dist-javascript-algorithms-and-data-structures/dist/algorithms/math/fourier-transform/__test__/fastFourierTransform.test.js

Algorithms and data-structures implemented on JavaScript

"use strict";

var _fastFourierTransform = _interopRequireDefault(require("../fastFourierTransform"));

var _ComplexNumber = _interopRequireDefault(require("../../complex-number/ComplexNumber"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * @param {ComplexNumber[]} sequence1
 * @param {ComplexNumber[]} sequence2
 * @param {Number} delta
 * @return {boolean}
 */
function sequencesApproximatelyEqual(sequence1, sequence2, delta) {
  if (sequence1.length !== sequence2.length) {
    return false;
  }

  for (let numberIndex = 0; numberIndex < sequence1.length; numberIndex += 1) {
    if (Math.abs(sequence1[numberIndex].re - sequence2[numberIndex].re) > delta) {
      return false;
    }

    if (Math.abs(sequence1[numberIndex].im - sequence2[numberIndex].im) > delta) {
      return false;
    }
  }

  return true;
}

const delta = 1e-6;
describe('fastFourierTransform', () => {
  it('should calculate the radix-2 discrete fourier transform #1', () => {
    const input = [new _ComplexNumber.default({
      re: 0,
      im: 0
    })];
    const expectedOutput = [new _ComplexNumber.default({
      re: 0,
      im: 0
    })];
    const output = (0, _fastFourierTransform.default)(input);
    const invertedOutput = (0, _fastFourierTransform.default)(output, true);
    expect(sequencesApproximatelyEqual(expectedOutput, output, delta)).toBe(true);
    expect(sequencesApproximatelyEqual(input, invertedOutput, delta)).toBe(true);
  });
  it('should calculate the radix-2 discrete fourier transform #2', () => {
    const input = [new _ComplexNumber.default({
      re: 1,
      im: 2
    }), new _ComplexNumber.default({
      re: 2,
      im: 3
    }), new _ComplexNumber.default({
      re: 8,
      im: 4
    })];
    const expectedOutput = [new _ComplexNumber.default({
      re: 11,
      im: 9
    }), new _ComplexNumber.default({
      re: -10,
      im: 0
    }), new _ComplexNumber.default({
      re: 7,
      im: 3
    }), new _ComplexNumber.default({
      re: -4,
      im: -4
    })];
    const output = (0, _fastFourierTransform.default)(input);
    const invertedOutput = (0, _fastFourierTransform.default)(output, true);
    expect(sequencesApproximatelyEqual(expectedOutput, output, delta)).toBe(true);
    expect(sequencesApproximatelyEqual(input, invertedOutput, delta)).toBe(true);
  });
  it('should calculate the radix-2 discrete fourier transform #3', () => {
    const input = [new _ComplexNumber.default({
      re: -83656.9359385182,
      im: 98724.08038374918
    }), new _ComplexNumber.default({
      re: -47537.415125808424,
      im: 88441.58381765135
    }), new _ComplexNumber.default({
      re: -24849.657029355192,
      im: -72621.79007878687
    }), new _ComplexNumber.default({
      re: 31451.27290052717,
      im: -21113.301128347346
    }), new _ComplexNumber.default({
      re: 13973.90836288876,
      im: -73378.36721594246
    }), new _ComplexNumber.default({
      re: 14981.520420492234,
      im: 63279.524958963884
    }), new _ComplexNumber.default({
      re: -9892.575367044381,
      im: -81748.44671677813
    }), new _ComplexNumber.default({
      re: -35933.00356823792,
      im: -46153.47157161784
    }), new _ComplexNumber.default({
      re: -22425.008561855735,
      im: -86284.24507370662
    }), new _ComplexNumber.default({
      re: -39327.43830818355,
      im: 30611.949874562706
    })];
    const expectedOutput = [new _ComplexNumber.default({
      re: -203215.3322151,
      im: -100242.4827503
    }), new _ComplexNumber.default({
      re: 99217.0805705,
      im: 270646.9331932
    }), new _ComplexNumber.default({
      re: -305990.9040412,
      im: 68224.8435751
    }), new _ComplexNumber.default({
      re: -14135.7758282,
      im: 199223.9878095
    }), new _ComplexNumber.default({
      re: -306965.6350922,
      im: 26030.1025439
    }), new _ComplexNumber.default({
      re: -76477.6755206,
      im: 40781.9078990
    }), new _ComplexNumber.default({
      re: -48409.3099088,
      im: 54674.7959662
    }), new _ComplexNumber.default({
      re: -329683.0131713,
      im: 164287.7995937
    }), new _ComplexNumber.default({
      re: -50485.2048527,
      im: -330375.0546527
    }), new _ComplexNumber.default({
      re: 122235.7738708,
      im: 91091.6398019
    }), new _ComplexNumber.default({
      re: 47625.8850387,
      im: 73497.3981523
    }), new _ComplexNumber.default({
      re: -15619.8231136,
      im: 80804.8685410
    }), new _ComplexNumber.default({
      re: 192234.0276101,
      im: 160833.3072355
    }), new _ComplexNumber.default({
      re: -96389.4195635,
      im: 393408.4543872
    }), new _ComplexNumber.default({
      re: -173449.0825417,
      im: 146875.7724104
    }), new _ComplexNumber.default({
      re: -179002.5662573,
      im: 239821.0124341
    })];
    const output = (0, _fastFourierTransform.default)(input);
    const invertedOutput = (0, _fastFourierTransform.default)(output, true);
    expect(sequencesApproximatelyEqual(expectedOutput, output, delta)).toBe(true);
    expect(sequencesApproximatelyEqual(input, invertedOutput, delta)).toBe(true);
  });
});