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Fix namespace and logic errrors in statesp.freqresp + unit tests #196

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Merged
murrayrm merged 3 commits into from
Jul 2, 2018
Merged

Fix namespace and logic errrors in statesp.freqresp + unit tests #196

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057c5ca
Fix namespace and logic errrors in statesp.freqresp + unit tests
murrayrm Feb 24, 2018
55f4bb6
Fix warning check for python 2.7
murrayrm Feb 25, 2018
f2af185
updated freqresp unit tests + use abs(omega) in statespace.freqresp
murrayrm Jul 2, 2018
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6 changes: 2 additions & 4 deletions control/statesp.py
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Original file line number Diff line number Diff line change
Expand Up @@ -460,10 +460,8 @@ def freqresp(self, omega):
if isdtime(self, strict=True):
dt = timebase(self)
cmplx_freqs = exp(1.j * omega * dt)
if ((omega * dt).any() > pi):
warn_message = ("evalfr: frequency evaluation"
" above Nyquist frequency")
warnings.warn(warn_message)
if max(abs(omega)) * dt > math.pi:
warn("freqresp: frequency evaluation above Nyquist frequency")
else:
cmplx_freqs = omega * 1.j

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67 changes: 62 additions & 5 deletions control/tests/freqresp_test.py
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,8 @@
import numpy as np
import control as ctrl
from control.statesp import StateSpace
from control.matlab import ss, tf, bode
from control.xferfcn import TransferFunction
from control.matlab import ss, tf, bode, rss
from control.exception import slycot_check
import matplotlib.pyplot as plt

Expand Down Expand Up @@ -45,7 +46,7 @@ def test_superimpose(self):
ctrl.bode_plot(ctrl.tf([5], [1, 1]))

# Check to make sure there are two axes and that each axes has two lines
assert len(plt.gcf().axes) == 2
self.assertEqual(len(plt.gcf().axes), 2)
for ax in plt.gcf().axes:
# Make sure there are 2 lines in each subplot
assert len(ax.get_lines()) == 2
Expand All @@ -55,7 +56,7 @@ def test_superimpose(self):
ctrl.bode_plot([ctrl.tf([1], [1,2,1]), ctrl.tf([5], [1, 1])])

# Check to make sure there are two axes and that each axes has two lines
assert len(plt.gcf().axes) == 2
self.assertEqual(len(plt.gcf().axes), 2)
for ax in plt.gcf().axes:
# Make sure there are 2 lines in each subplot
assert len(ax.get_lines()) == 2
Expand All @@ -67,7 +68,7 @@ def test_superimpose(self):
ctrl.bode_plot(ctrl.tf([5], [1, 1]))

# Check to make sure there are two axes and that each axes has one line
assert len(plt.gcf().axes) == 2
self.assertEqual(len(plt.gcf().axes), 2)
for ax in plt.gcf().axes:
# Make sure there is only 1 line in the subplot
assert len(ax.get_lines()) == 1
Expand All @@ -77,7 +78,7 @@ def test_superimpose(self):
if ax.get_label() == 'control-bode-magnitude':
break
ax.semilogx([1e-2, 1e1], 20 * np.log10([1, 1]), 'k-')
assert len(ax.get_lines()) == 2
self.assertEqual(len(ax.get_lines()), 2)

def test_doubleint(self):
# 30 May 2016, RMM: added to replicate typecast bug in freqresp.py
Expand Down Expand Up @@ -107,6 +108,62 @@ def test_mimo(self):
#plt.figure(4)
#bode(sysMIMO,self.omega)

def test_discrete(self):
# Test discrete time frequency response

# SISO state space systems with either fixed or unspecified sampling times
sys = rss(3, 1, 1)
siso_ss1d = StateSpace(sys.A, sys.B, sys.C, sys.D, 0.1)
siso_ss2d = StateSpace(sys.A, sys.B, sys.C, sys.D, True)

# MIMO state space systems with either fixed or unspecified sampling times
A = [[-3., 4., 2.], [-1., -3., 0.], [2., 5., 3.]]
B = [[1., 4.], [-3., -3.], [-2., 1.]]
C = [[4., 2., -3.], [1., 4., 3.]]
D = [[-2., 4.], [0., 1.]]
mimo_ss1d = StateSpace(A, B, C, D, 0.1)
mimo_ss2d = StateSpace(A, B, C, D, True)

# SISO transfer functions
siso_tf1d = TransferFunction([1, 1], [1, 2, 1], 0.1)
siso_tf2d = TransferFunction([1, 1], [1, 2, 1], True)

# Go through each system and call the code, checking return types
for sys in (siso_ss1d, siso_ss2d, mimo_ss1d, mimo_ss2d,
siso_tf1d, siso_tf2d):
# Set frequency range to just below Nyquist freq (for Bode)
omega_ok = np.linspace(10e-4,0.99,100) * np.pi/sys.dt

# Test frequency response
ret = sys.freqresp(omega_ok)

# Check for warning if frequency is out of range
import warnings
warnings.simplefilter('always', UserWarning) # don't supress
with warnings.catch_warnings(record=True) as w:
omega_bad = np.linspace(10e-4,1.1,10) * np.pi/sys.dt
ret = sys.freqresp(omega_bad)
print("len(w) =", len(w))
self.assertEqual(len(w), 1)
self.assertIn("above", str(w[-1].message))
self.assertIn("Nyquist", str(w[-1].message))

# Test bode plots (currently only implemented for SISO)
if (sys.inputs == 1 and sys.outputs == 1):
# Generic call (frequency range calculated automatically)
ret_ss = bode(sys)

# Convert to transfer function and test bode again
systf = tf(sys);
ret_tf = bode(systf)

# Make sure we can pass a frequency range
bode(sys, omega_ok)

else:
# Calling bode should generate a not implemented error

@roryyorke roryyorke Mar 13, 2018

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how about self.assertRaises(NotImplementedError, bode, (sys,)) ?

self.assertRaises(NotImplementedError, bode, (sys,))

def suite():
return unittest.TestLoader().loadTestsFromTestCase(TestTimeresp)

Expand Down