gmatrix

A simple library for geometrically manipulating matrices

Install

npm install gmatrix

Usage

For Node:

const matrix = require("gmatrix");

For browsers:

<script src="/node_modules/gmatrix/dist/gmatrix.min.js"></script>

In either case, create a matrix:

const myMatrix = matrix([
  [0, 1, 2, 3, 4],
  [5, 6, 7, 8, 9],
  [10, 11, 12, 13, 14],
  [15, 16, 17, 18, 19],
  [20, 21, 22, 23, 24]
]);
// myMatrix is now equipped with the geometric functions detailed below

toJSON

const json = myMatrix.toJSON();
// json is a two dimensional array of the matrix

width

const width = myMatrix.width();
// width is 5

height

const height = myMatrix.height();
// height is 5

get

// by index
const value = myMatrix.get(3); 
// 2

// or by row & column index
const value = myMatrix.get(0, 3);
// 3

equals

const a = matrix([
  [1, 2],
  [3, 4]
]);
const b = matrix([
  [5, 6],
  [7, 8]
]);
const equality = a.equals(b);
// false

clone

const clone = myMatrix.clone();
// clone is a new matrix that's a copy of the original

subMatrix

const sub = myMatrix.subMatrix(5, 2, 2);
// sub is a new 2x2 matrix starting from index 4
// [[5, 6],
//  [10, 11]]

surrounding

const surrounding = myMatrix.surrounding(12);
// surrounding is a new 3x3 matrix containing the elements that surrounded index 4
// [[6, 7, 8],
//  [11, 12, 13],
//  [16, 17, 18]]

forEach

myMatrix.forEach((element, index, rowIndex, columnIndex) => {
  // do something with element
  // given element's index, row index, and column index
  // return false to break early
});

forEachRow

myMatrix.forEachRow((row, rowIndex) => {
  // do something with row of elements
  // given row's index
  // return false to break early
});

map

const results = myMatrix.map((element, index, rowIndex, columnIndex) => {
  // similar to forEach but returns a 2d array of results based on what you return in the callback
  // given element's index, row index, and column index
  return element + 1;
});
// results is 2d array of each return 
// [[1, 2, 3, 4, 5], [5, 6, 7, 8, 9], etc...]

flatMap

const results = myMatrix.flatMap((element, index, rowIndex, columnIndex) => {
  // similar to forEach but returns a flattened array of results based on what you return in the callback
  // given element's index, row index, and column index
  return element; // by returning element we will be creating an flattened array of the matrix values
});
// results is flattened array of each return
// [0, 1, 2, 3, 4, 5, 6, 7, 8, etc...]

rotateLeft

const rotatedMatrix = myMatrix.rotateLeft();
// rotatedMatrix is a new matrix rotated 90 degrees to the left

rotateRight

const rotatedMatrix = myMatrix.rotateRight();
// rotatedMatrix is a new matrix rotated 90 degrees to the right

rotate180

const rotatedMatrix = myMatrix.rotate180();
// rotatedMatrix is a new matrix rotated 180 degrees

flipHorizontal

const flippedMatrix = myMatrix.flipHorizontal();
// flippedMatrix is a new matrix flipped over the horizontal axis

flipVertical

const flippedMatrix = myMatrix.flipVertical();
// flippedMatrix is a new matrix flipped over the vertical axis