mathjs/test/function/statistics/mad.test.js

var assert = require('assert');
var approx = require('../../../tools/approx');
var math = require('../../../index');
var BigNumber = math.type.BigNumber;
var DenseMatrix = math.type.DenseMatrix;
var mad = math.mad;

describe('mad', function() {

  it('should return the median absolute deviation of numbers', function() {
    assert.equal(mad(10), 0);
    assert.equal(mad(4,6,8), 2);
    assert.equal(mad(1, 10, 20, 30), 9.5);
  });

  it('should return the median absolute deviation of big numbers', function() {
    assert.deepEqual(mad(new BigNumber(4),new BigNumber(6),new BigNumber(8)),
      new BigNumber(2));
  });

  it('should return the median absolute deviation from an array', function() {
    assert.equal(mad([10]), 0);
    assert.equal(mad([4,6,8]), 2);
    assert.equal(mad([1, 10, 20, 30]), 9.5);
  });

  it('should return the median absolute deviation from an 1d matrix', function() {
    assert.equal(mad(new DenseMatrix([10])), 0);
    assert.equal(mad(new DenseMatrix([4,6,8])), 2);
    assert.equal(mad(new DenseMatrix([1, 10, 20, 30])), 9.5);
  });

  it('should return the median absolute deviation element from a 2d array', function() {
    assert.deepEqual(mad([
      [2,4,6],
      [1,3,5]
    ]), 1.5);
  });

  it('should return the median absolute deviation element from a 2d matrix', function() {
    assert.deepEqual(mad(new DenseMatrix([
      [2,4,6],
      [1,3,5]
    ])), 1.5);
  });

  it('should throw an error if called with invalid number of arguments', function() {
    assert.throws(function() {mad()});
  });

  it('should throw an error if called with an empty array', function() {
    assert.throws(function() {mad([])});
  });

  it('should LaTeX mad', function () {
    var expression = math.parse('mad(1,2,3)');
    assert.equal(expression.toTex(), '\\mathrm{mad}\\left(1,2,3\\right)');
  });

});