public void Visit(Compiled.UnaryFunc elem)
            {
                double arg = ValueOf(elem.Arg);

                elem.Value            = elem.Eval(arg);
                elem.Inputs[0].Weight = elem.Diff(arg);
            }
 public void Visit(Compiled.UnaryFunc elem)
 {
     elem.Value = elem.Eval(ValueOf(elem.Arg));
 }