Org-mode version 8.0-pre (release_8.0-pre-203-g993e3e @
/home/evan/Documents/org/elisp/org-mode/lisp/)
GNU Emacs 24.3.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10) of
2013-03-21 on evan-Dell-System-Inspiron-N7110 [2 times]

I installed the patched version.  It does hold session definition:

#+name: second-deriv-function
#+begin_src python :session  :results output :exports code
  def diff2(f, x, h=1E-6):
        """Function that takes the second derivative"""
        r=(f(x-h)-2*f(x)+f(x+h))/float(h*h)
        return r

#+end_src
#+RESULTS: second-deriv-function

Now let's write a target function, say $g(t)=t^{-6}$:
#+name: target-funtion
#+begin_src python :session :results output :exports code
  def g(t):
      """well behaved target function"""
      return t**(-6)

#+end_src

#+RESULTS: target-funtion

Now let's define the second derivative and evaluate it at $t=1.2$

#+name: evaluating-the-target
#+begin_src python :session  :results output :exports both
  t=1.2
  d2g = diff2(g,t)
  print "g''(%f)=%f" % (t, d2g)
#+end_src

#+RESULTS: evaluating-the-target
:
: >>> g''(1.200000)=9.767798

But it does not appear to support named session:

Works with a named session.
#+begin_src python :session foo
  x = 9
  x
#+end_src

#+RESULTS:
: None

#+begin_src python :session foo
  x
#+end_src

#+RESULTS:

Thanks,

Evan



On Fri, Mar 29, 2013 at 12:59 PM, Eric Schulte <schulte.eric@gmail.com>wrote:

> Andreas Röhler <andreas.roehler@easy-emacs.de> writes:
>
> > Am 29.03.2013 17:20, schrieb Eric Schulte:
> >
> >> A valid opinion, in fact I think I defended that point of view myself,
> >
> > Hi Eric,
> >
> > so, if I'm saying: let's make things considerably easier, working right
> from the spot,
> > why not try that?
> >
> > What I need still is a specification, what :session and the other header
> arguments shall do.
> > Presently they do quite different things. Also can't read a bulk of
> mails to figure out some guessing.
> >
> > Please write a specification and with the help of the other guys let's
> have some tiny and
> > effective ob-python.
> >
>
> Sorry, I'm not going to do this work for you.  If you want to take a
> shot at re-working ob-python, then you're welcome to.  However, I would
> recommend first reading through some of the history which lead to its
> current state, and fully understanding what that current state is (which
> at a minimum means reading and digesting the relevant documentation).
>
> > Let's see of we need more lines than ob-emacs-lisp.el :)
> >
>
> You will. :)
>
> Best of luck,
>
> >
> > Cheers
>
> --
> Eric Schulte
> http://cs.unm.edu/~eschulte
>
>


-- 
Evan Misshula
Doctoral Student (Criminal Justice)
CUNY John Jay
"Let us reform our schools, and we shall find little reform needed in our
prisons."
       John Ruskin, Unto This Last, essay 2 (1862)
       English critic, essayist, & reformer (1819 - 1900)

"Instruction does much, but encouragement does everything." Johann Wolfgang
Von Goethe
www.snrg-nyc.org