dolfin team mailing list archive

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

On Wed, Dec 17, 2008 at 6:35 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> On Wed, Dec 17, 2008 at 05:54:23PM +0100, Martin Sandve Alnæs wrote:
>> On Wed, Dec 17, 2008 at 5:42 PM, Johan Hake <hake@xxxxxxxxx> wrote:
>> > On Wednesday 17 December 2008 16:34:16 Anders Logg wrote:
>> >> On Wed, Dec 17, 2008 at 01:58:35PM +0100, Martin Sandve Alnæs wrote:
>> >> > Using latest hg versions of everything, I'm trying to plot a Function
>> >> > from C++ based on a SFC-generated function space and I get:
>> >> >
>> >> > Failed to read DOLFIN mesh or function XML file for plotting:
>> >> >   *** Error: Unable to find dof map in library:
>> >> > "FiniteElement('Lagrange', 'triangle', 1)".
>> >> > Unable to plot (DOLFIN Python module or Viper plotter not available).
>> >> >
>> >> > Can I suggest using Function::interpolate to make a .vtu file to plot
>> >> > instead of relying on a form compiler specific precompiled element
>> >> > library?
>> >> >
>> >> > Martin
>> >>
>> >> Sounds like a good idea. We now generate Python script that loads the
>> >> Function (or Mesh) from file and then calls Viper from Python.
>> >>
>> >> Does Viper support direct plotting of .vtu files? In that case, we
>> >> would not need to call Python from C++. We could generate a .vtu file
>> >> and then call Viper with that file (using system()).
>> >>
>> >> I don't have time to fix this now, so either find someone to fix it or
>> >> put it on the TODO list.
>>
>> What is in use, the text file or bugzilla?
>
> Both, and both are mostly ignored. :-)
>
> Our problem is that everyone is occupied with development. It is rare
> that I find time to look at TODO lists.
>
> Anyway, I think it would be good if we could use Bugzilla more. It is
> built to handle bug reports and requests and it's more visible than
> the TODO file.
>
>> > We could also plot a cpp.Function instead of a dolfin.Function. That fix would
>> > not be so extensive. I had a brief look at it but couldn't find out where
>> >
>> >   Function(filename)
>> >
>> > was called.
>
> You mean from the generated plot script?
>
> Look for the following lines in plot.cpp:
>
>  plot_class = eval(plot_type)
>  f = plot_class(data_name)
>
>> I also want to write a Function to file in C++.
>> What are the requirements on the FunctionSpace
>> to be able to do that?
>
> No requirements other than that the FunctionSpace exists. We end up
> calling interpolate_vertex_values.

That's the vtk file writing that I fixed up recently, but I meant storing
an actual Function which can be read back, not its interpolant.

> PS: Maybe interpolate_vertex_values is a good name for one of the
> interpolate functions.

I think that's clear and good.

Martin