python-control-announce — Announcements about the Python Control Systems Library

[python-control-announce] Version 0.4c of python-control released

[Richard M. <mu...@cd...>]

Version 0.4c of the Python Control Systems Library (python-control) has been posted to SourceForge.  The main changes for this version are:

* Added matrix solvers from LTH (Ola Johnsson, Jerker Nordh, Bjorn Olofsson, Vanessa Romero Segovia.  These implement the lyap, dlyap, care and dare functions using slycot.

* Added tfvis, Simple GUI application for visualizing how the poles/zeros of the transfer function effects the Bode, Nyquist and step response of a SISO system.  Contributed by Vanessa Romero Segovia, Ola Johnsson, Jerker Nordh.

You can download this version of the code from SourceForge

 https://sourceforge.net/projects/python-control/files

A more detailed list of changes is included below (starting from 0.4b).

-richard


2011-06-17  Richard Murray  <mu...@dh...>

	* examples/tfvis.py: Added tfvis, Simple GUI application for
	visualizing how the poles/zeros of the transfer function effects the
	bode, nyquist and step response of a SISO system.  Contributed by
	Vanessa Romero Segovia, Ola Johnsson, Jerker Nordh.

2011-06-16  Richard Murray  <murray@malabar.local>

	* src/matlab.py: import mateqn functions

	* src/__init__.py: import mateqn functions

	* tests/test_all.py: added unit tests for matrix solvers, converting
	to standard format along the way.  Seems to work even if slycot
	routines are not in place, but I'm not sure if this is for the right
	reasons...

	* src/mateqn.py: added matrix solvers from LTH (Ola Johnsson, Jerker
	Nordh, Bjorn Olofsson, Vanessa Romero).  Moved slycot function
	checks to the portion of the code where they are used, so that
	missing slycot doesn't mess up initialization if proper version of
	slycot is not available.

2011-04-02  Richard Murray  <murray@malabar.local>

	* src/xferfcn.py (TransferFunction.__add__): fixed bug when adding a
	transfer function to state space system; _convertToTransferFunction
	was being called with input/output keywords.  Picked up in unit test.

	* tests/matlab_test.py: added calls to all of the functions that are
	currently implemented in the library, to make sure there are no
	hidden issues.  These calls do *not* test functionality, they just
	make sure that MATLAB compatibility functions accept the right types
	of arguments.

	* examples/secord-matlab.py: added root locus plot to list of
	figures that are produced

	* src/__init__.py: added rlocus to list of modules that are imported
	by control module

	* src/exception.py (ControlMIMONotImplemented): added exception for
	functions that are not yet implemented for MIMO systems

	* src/xferfcn.py (TransferFunction.__init__): convert integer
	numerator and denominator objects to floats to eliminate errors when
	creating common denominator (also used on pole command).  This fixes
	and error were tf([1], [1, 2, 1]).pole() would generate an error.

	* src/freqplot.py (bode): Tweaked documentation string to remove 'h'
	from mag and phase return arguments

	* src/rlocus.py (RootLocus): removed commands that set figure number
	inside of RootLocus command, for consistency with other frequency
	plot routines.  Added Plot=True argument and updated documentation.

	* src/matlab.py: added rlocus() command (calls RootLocus)

	* MANIFEST.in: Added MANIFEST.in file to include examples and tests
	in source distribution

	* README: Updated to include information on how to run unit tests.

	* setup.py: updated version number to 0.4c

[python-control-announce] Version 0.4b of python-control released

[Richard M. <mu...@cd...>]

Version 0.4b of the Python Control Systems Library (python-control) has just been posted to SourceForge.  The main changes for this version are:

* Initial implementation of model reduction functions: hsvd(), modred(), balred(), courtesy of Brandt Belson, Steve Brunton, Kevin Chen, and Lauren Padilla. 

* Changes to (eventually) support MIMO transfer functions.  These should be transparent to users of the MATLAB interface (control.matlab), but control functions now use a separate class structure.  Courtesy randt Belson, Steve Brunton, Kevin Chen, and Lauren Padilla.

* Updated functionality for Nichols charts, courtesy Allan McInnes.

* Improvements in unwrap function, courtesy Sawyer Fuller.

