int user_fdf(const gsl_vector * x, void *params, gsl_vector * f, gsl_matrix * J) { int status = user_f (x, params, f); if (status) return status; status = user_df (x, params, J); return status; }
int user_fdf(const gsl_vector *x, void *params, gsl_vector *f, gsl_matrix *J) { user_f(x, params, f); user_df(x, params, J); return GSL_SUCCESS; }