ml-matrix

What is ml-matrix?

The ml-matrix npm package provides a comprehensive set of tools for matrix operations and linear algebra. It is designed to be used in machine learning and data science applications, offering a variety of functionalities such as matrix creation, manipulation, decomposition, and solving linear systems.

What are ml-matrix's main functionalities?

Matrix Creation

This feature allows you to create matrices from arrays. The code sample demonstrates how to create a 2x2 matrix and print it.

const { Matrix } = require('ml-matrix');
const A = new Matrix([[1, 2], [3, 4]]);
console.log(A.toString());

Matrix Operations

This feature supports various matrix operations such as addition, subtraction, multiplication, etc. The code sample shows how to add two matrices.

const { Matrix } = require('ml-matrix');
const A = new Matrix([[1, 2], [3, 4]]);
const B = new Matrix([[5, 6], [7, 8]]);
const C = A.add(B);
console.log(C.toString());

Matrix Decomposition

This feature provides methods for matrix decomposition like Singular Value Decomposition (SVD), LU decomposition, etc. The code sample demonstrates how to perform SVD on a matrix.

const { Matrix, SingularValueDecomposition } = require('ml-matrix');
const A = new Matrix([[1, 2], [3, 4]]);
const svd = new SingularValueDecomposition(A);
console.log(svd.diagonalMatrix.toString());

Solving Linear Systems

This feature allows solving linear systems of equations. The code sample shows how to solve the system Ax = b.

const { Matrix } = require('ml-matrix');
const A = new Matrix([[1, 2], [3, 4]]);
const b = [5, 6];
const x = A.solve(b);
console.log(x.toString());

Other packages similar to ml-matrix

mathjs

Math.js is an extensive math library for JavaScript and Node.js. It provides a wide range of mathematical functions and supports complex numbers, matrices, units, and more. Compared to ml-matrix, math.js offers a broader range of mathematical functionalities but may not be as specialized in matrix operations and linear algebra.

numeric

Numeric.js is a library for numerical computations in JavaScript. It provides functions for matrix operations, solving linear systems, and performing numerical integration. While it offers similar functionalities to ml-matrix, it is more focused on numerical methods and less on machine learning applications.

ndarray

Ndarray is a JavaScript library for multidimensional arrays. It provides efficient storage and manipulation of large datasets. While it can be used for matrix operations, it is more general-purpose and not specifically tailored for linear algebra like ml-matrix.

README

ml-matrix

Matrix manipulation and computation library.

Installation

$ npm install ml-matrix

Usage

As an ES module

import { Matrix } from 'ml-matrix';

const matrix = Matrix.ones(5, 5);

As a CommonJS module

const { Matrix } = require('ml-matrix');

const matrix = Matrix.ones(5, 5);

API Documentation

Examples

Standard operations

const { Matrix } = require('ml-matrix');

var A = new Matrix([[1, 1], [2, 2]]);
var B = new Matrix([[3, 3], [1, 1]]);
var C = new Matrix([[3, 3], [1, 1]]);

// ============================
// Operations with the matrix :
// =============================

// operations :
const addition = Matrix.add(A, B); // addition = Matrix [[4, 4], [3, 3], rows: 2, columns: 2]
const subtraction = Matrix.sub(A, B); // subtraction = Matrix [[-2, -2], [1, 1], rows: 2, columns: 2]
const multiplication = A.mmul(B); // multiplication = Matrix [[4, 4], [8, 8], rows: 2, columns: 2]
const mulByNumber = Matrix.mul(A, 10); // mulByNumber = Matrix [[10, 10], [20, 20], rows: 2, columns: 2]
const divByNumber = Matrix.div(A, 10); // divByNumber = Matrix [[0.1, 0.1], [0.2, 0.2], rows: 2, columns: 2]
const modulo = Matrix.mod(B, 2); // modulo = Matrix [[ 1, 1], [1, 1], rows: 2, columns: 2]
const maxMatrix = Matrix.max(A, B); // max = Matrix [[3, 3], [2, 2], rows: 2, columns: 2]
const minMatrix = Matrix.min(A, B); // max = Matrix [[1, 1], [1, 1], rows: 2, columns: 2]

// Inplace operations : (consider that Cinit = C before all the operations below)
C.add(A); // => C = Cinit + A
C.sub(A); // => C = Cinit
C.mul(10); // => C = 10 * Cinit
C.div(10); // => C = Cinit
C.mod(2); // => C = Cinit % 2

// Standard Math operations : (abs, cos, round, etc.)
var A = new Matrix([[1, 1], [-1, -1]]);
var expon = Matrix.exp(A); // expon = Matrix [[Math.exp(1), Math.exp(1)], [Math.exp(-1), Math.exp(-1)], rows: 2, columns: 2].
var cosinus = Matrix.cos(A); // cosinus = Matrix [[Math.cos(1), Math.cos(1)], [Math.cos(-1), Math.cos(-1)], rows: 2, columns: 2].
var absolute = Matrix.abs(A); // expon = absolute [[1, 1], [1, 1], rows: 2, columns: 2].
// you can use 'abs', 'acos', 'acosh', 'asin', 'asinh', 'atan', 'atanh', 'cbrt', 'ceil', 'clz32', 'cos', 'cosh', 'exp', 'expm1', 'floor', 'fround', 'log', 'log1p', 'log10', 'log2', 'round', 'sign', 'sin', 'sinh', 'sqrt', 'tan', 'tanh', 'trunc'
// Note : you can do it inplace too as A.abs()

