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[python-control-discuss] SF.net SVN: python-control:[144] branches/control-0.4b
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From: <mur...@us...> - 2011-04-02 15:52:46
|
Revision: 144
http://python-control.svn.sourceforge.net/python-control/?rev=144&view=rev
Author: murrayrm
Date: 2011-04-02 15:52:38 +0000 (Sat, 02 Apr 2011)
Log Message:
-----------
* Moved nichols() code to separate file, added unit test; add'l updates pending
* Moved slycot imports inside functions that need them
* Updated pvtol-nested example to work with v0.4
* See ChangeLog for detailed listing of changes
Modified Paths:
--------------
branches/control-0.4b/ChangeLog
branches/control-0.4b/examples/pvtol-nested.py
branches/control-0.4b/src/__init__.py
branches/control-0.4b/src/freqplot.py
branches/control-0.4b/src/matlab.py
branches/control-0.4b/src/statesp.py
branches/control-0.4b/src/xferfcn.py
Added Paths:
-----------
branches/control-0.4b/src/nichols.py
branches/control-0.4b/tests/nichols_test.py
Modified: branches/control-0.4b/ChangeLog
===================================================================
--- branches/control-0.4b/ChangeLog 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/ChangeLog 2011-04-02 15:52:38 UTC (rev 144)
@@ -1,3 +1,27 @@
+2011-03-31 Richard Murray <mu...@ma...>
+
+ * examples/pvtol-nested.py: updated stability margin plot to use
+ proper calling format for bode().
+
+ * src/statesp.py (_convertToStateSpace): moved slycot import
+ to the location where it is actually needed (allows running some
+ commands without slycot installed)
+
+ * src/xferfcn.py (_convertToTransferFunction): moved slycot import
+ to the location where it is actually needed (allows running some
+ commands without slycot installed)
+
+ * src/nichols.py: new file for Nichols plot routines; move
+ nichols(), nichols_grid(), closed_loop_contours(), m_circles(),
+ n_circles()
+
+ * src/__init__.py, src/freqresp.py, src/matlab.py: updated to match
+ new file structure for Nichols charts
+
+ * src/nichols.py (nichols): updated processing of freqresp to take
+ into account the fact that return arguments are now a matrix of
+ results (even for a SISO system)
+
2011-03-30 Richard Murray <mu...@ma...>
* tests/: added top level subdirectory, to be used for unit tests.
Modified: branches/control-0.4b/examples/pvtol-nested.py
===================================================================
--- branches/control-0.4b/examples/pvtol-nested.py 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/examples/pvtol-nested.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -84,22 +84,22 @@
# (gm, pm, wgc, wpc) = margin(L);
#! TODO: this figure has something wrong; axis limits mismatch
-figure(6); clf; subplot(221);
-(magh, phaseh) = bode(L);
+figure(6); clf;
+bode(L);
# Add crossover line
-subplot(magh); hold(True);
-loglog([10^-4, 10^3], [1, 1], 'k-')
+subplot(211); hold(True);
+loglog([1e-4, 1e3], [1, 1], 'k-')
# Replot phase starting at -90 degrees
bode(L, logspace(-4, 3));
(mag, phase, w) = freqresp(L, logspace(-4, 3));
phase = phase - 360;
-subplot(phaseh);
-semilogx([10^-4, 10^3], [-180, -180], 'k-')
+subplot(212);
+semilogx([1e-4, 1e3], [-180, -180], 'k-')
hold(True);
semilogx(w, np.squeeze(phase), 'b-')
-axis([10^-4, 10^3, -360, 0]);
+axis([1e-4, 1e3, -360, 0]);
xlabel('Frequency [deg]'); ylabel('Phase [deg]');
# set(gca, 'YTick', [-360, -270, -180, -90, 0]);
# set(gca, 'XTick', [10^-4, 10^-2, 1, 100]);
Modified: branches/control-0.4b/src/__init__.py
===================================================================
--- branches/control-0.4b/src/__init__.py 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/src/__init__.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -59,6 +59,7 @@
from xferfcn import *
from statesp import *
from freqplot import *
+from nichols import *
from bdalg import *
from statefbk import *
from delay import *
Modified: branches/control-0.4b/src/freqplot.py
===================================================================
--- branches/control-0.4b/src/freqplot.py 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/src/freqplot.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -212,139 +212,7 @@
plt.plot([-1], [0], 'r+')
return x, y, omega
-# Nichols plot
-# Contributed by Allan McInnes <All...@ca...>
-#! TODO: need unit test code
-def nichols(syslist, omega=None):
- """Nichols plot for a system
- Usage
- =====
- magh = nichols(sys, omega=None)
-
- Plots a Nichols plot for the system over a (optional) frequency range.
