Skip to content

Latest commit

 

History

History
151 lines (126 loc) · 14 KB

README.md

File metadata and controls

151 lines (126 loc) · 14 KB
Raw

MatlabJS

A lightweight JavaScript library for MATLAB/Octave users

This library gives you some essential array and matrix functions written in JavaScript for easing your scientific computing projects or code conversion from Matlab or Octave.

Documentation

To see how it works, go to https://VivekTRamamoorthy.github.io/MatlabJS. The library is loaded on the webpage and you may start testing it in the console. The website also contains a cheatsheet.

Examples

    tic()
    a=linspace(0,1,100) 
    disp(a) ;
    b=eye(4); 
    c=rand(4); 
    d=mul(b,c) ;
    disp(d)
    toc();

Using in your projects

Method 1: CDN (Loads the latest update)

  • Include the following script tag to your html. This will include all updates and bug fixes.
<script src="https://cdn.jsdelivr.net/gh/VivekTRamamoorthy/MatlabJS/Matlab.js"></script>

This would only give the standard functions. To use plotting tools, additionally includeplotlib.js file:

<script src="https://cdn.jsdelivr.net/gh/VivekTRamamoorthy/MatlabJS/plotlib.js"></script>

Method 2: Including file using script tag

  • Download theMatlab.jsfile to your project folder.
  • Include the file in a script tag:
<script src="Matlab.js"></script>

Node:

Install using npm install matlabjs

Use in your projects like below

const MatlabJS = require("matlabjs")
let A = MatlabJS.zeros(10,10) // [[0,0,0,...],  [0,0,0,...], [0,0,0,...], .... ]

or

const {add, linspace} = require("matlabjs")
let A = add(linspace(0,1),200) // [ 200, 201.010101... , 202.020202... , ...]

A note of caution

  • Operator overloading is not yet permitted in JavaScript and doesn't seem like it will be anytime soon. So it is not possible to writec=A*b for matrices in Javascript. Instead, one has to resort to the syntactically inconvenient universal functions, for example,c=mul(A,b).
  • When using the script tag method, all functions are loaded into the global scope usingvars and users may overwrite them if needed like in Matlab. If you prefer a namespace import, use it as a module.
  • The code may not be optimised for efficiency. For intensive computations, users can manually optimise the code for their use case if performance is an issue.
  • This project is in its initial stage. Additional functionalities may be included as time progresses.

Contributing

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 theMatlab.js file. For example:
    var add2 = function(a){
     return a+2;
     }
  • Write testing scripts for the new function intests/run_tests.js file by includingtest("your_function_name(args)","expectedoutput").
    • An example would betest("add2(4)",6)
  • Test on the browser
    • Serve and openindex.html and click theRun tests button on the web page displayed. This will callrun_tests.js and print results in a popup.
  • Test on Node
    • To initiate the testing suite, executenpm test from the terminal.
  • If these tests pass, you may commit and raise a pull request to themain branch.

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
a number, 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 an 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]]		 Transposes 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 with values uniformly random in [0,1]
randi randi(N,rows,cols) disp(randi(5))
// random num in {1,2...5}
disp(randi(5,3))
disp(randi(5,3,2))
// 3x2 random in {1,2...5}		 Generate random integer matrices with values in[0,1,2,...,N]
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
Getting values
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 values of a submatrix
Setting values in matrices
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)		 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
set(A,0,100) // A(end)=20
set(A,-1,20) // A(end-1)=20
disp(A) // [1, 10, 3, 4, 20, 100]		 Set values to a submatrix
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
Uses ndarrayjs
Include ndarray.js file in your project.
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(function,
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

License

MIT License 2.0

Vivek Thaminni Ramamoorthy