[python-control-discuss] SF.net SVN: python-control:[137] trunk/src/freqplot.py

[<all...@us...>]

Revision: 137
          http://python-control.svn.sourceforge.net/python-control/?rev=137&view=rev
Author:   allanmcinnes
Date:     2011-02-19 03:15:18 +0000 (Sat, 19 Feb 2011)

Log Message:
-----------
Bugfix freqplot.default_frequency_range(), which failed to deal properly with single systems. Also add an option to control the number of points. Set default to a larger number of points than the logspace default, so that we're more likely to get a smooth curve on bode, nyquist, and nichols plots.

Modified Paths:
--------------
    trunk/src/freqplot.py

Modified: trunk/src/freqplot.py
===================================================================
--- trunk/src/freqplot.py	2011-02-19 03:02:07 UTC (rev 136)
+++ trunk/src/freqplot.py	2011-02-19 03:15:18 UTC (rev 137)
@@ -192,10 +192,10 @@
 
     Parameters
     ----------
-    cl_mags : array-like (dB)
+    cl_mags : array-like (dB), optional
         Array of closed-loop magnitudes defining a custom set of
         M-circle iso-gain lines.
-    cl_phases : array-like (degrees)
+    cl_phases : array-like (degrees), optional
         Array of closed-loop phases defining a custom set of
         N-circle iso-phase lines. Must be in the range -180.0 < cl_phases < 180.0
 
@@ -273,8 +273,8 @@
         List of linear input/output systems (single system is OK)
     omega : freq_range
         Range of frequencies (list or bounds) in rad/sec
-    grid : boolean
-        True if the plot should include a Nichols-chart grid
+    grid : boolean, optional
+        True if the plot should include a Nichols-chart grid. Default is True.
 
     Return values
     -------------
@@ -326,10 +326,10 @@
 
     Parameters
     ----------
-    cl_mags : array-like (dB)
+    cl_mags : array-like (dB), optional
         Array of closed-loop magnitudes defining the iso-gain lines on a
         custom Nichols chart.
-    cl_phases : array-like (degrees)
+    cl_phases : array-like (degrees), optional
         Array of closed-loop phases defining the iso-phase lines on a custom
         Nichols chart. Must be in the range -360 < cl_phases < 0
 
@@ -468,7 +468,7 @@
 #
    
 # Compute reasonable defaults for axes
-def default_frequency_range(syslist):
+def default_frequency_range(syslist, num=1000):
     """Compute a reasonable default frequency range for frequency
     domain plots.
 
@@ -483,6 +483,8 @@
     ----------
     syslist : linsys
         List of linear input/output systems (single system is OK)
+    num : integer, optional
+        Number of samples to generate. Default is 50.
 
     Return values
     -------------
@@ -495,6 +497,10 @@
     # integer.  It excludes poles and zeros at the origin.  If no features
     # are found, it turns logspace(-1, 1)
     
+    # If argument was a singleton, turn it into a list
+    if (not getattr(syslist, '__iter__', False)):
+        syslist = (syslist,)
+
     # Find the list of all poles and zeros in the systems
     features = np.array(())
     for sys in syslist:
@@ -513,7 +519,7 @@
 
     # Set the range to be an order of magnitude beyond any features
     omega = sp.logspace(np.floor(np.min(features))-1, 
-                        np.ceil(np.max(features))+1)   
+                        np.ceil(np.max(features))+1, num)
                         
     return omega
 


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