docs: function partial( mu, sigma ) {
  	var sqrt2xSigma = sqrt( 2 ) * sigma;
  	/**
  	* FUNCTION: cdf( x )
  	*	Evaluates the cumulative distribution function (CDF) for a Lognormal distribution.
  	*
  	* @private
  	* @param {Number} x - input value
  	* @returns {Number} evaluated CDF
  	*/
  	return function cdf( x ) {
  		var z;
  		z = ln( x ) - mu;
  		z /= sqrt2xSigma;
  		return 0.5 + 0.5 * erf( z );
  	};
  }