def test_iosys_print(self):
# Send the output to /dev/null
import os
f = open(os.devnull,"w")
# Simple I/O system
iosys = ct.ss2io(self.siso_linsys)
print(iosys, file=f)
# I/O system without ninputs, noutputs
ios_unspecified = ios.NonlinearIOSystem(secord_update, secord_output)
print(ios_unspecified, file=f)
# I/O system with derived inputs and outputs
ios_linearized = ios.linearize(ios_unspecified, [0, 0], [0])
print(ios_linearized, file=f)
f.close()
def test_params(self):
# Start with the default set of parameters
ios_secord_default = ios.NonlinearIOSystem(
secord_update, secord_output, inputs=1, outputs=1, states=2)
lin_secord_default = ios.linearize(ios_secord_default, [0, 0], [0])
w_default, v_default = np.linalg.eig(lin_secord_default.A)
# New copy, with modified parameters
ios_secord_update = ios.NonlinearIOSystem(
secord_update, secord_output, inputs=1, outputs=1, states=2,
params={'omega0':2, 'zeta':0})
# Make sure the default parameters haven't changed
lin_secord_check = ios.linearize(ios_secord_default, [0, 0], [0])
w, v = np.linalg.eig(lin_secord_check.A)
np.testing.assert_array_almost_equal(np.sort(w), np.sort(w_default))
# Make sure updated system parameters got set correctly
lin_secord_update = ios.linearize(ios_secord_update, [0, 0], [0])
w, v = np.linalg.eig(lin_secord_update.A)
np.testing.assert_array_almost_equal(np.sort(w), np.sort([2j, -2j]))
# Change the parameters of the default sys just for the linearization
lin_secord_local = ios.linearize(ios_secord_default, [0, 0], [0],
params={'zeta':0})
w, v = np.linalg.eig(lin_secord_local.A)
np.testing.assert_array_almost_equal(np.sort(w), np.sort([1j, -1j]))
# Change the parameters of the updated sys just for the linearization
lin_secord_local = ios.linearize(ios_secord_update, [0, 0], [0],
params={'zeta':0, 'omega0':3})
w, v = np.linalg.eig(lin_secord_local.A)
np.testing.assert_array_almost_equal(np.sort(w), np.sort([3j, -3j]))
# Make sure that changes propagate through interconnections
ios_series_default_local = ios_secord_default * ios_secord_update
lin_series_default_local = ios.linearize(
ios_series_default_local, [0, 0, 0, 0], [0])
w, v = np.linalg.eig(lin_series_default_local.A)
np.testing.assert_array_almost_equal(
np.sort(w), np.sort(np.concatenate((w_default, [2j, -2j]))))
# Show that we can change the parameters at linearization
lin_series_override = ios.linearize(
ios_series_default_local, [0, 0, 0, 0], [0],
params={'zeta':0, 'omega0':4})
w, v = np.linalg.eig(lin_series_override.A)
np.testing.assert_array_almost_equal(w, [4j, -4j, 4j, -4j])
# Check for warning if we try to set params for LinearIOSystem
linsys = self.siso_linsys
iosys = ios.LinearIOSystem(linsys)
T, U, X0 = self.T, self.U, self.X0
lti_t, lti_y, lti_x = ct.forced_response(linsys, T, U, X0)
with warnings.catch_warnings(record=True) as warnval:
# Turn off deprecation warnings
warnings.simplefilter("ignore", category=DeprecationWarning)
warnings.simplefilter("ignore", category=PendingDeprecationWarning)
# Trigger a warning
ios_t, ios_y = ios.input_output_response(
iosys, T, U, X0, params={'something':0})
# Verify that we got a warning
self.assertEqual(len(warnval), 1)
self.assertTrue(issubclass(warnval[-1].category, UserWarning))
self.assertTrue("LinearIOSystem" in str(warnval[-1].message))
self.assertTrue("ignored" in str(warnval[-1].message))
# Check to make sure results are OK
np.testing.assert_array_almost_equal(lti_t, ios_t)
np.testing.assert_array_almost_equal(lti_y, ios_y, decimal=3)