-
- Parameters
- ----------
- syslist : linsys
- List of linear input/output systems (single system is OK)
- omega : freq_range
- Range of frequencies (list or bounds) in rad/sec
-
- Return values
- -------------
- None
- """
-
- # If argument was a singleton, turn it into a list
- if (not getattr(syslist, '__iter__', False)):
- syslist = (syslist,)
-
- # Select a default range if none is provided
- if (omega == None):
- omega = default_frequency_range(syslist)
-
- for sys in syslist:
- # Get the magnitude and phase of the system
- mag, phase, omega = sys.freqresp(omega)
-
- # Convert to Nichols-plot format (phase in degrees,
- # and magnitude in dB)
- x = unwrap(sp.degrees(phase), 360)
- y = 20*sp.log10(mag)
-
- # Generate the plot
- plt.plot(x, y)
-
- plt.xlabel('Phase (deg)')
- plt.ylabel('Magnitude (dB)')
- plt.title('Nichols Plot')
-
- # Mark the -180 point
- plt.plot([-180], [0], 'r+')
-
-# Nichols grid
-def nichols_grid():
- """Nichols chart grid
-
- Usage
- =====
- nichols_grid()
-
- Plots a Nichols chart grid on the current axis.
-
- Parameters
- ----------
- None
-
- Return values
- -------------
- None
- """
- mag_min_default = -40.0 # dB
- mag_step = 20.0 # dB
-
- # Chart defaults
- phase_min, phase_max, mag_min, mag_max = -360.0, 0.0, mag_min_default, 40.0
-
- # Set actual chart bounds based on current plot
- if plt.gcf().gca().has_data():
- phase_min, phase_max, mag_min, mag_max = plt.axis()
-
- # M-circle magnitudes.
- # The "fixed" set are always generated, since this guarantees a recognizable
- # Nichols chart grid.
- mags_fixed = np.array([-40.0, -20.0, -12.0, -6.0, -3.0, -1.0, -0.5, 0.0,
- 0.25, 0.5, 1.0, 3.0, 6.0, 12.0])
-
- if mag_min < mag_min_default:
- # Outside the "fixed" set of magnitudes, the generated M-circles
- # are extended in steps of 'mag_step' dB to cover anything made
- # visible by the range of the existing plot
- mags_adjust = np.arange(mag_step*np.floor(mag_min/mag_step),
- mag_min_default, mag_step)
- mags = np.concatenate((mags_adjust, mags_fixed))
- else:
- mags = mags_fixed
-
- # N-circle phases (should be in the range -360 to 0)
- phases = np.array([-0.25, -10.0, -20.0, -30.0, -45.0, -60.0, -90.0,
- -120.0, -150.0, -180.0, -210.0, -240.0, -270.0,
- -310.0, -325.0, -340.0, -350.0, -359.75])
-
- # Find the M-contours
- m = m_circles(mags, phase_min=np.min(phases), phase_max=np.max(phases))
- m_mag = 20*sp.log10(np.abs(m))
- m_phase = sp.mod(sp.degrees(sp.angle(m)), -360.0) # Unwrap
-
- # Find the N-contours
- n = n_circles(phases, mag_min=np.min(mags), mag_max=np.max(mags))
- n_mag = 20*sp.log10(np.abs(n))
- n_phase = sp.mod(sp.degrees(sp.angle(n)), -360.0) # Unwrap
-
- # Plot the contours behind other plot elements.
