dolfin team mailing list archive

[Johan Jansson <johanjan@xxxxxxxxxxxxxxxx>]

On Mon, Feb 13, 2006 at 09:39:14AM -0600, Anders Logg wrote:
> On Mon, Feb 13, 2006 at 02:46:04PM +0100, Johan Jansson wrote:
> 
> > I think two remaining features to implement are:
> > 
> > 1. Loading Functions (DiscreteFunction) from file.
> 
> ok, which format do we want to do initially? DOLFIN XML?
> 
> Maybe we should also consider some binary format that is quicker to
> write and parse? Could be useful mostly during computations (and less
> useful for storing solutions for future reference) for example when
> solving the dual problem and linearizing around a previously computed
> solution (or time sequence of solutions) that doesn't fit in memory.

Isn't a natural candidate the VTK format? This is the standard output
format for DOLFIN, isn't it natural to be able to read it back in?

> > 2. An interface for projecting/interpolating between Functions. The
> > main example which requires some manual work in solvers is defining
> > the initial values by a UserFunction and wanting to represent that as
> > a DiscreteFunction.
> 
> I'm not sure what you mean. I thought I solved this with the new
> functionality I added to the Function class last week. You can define
> a Function for the initial value by overloading eval(), or even by
> 
> Function u = 0.0;
> 
> and then u can change from being a user-defined Function to a discrete
> Function. See new convection-diffusion demo.
> 
> You can also do
> 
> Function u(x, mesh, element);
> u = f;
> 
> to interpolate f to u.
> 

Ok, great! I'm sorry, I didn't realize this was what you added last
week.

I think interpolation is enough, projection can wait.

> I have limited time to work on new features before Geilo, but I can
> probably fit something in if I get some help.
> 

Yes, I also have limited time. But maybe we can at least start looking
at Function input and decide what we should do, i.e. if we should
design a DOLFIN XML data format for Functions or use the VTK format.

  Johan