Anders Logg wrote: > On Wed, Apr 29, 2009 at 08:34:43AM +0200, Martin Sandve Alnæs wrote: >> On Wed, Apr 29, 2009 at 4:50 AM, Shawn Walker <[email protected]> wrote: >>> >>> On Tue, 28 Apr 2009, Anders Logg wrote: >>> >>>> On Mon, Apr 27, 2009 at 11:39:08PM -0400, Shawn Walker wrote: >>>>> >>>>> On Mon, 27 Apr 2009, Martin Sandve Aln?s wrote: >>>>> >>>>>> On Mon, Apr 27, 2009 at 3:32 PM, Garth N. Wells <[email protected]> wrote: >>>>>>> >>>>>>> Anders Logg wrote: >>>>>>>> On Mon, Apr 27, 2009 at 09:21:58AM -0400, Shawn Walker wrote: >>>>>>>>> On Mon, 27 Apr 2009, Anders Logg wrote: >>>>>>>>> >>>>>>>>>> On Mon, Apr 27, 2009 at 11:26:13AM +0200, Kent Andre wrote: >>>>>>>>>>> On l?., 2009-04-25 at 00:14 +0200, Anders Logg wrote: >>>>>>>>>>>> On Wed, Apr 22, 2009 at 05:28:30PM -0400, Shawn Walker wrote: >>>>>>>>>>>>> Here is the changeset that adds a `higher_order_coordinates' >>>>>>>>>>>>> variable for >>>>>>>>>>>>> storing higher order mesh data. This is a very minor change so >>>>>>>>>>>>> please >>>>>>>>>>>>> push this. >>>>>>>>>>>>> >>>>>>>>>>>>> A changeset for DOLFIN is coming immediately after this. >>>>>>>>>>>>> >>>>>>>>>>>>> - Shawn >>>>>>>>>>>> I'm not sure what to do about this. It's problematic to add >>>>>>>>>>>> experimental work to UFC since it must be stable. In particular, >>>>>>>>>>>> any >>>>>>>>>>>> small change to ufc.h means that all forms must be recompiled >>>>>>>>>>>> everywhere for everyone. >>>>>>>>>>>> >>>>>>>>>>>> So before we make a change to UFC, we need to know exactly what we >>>>>>>>>>>> need. Which also means I can't import your DOLFIN patch since it >>>>>>>>>>>> depends on the UFC patch. >>>>>>>>>>>> >>>>>>>>>>>> I see you've added >>>>>>>>>>>> >>>>>>>>>>>> double** higher_order_coordinates; >>>>>>>>>>>> >>>>>>>>>>>> to ufc::cell. This is analogous to what is now implemented in >>>>>>>>>>>> MeshGeometry and the mesh XML format so I think it's good. >>>>>>>>>>>> >>>>>>>>>>>> The question is what other information we need. As it works now >>>>>>>>>>>> (for >>>>>>>>>>>> the standard ufc::cell), UFC code generated by a form compiler >>>>>>>>>>>> knows >>>>>>>>>>>> what to expect from for a ufc::cell argument. If higher order >>>>>>>>>>>> mappings >>>>>>>>>>>> should work the same way, then the generated code and thus the >>>>>>>>>>>> form >>>>>>>>>>>> compilers need to know which mapping should be used and also the >>>>>>>>>>>> length of higher_order_coordinates. Is this what you were >>>>>>>>>>>> thinking? >>>>>>>>>>>> >>>>>>>>>>>> Before we do much more about it, more people need to weigh in on >>>>>>>>>>>> it as >>>>>>>>>>>> it affects DOLFIN, UFC, SyFi and FFC. >>>>>>>>>>>> >>>>>>>>>>> But is there any other way around this. It would be nice with >>>>>>>>>>> higher >>>>>>>>>>> order meshes and UFC should not stop this. >>>>>>>>>>> >>>>>>>>>>> An alternative to changing the cell class would be to make a >>>>>>>>>>> subclass >>>>>>>>>>> of cell. Would this work ? >>>>>>>>>> How about just using the current ufc::cell data structure as it is >>>>>>>>>> but >>>>>>>>>> let coordinates hold all the coordinates? >>>>>>>>>> >>>>>>>>>> This could also be the final solution. Then everything that's needed >>>>>>>>>> is an extra argument to tabulate_tensor that tells the generated >>>>>>>>>> code >>>>>>>>>> whether the cell is affinely mapped or not. The flag could simply be >>>>>>>>>> an integer: 1 means affine, 2 means quadratic etc. >>>>>>>>> But you still need to modify the ufc::cell code, I think. There is >>>>>>>>> also >>>>>>>>> an implicit assumption that the higher order coordinates should >>>>>>>>> contain >>>>>>>>> the standard mesh vertex coordinates. Of course, this is true for >>>>>>>>> most >>>>>>>>> practical cases. But for more fancy mappings, maybe this is not the >>>>>>>>> case. >>>>>>>> It seems to me that a reasonable assumption would be to limit the >>>>>>>> cases to P1, P2, P3, etc, that is, mappings that can be written down >>>>>>>> using standard Lagrange bases so then the vertices will always be >>>>>>>> included. They would also be first in the list meaning that the code >>>>>>>> would actually work (but might not give accurate results) even if it >>>>>>>> were generated for affine mappings. >>>>>>>> >>>>>>>>> Also, in the ufc::cell code, you currently read in the cell >>>>>>>>> coordinates >>>>>>>>> using info in MeshTopology. However, the higher order coordinate >>>>>>>>> info >>>>>>>>> resides in MeshGeometry (which is where it belongs). So you would >>>>>>>>> still >>>>>>>>> need to modify ufc.h. Remember, there is