mathjs/lib/function/arithmetic/exp.js

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

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

      isNumber = util.number.isNumber,
      isBoolean = util['boolean'].isBoolean,
      isComplex = Complex.isComplex,
      isCollection = collection.isCollection;

  /**
   * Calculate the exponent of a value
   *
   *     exp(x)
   *
   * For matrices, the function is evaluated element wise.
   *
   * @param {Number | Boolean | Complex | Array | Matrix} x
   * @return {Number | Complex | Array | Matrix} res
   */
  math.exp = function exp (x) {
    if (arguments.length != 1) {
      throw new math.error.ArgumentsError('exp', arguments.length, 1);
    }

    if (isNumber(x)) {
      return Math.exp(x);
    }

    if (isComplex(x)) {
      var r = Math.exp(x.re);
      return new Complex(
          r * Math.cos(x.im),
          r * Math.sin(x.im)
      );
    }

    if (x instanceof BigNumber) {
      // TODO: implement BigNumber support
      // downgrade to Number
      return exp(x.toNumber());
    }

    if (isCollection(x)) {
      return collection.deepMap(x, exp);
    }

    if (isBoolean(x)) {
      return Math.exp(x);
    }

    throw new math.error.UnsupportedTypeError('exp', x);
  };
};