You can download this version of the code from SourceForge

  https://sourceforge.net/projects/python-control/files

There examples subdirectory has also been updated to contain the code for the PVTOL LQR and nested controller design (see project wiki page).  If you would like all of the test files and additional examples, you can check out the source distribution using subversion:

  svn co https://python-control.svn.sourceforge.net/svnroot/python-control/tags/control-0.4b control-0.4b

A more detailed list of changes is included below (starting from 0.4a, which was the Princeton branch of the code).

-richard

2011-04-02  Richard Murray  <murray@malabar.local>

	* src/__init__.py: removed import of tests module (moved to tests/)

	* src/matlab.py: Added hsvd, balred, modred to list of functions
	that are imported for use as is.  Updated documentation string to
	indicate that these are implemented, along with a few other
	functions (zero, lqr) that weren't properly listed.

	* src/modelsimp.py (balred): Removed extraneous print statements
	(modred): Set method to be 'matchdc' by default (to match MATLAB)

	* src/__init__.py: added missing import of modelsimp functions

	* tests/slycot_convert_test.py (TestSlycot.testTF): turned off print
	statements in unit test to make it easier to see results.  Use
	verbose=True to turn back on.

	* tests/convert_test.py (TestConvert.testConvert): got rid of print
	statements in unittest; clutters the output so that you can't see
	the errors clearly.  Use verbose=True to turn back on.

	* src/statesp.py (_convertToStateSpace): removed "buggy" print
	statements 

	* src/xferfcn.py (_convertToTransferFunction): removed "buggy" print
	statements 

	* tests/nichols_test.py (TestStateSpace.testNgrid): updated testcode
	to turn off grid in initial Nichols chart plot.

	* src/freqplot.py: updated comments at top of file to reflect
	nichols chart move

	* src/nichols.py: transferred over changes from v0.3d

	* src/matlab.py (ngrid): moved import to function

2011-03-31  Richard Murray  <murray@malabar.local>

	* examples/pvtol-nested.py: updated stability margin plot to use
	proper calling format for bode().

	* src/statesp.py (_convertToStateSpace): moved slycot import
	to the location where it is actually needed (allows running some
	commands without slycot installed)

	* src/xferfcn.py (_convertToTransferFunction): moved slycot import
	to the location where it is actually needed (allows running some
	commands without slycot installed)

	* src/nichols.py: new file for Nichols plot routines; move
	nichols(), nichols_grid(), closed_loop_contours(), m_circles(),
	n_circles()

	* src/__init__.py, src/freqresp.py, src/matlab.py: updated to match
	new file structure for Nichols charts

	* src/nichols.py (nichols): updated processing of freqresp to take
	into account the fact that return arguments are now a matrix of
	results (even for a SISO system)

2011-03-30  Richard Murray  <murray@malabar.local>

	* tests/: added top level subdirectory, to be used for unit tests.
	The idea in putting the code here is that you can do 'setup.py test'
	during installation to make sure everything is working correctly.
	The test code would normally *not* be callable from the installed
	module. 

	* tests/*_test.py: moved from src/Test*.py

	* setup.py: updated version number.

2011-02-13  Richard Murray  <murray@sumatra.local>

	* src/*.py: added svn:keywords Id properly

	* src/matlab.py (ngrid): added ngrid() from v0.3d

	* src/freqplot.py (nichols_grid, closed_loop_contours, m_circles,
	n_circles): copied over changes from Allan McInnes in v0.3d; ngrid()
	functiality + split out some of the nichols chart code into separate
	functions

[python-control-announce] Version 0.3d of python-control released

[Richard M. <mu...@cd...>]

Version 0.3d of the Python Control Systems Library (python-control) has just been posted to SourceForge.  The main changes for this version are:

* New function: rlocus(), courtesy Ryan Krauss <rk...@si...>
* New function: pade(), courtesy Sawyer Fuller <mi...@ca...>
* New functions: nichols(), ngrid(), courtesy Allan McInnes <All...@ca...>
* Added lsim() wrapper to allow systems with poles at origin.  Still need to fix this for step() and impulse()

A detailed list of changes is included below.

