Matrix

Installation

$ npm i universal-matrix --save

Usage

import Matrix from 'universal-matrix';

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

const Matrix = require('universal-matrix');

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

API

All methods are chainable and work directly on the matrix data (except for clone).

[static] Matrix.zero(rows[, cols])

Create a zero matrix of size rows * cols, or a square matrix of size rows * rows.

Arguments

• rows {Number} : the number or rows
• cols {Number} (optional) : the number of columns (equals to rows if not specified)

Return

• {Matrix} : a zero matrix of size rows * columns.

Example

const square = Matrix.zero(3);
// 0  0  0
// 0  0  0
// 0  0  0

const matrix = Matrix.zero(2, 4);
// 0  0  0  0
// 0  0  0  0

[static] Matrix.identity(n)

Create an identity matrix of size n * n.

Arguments

• n {Number} : the size of the identity matrix

Return

• {Matrix} : an identity matrix of size n.

Example

const matrix = Matrix.identity(3);
// 1  0  0
// 0  1  0
// 0  0  1

[static] Matrix.randomize(matrix[[, min][, max]])

Randomize the given matrix data.

Arguments

• matrix {Matrix} : the matrix to randomize
• min {Number} (optional) : the minimum value (default 0)
• max {Number} (optional) : the maximum value (default 1)

Return

• {Matrix} : matrix instance for method chaining

Example

const matrices = [
  // random matrix of size 3 x 3, with values between [0, 1[
  Matrix.randomize(Matrix.zero(3)),

  // random matrix of size 3 x 3, with values between [0, 10[
  Matrix.randomize(Matrix.zero(3), 10),

  // random matrix of size 3 x 3, with values between [-3, 5[
  Matrix.randomize(Matrix.zero(3), -3, 5),
];

[static] Matrix.determinant(matrix)

Return the matrix determinant. The given matrix must be square, and contain at least 2 rows.

Arguments

• matrix {Matrix} : the matrix to calculate the determinant for

Return

• {Number} : the determinant

Example

const matrix = new Matrix([6, 1, 1], [4, -2, 5], [2, 8, 7]);

Matrix.determinant(matrix);
//  -306

[constructor] Matrix(...rows)

Create a new matrix with the given row values. Every row must be of same size, otherwise an error will be thrown.

Arguments

• ...rows {Array} : a list of arrays identifying each rows of the Matrix

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);
// 1  2  3
// 4  5  6
// 7  8  9

matrix.rows;
// 3

matrix.columns;
// 3

matrix.data;
// [1, 2, 3, 4, 5, 6, 7, 8, 9];

matrix.get(row, col)

Get the value from the matrix. The rows and columns are 0-based.

arguments

• row {Number} : the row from 0 to matrix.rows - 1
• col {Number} : the column from 0 to matrix.columns - 1

Return

• {Number} : the matrix value

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.get(2, 0);
// 7

matrix.getRow(row)

Get the entire row from the matrix. The rows are 0-based.

arguments

• row {Number} : the row from 0 to matrix.rows - 1

Return

• {Array} : the matrix row

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.getRow(2);
// [7  8  9]

matrix.getColumn(col)

Get the entire column from the matrix. The columns are 0-based.

arguments

• col {Number} : the col from 0 to matrix.columns - 1

Return

• {Array} : the matrix column

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.getColumn(2);
// [3, 6, 9]

matrix.set(row, col, value)

Set the value of the matrix. The rows and columns are 0-based.

arguments

• row {Number} : the row from 0 to matrix.rows - 1
• col {Number} : the column from 0 to matrix.columns - 1
• value {Number} : the value to set

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.set(2, 1, -88);
//  1   2   3
//  4   5   6
//  7 -88   9

matrix.setRow(row, data)

Set the entire row of the matrix. The rows are 0-based.

arguments

• row {Number} : the row from 0 to matrix.rows - 1
• data {Array} : an array of data having the same length as matrix.columns

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.setRow(2, [-9, -8, -7]);
//  1   2   3
//  4   5   6
// -9  -8  -7

matrix.setColumn(col, data)

