Create option set for computing Hankel singular values and input/output balancing
opts = hsvdOptions
opts = hsvdOptions('OptionName', OptionValue)
opts = hsvdOptions returns the default options for the hsvd and balreal commands.
opts = hsvdOptions('OptionName', OptionValue) accepts one or more comma-separated name/value pairs. Specify OptionName inside single quotes.
Absolute and relative error tolerance for stable/unstable decomposition. Positive scalar values. For an input model G with unstable poles, hsvd and balreal first extract the stable dynamics by computing the stable/unstable decomposition G → GS + GU. The AbsTol and RelTol tolerances control the accuracy of this decomposition by ensuring that the frequency responses of G and GS + GU differ by no more than AbsTol + RelTol*abs(G). Increasing these tolerances helps separate nearby stable and unstable modes at the expense of accuracy. See stabsep for more information.
Default: AbsTol = 0; RelTol = 1e-8
Offset for the stable/unstable boundary. Positive scalar value. In the stable/unstable decomposition, the stable term includes only poles satisfying:
Increase the value of Offset to treat poles close to the stability boundary as unstable.
Compute the Hankel singular values of the system given by:
Use the Offset option to force hsvd to exclude the pole at s = 10–6 from the stable term of the stable/unstable decomposition.
sys = zpk(-.5,[-1e-6 -2],1); opts = hsvdOptions('Offset',.001); % create option set hsvd(sys,opts) % treats -1e-6 as unstable