Re: [python-control-discuss] Python Control

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

Thanks Jerker, Björn, Ola and Vanessa!  Cc'ing the discussion list so they know about these changes.  I'll work to integrate as soon as possible (hopefully the next few weeks).

-richard

On 13 Jun 2011, at 6:59 , Jerker Nordh wrote:

> Hi
> 
> Attached in this email you will find the code Björn wrote to add lyap, dlyap, care and dare. Probably you want to merge this into one of the other files, but we leave the file/directory structure up to you.
> 
> Also there are some test cases (using nosetests, http://somethingaboutorange.com/mrl/projects/nose/1.0.0/) for this code.
> 
> For using the new functions you will need my modifications to slycot, they haven't yet been merged into the official slycot code, so until Avventi does that you can use my version of the code which you can find at:
> https://github.com/jerkern/Slycot
> 
> Also attached is "tfvis.py", which is a small application with takes the coefficients of the denominator/numerator of a SISO transfer function and plots pzmap,bode,nyquist and step response. You can drag-n-drop the poles/zeros in the pzmap, and when you release them the other figures will be updated accordingly.
> 
> I was thinking this might be nice to distribute in an example/ subdirectory or such, and perhaps someone will want to extend it in the future. It is a quite nice visualization tool for eg. a basic course in control.
> 
> It uses the Pmw library for the GUI elements, which I think is fairly standard but perhaps not present on all computers. You can find it at:
> http://pmw.sourceforge.net/
> 
> BR
> Jerker, Björn, Ola, Vanessa
> 
> 
> 
> On 2011-06-05 16:26, Richard Murray wrote:
>> Hi Jerker.  Sorry for the delay in replying.  It would be great to get the functions below into python-control and also a simple GUI, if you are willing to contribute it.  Let me know when one are both are ready and I can have a look.
>> 
>> -richard
>> 
>> On 1 Jun 2011, at 5:00 , Jerker Nordh wrote:
>> 
>>> Hi
>>> 
>>> We didn't get started on this as soon as we had expected, but now we've had some progress.
>>> 
>>> I've uploaded some code to github which I hoped will be merged to the official Slycot release shortly.
>>> 
>>> Using these additional wrappers in slycot we intend (mostly done) to implement:
>>> - lyap, dlyap
>>> - care, dare
>>> 
>>> If it's interesting we will perhaps also be able to contribute a simple gui application that helps visualize the effect of poles/zeros on a systems step respone/nyquist plot. This could perhaps be nice to distribute as an example along side python control?
>>> 
>>> //Jerker
>>> 
>>> On 2011-04-13 17:55, Richard Murray wrote:
>>>> That's great that you will be able to participate in this.  We are building on SLICOT (and the python version slycot) for most of the numerical functionality, so implementing the following functions would be useful and not too much work:
>>>> 
>>>> --
>>>> Matrix equation solvers and linear algebra
>>>>   lyap, dlyap         - solve Lyapunov equations
>>>>   lyapchol, dlyapchol - square-root Lyapunov solvers
>>>>   care, dare          - solve algebraic Riccati equations
>>>>   gcare, gdare        - generalized Riccati solvers
>>>>   bdschur             - block diagonalization of a square matrix
>>>> --
>>>> 
>>>> -richard
>>>> 
>>>> On 13 Apr 2011, at 5:18 , Jerker Nordh wrote:
>>>> 
>>>>> Hi again
>>>>> 
>>>>> We've cleared the idea with course instructor, so it won't be any problem for us to do some work on python-control.
>>>>> 
>>>>> Atleast Björn and me will be working on this, perhaps someone else as well. I talked to Per Hagander here at the department, he suggested implementing something around Luaponov/Riccati equations.
>>>>> 
>>>>> After doing some googling I found the pyDARE package (http://code.google.com/p/pydare/), so perhaps it would be redundant to implement something similar in python-control when it already exists elsewhere?
>>>>> 
>>>>> So I guess we will get back to you when we have settled more exactly what we'll be doing.
>>>>> 
>>>>> BR
>>>>> Jerker
>>>>> 
>>>>> On 2011-04-02 21:33, Richard Murray wrote:
>>>>>> I've update the list of functions that are implemented on the python-control wiki pages:
>>>>>> 
>>>>>>   https://sourceforge.net/apps/mediawiki/python-control/index.php?title=Developer_assignments
>>>>>> 
>>>>>> -richard
>>>>>> 
>>>>>> On 30 Mar 2011, at 7:46 , Richard Murray wrote:
>>>>>> 
>>>>>>> It would be great to get your help.  There *lots* of work to be done.  I'll try to spend some time this week updating the wiki pages to reflect what is done and what needs to be done.  What would probably make sense is for you to pick some collection of unimplemented functions that go together and then start working on them.  Being novices with python definitely won't be a problem.
>>>>>>> 
>>>>>>> Let me know if something like that makes sense and if you can get permission from your instructor.
>>>>>>> 
>>>>>>> -richard
>>>>>>> 
>>>>>>> On 30 Mar 2011, at 1:44 , Jerker Nordh wrote:
>>>>>>> 
>>>>>>>> Hi
>>>>>>>> 
>>>>>>>> We are a small group of graduate students within automatic control in Lund who are currently following a basic course in Python which contains a small project part. We are thinking that instead of doing the standard project within the course we could probably convince the course lectutrer to allow us to do something more "productive".
>>>>>>>> 
>>>>>>>> Our idea is that we could help with some of the implementation work in control-python. Is the project in a state were you could accept some outside help, and are there any parts suitable for "novice" python programmers corresponding roughly to one week full time work for 3-4 people?
>>>>>>>> 
>>>>>>>> Best regards,
>>>>>>>> Jerker Nordh
>>>>>>> 
>>>>>> 
>>>> 
>> 
> 
> <pyctrl_lin_alg.py><test_pyctrl_lin_alg.py><tfvis.py>