mathjs/lib/function/complex/re.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

'use strict';

var deepMap = require('../../utils/collection/deepMap');

function factory(type, config, load, typed) {
  /**
   * Get the real part of a complex number.
   * For a complex number `a + bi`, the function returns `a`.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.re(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 0
   *    math.re(math.complex(2.4))     // returns number 2.4
   *
   * See also:
   *
   *    im, conj, abs, arg
   *
   * @param {number | BigNumber | Complex | Array | Matrix} x
   *            A complex number or array with complex numbers
   * @return {number | BigNumber | Array | Matrix} The real part of x
   */
  var re = typed('re', {
    'number': function number(x) {
      return x;
    },
    'BigNumber': function BigNumber(x) {
      return x;
    },
    'Complex': function Complex(x) {
      return x.re;
    },
    'Array | Matrix': function ArrayMatrix(x) {
      return deepMap(x, re);
    }
  });
  re.toTex = {
    1: "\\Re\\left\\lbrace${args[0]}\\right\\rbrace"
  };
  return re;
}

exports.name = 're';
exports.factory = factory;