- # The "phase offset" is used to produce copies of the chart that cover
- # the entire range of the plotted data, starting from a base chart computed
- # over the range -360 < phase < 0 (see above). Given the range
- # the base chart is computed over, the phase offset should be 0
- # for -360 < phase_min < 0.
- phase_offset_min = 360.0*np.ceil(phase_min/360.0)
- phase_offset_max = 360.0*np.ceil(phase_max/360.0) + 360.0
- phase_offsets = np.arange(phase_offset_min, phase_offset_max, 360.0)
- for phase_offset in phase_offsets:
- plt.plot(m_phase + phase_offset, m_mag, color='gray',
- linestyle='dashed', zorder=0)
- plt.plot(n_phase + phase_offset, n_mag, color='gray',
- linestyle='dashed', zorder=0)
-
- # Add magnitude labels
- for x, y, m in zip(m_phase[:][-1], m_mag[:][-1], mags):
- align = 'right' if m < 0.0 else 'left'
- plt.text(x, y, str(m) + ' dB', size='small', ha=align)
-
- # Make sure axes conform to any pre-existing plot.
- plt.axis([phase_min, phase_max, mag_min, mag_max])
-
# Gang of Four
#! TODO: think about how (and whether) to handle lists of systems
def gangof4(P, C, omega=None):
@@ -462,84 +330,3 @@
return omega
-# Compute contours of a closed-loop transfer function
-def closed_loop_contours(Hmag, Hphase):
- """Contours of the function H = G/(1+G).
-
- Usage
- =====
- contours = closed_loop_contours(mags, phases)
-
- Parameters
- ----------
- mags : array-like
- Meshgrid array of magnitudes of the contours
- phases : array-like
- Meshgrid array of phases in radians of the contours
-
- Return values
- -------------
- contours : complex array
- Array of complex numbers corresponding to the contours.
- """
- # Compute the contours in H-space
- H = Hmag*sp.exp(1.j*Hphase)
-
- # Invert H = G/(1+G) to get an expression for the contours in G-space
- return H/(1.0 - H)
-
-# M-circle
-def m_circles(mags, phase_min=-359.75, phase_max=-0.25):
- """Constant-magnitude contours of the function H = G/(1+G).
-
- Usage
- =====
- contours = m_circles(mags)
-
- Parameters
- ----------
- mags : array-like
- Array of magnitudes in dB of the M-circles
- phase_min : degrees
- Minimum phase in degrees of the N-circles
- phase_max : degrees
- Maximum phase in degrees of the N-circles
-
- Return values
- -------------
- contours : complex array
- Array of complex numbers corresponding to the contours.
- """
- # Convert magnitudes and phase range into a grid suitable for
- # building contours
- phases = sp.radians(sp.linspace(phase_min, phase_max, 500))
- Hmag, Hphase = sp.meshgrid(10.0**(mags/20.0), phases)
- return closed_loop_contours(Hmag, Hphase)
-
-# N-circle
-def n_circles(phases, mag_min=-40.0, mag_max=12.0):
- """Constant-phase contours of the function H = G/(1+G).
-
- Usage
- =====
- contour = n_circles(angles)
-
- Parameters
- ----------
- phases : array-like
- Array of phases in degrees of the N-circles
- mag_min : dB
- Minimum magnitude in dB of the N-circles
- mag_max : dB
- Maximum magnitude in dB of the N-circles
-
- Return values
- -------------
- contours : complex array
- Array of complex numbers corresponding to the contours.
