B=[[1,2,3],[4,5,6],[7,8,9]]
    disp(B)
    disp(min(B,1)) // elemwise min
    disp(min(B,4)) //
    disp(min(B,[],1)) // column min
    disp(min(B,[],2)) // row min     		Minimum of array or matrix
    max max Similar to min Maximum of an array or matrix
    a:b:c range(a,b,c) range(2,0.5,4)
    // [2,2.5,3,3.5,4]    		 Array from a to c in steps of b
    triu triu(Matrix,k) disp(triu(rand(4)))
    disp(triu(rand(4),1))    		 Upper trianular matrix
    [A, B] concatRows(A,B) A=ones(3,3)
    disp(A)
    B=rand(3,3)
    disp(B)
    C=concatRows(A,B)
    disp(C)
    // 3 x 6 matrix     		Concatenate rows of two matrices
    [A; B] concatCols(A,B) A=ones(3,3)
    disp(A)
    B=rand(3,3)
    disp(B)
    C=concatCols(A,B)
    disp(C)
    // 6 x 3 matrix     		Concatenate columns of two matrices
    A' transpose(A) A=[[1,2,3],[4,5,6]]
    transpose(A)
    // [[1,4],[2,5],[3,6]]     		transpose of a matrix
    ones ones disp(ones(3))
    // 3x3 matrix of 1s
    disp(ones(3,2))
    // 3x2 matrix of 1s
    disp(ones(3,1))
    // column of 1s     		Matrix of ones
    eye eye disp(eye(3))// 3x3 identity matrix
    disp(eye(4)) // 4x4 matrix of 1s
    disp(eye(10)) // column of 1s     		Generates identity matrices
    zeros zeros disp(zeros(3))
    // 3x3 matrix of 0s
    disp(zeros(3,2))
    // 3x2 matrix of 0s
    disp(zeros(3,1))
    // column of 0s     		Generates zero matrices
    rand rand disp(rand())
    // random no in [0,1]
    disp(rand(3))
    // 3x3 random
    disp(rand(3,2))
    // 3x2 random
    disp(rand(3,1))
    // column of random     		Generates matrix of random numbers in [0,1]
    randi randi(N,rows,cols) disp(randi(5))
    // random integer in {1,2...5}
    disp(randi(5,3))
    //3x3 matrix of random integers in {1,2...5}
    disp(randi(5,3,2))
    // 3x2 random in {1,2...5}
    		 Generate random integer matrices
    diag diag(D) disp(diag([5,3,2]))
    // returns:
    // [ [5, 0, 0],
    // [0, 3, 0],
    // [0, 0, 2] ]     		Diagonal matrix from an array
    reshape reshape reshape([1,2,3,4,5,6],2,3)
    // [1,2,3; 4,5,6]     		Reshape a vector or a matrix
    A(rowrange,colrange)
    A(1:3,1:3)
    A(10,10)
    A(end,end-1)    		 get(A,rowrange,colrange)
    get(A,[1,2,3],[1,2,3])
    get(A,10,10)
    get(A,0,-1)    		 A=rand(10,10);disp(A)
    B=get(A,[1,2,3],[2,5,7])
    disp(B)
    B=get(A,':',[1,2,3])
    disp(B) // gets all rows & first 3 cols     		Get a submatrix
    A(rowrange,colrange)=B
    A(1:3,1:3)=B
    A(end-5:end,:)=2
    a(arrayrange)=b
    a(1:3)=[10 20 30]
    a(1)=10
    a(end-2)=8





    		 set(A,rowrange,colrange,B)
    set(A,[1,2,3],[1,2,3],B)
    set(A,range(-5,0),':',2)
    set(a,arrayrange,b)
    set(a,[1,2,3],[10,20,30])
    set(a,1,10)
    set(a,-2,8)

    B can be a matrix or a number
    rrange and crange can be number or arrays or ':'     		Matrix example:
    A=rand(5,5)
    set(A,range(1,3),range(1,3),0)
    disp(A)
    // sets first 3 rows and cols to 0 set(A,range(1,3),range(1,3),randi(2,3,3))
    disp(A)
    // sets first 3 rows and cols to random in {1,2}

