/// Hyperbolic cosine integral. double Chi(double x) { gsl_sf_result result; int stat = gsl_sf_Chi_e(x, &result); if (stat != GSL_SUCCESS) { std::ostringstream msg("Error in Chi:"); msg << " x=" << x; throw std::runtime_error(msg.str()); } else return result.val; }
double gsl_sf_Chi(const double x) { EVAL_RESULT(gsl_sf_Chi_e(x, &result)); }