Problem defining two python functions in org-mode

Question

I am testing the possibility of including python code in org-mode files in emacs. As it is my first time with I ran into an error that probably it is easy to fix, but I cannot see the solution. I want to define some onstants and functions and use them later in the file. If I do this witho only one function there is no problem, as in this simple example:

* Initialization block containing constants and function definition
#+NAME: init_block 
#+BEGIN_SRC python :session 
  # Constants 
  a_constant = 287.
  #
  # 
  ##########################
  def m_T(E_val):
    import numpy as np
    A_val = 6.1094
    return A_val*np.log(E_val/A_val)
#+END_SRC

#+RESULTS: init_block



* Example

#+BEGIN_SRC python  :session   :results output
print "Hello, world! This is my zero trial ", a_constant
print m_T(10.)
#+end_src

#+RESULTS:
: Hello, world! This is my zero trial  287.0
: 3.01044670959

However, when I try to include the definition of two functions errors pop up:

* Initialization block containing constants and function definition
#+NAME: init_block 
#+BEGIN_SRC python :session b
  # Constants 
  a_constant = 287.
  #
  # 
  ##########################
  def m_T(E_val):
    import numpy as np
    A_val = 6.1094
    return A_val*np.log(E_val/A_val)
  #################
  b_constant = 287.
  #################
  def m_E(T_val):
    import numpy as np
    A_val = 6.1094
    return A_val*np.exp(T_val/A_val)
  #################
  c_constant = 287.
  ##########################
#+END_SRC

#+RESULTS: init_block



* Example

#+BEGIN_SRC python  :session b  :results output
print "Hello, world! This is my zero trial ", a_constant, b_constant, c_constant
print m_T(10.)
print m_E(12.3)
#+end_src

#+RESULTS:
#+begin_example
Hello, world! This is my zero trial  287.0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'b_constant' is not defined
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'm_T' is not defined
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'm_E' is not defined
#+end_example

I would appreciate any help to understand what am I doing wrong in this case.

Answer 1

Your problem reminds me why I hate Python ^{_{(I very seldom give such a statement about a programming language)}}. Whitespace is syntactically relevant in Python. Your problem is superfluous indention.

You can switch to the python console for session b with C-x b *b* RET. There you also get the error messages of the python interpreter.

Maybe you should use rather org-edit-special (C-c ', it est C-c and a quote character) in python source blocks to avoid indention problems. With point in a source block org-edit-special translates to org-edit-src-code.

The following org file works:

* Initialization block containing constants and function definition
#+NAME: init_block
#+BEGIN_SRC python :session b
# Constants
a_constant = 287.
#
#
##########################
def m_T(E_val):
 import numpy as np
 A_val = 6.1094
 return A_val*np.log(E_val/A_val)

#################
b_constant = 287.
#################
def m_E(T_val):
 import numpy as np
 A_val = 6.1094
 return A_val*np.exp(T_val/A_val)

#################
c_constant = 287.
##########################
#+END_SRC

#+RESULTS: init_block

* Example

#+BEGIN_SRC python  :session b  :results output
print "Hello, world! This is my zero trial ", a_constant, b_constant, c_constant
print m_T(10.)
print m_E(12.3)
#+end_src

#+RESULTS:
: Hello, world! This is my zero trial  287.0 287.0 287.0
: 3.01044670959
: 45.7466956505