function cdf( x ) {
		var i;
		var p;
		if ( isnan( x ) ) {
			return NaN;
		}
		if ( x < 0.0 ) {
			return 0.0;
		}
		x = round( x );
		if ( x >= mlim ) {
			return 1.0;
		}
		p = 0;
		for ( i = 0; i <= x; i++ ) {
			p += weights( i, n ) * pui;
		}
		return p;
	}
Evaluates the cumulative distribution function (CDF) for the distribution of the Wilcoxon signed rank test statistic.

@private
@param {number} x - input value
@returns {Probability} evaluated CDF

@example
var y = cdf( 2 );
// returns <number>