dolfin team mailing list archive

[Johan Hake <hake@xxxxxxxxx>]

On Thursday 26 March 2009 21:44:50 Anders Logg wrote:
> FFC is now fully functional w.r.t. compilation of UFL forms, at least
> judging by the demos in FFC which now all produce correct results.
>
> The Poisson demo in DOLFIN has also been moved to UFL.

Should we also include the ufl version of the Poission python demo too?

This could be done by putting:

from dolfin import *
try:
    from dolfin.ufl import *
except:
    pass
    
at the top of the poission demo. 

If we want that we should probably release viper too, as a recent patch made 
it possible to plot ufl based PyDOLFIN Functions.

> I therefore suggest we make new releases of FFC, UFL and DOLFIN:
>
>   DOLFIN 0.9.2
>   FFC 0.6.2
>   UFL 0.1.0 ?
>   SyFi/SFC?

The added ufc.build_ufc_module is needed for the PyDOLFIN/ffc.jit so we will 
also need a UFC 1.1.2 release.

Johan


> This batch of releases will support both the old .form format and the
> new .ufl format. After the release, we can get started on cleaning up
> and removing the .form format.
>
> In it's simplest form, the UFL form language looks very much like the
> FFC form language. Here's a comparison for the Poisson demo:
>
> FFC
> ---
>
>   element = FiniteElement("Lagrange", "triangle", 1)
>
>   v = TestFunction(element)
>   u = TrialFunction(element)
>   f = Function(element)
>
>   a = dot(grad(v), grad(u))*dx
>   L = v*f*dx
>
> UFL
> ---
>
>   element = FiniteElement("Lagrange", triangle, 1)
>
>   v = TestFunction(element)
>   u = TrialFunction(element)
>   f = Function(element)
>
>   a = inner(grad(v), grad(u))*dx # dot also works
>   L = v*f*dx
>
> However, UFL does much more, like treatment of tensor expressions,
> nonlinear operators like sin, cos, exp, sqrt, differentiation of forms
> w.r.t. variables etc. For more information, look at Martin's summary:
>
>   http://www.fenics.org/wiki/UFL
>
> UFL includes a script form2ufl that can be used to convert from the
> old FFC form language to the new UFL form language. The script is not
> foolproof but it may help in converting to the new format.
>
> So, let's make a new release now (after getting the buildbot green
> again for DOLFIN) and then make the full transition after the release.
>
> It's also time to promote UFL from a development project (/dev) to a
> proper project (/hg) since now FFC, SFC and DOLFIN will depend on it.
> Any objections?