sample:
    model:
        comment: Modulated Sine Wave SLD
        stack: air | wave 200 | Si
        sub_stacks:
          wave:
            sub_stack_class: FunctionTwoElements
            material1: Ni
            material2: Ti
            function: (0.5+0.5*sin(x*20.0*2*pi))*exp(-(x-0.5)**2/0.25**2)