- """
- # Convert phases and magnitude range into a grid suitable for
- # building contours
- mags = sp.linspace(10**(mag_min/20.0), 10**(mag_max/20.0), 2000)
- Hphase, Hmag = sp.meshgrid(sp.radians(phases), mags)
- return closed_loop_contours(Hmag, Hphase)
Modified: branches/control-0.4b/src/matlab.py
===================================================================
--- branches/control-0.4b/src/matlab.py 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/src/matlab.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -74,7 +74,8 @@
# Import MATLAB-like functions that can be used as-is
from ctrlutil import unwrap
-from freqplot import nyquist, nichols, gangof4
+from freqplot import nyquist, gangof4
+from nichols import nichols, nichols_grid
from bdalg import series, parallel, negate, feedback
from pzmap import pzmap
from statefbk import ctrb, obsv, gram, place, lqr
@@ -752,7 +753,7 @@
=====
ngrid()
"""
- freqplot.nichols_grid()
+ nichols_grid()
#
# Modifications to scipy.signal functions
Added: branches/control-0.4b/src/nichols.py
===================================================================
--- branches/control-0.4b/src/nichols.py (rev 0)
+++ branches/control-0.4b/src/nichols.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -0,0 +1,267 @@
+# nichols.py - Nichols plot
+#
+# Contributed by Allan McInnes <All...@ca...>
+#
+# This file contains some standard control system plots: Bode plots,
+# Nyquist plots, Nichols plots and pole-zero diagrams
+#
+# Copyright (c) 2010 by California Institute of Technology
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the California Institute of Technology nor
+# the names of its contributors may be used to endorse or promote
+# products derived from this software without specific prior
+# written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CALTECH
+# OR THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $Id: freqplot.py 139 2011-03-30 16:19:59Z murrayrm $
+
+import matplotlib.pyplot as plt
+import scipy as sp
+import numpy as np
+from ctrlutil import unwrap
+from freqplot import default_frequency_range
+
+def nichols(syslist, omega=None):
+ """Nichols plot for a system
+
+ Usage
+ =====
+ magh = nichols(sys, omega=None)
+
+ Plots a Nichols plot for the system over a (optional) frequency range.
+
+ Parameters
+ ----------
+ syslist : linsys
+ List of linear input/output systems (single system is OK)
+ omega : freq_range
+ Range of frequencies (list or bounds) in rad/sec
+
+ Return values
+ -------------
+ None
+ """
+
+ # If argument was a singleton, turn it into a list
+ if (not getattr(syslist, '__iter__', False)):
+ syslist = (syslist,)
+
+ # Select a default range if none is provided
+ if (omega == None):
+ omega = default_frequency_range(syslist)
+
+ for sys in syslist:
+ # Get the magnitude and phase of the system
+ mag_tmp, phase_tmp, omega = sys.freqresp(omega)
+ mag = np.squeeze(mag_tmp)
+ phase = np.squeeze(phase_tmp)
+
+ # Convert to Nichols-plot format (phase in degrees,
+ # and magnitude in dB)
+ x = unwrap(sp.degrees(phase), 360)
+ y = 20*sp.log10(mag)
+
+ # Generate the plot
+ plt.plot(x, y)
+
+ plt.xlabel('Phase (deg)')
+ plt.ylabel('Magnitude (dB)')
+ plt.title('Nichols Plot')
+
+ # Mark the -180 point
+ plt.plot([-180], [0], 'r+')
+
+# Nichols grid
+def nichols_grid():
+ """Nichols chart grid
+
+ Usage
+ =====
+ nichols_grid()
+
+ Plots a Nichols chart grid on the current axis.
+
+ Parameters
+ ----------
+ None
+
+ Return values
+ -------------
+ None
+ """
+ mag_min_default = -40.0 # dB
+ mag_step = 20.0 # dB
+
+ # Chart defaults
+ phase_min, phase_max, mag_min, mag_max = -360.0, 0.0, mag_min_default, 40.0
+
+ # Set actual chart bounds based on current plot
+ if plt.gcf().gca().has_data():
+ phase_min, phase_max, mag_min, mag_max = plt.axis()
+
+ # M-circle magnitudes.
+ # The "fixed" set are always generated, since this guarantees a recognizable
+ # Nichols chart grid.
