func UgaussianTail(r *rng.GslRng, a float64) float64 { return float64(C.gsl_ran_ugaussian_tail((*C.gsl_rng)(unsafe.Pointer(r.Ptr())), C.double(a))) }
// UgaussianTail provides random variates from a unit Gaussian tail // distribution func UgaussianTail(rng RngState, a float64) float64 { return float64(C.gsl_ran_ugaussian_tail(rng.state, C.double(a))) }