mathjs/src/function/complex/im.js

'use strict'

const deepMap = require('../../utils/collection/deepMap')

function factory (type, config, load, typed) {
  /**
   * Get the imaginary part of a complex number.
   * For a complex number `a + bi`, the function returns `b`.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.im(x)
   *
   * Examples:
   *
   *    const a = math.complex(2, 3)
   *    math.re(a)                     // returns number 2
   *    math.im(a)                     // returns number 3
   *
   *    math.re(math.complex('-5.2i')) // returns number -5.2
   *    math.re(math.complex(2.4))     // returns number 0
   *
   * See also:
   *
   *    re, conj, abs, arg
   *
   * @param {number | BigNumber | Complex | Array | Matrix} x
   *            A complex number or array with complex numbers
   * @return {number | BigNumber | Array | Matrix} The imaginary part of x
   */
  const im = typed('im', {
    'number': function (x) {
      return 0
    },

    'BigNumber': function (x) {
      return new type.BigNumber(0)
    },

    'Complex': function (x) {
      return x.im
    },

    'Array | Matrix': function (x) {
      return deepMap(x, im)
    }
  })

  im.toTex = { 1: `\\Im\\left\\lbrace\${args[0]}\\right\\rbrace` }

  return im
}

exports.name = 'im'
exports.factory = factory