[SciPy-User] ubuntu's PYTHONPATH and installing scipy

Darren Dale dsdale24@gmail....
Wed Dec 9 10:41:46 CST 2009

On Wed, Dec 9, 2009 at 2:06 AM, Charles R Harris
<charlesr.harris@gmail.com> wrote:
> On Tue, Dec 8, 2009 at 6:31 PM, Darren Dale <dsdale24@gmail.com> wrote:
>> On Tue, Dec 8, 2009 at 7:10 PM, John Schulman <joschu@caltech.edu> wrote:
>> > Hi,
>> > There's an issue with ubuntu PYTHONPATH that causes problems for scipy
>> > installation. I eventually found a workaround, but I want to point out
>> > the problem.
>> >
>> > PYTHONPATH is different when sudoing, so that packages installed by
>> > aptitute appear first in the path.*
>> >
>> > The svn version scipy imports numpy in the setup script. "python
>> > setup.py build" works as it should, but then "sudo python setup.py
>> > install" gives the error "ImportError: cannot import name get_info",
>> > since it's trying to use numpy1.3 (which was a dependency for some
>> > package I installed).
>> >
>> > The workaround is simple:
>> > sudo PYTHONPATH=/usr/local/lib/python2.6/dist-packages: python setup.py
>> > install
>> >
>> > *In ubuntu, packages that you install through the apt package manager
>> > goes into /usr/lib/python2.6/dist-packages, but python setup.py
>> > install puts stuff in /usr/local/lib/python2.6/dist-packages. There's
>> > a line in /etc/profile (I didn't put it there--it must be Ubuntu):
>> > export PYTHONPATH=/usr/local/lib/python2.6/dist-packages:$PYTHONPATH.
>> > I guess this is a kludge to fix the problem.
>> You can also use visudo to edit your sudo options, so that your
>> PYTHONPATH is carried over.
> Oh, that's too clever. I used locate to find all the numpy installations and
> deleted those with the wrong date ;) There are actually *three* different
> directories in which python stuff gets installed. I haven't a clue why.

Debian's python policy is described at
http://www.debian.org/doc/packaging-manuals/python-policy/ , but I
don't think that page reflects changes in debian unstable/ubuntu. I
don't understand the reason for using dist-packages instead of
site-packages. And now manually installed packages go into /usr/local
instead of /usr, but recently they changed things so /usr appears
higher in the python search path, so it is difficult to manually
upgrade software provided by the package manager. Maybe the
debian/ubuntu maintainers were trying to make it more difficult for
users to break packages installed by the package manager? In my
opinion, the policy is in unintuitive and in the way.

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