[python-control-discuss] SF.net SVN: python-control:[120] branches/control-0.4a/src

[<kk...@us...>]

Revision: 120
          http://python-control.svn.sourceforge.net/python-control/?rev=120&view=rev
Author:   kkchen
Date:     2011-02-08 22:19:44 +0000 (Tue, 08 Feb 2011)

Log Message:
-----------
Created copy constructors for StateSpace and TransferFunction.

The copy() methods have been removed, since copy constructors should be used.
Also, calling ss on a StateSpace object and tf on a TransferFunction object now
return deep copies.

Kevin K. Chen <kk...@pr...>

Modified Paths:
--------------
    branches/control-0.4a/src/matlab.py
    branches/control-0.4a/src/statesp.py
    branches/control-0.4a/src/xferfcn.py

Modified: branches/control-0.4a/src/matlab.py
===================================================================
--- branches/control-0.4a/src/matlab.py	2011-02-08 22:19:39 UTC (rev 119)
+++ branches/control-0.4a/src/matlab.py	2011-02-08 22:19:44 UTC (rev 120)
@@ -59,6 +59,7 @@
 import scipy as sp              # SciPy library (used all over)
 import numpy as np              # NumPy library
 import scipy.signal as signal   # Signal processing library
+from copy import deepcopy
 
 # Import MATLAB-like functions that are defined in other packages
 from scipy.signal import zpk2ss, ss2zpk, tf2zpk, zpk2tf
@@ -305,7 +306,7 @@
     elif len(args) == 1:
         sys = args[0]
         if isinstance(sys, StateSpace):
-            return sys
+            return deepcopy(sys)
         elif isinstance(sys, TransferFunction):
             return tf2ss(sys)
         else:
@@ -366,7 +367,7 @@
         if isinstance(sys, StateSpace):
             return ss2tf(sys)
         elif isinstance(sys, TransferFunction):
-            return sys
+            return deepcopy(sys)
         else:
             raise TypeError("tf(sys): sys must be a StateSpace or \
 TransferFunction object.  It is %s." % type(sys)) 

Modified: branches/control-0.4a/src/statesp.py
===================================================================
--- branches/control-0.4a/src/statesp.py	2011-02-08 22:19:39 UTC (rev 119)
+++ branches/control-0.4a/src/statesp.py	2011-02-08 22:19:44 UTC (rev 120)
@@ -78,7 +78,6 @@
 from numpy.linalg import inv, det, solve
 from numpy.linalg.linalg import LinAlgError
 from scipy.signal import lti
-from copy import deepcopy
 from slycot import td04ad
 from lti import Lti
 import xferfcn
@@ -96,9 +95,30 @@
     
     """
 
-    def __init__(self, A=0, B=0, C=0, D=1): 
-        """Construct a state space object.  The default is unit static gain."""
+    def __init__(self, *args): 
+        """Construct a state space object.
         
+        The default constructor is StateSpace(A, B, C, D), where A, B, C, D are
+        matrices or equivalent objects.  To call the copy constructor, call
+        StateSpace(sys), where sys is a StateSpace object.
+
+        """
+        
+        if len(args) == 4:
+            # The user provided A, B, C, and D matrices.
+            (A, B, C, D) = args
+        elif len(args) == 1:
+            # Use the copy constructor.
+            if not isinstance(args[0], StateSpace):
+                raise TypeError("The one-argument constructor can only take in \
+a StateSpace object.  Recived %s." % type(args[0]))
+            A = args[0].A
+            B = args[0].B
+            C = args[0].C
+            D = args[0].D
+        else:
+            raise ValueError("Needs 1 or 4 arguments; received %i." % len(args))
+
         # Here we're going to convert inputs to matrices, if the user gave a
         # non-matrix type.
         matrices = [A, B, C, D] 
@@ -171,11 +191,6 @@
         self.inputs = self.B.shape[1]
         self.outputs = self.C.shape[0]
 
-    def copy(self):
-        """Return a deep copy of the instance."""
-
-        return deepcopy(self)
-
     def __str__(self):
         """String representation of the state space."""
 

Modified: branches/control-0.4a/src/xferfcn.py
===================================================================
--- branches/control-0.4a/src/xferfcn.py	2011-02-08 22:19:39 UTC (rev 119)
+++ branches/control-0.4a/src/xferfcn.py	2011-02-08 22:19:44 UTC (rev 120)
@@ -101,9 +101,29 @@
     
     """
     
-    def __init__(self, num=1, den=1):
-        """Construct a transfer function.  The default is unit static gain."""
+    def __init__(self, *args):
+        """Construct a transfer function.
+        
+        The default constructor is TransferFunction(num, den), where num and den
+        are lists of lists of arrays containing polynomial coefficients.  To
+        call the copy constructor, call TransferFunction(sys), where sys is a
+        TransferFunction object.
 
+        """
+
+        if len(args) == 2:
+            # The user provided a numerator and a denominator.
+            (num, den) = args
+        elif len(args) == 1:
+            # Use the copy constructor.
+            if not isinstance(args[0], TransferFunction):
+                raise TypeError("The one-argument constructor can only take in \
+a TransferFunction object.  Received %s." % type(args[0]))
+            num = args[0].num
+            den = args[0].den
+        else:
+            raise ValueError("Needs 1 or 2 arguments; receivd %i." % len(args))
+
         # Make num and den into lists of lists of arrays, if necessary.  Beware:
         # this is a shallow copy!  This should be okay, but be careful.
         data = [num, den]
@@ -211,11 +231,6 @@
                         data[p][i][j] = data[p][i][j][nonzero:]        
         [self.num, self.den] = data
     
-    def copy(self):
-        """Return a deep copy of the instance."""
-
-        return deepcopy(self)
-
     def __str__(self):
         """String representation of the transfer function."""
         


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