// ============================
// Manipulation of the matrix :
// =============================

var numberRows = A.rows; // A has 2 rows
var numberCols = A.columns; // A has 2 columns
var firstValue = A.get(0, 0); // get(rows, columns)
var numberElements = A.size; // 2 * 2 = 4 elements
var isRow = A.isRowVector(); // false because A has more that 1 row
var isColumn = A.isColumnVector(); // false because A has more that 1 column
var isSquare = A.isSquare(); // true, because A is 2 * 2 matrix
var isSym = A.isSymmetric(); // false, because A is not symmetric
// remember : A = Matrix [[1, 1], [-1, -1], rows: 2, columns: 2]
A.set(1, 0, 10); // A = Matrix [[1, 1], [10, -1], rows: 2, columns: 2]. We have change the second row and the first column
var diag = A.diag(); // diag = [1, -1], i.e values in the diagonal.
var m = A.mean(); // m = 2.75
var product = A.prod(); // product = -10, i.e product of all values of the matrix
var norm = A.norm(); // norm = 10.14889156509222, i.e Frobenius norm of the matrix
var transpose = A.transpose(); // transpose = Matrix [[1, 10], [1, -1], rows: 2, columns: 2]

// ============================
// Instantiation of matrix :
// =============================

var z = Matrix.zeros(3, 2); // z = Matrix [[0, 0], [0, 0], [0, 0], rows: 3, columns: 2]
var z = Matrix.ones(2, 3); // z = Matrix [[1, 1, 1], [1, 1, 1], rows: 2, columns: 3]
var z = Matrix.eye(3, 4); // Matrix [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], rows: 3, columns: 4]. there are 1 only in the diagonal

Maths

const {
  Matrix,
  inverse,
  solve,
  linearDependencies,
  QrDecomposition,
  LuDecomposition,
  CholeskyDecomposition,
} = require('ml-matrix');

//===========================
// inverse and pseudo-inverse
//===========================

var A = new Matrix([[2, 3, 5], [4, 1, 6], [1, 3, 0]]);
var inverseA = inverse(A);
var B = A.mmul(inverseA); // B = A * inverse(A), so B ~= Identity

// if A is singular, you can use SVD :
var A = new Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]]); // A is singular, so the standard computation of inverse won't work (you can test if you don't trust me^^)
var inverseA = inverse(A, (useSVD = true)); // inverseA is only an approximation of the inverse, by using the Singular Values Decomposition
var B = A.mmul(inverseA); // B = A * inverse(A), but inverse(A) is only an approximation, so B doesn't really be identity.

// if you want the pseudo-inverse of a matrix :
var A = new Matrix([[1, 2], [3, 4], [5, 6]]);
var pseudoInverseA = A.pseudoInverse();
var B = A.mmul(pseudoInverseA).mmul(A); // with pseudo inverse, A*pseudo-inverse(A)*A ~= A. It's the case here

//=============
// Least square
//=============

// Least square is the following problem : We search x, such as A.x = b (A, x and b are matrix or vectors).
// Below, how to solve least square with our function

// If A is non singular :
var A = new Matrix([[3, 1], [4.25, 1], [5.5, 1], [8, 1]]);
var b = Matrix.columnVector([4.5, 4.25, 5.5, 5.5]);
var x = solve(A, b);
var error = Matrix.sub(b, A.mmul(x)); // The error enables to evaluate the solution x found.

// If A is non singular :
var A = new Matrix([[1, 2, 3], [4, 5, 6], [7, 8, 9]]);
var b = Matrix.columnVector([8, 20, 32]);
var x = solve(A, b, (useSVD = true)); // there are many solutions. x can be [1, 2, 1].transpose(), or [1.33, 1.33, 1.33].transpose(), etc.
var error = Matrix.sub(b, A.mmul(x)); // The error enables to evaluate the solution x found.

//===============
// Decompositions
//===============

// QR Decomposition

var A = new Matrix([[2, 3, 5], [4, 1, 6], [1, 3, 0]]);
var QR = new QrDecomposition(A);
var Q = QR.orthogonalMatrix;
var R = QR.upperTriangularMatrix;
// So you have the QR decomposition. If you multiply Q by R, you'll see that A = Q.R, with Q orthogonal and R upper triangular

// LU Decomposition

var A = new Matrix([[2, 3, 5], [4, 1, 6], [1, 3, 0]]);
var LU = new LuDecomposition(A);
var L = LU.lowerTriangularMatrix;
var U = LU.upperTriangularMatrix;
var P = LU.pivotPermutationVector;
// So you have the LU decomposition. P includes the permutation of the matrix. Here P = [1, 2, 0], i.e the first row of LU is the second row of A, the second row of LU is the third row of A and the third row of LU is the first row of A.

// Cholesky Decomposition

var A = new Matrix([[2, 3, 5], [4, 1, 6], [1, 3, 0]]);
var cholesky = new CholeskyDecomposition(A);
var L = cholesky.lowerTriangularMatrix;

// Eigenvalues & eigenvectors

var A = new Matrix([[2, 3, 5], [4, 1, 6], [1, 3, 0]]);
var e = new EigenvalueDecomposition(A);
var real = e.realEigenvalues;
var imaginary = e.imaginaryEigenvalues;
var vectors = e.eigenvectorMatrix;

//=======
// Others
//=======

// Linear dependencies
var A = new Matrix([
  [2, 0, 0, 1],
  [0, 1, 6, 0],
  [0, 3, 0, 1],
  [0, 0, 1, 0],
  [0, 1, 2, 0],
]);
var dependencies = linearDependencies(A); // dependencies is a matrix with the dependencies of the rows. When we look row by row, we see that the first row is [0, 0, 0, 0, 0], so it means that the first row is independent, and the second row is [ 0, 0, 0, 4, 1 ], i.e the second row = 4 times the 4th row + the 5th row.

License

MIT

Changelog

6.6.0 (2021-01-04)

Features

• add support for empty matrices (#116) (211de6e)