An adder circuit for determining the sum of two operands including a set of PGK circuits, at least one tier of group circuits, and a carry generation circuit. A sacrificial layer is formed within a recess in a structural layer. The first communication network has a first OAM protocol adapted to monitor integrity of the first communication network and the second communication network has a second OAM protocol adapted to monitor integrity of the second communication network. In fitting the TPS, functions are activated, such as automatic arrangement of control points, addition of target points to the outside of an image, use of a known model, and fitting to at least either absolute value components of MR data or phase components of the MR data.