^[a] The mnemonic all cannot be used when REGFE is run as a stand-alone program. In this mode each atom type must have an atrad line to establish the scattering factor type.

^[a] The plane ID or line ID may be any one from the predefined plane list or line list, or can be a group of atom labels which are adequate to define a plane or line. Different types of functions require different numbers and types of components. The sequence of components is important. For example, function PDA (distance from plane to atom) should be followed by a plane ID and an atom label, but not an atom label and a plane ID. A plane can also be defined by entering three atom labels and a line can be defined by entering two atom labels.