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From: John Kitchin <jkitchin@andrew.cmu.edu>
To: emacs-orgmode@gnu.org
Subject: odd/unexpected behavior with Python src blocks
Date: Sun, 28 Sep 2014 18:11:46 -0400	[thread overview]
Message-ID: <m2d2aftmxp.fsf@andrew.cmu.edu> (raw)


* Odd behavior in python src-blocks in org-mode

I found that some code blocks in Python execute due to apparently silent
errors! here is how to reproduce it with a vanilla emacs -q.

#+BEGIN_SRC emacs-lisp
(org-babel-do-load-languages
 'org-babel-load-languages
 '((emacs-lisp . t)
   (python . t)))

(setq org-confirm-babel-evaluate nil)
#+END_SRC

#+RESULTS:

This block should raise an error (and does) because k is not defined.
#+BEGIN_SRC python
def f(y, x):
    return k * y

print(f(1, 0))
#+END_SRC

#+RESULTS:

It raises this error.

#+BEGIN_EXAMPLE
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
  File "<stdin>", line 2, in f
NameError: global name 'k' is not defined
#+END_EXAMPLE

However, this code block actually executes, and gives the wrong answer! If I open the source block in Python mode, it does not run without error.

#+BEGIN_SRC python :results output
from scipy.integrate import odeint

def f(y, x):
    return k * y

print(odeint(f, 1, [0, 1]))
#+END_SRC

#+RESULTS:
: [[ 1.]
:  [ 1.]]

Here is the correct answer.

#+BEGIN_SRC python :results output
from scipy.integrate import odeint

k = -1
def f(y, x):
    return k * y

print(odeint(f, 1, [0, 1]))
#+END_SRC

#+RESULTS:
: [[ 1.        ]
:  [ 0.36787947]]

I am not sure why this happens, but it seems like incorrect behavior to
me.

-- 
-----------------------------------
John Kitchin
http://kitchingroup.cheme.cmu.edu

next             reply	other threads:[~2014-09-28 22:12 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-28 22:11 John Kitchin [this message]
2014-09-29  1:27 ` odd/unexpected behavior with Python src blocks Aaron Ecay
2014-09-29 15:56   ` Instructor account
2014-09-29 18:03     ` John Kitchin

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