Create a model named 'archModel', add an
interface, create an interface element with a name 'x', and set the
type for the interface element 'single'.
modelName = 'archModel';
arch = systemcomposer.createModel(modelName); % Create model
interface = arch.InterfaceDictionary.addInterface('interface'); % Add interface
elem = interface.addElement('x'); % Create interface element
setType(elem,'single'); % Set type for interface element