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[python-control-discuss] SF.net SVN: python-control:[51] branches/control-0.4a/src
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From: <kk...@us...> - 2011-02-08 22:14:00
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Revision: 51
http://python-control.svn.sourceforge.net/python-control/?rev=51&view=rev
Author: kkchen
Date: 2011-02-08 22:13:53 +0000 (Tue, 08 Feb 2011)
Log Message:
-----------
*Class structure change*
Added Lti2 superclass in lti2.py.
Started the transfer function subclass in xferfcn.py, currently implemented as xTrasferFunction.
Edits to the StateSpace class in statesp.py.
Kevin K. Chen <kk...@pr...>
Modified Paths:
--------------
branches/control-0.4a/src/statesp.py
branches/control-0.4a/src/xferfcn.py
Added Paths:
-----------
branches/control-0.4a/src/lti2.py
Added: branches/control-0.4a/src/lti2.py
===================================================================
--- branches/control-0.4a/src/lti2.py (rev 0)
+++ branches/control-0.4a/src/lti2.py 2011-02-08 22:13:53 UTC (rev 51)
@@ -0,0 +1,9 @@
+class Lti2:
+ """The Lti2 is a parent class to the StateSpace and TransferFunction child
+ classes. It only contains the number of inputs and outputs, but this can be
+ expanded in the future."""
+
+ def __init__(self, inputs=1, outputs=1):
+ # Data members common to StateSpace and TransferFunction.
+ self.inputs = inputs
+ self.outputs = outputs
\ No newline at end of file
Modified: branches/control-0.4a/src/statesp.py
===================================================================
--- branches/control-0.4a/src/statesp.py 2011-02-08 22:13:47 UTC (rev 50)
+++ branches/control-0.4a/src/statesp.py 2011-02-08 22:13:53 UTC (rev 51)
@@ -42,46 +42,25 @@
# $Id: statesp.py 21 2010-06-06 17:29:42Z murrayrm $
import scipy as sp
-import scipy.signal as signal
-import xferfcn
from scipy import concatenate, zeros
+import xferfcn
+from lti2 import Lti2
-class Lti2:
- """The Lti2 is a parent class to the StateSpace and TransferFunction child
- classes. It only contains the number of inputs and outputs, but this can be
- expanded in the future."""
-
- def __init__(self, inputs=1, outputs=1):
- # Data members common to StateSpace and TransferFunction.
- self.inputs = inputs
- self.outputs = outputs
-
class StateSpace(Lti2):
"""The StateSpace class is used throughout the python-control library to
represent systems in state space form. This class is derived from the Lti2
base class."""
- def __init__(self, A, B, C, D):
- # Here we're going to convert inputs to matrices, if the user gave a non
- # 2-D array or matrix type.
- matrices = [A, B, C, D]
+ def __init__(self, A=0, B=0, C=0, D=1):
+ """StateSpace constructor. The default constructor is the unit gain
+ direct feedthrough system."""
+
+ # Here we're going to convert inputs to matrices, if the user gave a
+ # non-matrix type.
+ matrices = [A, B, C, D]
for i in range(len(matrices)):
- if (isinstance(matrices[i], (int, long, float, complex))):
- # Convert scalars to matrices, if necessary.
- matrices[i] = sp.matrix(matrices[i])
- elif isinstance(matrices[i], sp.ndarray):
- # Convert 0- or 1-D arrays to matrices, if necessary.
- if len(matrices[i].shape) < 2:
- matrices[i] = sp.matrix(matrices[i])
- elif len(matrices[i].shape) == 2:
- # If we're already a 2-D array or a matrix, then perfect!
- pass
- else:
- raise ValueError("A, B, C, and D cannot have > 2 \
- dimensions.")
- else:
- # If the user gave us a non-numeric type.
- raise ValueError("A, B, C, and D must be arrays or matrices.")
+ # Convert to matrix first, if necessary.
+ matrices[i] = sp.matrix(matrices[i])
[A, B, C, D] = matrices
self.A = A
Modified: branches/control-0.4a/src/xferfcn.py
===================================================================
--- branches/control-0.4a/src/xferfcn.py 2011-02-08 22:13:47 UTC (rev 50)
+++ branches/control-0.4a/src/xferfcn.py 2011-02-08 22:13:53 UTC (rev 51)
@@ -51,7 +51,69 @@
import scipy.signal as signal
import bdalg as bd
import statesp
+from lti2 import Lti2
+class xTransferFunction(Lti2):
+ """The TransferFunction class is derived from the Lti2 parent class. The
+ main data members are 'num' and 'den', which are 3-D numpy arrays of
+ MIMO numerator and denominator coefficients. For instance,
+
+ >>> num[2, 5] = numpy.array([1, 4, 8])
+
+ means that the numerator of the transfer function from the 6th input to the
+ 3rd output is set to s^2 + 4s + 8.
+
+ Note that numpy requires all polynomials in within an array to have the same
+ order. Be sure to pad leading coefficients with 0 as necessary."""
+
+ def __init__(self, num=sp.array([[[1.]]]), den=sp.array([[[1.]]])):
+ """This is the constructor. The default transfer function is 1 (unit
+ gain direct feedthrough)."""
+
+ # Make num and den into 3-d numpy arrays, if necessary.
+ data = [num, den]
+ for i in range(len(data)):
+ if isinstance(data[i], (int, long, float, complex)):
+ # Convert scalar to 3-d array.
+ data[i] = sp.array([[[data[i]]]])
+ elif isinstance(data[i], sp.ndarray):
+ if data[i].ndim == 0:
+ # Convert scalar to 3-d array.
+ data[i] = sp.array([[[data[i]]]])
+ elif data[i].ndim == 1:
+ # Convert SISO transfer function polynomial to 3-d array.
+ data[i] = sp.array([[data[i]]])
+ elif data[i].ndim == 3:
+ # We already have a MIMO system.
+ pass
+ else:
+ # If the user passed in a anything else, then it's unclear
+ # what the meaning is.
+ raise ValueError("The numerator and denominator inputs \
+ must be scalars or vectors (for SISO), or 3-d arrays (for \
+ MIMO).")
+ [num, den] = data
+
+ print num
+ print den
+
+ inputs = num.shape[1]
+ outputs = num.shape[0]
+
+ if inputs != den.shape[1]:
+ raise ValueError("The numerator and denominator matrices must have \
+ the same column (input) size.")
+ if outputs != den.shape[0]:
+ raise ValueError("The numerator and denominator matrices must have \
+ the same row (output) size.")
+
+ self.num = num
+ self.den = den
+ Lti2.__init__(self, inputs, outputs)
+
+ print self.inputs
+ print self.outputs
+
class TransferFunction(signal.lti):
"""The TransferFunction class is used to represent linear
input/output systems via its transfer function.
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