Double_t RooIpatia2__BK(Double_t ni, Double_t x) {
Double_t nu = TMath::Abs(ni);
if ( x < 1.e-06 && nu > 0.) return RooIpatia2__low_x_BK(nu,x);
if ( x < 1.e-04 && nu > 0. && nu < 55.) return RooIpatia2__low_x_BK(nu,x);
if ( x < 0.1 && nu >= 55.) return RooIpatia2__low_x_BK(nu,x);
return gsl_sf_bessel_Knu(nu, x);
//return ROOT::Math::cyl_bessel_k(nu, x);
}
Double_t RooGeneralizedHyperbolic__BK(Double_t ni, Double_t x) {
Double_t nu = abs(ni);
if ( x < 1e-06 && nu > 0) return RooGeneralizedHyperbolic__low_x_BK(nu,x);
if ( x < 1e-04 && nu > 0 && nu < 55) return RooGeneralizedHyperbolic__low_x_BK(nu,x);
if ( x < 0.1 && nu >= 55) return RooGeneralizedHyperbolic__low_x_BK(nu,x);
return gsl_sf_bessel_Knu(nu, x);
//return ROOT::Math::cyl_bessel_k(nu, x);
}
//--------------------------------------------------------------------------------------------------
double matern_kernel( const double& h, const double& v, const double& sigma, const double& theta ) {
double H = sqrt( v ) * h / theta;
if ( H > 0 ) {
return sigma * sigma * 2 * pow( H, v ) * gsl_sf_bessel_Knu( v, 2 * H ) / gsl_sf_gamma( v );
}
else {
return 1.0;
}
}
inline long double cyl_bessel_k(long double a, long double x)
{ return gsl_sf_bessel_Knu(a, x); }
inline double cyl_bessel_k(double a, double x)
{ return gsl_sf_bessel_Knu(a, x); }
inline float cyl_bessel_k(float a, float x)
{ return (float)gsl_sf_bessel_Knu(a, x); }