Function gsl_sys::gsl_multimin_fdfminimizer_set

pub unsafe extern "C" fn gsl_multimin_fdfminimizer_set(
    s: *mut gsl_multimin_fdfminimizer, 
    fdf: *mut gsl_multimin_function_fdf, 
    x: *const gsl_vector, 
    step_size: f64, 
    tol: f64
) -> c_int