mathjs/lib/function/complex/arg.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) {
  /**
   * Compute the argument of a complex value.
   * For a complex number `a + bi`, the argument is computed as `atan2(b, a)`.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.arg(x)
   *
   * Examples:
   *
   *    const a = math.complex(2, 2)
   *    math.arg(a) / math.pi          // returns number 0.25
   *
   *    const b = math.complex('2 + 3i')
   *    math.arg(b)                    // returns number 0.982793723247329
   *    math.atan2(3, 2)               // returns number 0.982793723247329
   *
   * See also:
   *
   *    re, im, conj, abs
   *
   * @param {number | BigNumber | Complex | Array | Matrix} x
   *            A complex number or array with complex numbers
   * @return {number | BigNumber | Array | Matrix} The argument of x
   */
  var arg = typed('arg', {
    'number': function number(x) {
      return Math.atan2(0, x);
    },
    'BigNumber': function BigNumber(x) {
      return type.BigNumber.atan2(0, x);
    },
    'Complex': function Complex(x) {
      return x.arg();
    },
    // TODO: implement BigNumber support for function arg
    'Array | Matrix': function ArrayMatrix(x) {
      return deepMap(x, arg);
    }
  });
  arg.toTex = {
    1: "\\arg\\left(${args[0]}\\right)"
  };
  return arg;
}

exports.name = 'arg';
exports.factory = factory;