def _argus_phi(chi):
 return ((_norm_cdf(chi) - (chi * _norm_pdf(chi))) - 0.5)

def _argus_phi ( chi ) : return ( ( _norm_cdf ( chi ) - ( chi * _norm_pdf ( chi ) ) ) - 0.5 )
utility function for the argus distribution used in the cdf and norm of the argus funktion .