Fix warnings in test-reponse.py example

roryyorke · roryyorke · commit 4084ae8c7724 · 2021-01-24T14:32:02.000+02:00
diff --git a/examples/test-response.py b/examples/test-response.py
@@ -4,7 +4,9 @@
 import os
 import matplotlib.pyplot as plt  # MATLAB plotting functions
 from control.matlab import *    # Load the controls systems library
-from scipy import arange        # function to create range of numbers
+from numpy import arange        # function to create range of numbers
+
+from control import reachable_form
 
 # Create several systems for testing
 sys1 = tf([1], [1, 2, 1])
@@ -13,10 +15,18 @@
 # Generate step responses
 (y1a, T1a) = step(sys1)
 (y1b, T1b) = step(sys1, T=arange(0, 10, 0.1))
-(y1c, T1c) = step(sys1, X0=[1, 0])
+# convert to reachable canonical SS to specify initial state
+sys1_ss = reachable_form(ss(sys1))[0]
+(y1c, T1c) = step(sys1_ss, X0=[1, 0])
 (y2a, T2a) = step(sys2, T=arange(0, 10, 0.1))
 
-plt.plot(T1a, y1a, T1b, y1b, T1c, y1c, T2a, y2a)
+plt.plot(T1a, y1a, label='$g_1$ (default)', linewidth=5)
+plt.plot(T1b, y1b, label='$g_1$ (w/ spec. times)', linestyle='--')
+plt.plot(T1c, y1c, label='$g_1$ (w/ init cond.)')
+plt.plot(T2a, y2a, label='$g_2$ (w/ spec. times)')
+plt.xlabel('time')
+plt.ylabel('output')
+plt.legend()
 
 if 'PYCONTROL_TEST_EXAMPLES' not in os.environ:
-    plt.show()
+    plt.show()
