ffc team mailing list archive

["Garth N. Wells" <g.n.wells@xxxxxxxxxx>]

Anders Logg wrote:
> On Thu, Feb 01, 2007 at 10:59:05AM +0100, Garth N. Wells wrote:
> > Åsmund Ødegård wrote:
> > > Wed, 31 Jan skrev Anders Logg:
> > > > On Wed, Jan 31, 2007 at 11:11:40PM +0100, Garth N. Wells wrote:
> > > > > Anders Logg wrote:
> > > > > > On Wed, Jan 31, 2007 at 07:13:22PM +0100, Garth N. Wells wrote:
> > > > > > > When running ffc under Cygwin, I get the following error:
> > > > > > >
> > > > > > > Traceback (most recent call last):
> > > > > > >   File "/usr/bin/ffc", line 20, in ?
> > > > > > >     from ffc.common.debug import *
> > > > > > >   File "/usr/lib/python2.4/site-packages/ffc/__init__.py", line 2, in ?
> > > > > > >     from ffc.compiler.compiler import *
> > > > > > >   File "/usr/lib/python2.4/site-packages/ffc/compiler/compiler.py", line 37, in ?
> > > > > > >     from ffc.format import ufcformat
> > > > > > >   File "/usr/lib/python2.4/site-packages/ffc/format/ufcformat.py", line 14, in ?
> > > > > > >     from ufc import *
> > > > > > > ImportError: No module named ufc
> > > > > > >
> > > > > > > I have installed ufc.
> > > > > > Do you get the same error if you just write a simple Python script
> > > > > > test.py containing only the line
> > > > > >
> > > > > > from ufc import *
> > > > > >
> > > > > > and then run it by python test.py?
> > > > > The problem is that Cywgin does not have
> > > > >
> > > > >    /usr/local/lib/python2.X/site-packages
> > > > >
> > > > > in the path.
> > > > >
> > > > > Is there a reason why ufc installs under /usr/local/lib/python2.x, while 
> > > > > other FEniCS packages install under /usr/lib/python2.x?
> > > > I don't know, let's ask the other guys.
> > > >
> > > > Can we change the default location for the installation of UFC to
> > > > /usr?
> > > >
> > > > Garth, in the meantime, just change the variable PREFIX in the UFC
> > > > Makefile to /usr. The installation is just a single header file (and
> > > > some Python modules) so we have a very simple Makefile instead of a big
> > > > build system like scons, autotools etc.
> > > In my opinion, default install prefix should _never_ be /usr unless the
> > > native package system of your platform is used. Installing directly in /usr
> > > tends to be messy. There is a reason for the PREFIX possibility, use it if
> > > you deliberately want to mess thing up. /usr/local is the way to go.
> > >
> > > Just my 2øre.
> > I agree. How about changing all project to install under /usr/local by 
> > default?
> >
> > Garth
>
> Sounds like a good idea, but I don't know how to do this. How does
> distutils find where to install?

From http://docs.python.org/inst/standard-install.html

"Most Linux distributions include Python as a standard part of the 
system, so prefix and exec-prefix are usually both /usr on Linux. If you 
build Python yourself on Linux (or any Unix-like system), the default 
prefix and exec-prefix are /usr/local."

I'm going to change my mind and suggest that all FEniCS Python 
components install themselves wherever Python want to,

  python setup.py install

If we do something else, we run into the problem that packages are 
installed outside of the Python path which is a headache for users. UFC 
does

  python setup.py install --prefix=/usr/local

which is not necessarily in the Python path.

Garth


> The manual (http://www.python.org/doc/2.4/inst/alt-install-windows.html)
> only talks about how to choose /usr/local instead of /usr, not how to
> specify this by default.
>
> Ola?
>
> /Anders
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