public Vector4 GetRow(int index)
{
if ((index < 0) || (index > 3))
throw new ArgumentException("Invalid row index was specified.", "index");
return (index == 0) ? new Vector4(V00, V01, V02, V03) :
(index == 1) ? new Vector4(V10, V11, V12, V13) :
(index == 2) ? new Vector4(V20, V21, V22, V23) : new Vector4(V30, V31, V32, V33);
}