Probabilities::GenExtValueCDFInv Function

double GenExtValueCDFInv(double p, double k, double Mu, double sigma);

Generalized extreme value (GEV) percent point function (PPF, quantile / inverse CDF).

#NameTypeDescription
1pdoubleProbability, real value on the closed interval [0,1].
2kdoubleDistribution shape parameter, real value.
3MudoubleDistribution location parameter, real value.
4sigmadoubleDistribution scale parameter, positive real value (sigma>0).

Returns: the value x such that GenExtValueCDF(x,k,Mu,sigma)=p, using shape k, location Mu and positive scale sigma. Returns NaN if sigma<=0 or p is outside [0,1].

Remarks:

The GEV inverse CDF has a closed form. With z defined below,

CDFInv(p | k,mu,sigma) = mu + sigma z ,   z = { ((-ln p)^(-k)-1)/k,  if k != 0
                                              { [1.2ex] -ln(-ln p),  if k=0   ,   0 < p < 1 .

Boundary values: at p=0 or p=1 the result is mu-sigma/k or +/-inf according to the sign of k. Returns NaN for sigma<=0 or p outside [0,1].

See Also: Probabilities::GenExtValuePDF, Probabilities::GenExtValueCDF
Declared in Dew::Math::Units::Probabilities · Dew.Math/Units.Probabilities.h · Cross-compiler