mathjs/lib/function/construction/complex.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser and offers an integrated solution to work with numbers, big numbers, complex numbers, units, and matrices.

module.exports = function (math) {
  var util = require('../../util/index'),

      BigNumber = math.type.BigNumber,
      Complex = require('../../type/Complex'),
      collection = require('../../type/collection'),

      isCollection = collection.isCollection,
      isNumber = util.number.isNumber,
      isString = util.string.isString,
      isComplex = Complex.isComplex;

  /**
   * Create a complex value or convert a value to a complex value.
   *
   * The method accepts the following arguments:
   *     complex()                           creates a complex value with zero
   *                                         as real and imaginary part.
   *     complex(re : number, im : string)   creates a complex value with provided
   *                                         values for real and imaginary part.
   *     complex(re : number)                creates a complex value with provided
   *                                         real value and zero imaginary part.
   *     complex(complex : Complex)          clones the provided complex value.
   *     complex(arg : string)               parses a string into a complex value.
   *     complex(array : Array)              converts the elements of the array
   *                                         or matrix element wise into a
   *                                         complex value.
   *     complex({re: number, im: number})   creates a complex value with provided
   *                                         values for real an imaginary part.
   *     complex({r: number, phi: number})   creates a complex value with provided
   *                                         polar coordinates
   *
   * Example usage:
   *     var a = math.complex(3, -4);     // 3 - 4i
   *     a.re = 5;                        // a = 5 - 4i
   *     var i = a.im;                    // -4;
   *     var b = math.complex('2 + 6i');  // 2 + 6i
   *     var c = math.complex();          // 0 + 0i
   *     var d = math.add(a, b);          // 5 + 2i
   *
   * @param {* | Array | Matrix} [args]
   * @return {Complex | Array | Matrix} value
   */
  math.complex = function complex(args) {
    switch (arguments.length) {
      case 0:
        // no parameters. Set re and im zero
        return new Complex(0, 0);

      case 1:
        // parse string into a complex number
        var arg = arguments[0];

        if (isNumber(arg)) {
          return new Complex(arg, 0);
        }

        if (arg instanceof BigNumber) {
          // convert to Number
          return new Complex(arg.toNumber(), 0);
        }

        if (isComplex(arg)) {
          // create a clone
          return arg.clone();
        }

        if (isString(arg)) {
          var c = Complex.parse(arg);
          if (c) {
            return c;
          }
          else {
            throw new SyntaxError('String "' + arg + '" is no valid complex number');
          }
        }

        if (isCollection(arg)) {
          return collection.deepMap(arg, complex);
        }

        if (typeof arg === 'object') {
          if('re' in arg && 'im' in arg) {
            return new Complex(arg.re, arg.im);
          } else if ('r' in arg && 'phi' in arg) {
            return Complex.fromPolar(arg.r, arg.phi);
          }
        } 

        throw new TypeError('Two numbers, single string or an fitting object expected in function complex');

      case 2:
        // re and im provided
        var re = arguments[0],
            im = arguments[1];

        // convert re to number
        if (re instanceof BigNumber) {
          re = re.toNumber();
        }

        // convert im to number
        if (im instanceof BigNumber) {
          im = im.toNumber();
        }

        if (isNumber(re) && isNumber(im)) {
          return new Complex(re, im);
        }
        else {
          throw new TypeError('Two numbers or a single string expected in function complex');
        }

      default:
        throw new math.error.ArgumentsError('complex', arguments.length, 0, 2);
    }
  };
};