“…However, this algorithm fails if the system has not the same number of inputs and outputs or if one of the matrices B or C does not have full column or full row rank respectively. For this reason, in the LinearSystems library the algorithm from [5] is used to calculate the invariant zeros of arbitrary StateSpace systems, i.e., with arbitrary numbers of inputs and outputs and rank deficient matrices. The approach is to compress the matrices (A, B, C, D) with QR-decompositions to (A r , B r , C r , D r ) such that a reduced order system matrix…”