control.norm

control.norm(system, p=2, tol=1e-06, print_warning=True, method=None)[source]

Computes norm of system.

Parameters

  • system (LTI (StateSpace or TransferFunction)) – System in continuous or discrete time for which the norm should be computed.

  • p (int or str) – Type of norm to be computed. p=2 gives the H2 norm, and p='inf' gives the L-infinity norm.

  • tol (float) – Relative tolerance for accuracy of L-infinity norm computation. Ignored unless p='inf'.

  • print_warning (bool) – Print warning message in case norm value may be uncertain.

  • method (str, optional) – Set the method used for computing the result. Current methods are 'slycot' and 'scipy'. If set to None (default), try 'slycot' first and then 'scipy'.

Returns

norm_value – Norm value of system.

Return type

float

Notes

Does not yet compute the L-infinity norm for discrete time systems with pole(s) in z=0 unless Slycot is used.

Examples

>>> Gc = ct.tf([1], [1, 2, 1])
>>> round(ct.norm(Gc, 2), 3)
0.5
>>> round(ct.norm(Gc, 'inf', tol=1e-5, method='scipy'), 3)
np.float64(1.0)