fenics team mailing list archive

["Martin Sandve Alnæs" <martinal@xxxxxxxxx>]

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.

-- 
Martin