Re: [igraph] Unable to install python-igraph on Linux Mint 12

[Tamás Nepusz]

Hi,

> 1) Adding the igraph PPA (https://launchpad.net/~igraph/+archive/ppa), to my 
> sources.list, running apt-get update, and then apt-get install python-igraph. 
> This gives this error message:
> 
> The following packages have unmet dependencies:
>  python-igraph : Depends: python (< 2.7) but 2.7.2-7ubuntu2 is to be installed
> E: Unable to correct problems, you have held broken packages.
> 
> Some googling suggests that this is a longstanding issue (see this post from 
> 2010: http://lists.gnu.org/archive/html/igraph-help/2010-10/msg00070.html)
Can you please post the lines from your /etc/apt/sources.list that refer to our 
PPA? I find the above message quite weird because python-igraph for Ubuntu 
Quantal, Precise and Raring depend on python >= 2.7 (< 2.8), so they should be 
just fine for you.

> 2) `easy_install python-igraph` gives a message about a missing header file:
> 
> src/random.c:27:27: fatal error: igraph_random.h: No such file or directory 
> compilation terminated.
> 
> Which I learned is because I need to install the C library before installing 
> the bindings.
Yes, exactly.

> Then I reran easy_install, which seemed to be successful. Then when I try to 
> import igraph in python, I get:
> 
> >>> from igraph import Graph
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File 
> "/usr/local/lib/python2.7/dist-packages/python_igraph-0.6.5-py2.7-linux-x86_64.egg/igraph/__init__.py",
>  line 34, in <module>
>     from igraph._igraph import *
> ImportError: 
> /usr/local/lib/python2.7/dist-packages/python_igraph-0.6.5-py2.7-linux-x86_64.egg/igraph/_igraph.so:
>  undefined symbol: igraph_warning_handler_ignore
Do you have any old version of igraph lying around on your computer, anywhere? 
Look for files named libigraph.so.*. If you find any of these, then:

1) delete _all_ of them
2) uninstall the Python interface
3) go to the directory where you compiled the C core for 0.6.5 and run "make 
install"
4) try "pip install python-igraph" again

Hope this helps. Keep us posted if you run into any issues.

All the best
Tamas