Thanks! I think I know how to go about this now. On Mon, Jul 6, 2009 at 10:36 AM, Yves Renard<[email protected]> wrote: > > Dear Jehanzeb, > > Ok, I just believed you use the Matlab interface. For C++ programs, you can > view a huge number of examples of assembly procedures in the file > src/getfem/getfem_assembling.h including some mixed terms (such as > asm_stokes_B(...) for the Stokes problem). You should use the > generic_assembly object (see Getfem documentation). > > Yves. > > On lundi 6 juillet 2009, Jehanzeb Hameed wrote: >> Dear Renard, >> >> I cant seem to find the function "gf_asm" to use in C++ code. I see it >> in a .cc file in the source code for getfem, but there seems to be no >> prototype for it in a header file. >> >> Do you mean that I should use getfem::generic_assembly in the way you >> have described? >> >> Thanks, >> -Jehanzeb >> >> On Sun, Jul 5, 2009 at 3:39 PM, Renard Yves<[email protected]> wrote: >> > Dear Jehanzeb, >> > >> > You have to use a volumic assembly . An example for the matrix of the >> > Laplace operator is >> > >> > gf_asm('volumic',['a=data(#2); ',... >> > 'M(#1,#1)+=sym(comp(Grad(#1).Grad(#1).Base(#2))(:,i,:,i,j).a(j))'], >> > mim, mf, mf_data, A); >> > >> > A matrix for a mixed term can be obtained in a same way with two mf : >> > >> > gf_asm('volumic', 'M(#1,#1)+=comp(Grad(#1).Base(#2))(:,i,i,:)', mim, >> > mf1, mf2); >> > >> > where mf1 should be a vectorial fem (for more details see the Getfem++ >> > documentation). >> > >> > Yves. >> > >> > Jehanzeb Hameed <[email protected]> a écrit : >> >> I had a look at the Stokes example. It uses model bricks to form the >> >> system. From the documentation, it seems using model bricks implicitly >> >> chooses the bilinear variational form. I would like to define my own >> >> bilinear form to form the matrix, in which I can define terms like >> >> div(q) + c u (q = vector, c = constant, u = another variable besides >> >> q). How would I go about this? >> >> >> >> Thanks, >> >> -Jehanzeb >> >> >> >> On Sun, Jul 5, 2009 at 11:05 AM, Iago Barbeiro<[email protected]> >> >> >> >> wrote: >> >>> Dear Jehanzeb, >> >>> >> >>> I think you may start by looking the Stokes example. >> >>> It deals with two variables (û=uî+v^j and p) and has the term >> >>> div(û).dp. Bon courage! >> >>> >> >>> Iago >> >>> >> >>> On Sun, Jul 5, 2009 at 6:07 AM, Jehanzeb Hameed <[email protected]> >> >>> >> >>> wrote: >> >>>> Hello, >> >>>> >> >>>> Is there a simple example in getfem where assembly is for two >> >>>> variables? E.g. we may want to solve for "u" and "q" (with an equation >> >>>> defining the relationship between u and q) . Such a case arises in >> >>>> mixed methods. Is there an example for mixed-poisson problem >> >>>> somewhere? I know mixed-elasticity problem is given with getfem, but I >> >>>> am not familiar with that particular problem. >> >>>> >> >>>> In particular, I am not sure how to refer to "q" and "u" in >> >>>> generic_assembly routines. Say my weak form involves div(q) . v ? How >> >>>> will I write this in "assem.set" routine? (I am guessing thats what I >> >>>> am supposed to do). >> >>>> >> >>>> Thanks, >> >>>> -Jehanzeb >> >>>> >> >>>> _______________________________________________ >> >>>> Getfem-users mailing list >> >>>> [email protected] >> >>>> https://mail.gna.org/listinfo/getfem-users >> >> >> >> _______________________________________________ >> >> Getfem-users mailing list >> >> [email protected] >> >> https://mail.gna.org/listinfo/getfem-users > > > > -- > > Yves Renard ([email protected]) tel : (33) 04.72.43.87.08 > Pole de Mathematiques, INSA-Lyon fax : (33) 04.72.43.85.29 > 20, rue Albert Einstein > 69621 Villeurbanne Cedex, FRANCE > http://math.univ-lyon1.fr/~renard > > --------- >
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