function quantile( p, lambda ) {
	if ( isnan( lambda ) || isnan( p ) || lambda <= 0.0 || p < 0.0 || p > 1.0 ) { // eslint-disable-line max-len
		return NaN;
	}
	if ( p === 1.0 ) {
		return PINF;
	}
	return ceil( -ln( 1.0-p ) / lambda ) - 1.0;
}
Evaluates the quantile function for a Planck distribution with shape parameter `lambda` at a probability `p`.

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

@example
var y = quantile( 0.8, 0.4 );
// returns 4

@example
var y = quantile( 0.5, 1.4 );
// returns 0

@example
var y = quantile( 0.9, 2.1 );
// returns 1

@example
var y = quantile( 0.2, -0.1 );
// returns NaN

@example
var y = quantile( NaN, 0.8 );
// returns NaN

@example
var y = quantile( 0.4, NaN );
// returns NaN

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

@example
var y = quantile( 1.5, 1.0 );
// returns NaN