Topology.submodel — select topology model type

This is used to select the type of topology model currently in use; see Topology.make() for more information. Note that it is not usually necessary to explicitly set Topology.submodel, since it is set for you automatically when you read a topology file (all of the standard MODELLER topology files include a '* MODELLER topology.submodel' header from which this information is derived). See Topology.read().