[python-control-discuss] Python controls lib - preferred python version?

[Tony V. <ton...@al...>]

Richard, 

After a fair bit of wrestling with the fact that various ramifications of OS X *also* having a older version of Python than what I had downloaded and installed, I've gotten the the Python Control Library v.0.3b to execute the 2nd order test-case.  (Not as far as I wanted to get, but it's a start...)  

But my experience of dealing with different Python versions (described below) on OS X has raised a question:

Do you have a preferred version of Python you'd like us to use? 

OS X 10.6 comes bundled Python 2.6.1; I've installed Python 2.6.5 (latest non-developmental release).  I recall Erik mentioned he'd installed Py2.7 in an earlier email.

Erik: If you've installed Py2.7 and not tried running the 2nd-order example case yet, then you might be about to run into the same issues I smacked into.  It turns out that various "default" packages (and tools) that either come with Python 2.6.1, or that Apple pre-builds for you, are *not* included in the Python 2.6.4+ distros available from python.org, and some these packages have to be installed by hand.

iPython, it turns out, needs a little extra care.  My first installation apparently "locked on" to the Apple Python distro rather than the one I installed.  A simple first check is to run iPython (no arguments) and see which version of Python you *really* get... see excerpt below; note different boldfaced version numbers.

I've got things cobbled together now, but I'm going to spend a little time ensuring it's clean.  If you hit a snag, I (fairly soon) should have some tips I can offer.  

-tv
 
43 acheron: /Users/tonyv> ipython
Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) 
Type "copyright", "credits" or "license" for more information.

IPython 0.10 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object'. ?object also works, ?? prints more.

In [1]: quit()
Do you really want to exit ([y]/n)? y

44 acheron: /Users/tonyv> python
Python 2.6.5 (r265:79359, Mar 24 2010, 01:32:55) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> quit()
45 acheron: /Users/tonyv>