    Array example:
    A=[1,2,3,4,5,6]
    set(A,2,10)// A(2)=10 :: sets 2nd elem to 10
    set(A,0,100) // A(end)=20 :: sets last elem to 100
    set(A,-1,20) // A(end-1)=20 :: sets end-1 (last but one) elem to 20
    disp(A) // [1, 10, 3, 4, 20, 100]     		Set a submatrix or a subarray
    repmat repmat(mat,rows,cols) A=rand(2,3)
    B=repmat(A,4,5)
    disp(B)     		Repeat matrix
    kron kron(X,Y) A=[[1,2,3],[2,3,4]];
    Y=[[1],[1],[1]];
    display(kron(A,Y))     		Kronecker tensor product
    union union(X,Y) A=[1,2,3,4];
    B=[5,3,10];
    display(union(A,B))
    //[1,2,3,4,5,10]     		Union of two sets
    unique unique(A) A=[10,2,3,3,4];
    display(unique(A))
    //[2,3,4,10]     		Unique items of a set
    sparse(I,J,K) sparse(I,J,K,nRows,nCols) A=sparse([1,2],[1,2],[10,10],10,10);
    disp(A)     		Initiate a sparse matrix
    I - row indices
    J - column indices
    K - element values
    nRows - no of rows
    nCols - no of cols
    B=A B=copy(A) A=rand(4)
    disp(A)
    B=A
    B[0][0]=20
    disp(A)
    // note: A changes
    // when B is changed
    C=copy(A); C[0][0]=100
    disp(A)
    disp(C)     		For array and matrices
    B=A; will not actually copy A
    but only creates a reference
    Use B=copy(A) instead.
    C=A+B C=add(A,B) disp(add(3,4))
    disp(add(ones(4,1),100))
    disp(add(100,rand(1,4)))
    disp(add(ones(4),100))
    disp(add(100,rand(4)))
    disp(add(ones(4),rand(4)))
    		 Universal add
    for
    number + number
    array + number
    array + array
    number + matrix
    C=A-B C=sub(A,B) disp(sub(3,4))
    disp(sub(ones(4,1),100))
    disp(sub(100,rand(1,4)))
    disp(sub(ones(4),100))
    disp(sub(100,rand(4)))
    disp(sub(ones(4),rand(4)))
    		 Universal subtract
    for
    number - number
    array - number
    array - array
    number - matrix
    C=A*B C=mul(A,B) disp(mul(3,4))
    disp(mul(ones(4,1),100))
    disp(mul(100,rand(1,4)))
    disp(mul(ones(4),100))
    disp(mul(100,rand(4)))
    disp(mul(ones(4),rand(4)))
    disp(mul(eye(4),rand(4)))
    disp(mul(rand(5,4),rand(4,3)))
    disp(mul(rand(5),rand(5,1)))
    disp(mul(rand(1,10),rand(10,1)))
    		 Universal multiply
    for
    number * number
    array * number
    array * array
    matrix(n by k) * matrix(k by m)
    C=A.*B C=dotmul(A,B) disp(dotmul(3,4))
    A=ones(4)
    B=rand(4)
    disp(dotmul(rand(10,1),rand(10,1)))
    disp(dotmul(A,B))
    disp(dotmul(eye(4),B))
    		 Elementwise multiply
    for
    number .* number
    array .* array
    matrix .* matrix
    C=A/B C=div(A,B) disp(div(3,4))
    disp(div(ones(4,1),100))
    disp(div(100,rand(1,4)))
    disp(div(ones(4),100))
    disp(div(100,rand(4)))
    disp(div(ones(4),rand(4)))
    		 Universal divide
    for
    number / number
    array / number
    array / array
    number / matrix
    C=A./B C=dotdiv(A,B) A=rand(1,4)
    B=mul(100,ones(1,4))
    disp(dotdiv(A,B))
    C=add(rand(10),1)
    disp(dotdiv(rand(10),C))
    disp(dotdiv(eye(4),rand(4)))
    		 Elementwise divide
    for
    number ./ number
    array ./ array
    matrix ./ matrix
    C=A^B C=pow(A,B) disp(pow(3,4))
    disp(pow(ones(4,1),100))
    disp(pow(100,rand(1,4)))
    disp(pow(ones(4),100))
    disp(pow(100,rand(4)))
    disp(pow(ones(4),rand(4)))
    disp(pow(eye(4),rand(4)))
    		 Universal power
    for
    number ^ number
    array ^ number
    array ^ array
    number ^ matrix
    matrix ^ number
    matrix ^ matrix
    A(:) colon(A) disp(A=rand(4))
    disp(colon(A))
    		 List all columns as vector
    x=A\b x=linsolve(A,b) A=[[2,3,4],[1,1,1],[1,0,1]]
    b=[[9],[3],[2]]
    x=linsolve(A,b)
    disp(x)
    disp(mul(A,x))     		Linear solve (or)
    mldivide
    solve a sys of
    linear equations
    all all all([[true,true],[true,false]]) // false
    all([true,true],[true,true]]) // true
    		 If all elements are true, returns true
    Multi-dimensional
    any any any([[false,false],[false,false]]) // false
    any([false,false],[true,false]]) // true
    		 If any element is true, returns true
    Multi-dimensional
    Not available map(funcion,arg1,arg2,arg3,...) map(x=>x>3, [1,2,3,4,5])
    // [false,false,false,true,true]
    map(x=>x>3, [[1,2,3],[4,5,6]])
    // [[false,false,false],[true,true,true]]
    map((a,b)=>a>b, [[1,2,3],[4,5,6]],3)
    // [[false,false,false],[true,true,true]]
    map((a,b)=>a+b, [[1,2,3],[4,5,6]],3,[[1,2,3],[4,5,6]] )
    // [[5,7,9],[11,13,15]]
    		Multi dimensional map:
    Applies function across all elements,
    If any arg is not an array, uses the value instead
    Considers two arguments at a time until the last
    exp exp(number or complex or array or complex array exp(1) // 2.718..
    a=exp(new cx(0,Math.PI/2))
    disp(a)// 0+1i i.e. a.re=0 a.im=1
    		Multi dimensional universal exponention function


    Contributing

    Your contributions are welcome. Please follow the instructions below to contribute.

    You can contribute to this repository by following these steps: - Fork the repository and clone it locally, and create a new branch. - Include your contribution in the Matlab.js file. For example: 
    
        var add2 = function(a){
            return a+2;
        }

    Unit testing

    To perform a quick check, you can run some unit tests on the browser by clicking the "Run tests" button.

    Issues

    For bugs, feedback and feature requests, raise an Issue in the GitHub repository

    License

    MIT License
    Copyright (c) 2021 Vivek T Ramamoorthy