mathjs/src/function/relational/equal.js

'use strict'

import { factory } from '../../utils/factory'
import { createAlgorithm03 } from '../../type/matrix/utils/algorithm03'
import { createAlgorithm07 } from '../../type/matrix/utils/algorithm07'
import { createAlgorithm12 } from '../../type/matrix/utils/algorithm12'
import { createAlgorithm13 } from '../../type/matrix/utils/algorithm13'
import { createAlgorithm14 } from '../../type/matrix/utils/algorithm14'

const name = 'equal'
const dependencies = [
  'typed',
  'matrix',
  'equalScalar',
  'type.DenseMatrix'
]

export const createEqual = /* #__PURE__ */ factory(name, dependencies, ({ typed, matrix, equalScalar, type: { DenseMatrix } }) => {
  const algorithm03 = createAlgorithm03({ typed })
  const algorithm07 = createAlgorithm07({ typed, type: { DenseMatrix } })
  const algorithm12 = createAlgorithm12({ typed, type: { DenseMatrix } })
  const algorithm13 = createAlgorithm13({ typed })
  const algorithm14 = createAlgorithm14({ typed })

  /**
   * Test whether two values are equal.
   *
   * The function tests whether the relative difference between x and y is
   * smaller than the configured epsilon. The function cannot be used to
   * compare values smaller than approximately 2.22e-16.
   *
   * For matrices, the function is evaluated element wise.
   * In case of complex numbers, x.re must equal y.re, and x.im must equal y.im.
   *
   * Values `null` and `undefined` are compared strictly, thus `null` is only
   * equal to `null` and nothing else, and `undefined` is only equal to
   * `undefined` and nothing else. Strings are compared by their numerical value.
   *
   * Syntax:
   *
   *    math.equal(x, y)
   *
   * Examples:
   *
   *    math.equal(2 + 2, 3)         // returns false
   *    math.equal(2 + 2, 4)         // returns true
   *
   *    const a = math.unit('50 cm')
   *    const b = math.unit('5 m')
   *    math.equal(a, b)             // returns true
   *
   *    const c = [2, 5, 1]
   *    const d = [2, 7, 1]
   *
   *    math.equal(c, d)             // returns [true, false, true]
   *    math.deepEqual(c, d)         // returns false
   *
   *    math.equal("1000", "1e3")    // returns true
   *    math.equal(0, null)          // returns false
   *
   * See also:
   *
   *    unequal, smaller, smallerEq, larger, largerEq, compare, deepEqual, equalText
   *
   * @param  {number | BigNumber | boolean | Complex | Unit | string | Array | Matrix} x First value to compare
   * @param  {number | BigNumber | boolean | Complex | Unit | string | Array | Matrix} y Second value to compare
   * @return {boolean | Array | Matrix} Returns true when the compared values are equal, else returns false
   */
  const equal = typed(name, {

    'any, any': function (x, y) {
      // strict equality for null and undefined?
      if (x === null) { return y === null }
      if (y === null) { return x === null }
      if (x === undefined) { return y === undefined }
      if (y === undefined) { return x === undefined }

      return equalScalar(x, y)
    },

    'SparseMatrix, SparseMatrix': function (x, y) {
      return algorithm07(x, y, equalScalar)
    },

    'SparseMatrix, DenseMatrix': function (x, y) {
      return algorithm03(y, x, equalScalar, true)
    },

    'DenseMatrix, SparseMatrix': function (x, y) {
      return algorithm03(x, y, equalScalar, false)
    },

    'DenseMatrix, DenseMatrix': function (x, y) {
      return algorithm13(x, y, equalScalar)
    },

    'Array, Array': function (x, y) {
      // use matrix implementation
      return equal(matrix(x), matrix(y)).valueOf()
    },

    'Array, Matrix': function (x, y) {
      // use matrix implementation
      return equal(matrix(x), y)
    },

    'Matrix, Array': function (x, y) {
      // use matrix implementation
      return equal(x, matrix(y))
    },

    'SparseMatrix, any': function (x, y) {
      return algorithm12(x, y, equalScalar, false)
    },

    'DenseMatrix, any': function (x, y) {
      return algorithm14(x, y, equalScalar, false)
    },

    'any, SparseMatrix': function (x, y) {
      return algorithm12(y, x, equalScalar, true)
    },

    'any, DenseMatrix': function (x, y) {
      return algorithm14(y, x, equalScalar, true)
    },

    'Array, any': function (x, y) {
      // use matrix implementation
      return algorithm14(matrix(x), y, equalScalar, false).valueOf()
    },

    'any, Array': function (x, y) {
      // use matrix implementation
      return algorithm14(matrix(y), x, equalScalar, true).valueOf()
    }
  })

  return equal
})