* Updated output arguments for matlab.py time response functions to

murrayrm · murrayrm · commit 5747e63f7e6e · 2011-07-13T16:03:32.000Z
match MATLAB conventions (they were switched)

* Added long version names for frequency plots: BodePlot, NyquistPlot, etc

* Fixed some import errors in rlocus.py

Details in ChangeLog.
diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,18 @@
+2011-07-11  Richard Murray  <murray@malabar.local>
+
+	* src/rlocus.py: added real() and imag() to list of functions
+	imported from numpy
+
+	* src/freqplot.py: renamed plotting functions to BodePlot,
+	NyquistPlot, GangOf4Plot and MarginPlot.  Set up aliases to the more
+	common names (bode, nyquest, gangof4, margin).  Mainly playing
+	around with idea for the eventual interface to use.
+
+	* tests/matlab_test.py: updated timeresp outputs to match MATLAB
+
+	* src/matlab.py (impulse, initial, lsim, step): switched outputs
+	from step, impulse, initial, lsim to match MATLAB standard
+
 2011-07-01  Richard Murray  <murray@malabar.local>
 
 	* src/rlocus.py: modified scipy import to only import those
diff --git a/src/freqplot.py b/src/freqplot.py
@@ -55,7 +55,7 @@
 #
    
 # Bode plot
-def bode(syslist, omega=None, dB=False, Hz=False, deg=True, 
+def BodePlot(syslist, omega=None, dB=False, Hz=False, deg=True, 
         color=None, Plot=True):
     """Bode plot for a system
 
@@ -178,7 +178,7 @@ def bode(syslist, omega=None, dB=False, Hz=False, deg=True,
         return mags, phases, omegas
 
 # Nyquist plot
-def nyquist(syslist, omega=None, Plot=True):
+def NyquistPlot(syslist, omega=None, Plot=True):
     """Nyquist plot for a system
 
     Plots a Nyquist plot for the system over a (optional) frequency range.
@@ -245,7 +245,7 @@ def nyquist(syslist, omega=None, Plot=True):
 
 # Gang of Four
 #! TODO: think about how (and whether) to handle lists of systems
-def gangof4(P, C, omega=None):
+def GangOf4Plot(P, C, omega=None):
     """Plot the "Gang of 4" transfer functions for a system
 
     Generates a 2x2 plot showing the "Gang of 4" sensitivity functions
@@ -302,7 +302,7 @@ def gangof4(P, C, omega=None):
 
 # gain and phase margins
 # contributed by Sawyer B. Fuller <minster@caltech.edu>
-def margin(sysdata, deg=True):
+def MarginPlot(sysdata, deg=True):
     """Calculate gain and phase margins and associated crossover frequencies
 
     Usage:
@@ -457,3 +457,8 @@ def default_frequency_range(syslist):
                         
     return omega
 
+# Function aliases
+bode = BodePlot
+nyquist = NyquistPlot
+gangof4 = GangOf4Plot
+margin = MarginPlot
diff --git a/src/matlab.py b/src/matlab.py
@@ -1165,12 +1165,12 @@ def step(sys, T=None, X0=0., input=0, output=0, **keywords):
 
     Returns
     -------
-    T: array
-        Time values of the output
-
     yout: array
         Response of the system
     
+    T: array
+        Time values of the output
+
     See Also
     --------
     lsim, initial, impulse
@@ -1181,7 +1181,7 @@ def step(sys, T=None, X0=0., input=0, output=0, **keywords):
     '''
     T, yout = timeresp.StepResponse(sys, T, X0, input, output, 
                                    transpose = True, **keywords)
-    return T, yout
+    return yout, T
 
 def impulse(sys, T=None, input=0, output=0, **keywords):
     '''
@@ -1216,10 +1216,10 @@ def impulse(sys, T=None, input=0, output=0, **keywords):
 
     Returns
     -------
-    T: array
-        Time values of the output
     yout: array
         Response of the system
+    T: array
+        Time values of the output
     
     See Also
     --------
@@ -1231,7 +1231,7 @@ def impulse(sys, T=None, input=0, output=0, **keywords):
     '''
     T, yout = timeresp.ImpulseResponse(sys, T, 0, input, output, 
                                    transpose = True, **keywords)
-    return T, yout
+    return yout, T
 
 def initial(sys, T=None, X0=0., input=0, output=0, **keywords):
     '''
@@ -1272,10 +1272,10 @@ def initial(sys, T=None, X0=0., input=0, output=0, **keywords):
 
     Returns
     -------
-    T: array
-        Time values of the output
     yout: array
         Response of the system
+    T: array
+        Time values of the output
     
     See Also
     --------
@@ -1287,7 +1287,7 @@ def initial(sys, T=None, X0=0., input=0, output=0, **keywords):
     '''
     T, yout = timeresp.InitialResponse(sys, T, X0, input, output, 
                                    transpose = True, **keywords)
-    return T, yout
+    return yout, T
 
 def lsim(sys, U=0., T=None, X0=0., **keywords):
     '''
@@ -1324,10 +1324,10 @@ def lsim(sys, U=0., T=None, X0=0., **keywords):
 
     Returns
     -------
-    T: array
-        Time values of the output. 
     yout: array
         Response of the system. 
+    T: array
+        Time values of the output. 
     xout: array
         Time evolution of the state vector. 
     