The next release of python-control will be a version 0.4a and will have some fairly significant changes in the underlying class structure, courtesy of Brandt Belson, Steve Brunton, Kevin Chen, and Lauren Padilla at Princeton.

-richard

2011-02-12  Richard Murray  <murray@sumatra.local>

	* setup.py: Updated version number to 0.3d, in preparation for release

	* src/statefbk.py (lqr): Updated sb02md calling signature to match
	latest slycot version (Lauren Padilla)

	* src/freqplot.py (nichols_grid): new function from Allan McInnes
	<all...@ca...> to generate a Nichols chart for a
	given plot (equivalent to ngrid in MATLAB).

	* src/matlab.py (ngrid): MATLAB compatible ngrid() command

2010-11-05  Richard Murray  <murray@sumatra.local>

	* external/yottalab.py: New file containing Roberto Bucher's control
	library functions.  OK to start pulling these into the main library,
	with attribution, but note that they use modifications of the
	default library => some rewrites will be needed.

2010-09-11  Richard Murray  <murray@sumatra.local>

	* src/matlab.py (step): Added local step response function that uses
	lsim2() instead of signal.step (which can't handle integrators).
	This function may not be needed when new scipy step2() function is
	available.
	(impulse): Added local impulse response function that sets the
	initial condition based on the input matrix and then uses the
	lsim2() function to compute the response.

	* examples/test-response.py: Added test script for making sure that
	time repsonse functions are working as desired

	* src/matlab.py (lsim): Added local version of lsim that calls
	signal.lsim2 (actual ODE integrator)

2010-09-06  Richard Murray  <murray@sumatra.local>

	* src/statefbk.py (ctrb): new function for testing controllability
	* src/statefbk.py (obsv): new function for testing observabiilty

2010-09-02  Richard Murray  <murray@sumatra.local>

	* src/statefbk.py (place): Use np.size() instead of len() for
	finding length of placed_eigs for better compatability with
	different python versions [courtesy of Roberto Bucher]

	* src/delay.py (pade): New file for delay-based computations +
	initial implementation of pade() [courtesy Sawyer Fuller]

2010-06-17  Richard Murray  <murray@sumatra.local>

	* src/rlocus.py: changed num, den to nump, denp for clarity
	* src/rlocus.py: new file with Ryan Krauss's root locus code

[python-control-announce] Version 0.3c of python-control is posted

[Richard M. <mu...@cd...>]

Version 0.3c of the python-control package is now released.  Major changes:

* Added place() and lqr() commands, using the SLICOT library (via Enrico Avventi's slycot wrappers).  LQR works on MIMO systems.

* Frequency range for Bode plots are now computed using the poles and zeros of the system.  

* Bode plots can how accept a list of systems: bode(sys1, ..., sysN)

* Put in docstrings for all user accessible functions

* Set up wiki with examples and download instructions

  http://python-control.sourceforge.net

Full list of changes below.

-richard

2010-06-06  Richard Murray  <murray@sumatra.local>

	* examples/pvtol-lqr.py: Added example to test out LQR routines

	* src/matlab.py (bode): created a wrapper that allows MATLAB style
	arguments for bode (eg, bode(sys1, sys2))

	* src/ctrlutil.py (issys): added new function to check if an object
	is a system (state space or transfer function).  Will generalize
	this latter to look for other compatible classes.

	* src/freqplot.py (bode): Compute frequency range of bode plot based
	on poles and zeros
	(bode): Allow bode plot to be passed a list (or tuple) as the first
	argument, in which case multiple bode plots are generated

	* src/statesp.py (StateSpace.zeros): new function to compute zeros
	for a state space system
	(StateSpace): defined new functions to compute poles of a state
	space system

	* src/xferfcn.py (TransferFunction): defined new functions to
	compute poles and zeros of a transfer function.

2010-05-31  Richard Murray  <murray@sumatra.local>

	* src/exception.py (ControlNotImplemented): added new exception, to
	be used for functions that are not yet implemented

	* src/statefbk.py (lqr): added lqr function (using slycot).  Still
	needs to be verified to make sure calculations are correct.

	* ChangeLog: converted to standard GNU formation (old style below)
	* setup.py: updated package number to v0.3, changed URL to
	sourceforge wiki