> > The diagonal precondtioner just stores the inverse (if nonzero) of the > diagonal of the matrix argument of the constructor. All matrix types are > allowed. But off course, the preconditioner has to be built only when the > the > matrix is filled. If you need to declare the preconditioner before you > fill > the matrix, you can declare it without argument, then use P.build_with(SM) > to > build the preconditioner. For instance: > > typedef gmm::row_matrix< gmm::wsvector<complex<double> > > mymatrixtype; > mymatrixtype C(N2,N2); > gmm::diagonal_precond<mymatrixtype> P(); > > // ... > ... fill C > // ... > > P.build_with(C); > > Sincerly, > > Yves. > > > > Le Jeudi 5 Octobre 2006 17:47, vous avez écrit : >> I have an embarassingly simple question. In the user manual for gmm++ >> there is the following: >> >> >>>>> gmm::diagonal_precond<matrix_type> P(SM) >> >> The question is what is SM? Is this the coefficient matrix from which >> the >> diagonal is extracted? If my coefficient matrix is of type: >> >> >>>>> gmm::row_matrix< gmm::wsvector<complex<double> > > >> >> what matrix type should matrices P and SM be? > > > > >> Hi: >> >> I am trying to solve a system of equations using iterative solver, QMR, >> in >> particular. I have a problem with getting preconditioners. I tried the >> following, where C(N2,N2) is the coefficient matrix: >> >> ********************** >> gmm::row_matrix< gmm::wsvector<complex<double> > > C(N2,N2); >> gmm::row_matrix<std::vector<std::complex<double> > > C1(N2,N2); >> gmm::copy(C,C1); >> gmm::diagonal_precond<gmm::row_matrix<std::vector<std::complex<double> > >> > > >> P(C1); >> >> **************** >> >> This did not work owing to the large size of C1(N2,N2). What is >> permissible for matrix_type in "gmm::diagonal_precond<matrix_type>? Note >> that the I tried the following and it did not work: >> >> gmm::diagonal_precond<gmm::row_matrix<std::vector<std::complex<double> > >> > >> >> > P(C); >> >> Please help. It appears that matrix_type cannot be: >> gmm::row_matrix< gmm::wsvector<complex<double> > > >> >> Sincerely, >> -- Bwalya >> Bwalya Malama, Ph.D. >> Center for Geophysical Research of the Shallow Subsurface >> Boise State University >> Boise, Idaho >> tel: 208-426-2959 >> email: [EMAIL PROTECTED] >> >> _______________________________________________ >> Getfem-users mailing list >> [email protected] >> https://mail.gna.org/listinfo/getfem-users > > -- > ------------------------------------------------------------------------- > Yves Renard ([EMAIL PROTECTED]) tel : (33) 04.72.43.80.11 > Pole de Mathematiques, INSA de Lyon fax : (33) 04.72.43.85.29 > Departement d'Informatique > Institut Camille Jordan - UMR 5208 > 20, rue Albert Einstein > 69621 Villeurbanne Cedex, FRANCE > http://math.univ-lyon1.fr/~renard > ------------------------------------------------------------------------- > > _______________________________________________ > Getfem-users mailing list > [email protected] > https://mail.gna.org/listinfo/getfem-users >
-- Bwalya Malama, Ph.D. Center for Geophysical Research of the Shallow Subsurface Boise State University Boise, Idaho tel: 208-426-2959 email: [EMAIL PROTECTED] _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
