Discussion of “A Half-Size Singularity Test Matrix for Fast and Reliable Passivity Assessment of Rational Models”

In this paper a half-size singularity test matrix for fast and reliable passivity assessment of rational models are discussed. The discussers would like to remark that the half-size singularity matrix test, in fact, applies only to symmetric systems, unlike the Hamiltonian matrix passivity test that is applicable to state-space systems without regard to symmetry considerations. The discussers have come up with a more elegant derivation of the singularity test matrix and new results concerning the stronger nature of the passivity condition.