func CdfGaussianPinv(p float64, sigma float64) float64 {
return float64(C.gsl_cdf_gaussian_Pinv(C.double(p), C.double(sigma)))
}
// GaussianPinv returns the inverse cumulative distribution function
// Pinv(x) for the lower tail of a Gaussian.
func GaussianPinv(P float64, sigma float64) float64 {
return float64(C.gsl_cdf_gaussian_Pinv(C.double(P), C.double(sigma)))
}