fenics team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, Mar 19, 2008 at 09:00:55PM +0100, Martin Sandve Alnæs wrote:
> 2008/3/18, Anders Logg <logg@xxxxxxxxx>:
> > On Tue, Mar 18, 2008 at 10:54:09AM -0500, Andy Ray Terrel wrote:
> > > Matthew Knepley wrote:
> > > > On Tue, Mar 18, 2008 at 10:34 AM, Anders Logg <logg@xxxxxxxxx> wrote:
> > > >
> > > >> On Sun, Mar 16, 2008 at 04:50:07PM +0100, Martin Sandve Alnæs wrote:
> > > >>  > I highly recommend that all Python projects in FEniCS use the module
> > > >>  > "logging" that comes with Python from version 2.3. It is very simple
> > > >>  > and very flexible, in particular for creating cross-module logs. For
> > > >>  > the most basic usage, look at output.py and the tests in UFL.
> > > >>  >
> > > >>  > Basic tutorial (good site for handy python modules):
> > > >>  > http://blog.doughellmann.com/2007/05/pymotw-logging.html
> > > >>  >
> > > >>  > Reference:
> > > >>  > http://docs.python.org/lib/module-logging.html
> > > >>
> > > >>  Sounds good, but the big problem is more likely to coordinate logging
> > > >>  from C++ (DOLFIN) and Python. Is there a nice solution for this?
> > > >>
> > > >
> > > > As long as whole lines are always written, and the file is line buffered, I
> > > > think writing from two different file descriptors should be fine. The nice
> > > > thing would be to replicate the format in C++.
> > > >
> > > >    Matt
> > > >
> > > >
> > >
> > > Or you could just write a C api that calls into python.  Is there any
> > > reason you would be needing to log from C++ and python at the same time?
> >
> > Yes, when running DOLFIN from Python. We then call DOLFIN C++ code,
> > DOLFIN Python code (not everything is done in SWIG), FFC Python code
> > and FIAT Python code (which is quiet most of the time).
> 
> You can subclass the "logging.Logger" class (or something similar) in
> PyDOLFIN, simply passing the log messages to the C++ DOLFIN log
> system. So nothing (or very little) needs to change in C++ DOLFIN.

Then what's the point of using the logging module in PyDOLFIN, instead
of just calling the DOLFIN log system directly?

-- 
Anders