+ mags_fixed = np.array([-40.0, -20.0, -12.0, -6.0, -3.0, -1.0, -0.5, 0.0,
+ 0.25, 0.5, 1.0, 3.0, 6.0, 12.0])
+
+ if mag_min < mag_min_default:
+ # Outside the "fixed" set of magnitudes, the generated M-circles
+ # are extended in steps of 'mag_step' dB to cover anything made
+ # visible by the range of the existing plot
+ mags_adjust = np.arange(mag_step*np.floor(mag_min/mag_step),
+ mag_min_default, mag_step)
+ mags = np.concatenate((mags_adjust, mags_fixed))
+ else:
+ mags = mags_fixed
+
+ # N-circle phases (should be in the range -360 to 0)
+ phases = np.array([-0.25, -10.0, -20.0, -30.0, -45.0, -60.0, -90.0,
+ -120.0, -150.0, -180.0, -210.0, -240.0, -270.0,
+ -310.0, -325.0, -340.0, -350.0, -359.75])
+
+ # Find the M-contours
+ m = m_circles(mags, phase_min=np.min(phases), phase_max=np.max(phases))
+ m_mag = 20*sp.log10(np.abs(m))
+ m_phase = sp.mod(sp.degrees(sp.angle(m)), -360.0) # Unwrap
+
+ # Find the N-contours
+ n = n_circles(phases, mag_min=np.min(mags), mag_max=np.max(mags))
+ n_mag = 20*sp.log10(np.abs(n))
+ n_phase = sp.mod(sp.degrees(sp.angle(n)), -360.0) # Unwrap
+
+ # Plot the contours behind other plot elements.
+ # The "phase offset" is used to produce copies of the chart that cover
+ # the entire range of the plotted data, starting from a base chart computed
+ # over the range -360 < phase < 0 (see above). Given the range
+ # the base chart is computed over, the phase offset should be 0
+ # for -360 < phase_min < 0.
+ phase_offset_min = 360.0*np.ceil(phase_min/360.0)
+ phase_offset_max = 360.0*np.ceil(phase_max/360.0) + 360.0
+ phase_offsets = np.arange(phase_offset_min, phase_offset_max, 360.0)
+ for phase_offset in phase_offsets:
+ plt.plot(m_phase + phase_offset, m_mag, color='gray',
+ linestyle='dashed', zorder=0)
+ plt.plot(n_phase + phase_offset, n_mag, color='gray',
+ linestyle='dashed', zorder=0)
+
+ # Add magnitude labels
+ for x, y, m in zip(m_phase[:][-1], m_mag[:][-1], mags):
+ align = 'right' if m < 0.0 else 'left'
+ plt.text(x, y, str(m) + ' dB', size='small', ha=align)
+
+ # Make sure axes conform to any pre-existing plot.
+ plt.axis([phase_min, phase_max, mag_min, mag_max])
+
+#
+# Utility functions
+#
+# This section of the code contains some utility functions for
+# generating Nichols plots
+#
+
+# Compute contours of a closed-loop transfer function
+def closed_loop_contours(Hmag, Hphase):
+ """Contours of the function H = G/(1+G).
+
+ Usage
+ =====
+ contours = closed_loop_contours(mags, phases)
+
+ Parameters
+ ----------
+ mags : array-like
+ Meshgrid array of magnitudes of the contours
+ phases : array-like
+ Meshgrid array of phases in radians of the contours
+
+ Return values
+ -------------
+ contours : complex array
+ Array of complex numbers corresponding to the contours.
+ """
+ # Compute the contours in H-space
+ H = Hmag*sp.exp(1.j*Hphase)
+
+ # Invert H = G/(1+G) to get an expression for the contours in G-space
+ return H/(1.0 - H)
+
+# M-circle
+def m_circles(mags, phase_min=-359.75, phase_max=-0.25):
+ """Constant-magnitude contours of the function H = G/(1+G).
+
+ Usage
+ =====
+ contours = m_circles(mags)
+
+ Parameters
+ ----------
+ mags : array-like
+ Array of magnitudes in dB of the M-circles
+ phase_min : degrees
+ Minimum phase in degrees of the N-circles
+ phase_max : degrees
+ Maximum phase in degrees of the N-circles
+
+ Return values
+ -------------
+ contours : complex array
+ Array of complex numbers corresponding to the contours.