@@ -1341,4 +1341,4 @@ def lsim(sys, U=0., T=None, X0=0., **keywords):
     '''
     T, yout, xout = timeresp.ForcedResponse(sys, T, U, X0,
                                              transpose = True, **keywords)
-    return T, yout, xout
+    return yout, T, xout
diff --git a/src/rlocus.py b/src/rlocus.py
@@ -46,7 +46,7 @@
 # $Id$
 
 # Packages used by this module
-from scipy import array, poly1d, row_stack, zeros_like
+from scipy import array, poly1d, row_stack, zeros_like, real, imag
 import scipy.signal             # signal processing toolbox
 import pylab                    # plotting routines
 import xferfcn                  # transfer function manipulation
diff --git a/tests/matlab_test.py b/tests/matlab_test.py
@@ -95,24 +95,24 @@ def testStep(self):
         t = np.linspace(0, 1, 10)
         youttrue = np.array([9., 17.6457, 24.7072, 30.4855, 35.2234, 39.1165, 
                              42.3227, 44.9694, 47.1599, 48.9776]) 
-        tout, yout = step(sys, T=t)
+        yout, tout = step(sys, T=t)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(tout, t)
 
         # Play with arguments
-        tout, yout = step(sys, T=t, X0=0)
+        yout, tout = step(sys, T=t, X0=0)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(tout, t)
 
         X0 = np.array([0, 0]);
-        tout, yout = step(sys, T=t, X0=X0)
+        yout, tout = step(sys, T=t, X0=X0)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(tout, t)
 
         #Test MIMO system, which contains ``siso_ss1`` twice
         sys = self.mimo_ss1
-        _t, y_00 = step(sys, T=t, input=0, output=0)
-        _t, y_11 = step(sys, T=t, input=1, output=1)
+        y_00, _t = step(sys, T=t, input=0, output=0)
+        y_11, _t = step(sys, T=t, input=1, output=1)
         np.testing.assert_array_almost_equal(y_00, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(y_11, youttrue, decimal=4)
 
@@ -122,14 +122,14 @@ def testImpulse(self):
         t = np.linspace(0, 1, 10)
         youttrue = np.array([86., 70.1808, 57.3753, 46.9975, 38.5766, 31.7344, 
                              26.1668, 21.6292, 17.9245, 14.8945]) 
-        tout, yout = impulse(sys, T=t)
+        yout, tout = impulse(sys, T=t)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(tout, t)
 
         #Test MIMO system, which contains ``siso_ss1`` twice
         sys = self.mimo_ss1
-        _t, y_00 = impulse(sys, T=t, input=0, output=0)
-        _t, y_11 = impulse(sys, T=t, input=1, output=1)
+        y_00, _t = impulse(sys, T=t, input=0, output=0)
+        y_11, _t = impulse(sys, T=t, input=1, output=1)
         np.testing.assert_array_almost_equal(y_00, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(y_11, youttrue, decimal=4)
 
@@ -140,15 +140,15 @@ def testInitial(self):
         x0 = np.matrix(".5; 1.")
         youttrue = np.array([11., 8.1494, 5.9361, 4.2258, 2.9118, 1.9092, 
                              1.1508, 0.5833, 0.1645, -0.1391]) 
-        tout, yout = initial(sys, T=t, X0=x0)
+        yout, tout = initial(sys, T=t, X0=x0)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(tout, t)
 
         #Test MIMO system, which contains ``siso_ss1`` twice
         sys = self.mimo_ss1
         x0 = np.matrix(".5; 1.; .5; 1.")
-        _t, y_00 = initial(sys, T=t, X0=x0, input=0, output=0)
-        _t, y_11 = initial(sys, T=t, X0=x0, input=1, output=1)
+        y_00, _t = initial(sys, T=t, X0=x0, input=0, output=0)
+        y_11, _t = initial(sys, T=t, X0=x0, input=1, output=1)
         np.testing.assert_array_almost_equal(y_00, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(y_11, youttrue, decimal=4)
 
@@ -160,18 +160,18 @@ def testLsim(self):
         u = np.array([1., 1, 1, 1, 1, 1, 1, 1, 1, 1])
         youttrue = np.array([9., 17.6457, 24.7072, 30.4855, 35.2234, 39.1165, 
                              42.3227, 44.9694, 47.1599, 48.9776]) 
-        tout, yout, _xout = lsim(self.siso_ss1, u, t)   
+        yout, tout, _xout = lsim(self.siso_ss1, u, t)   
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         np.testing.assert_array_almost_equal(tout, t)
-        _t, yout, _xout = lsim(self.siso_tf3, u, t)
+        yout, _t, _xout = lsim(self.siso_tf3, u, t)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         
         #test with initial value and special algorithm for ``U=0``
         u=0
         x0 = np.matrix(".5; 1.")
         youttrue = np.array([11., 8.1494, 5.9361, 4.2258, 2.9118, 1.9092, 
                              1.1508, 0.5833, 0.1645, -0.1391]) 
-        _t, yout, _xout = lsim(self.siso_ss1, u, t, x0)
+        yout, _t, _xout = lsim(self.siso_ss1, u, t, x0)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         
         #Test MIMO system, which contains ``siso_ss1`` twice
@@ -184,7 +184,7 @@ def testLsim(self):
                              [1.9092, 39.1165], [1.1508, 42.3227], 
                              [0.5833, 44.9694], [0.1645, 47.1599], 
                              [-0.1391, 48.9776]])
-        _t, yout, _xout = lsim(self.mimo_ss1, u, t, x0)
+        yout, _t, _xout = lsim(self.mimo_ss1, u, t, x0)
         np.testing.assert_array_almost_equal(yout, youttrue, decimal=4)
         
     def testDcgain(self):
@@ -206,7 +206,7 @@ def testDcgain(self):
         
         #Compute the gain with a long simulation
         t = linspace(0, 1000, 1000)
-        _t, y = step(sys_ss, t)
+        y, _t = step(sys_ss, t)
         gain_sim = y[-1]
         print 'gain_sim:', gain_sim
         
