% Create two new models with a component each
mSource = systemcomposer.createModel('Source_Model_Allocation',true);
sourceComp = mSource.Architecture.addComponent('Source_Component');
mTarget = systemcomposer.createModel('Target_Model_Allocation',true);
targetComp = mTarget.Architecture.addComponent('Target_Component');

% Create the allocation set with name 'MyNewAllocation'
allocSet = systemcomposer.allocation.createAllocationSet('MyNewAllocation',...
     'Source_Model_Allocation','Target_Model_Allocation');

% Get the default allocation scenario
defaultScenario = allocSet.getScenario('Scenario 1');

% Allocate components between models
allocation = defaultScenario.allocate(sourceComp,targetComp);

% Close the allocation set without saving
allocSet.close(true);

% Open the allocation editor 
systemcomposer.allocation.editor()