function quantile( p, k, lambda ) {
	if (
		isnan( k ) ||
		isnan( lambda ) ||
		isnan( p ) ||
		k <= 0.0 ||
		lambda <= 0.0 ||
		p < 0.0 ||
		p > 1.0
	) {
		return NaN;
	}
	return lambda * pow( -ln( 1.0 - p ), 1.0/k );
}
Evaluates the quantile function for a Weibull distribution with shape parameter `k` and scale parameter `lambda` at a probability `p`.

@param {Probability} p - input value
@param {PositiveNumber} k - shape parameter
@param {PositiveNumber} lambda - scale parameter
@returns {number} evaluated quantile function

@example
var y = quantile( 0.8, 1.0, 1.0 );
// returns ~1.609

@example
var y = quantile( 0.5, 2.0, 4.0 );
// returns ~3.33

@example
var y = quantile( 1.1, 1.0, 1.0 );
// returns NaN

@example
var y = quantile( -0.2, 1.0, 1.0 );
// returns NaN

@example
var y = quantile( NaN, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( 0.0, NaN, 1.0 );
// returns NaN

@example
var y = quantile( 0.0, 0.0, NaN );
// returns NaN

@example
var y = quantile( 0.5, 1.0, -1.0 );
// returns NaN