BornAgain

Currently, adding different ParticeLayouts to a multilayer assumes that the layouts are not restricted to certain domains of the sample. If we would add two different orientational domains as separate layouts, they would be added incoherently, assuming they both fill the x-y plane.
In such cases, it is much more natural to have a certain weight associated with each layout, which is then used to make an (incoherent) weighted sum, instead of a simple sum.