From fd80fc8e40af4dbabc7e61ae674d39def1f7ae97 Mon Sep 17 00:00:00 2001
From: Ben Greiner <code@bnavigator.de>
Date: Fri, 12 Mar 2021 22:26:33 +0100
Subject: [PATCH] support discrete system as input for FRD
---
control/frdata.py | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/control/frdata.py b/control/frdata.py
index 3398bfbee..c620984f6 100644
--- a/control/frdata.py
+++ b/control/frdata.py
@@ -110,9 +110,14 @@ def __init__(self, *args, **kwargs):
# the frequency range
otherlti = args[0]
self.omega = sort(np.asarray(args[1], dtype=float))
- numfreq = len(self.omega)
# calculate frequency response at my points
- self.fresp = otherlti(1j * self.omega, squeeze=False)
+ if otherlti.isctime():
+ s = 1j * self.omega
+ self.fresp = otherlti(s, squeeze=False)
+ else:
+ z = np.exp(1j * self.omega * otherlti.dt)
+ self.fresp = otherlti(z, squeeze=False)
+
else:
# The user provided a response and a freq vector
self.fresp = array(args[0], dtype=complex)
@@ -538,7 +543,10 @@ def _convert_to_FRD(sys, omega, inputs=1, outputs=1):
elif isinstance(sys, LTI):
omega = np.sort(omega)
- fresp = sys(1j * omega)
+ if sys.isctime():
+ fresp = sys(1j * omega)
+ else:
+ fresp = sys(np.exp(1j * omega * sys.dt))
if len(fresp.shape) == 1:
fresp = fresp[np.newaxis, np.newaxis, :]
return FRD(fresp, omega, smooth=True)