Set the entire column of the matrix. The columns are 0-based.

arguments

• col {Number} : the col from 0 to matrix.columns - 1
• data {Array} : an array of data having the same length as matrix.rows

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.setColumn(2, [11, 12, 13]);
//  1   2  11
//  4   5  12
//  7   8  13

matrix.apply(fn)

Apply a given function to the given values of the matrix. The function will receive three (3) arguments:

• val {Number} : the matrix value to apply the function to
• row {Number} : the current row in the Matrix
• col {Number} : the current column in the matrix

Arguments

• fn {Function} : the function to call on each value

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2], [3, 4]);

// matrix.apply(function (val) { return val * 2; });
matrix.apply(val => val * 2);
// 2  4
// 6  8

matrix.add(n|matrix)

Add a scalar value n to every matrix element, or add two matrices together. For matrix additions, both must have the same number of rows and columns.

Arguments

• n {Number} | matrix {Matrix} : a scalar or matrix to add to the current matrix elements

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([-6, 2], [4, 0]);

matrix.add(-3);
// -9  -1
//  1  -3

matrix.add(new Matrix([0, 1], [-1, 0]));
// -9   0
//  0  -3

matrix.multiply(n|matrix)

Multiply with a given scalar n or a specified matrix. For matrix multiplication, both rows and columns from each matrices must be compatible.

Arguments

• n {Number} | matrix {Matrix} : a scalar or matrix to multiply to the current matrix elements

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([2, 3, 4], [1, 0, 0]);

matrix.multiply(3);
// 6  9  12
// 3  0   0

matrix.multiply(new Matrix([0, 1000], [1, 100], [0, 10]));
// 9  7020
// 0  3000

matrix.mergeRows(removeRow, addToRow)

Take one row and merge (add) it to another row. All rows are zero-based, meaning that the first row is at position 0, and the last row is at position rows - 1

Arguments

• removeRow {Number} : the row to remove from the matrix
• addToRow {Number} : the row to add the removed row to

Return

• {Matrix} : matrix instance for method chaining

Example

const a = new Matrix([1, 2, 3], [0, 1, -6], [8, 2, 1]);

// merge the second row into the third row
a.mergeRows(1, 2);
//  1  2  3
//  8  3 -5

a.mergeRows(1, 0);
//  9  5 -2

matrix.multiplyRow(row, multiplier)

Multiply only a single row by a scalar.

Arguments

• row {Number} : the row to multiply
• n {Number} : the scalar value to multiply the row with

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [0, 0, 7]);

matrix.multiplyRow(1, 1 / 7);
//  1  2  3
//  0  0  1

matrix.removeRow(row)

Delete an entire row from the Matrix.

Arguments

• row {Number} : the row to remove

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.removeRow(0);
//  4  5  6
//  7  8  9

matrix.removeColumn(col)

Delete an entire column from the Matrix.

Arguments

• col {Number} : the column to remove

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6], [7, 8, 9]);

matrix.removeColumn(1);
//  1  3
//  4  6
//  7  9

matrix.transpose()

Transpose the matrix side ways, swaping rows and columns.

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6]);

matrix.transpose();
//  1  4
//  2  5
//  3  6

matrix.inverse()

Return the inverse matrix. The matrix must be square, and contain at least 2 rows.

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([3, 0, 2], [2, 0, -2], [0, 1, 1]);

matrix.inverse();
//  0.2   0.2   0
// -0.2   0.3   1
//  0.2  -0.3   0

matrix.inverse();
//  3  0  2
//  2  0 -2
//  0  1  1

matrix.clone()

Because all matrix operations operate directly on the data, some cases may require working on a different instance to preserve original data.

Return

• {Matrix} : matrix instance for method chaining

Example

const matrix = new Matrix([1, 2, 3], [4, 5, 6]);
const copy = matrix.clone();

copy.multiply(-3);
//  -3  -6  -9
// -12 -15 -18

matrix.add(1);
//   2   3   4
//   5   6   7

License

MIT