Graphene Junction Device - an error

[luca1982]

I know that this is only a tutorial but I am having an error when running the script conductance_t.py (on a Linux OS) from the tutorial on graphene junction (http://www.quantumwise.com/documents/tutorials/GrapheneJunctionDevice/XHTML/chap.conductance.html).

The error is the following one

Traceback (most recent call last):
  File "/tmp/9875255242915934.py", line 16, in <module>
    import pylab
  File "./build/atkpython/lib/python2.6/site-packages/pylab.py", line 1, in <module>
  File "./build/atkpython/lib/python2.6/site-packages/matplotlib/pylab.py", line 206, in <module>
  File "./build/atkpython/lib/python2.6/site-packages/matplotlib/mpl.py", line 1, in <module>
  File "./build/atkpython/lib/python2.6/site-packages/matplotlib/artist.py", line 5, in <module>
  File "./build/atkpython/lib/python2.6/site-packages/matplotlib/transforms.py", line 34, in <module>
ImportError: /home/liviu/QuantumWise/atk-11.2.b1/atkpython/lib/python2.6/site-packages/matplotlib/_path.so: undefined symbol: _ZNSs4_Rep20_S_empty_rep_storageE
NanoLanguageScript execution failure

When checking in the directory

atkpython/lib/python2.6/site-packages/

I have noticed that the python files are there but there extension .py is now .pyc

A small search on internet lead to this

http://stackoverflow.com/questions/378127/pyc-to-py-files

It seems that this error is related to the use of different version of python or something. I started recently to learn and to use python so I am not able to detect why this is happening but I started to work on it. 

Meanwhile I would appreciate any ideas from the more advanced python programmers or from the more advanced VNL/ATK users.

Thank you in advance!

[Anders Blom]

First of all, thank you for reporting the error in such detail, it helps for troubleshooting.

This particular one is a known problem, however unfortunately we do not, as of yet, have a solution available. It probably has something to do with library incompatibilities between our build machines and your Linux distribution. It is not related to py/pyc; a pyc file delivers the same functionality as a py file except it doesn't allow you to look at the code, not so easily at least.

We are working on finding a fix for this issue, but cannot promise when. It does not affect any core capability in ATK, only the plotting, so for now I will have to recommend you to plot the results using a different solution, or run ATK on Windows if you have possibility, there matplotlib works fine. At least for this tutorial, the plot of the results is rather trivial, it's just a simple graph, so using Gnuplot or something else should be easy.

[Anders Blom]

By the way, it would help to know which Linux version you are using (precisely) and also if you downloaded the GLIBC 2.3 version of ATK, or the "usual" one?

[luca1982]

1. I am using Ubuntu 10.10 (Maverick Meerkat) released in October 2010.
2. The ATK version I am using is the usual one. I've downloaded and tested this morning the GLIBC 2.3 version of ATK and it works fine.

Thank you for your answer!

[Anders Blom]

You mean with the GLIBC 2.3 version you could do the matplotlib plot? That's interesting.