int gsl_sf_complex_psi_e( const double x, const double y, gsl_sf_result * result_re, gsl_sf_result * result_im ) { if(x >= 0.0) { gsl_complex z = gsl_complex_rect(x, y); return psi_complex_rhp(z, result_re, result_im); } else { /* reflection formula [Abramowitz+Stegun, 6.3.7] */ gsl_complex z = gsl_complex_rect(x, y); gsl_complex omz = gsl_complex_rect(1.0 - x, -y); gsl_complex zpi = gsl_complex_mul_real(z, M_PI); gsl_complex cotzpi = gsl_complex_cot(zpi); int ret_val = psi_complex_rhp(omz, result_re, result_im); if(GSL_IS_REAL(GSL_REAL(cotzpi)) && GSL_IS_REAL(GSL_IMAG(cotzpi))) { result_re->val -= M_PI * GSL_REAL(cotzpi); result_im->val -= M_PI * GSL_IMAG(cotzpi); return ret_val; } else { GSL_ERROR("singularity", GSL_EDOM); } } }
/** Cotangent \ingroup complex \param[in] z Complex number \return \f$ \cot z \f$*/ complex cot(const complex& z) { return complex(gsl_complex_cot(z.as_gsl_type())); }