Hi! Thanks, I have created a FUNC class with methods eval() and derivative(), and used getfem_fem<FUNC> to create a new mesh_fem. This worked great. I verified that I could solve a PDE using this mesh_fem together with an approximate integration method.
Now I would like to create an integration method that is exact for products between polynomials and my new non-polynomial functions. I've looked at the examples in the source code, e.g. exact_simplex() in getfem_integration.cc. It uses a class "simplex_poly_integration_" that inherits from "poly_integration", and passes it to the constructor of "integration_method". Looking at "integration_method" in getfem_integration.h, it seems to me that in order to have "im_type = IM_EXACT", my mesh_fem must be polynomial? That is my impression, since the only constructor of "integration_method" that gives im_type = IM_EXACT is the one that takes an argument of type ppoly_integration. Does this mean that I cannot create an exact integration method for non-polynomial functions? Best regards Torquil Sørensen On 22 April 2014 21:19, Yves Renard <[email protected]> wrote: > > > Dear Torquil, > > There is an example in getfem_mesh_fem_global_function.cc which allows to > define a mesh_fem with some arbitry global functions (i.e. a spectral > method). Moreover, with getfem_mesh_fem_product.cc it is possible to obtain > the mulitplication of standard polynomial shape functions with these global > functions. It is in fact possible to define some elements with > non-polynomial shape functions by derivating the class getfem::fem<FUNC> > (see getfem_fem.h) where FUNC should be a class provinding a certain number > of operations such as derivative and eval. > > > Yves. > > > > ----- Original Message ----- > From: "Torquil Macdonald Sørensen" <[email protected]> > To: [email protected] > Sent: Tuesday, April 22, 2014 9:03:59 PM > Subject: [Getfem-users] Non-polynomial basis functions > > Hi! > > On the Getfem web page it says "Extensions are provided to describe > Hermite elements, piecewise polynomial or non-polynomial elements, > vector elements and XFEM.": > > http://download.gna.org/getfem/html/homepage/ > > How would I go about constructing a mesh_fem that uses e.g. the > exponential function in the definition of a basis function? After > reading mesh_fem.cc, I know how to specify polynomial basis functions. > But I have not found any examples of non-polynomial mesh_fem's other > than piecewise polynomial composite mesh_fem's. > > Best regards > Torquil Sørensen > > > _______________________________________________ > Getfem-users mailing list > [email protected] > https://mail.gna.org/listinfo/getfem-users >
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