higher order cell data >>>>>>>>> that is >>>>>>>>> contained in MeshGeometry. >>>>>>>> Where is MeshTopology used for this? I looked in UFCCell.h which is >>>>>>>> where the coordinates are copied to ufc::cell and there MeshGeometry >>>>>>>> is used. >>>>>>>> >>>>>>>>> Is it really that hard to change ufc.h? Other things have to be >>>>>>>>> recompiled, but isn't that automatic? >>>>>>>> Yes, it's easy to change, but a main point with UFC is that we >>>>>>>> shouldn't change it. >>>>>>>> >>>>>>> UFC will need to be extended as time goes on, but it is hard to know >>>>>>> from the outset how it should be done. What about using some IFDEF's or >>>>>>> non-pure virtual functions in the development version to allow >>>>>>> experimentation? These can then either be removed or added to UFC at >>>>>>> release time. >>>>>>> >>>>>>> Garth >>>>>> Or subclasses with non-pure virtual functions: >>>>>> >>>>>> class experimental_cell_integral: public ufc::cell_integral >>>>>> { >>>>>> void foo() const { throw ...("Experimental feature not implemented."); >>>>>> } >>>>>> }; >>>>>> >>>>>> or >>>>>> >>>>>> namespace eufc { >>>>>> class cell_integral: public ufc::cell_integral >>>>>> { >>>>>> void foo() const { throw ...("Experimental feature not implemented."); >>>>>> } >>>>>> }; >>>>>> } >>>>>> >>>>>> We can define these in "experimental_ufc.h" or "eufc.h" to keep the >>>>>> official header file constant. >>>>>> >>>>>> Then the DOLFIN code that uses experimental features must be clearly >>>>>> marked: >>>>>> >>>>>> ufc::cell_integral *itg = form.create_cell_integral(0) >>>>>> eufc::cell_integral *eitg = dynamic_cast<eufc::cell_integral>(itg); >>>>>> >>>>>> and can then use "if(eitg)" to select between experimental and >>>>>> non-experimental code. >>>>> In a similar vein, could we just have another file named eufc.h, and put >>>>> an IFNDEF somewhere that would use eufc.h instead of ufc.h? That way I >>>>> could modify eufc.h all I want, and people don't have to use it. But I'm >>>>> not sure how to do this. Ideally, this would be an option for scons like >>>>> enableExpUFC=true. Or is it only necessary to include eufc.h in files >>>>> that FFC generates? We just need something for testing. >>>>> >>>>> Obviously, I cannot just modify UFCCell.h. I tried that, but FFC cannot >>>>> access variables declared in the sub-class (woops... :( ). >>>> One option could be to create a file named ufc.h and put it in >>>> >>>> dolfin/fem/ufc.h >>>> >>>> and change all #include <ufc.h> to #include "ufc.h". >>>> >>>> Then the DOLFIN version of ufc.h will include either the installed >>>> ufc.h or another file named ufce.h which is placed in >>>> >>>> dolfin/fem/ufce.h >>>> >>>> That file contains data structures named the same way as in the >>>> official ufc.h but with modifications (so the rest of the code won't >>>> need to be changed much). >>>> >>>> Then in the DOLFIN ufc.h control file we place an #ifdef for whether >>>> to include the official ufc.h or the experimental one: >>>> >>>> #ifdef UFC_EXPERIMENTAL >>>> #include "ufce.h" >>>> #else >>>> #include <ufc.h> >>>> #endif >>>> >>>> You can set the flag by adding >>>> >>>> customCxxFlags="-DUFC_EXPERIMENTAL" >>>> >>>> to scons. >>> Wouldn't it make more sense to have this exp_ufc.h be a part of ufc? That >>> way when you install ufc, there can be an `enableExpUFC' option. In this >>> case, scons will copy exp_ufc.h to the build directory and rename it to >>> ufc.h. The exp_ufc.h file will basically be identical to ufc.h, so it makes >>> sense to keep it together. This will also put in a convenient `buffer' for >>> experimenting with ufc, and allow for easy moving over of additions to >>> ufc.h. Could someone please put this in? Please? :) > > It's better to have it in DOLFIN. It makes it easier to experiment (no > need to change UFC). When features have stabilized, we move it to UFC. > > I agree having both ufc.h and UFC.h is confusing. How about this > instead. In DOLFIN, we never include ufc.h, only UFC.h.
We do include ufc.h in a number of places. This needs to be fixed so that a ufc(e).h file can be placed in DOLFIN. Garth And at the top > of that file, we put > > #ifdef UFC_EXPERIMENTAL > #include "ufce.h" > #else > #include <ufc.h> > #endif > > That should work. > > > > ------------------------------------------------------------------------ > > _______________________________________________ > UFC-dev mailing list > [email protected] > http://fenics.org/mailman/listinfo/ufc-dev _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
