es. This is an integer value that changes which set of
atomic planes that the plane is inserted between. Changing this
effectively changes the termination planes.</p></li>
<li><p><strong>stackingfault_faultpos_rel</strong>: A fractional coordinate from 0 to 1
indicating where along the cutboxvector to position the fault plane.
Default value is 0.5, which if stackingfault_even is True will result
in the same termination planes at the free surface and the stacking
fault.</p></li>
<li><p><strong>sizemults</str