@rayyamhk/complex/lib/core/static/isEqual.js

A lightweight and easy-to-use library for you to manipulate complex numbers

"use strict";

/**
 * Determines whether two Complex Numbers are considered as identical.<br><br>
 * 
 * Two Complex Numbers are considered as identical if either
 * both are NaN or both real and imaginary parts are extremely closed.<br><br>
 * 
 * The test criterion is Math.abs(x - y) < 1 / (10 ** digit * 2).
 * For default value 15, it should be 5e-16.
 * That means if the difference of two numbers is less than 5e-16,
 * they are considered as same value.
 * @memberof Complex
 * @static
 * @param {Complex} num1 - Complex Number
 * @param {Complex} num2 - Complex Number
 * @param {number} [digit=15] - Number of significant digits
 * @returns {boolean} Returns true if two Complex Numbers are considered as identical
 */
function isEqual(num1, num2) {
  var digit = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 15;

  if (!(num1 instanceof this) || !(num2 instanceof this)) {
    return false;
  }

  if (!Number.isInteger(digit) || digit < 0) {
    throw new Error('Invalid argument: Expected a non-negative integer digit');
  }

  var EPSILON = 1 / (Math.pow(10, digit) * 2);
  var a = num1.getReal();
  var b = num1.getImaginary();
  var c = num2.getReal();
  var d = num2.getImaginary();

  if (Number.isNaN(a) && Number.isNaN(b) && Number.isNaN(c) && Number.isNaN(d)) {
    return true;
  }

  return Math.abs(a - c) < EPSILON && Math.abs(b - d) < EPSILON;
}

module.exports = isEqual;