+ """
+ # Convert magnitudes and phase range into a grid suitable for
+ # building contours
+ phases = sp.radians(sp.linspace(phase_min, phase_max, 500))
+ Hmag, Hphase = sp.meshgrid(10.0**(mags/20.0), phases)
+ return closed_loop_contours(Hmag, Hphase)
+
+# N-circle
+def n_circles(phases, mag_min=-40.0, mag_max=12.0):
+ """Constant-phase contours of the function H = G/(1+G).
+
+ Usage
+ =====
+ contour = n_circles(angles)
+
+ Parameters
+ ----------
+ phases : array-like
+ Array of phases in degrees of the N-circles
+ mag_min : dB
+ Minimum magnitude in dB of the N-circles
+ mag_max : dB
+ Maximum magnitude in dB of the N-circles
+
+ Return values
+ -------------
+ contours : complex array
+ Array of complex numbers corresponding to the contours.
+ """
+ # Convert phases and magnitude range into a grid suitable for
+ # building contours
+ mags = sp.linspace(10**(mag_min/20.0), 10**(mag_max/20.0), 2000)
+ Hphase, Hmag = sp.meshgrid(sp.radians(phases), mags)
+ return closed_loop_contours(Hmag, Hphase)
Modified: branches/control-0.4b/src/statesp.py
===================================================================
--- branches/control-0.4b/src/statesp.py 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/src/statesp.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -78,7 +78,6 @@
from numpy.linalg import inv, det, solve
from numpy.linalg.linalg import LinAlgError
from scipy.signal import lti
-from slycot import td04ad
from lti import Lti
import xferfcn
@@ -457,6 +456,7 @@
# Already a state space system; just return it
return sys
elif isinstance(sys, xferfcn.TransferFunction):
+ from slycot import td04ad
if len(kw):
raise TypeError("If sys is a TransferFunction, _convertToStateSpace \
cannot take keywords.")
Modified: branches/control-0.4b/src/xferfcn.py
===================================================================
--- branches/control-0.4b/src/xferfcn.py 2011-04-01 04:46:30 UTC (rev 143)
+++ branches/control-0.4b/src/xferfcn.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -79,7 +79,6 @@
polyadd, polymul, polyval, roots, sort, sqrt, zeros
from scipy.signal import lti
from copy import deepcopy
-from slycot import tb04ad
from lti import Lti
import statesp
@@ -707,6 +706,7 @@
return sys
elif isinstance(sys, statesp.StateSpace):
+ from slycot import tb04ad
if len(kw):
raise TypeError("If sys is a StateSpace, _convertToTransferFunction \
cannot take keywords.")
Added: branches/control-0.4b/tests/nichols_test.py
===================================================================
--- branches/control-0.4b/tests/nichols_test.py (rev 0)
+++ branches/control-0.4b/tests/nichols_test.py 2011-04-02 15:52:38 UTC (rev 144)
@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+#
+# nichols_test.py - test Nichols plot
+# RMM, 31 Mar 2011
+
+import unittest
+import numpy as np
+from control.matlab import *
+
+class TestStateSpace(unittest.TestCase):
+ """Tests for the Nichols plots."""
+
+ def setUp(self):
+ """Set up a system to test operations on."""
+
+ A = [[-3., 4., 2.], [-1., -3., 0.], [2., 5., 3.]]
+ B = [[1.], [-3.], [-2.]]
+ C = [[4., 2., -3.]]
+ D = [[0.]]
+
+ self.sys = StateSpace(A, B, C, D)
+
+ def testNichols(self):
+ """Generate a Nichols plot."""
+ nichols(self.sys)
+
+ def testNgrid(self):
+ """Generate a Nichols plot."""
+ nichols(self.sys)
+ ngrid()
+
+def suite():
+ return unittest.TestLoader().loadTestsFromTestCase(TestStateSpace)
+
+
+if __name__ == "__main__":
+ unittest.main()
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