Dear Renard,
Thanks for your answer. Yes you are right. In principle, using iterative solvers for a dense matrix is not a good idea. Maybe for special cases, but not in general. Please correct me if I am wrong. The reason that I am using a dense matrix type is that I am using a very large matrix where I fill each quarter separately. Two of quarters are dense and the others are very sparse. It is also possible to make the dense quarters more sparse that I am working on it. For this purpose I thought maybe it is better to use a dense matrix, however I leave mane zero cells in the memory. Do you have any suggestion? Is it possible to reference each quarter using a sparse format matrix like dense format in GMM++? Regards, D. On 2010-09-12 17:09, Renard Yves wrote: > > Dear Danesh, > > The template argument for the preconditionner is the matrix type. So > you should declare > > gmm::dense_matrix<double> A(100, 100); > > filling the matrix > > gmm::ilu_precond<gmm::dense_matrix<double> > P1(A); > > > > Of course, this is not very satisfactory because an incomplete LU > decomposition on a dense matrix is a complete LU decomposition. You > should work with sparse matrices instead. > > You can see on the following page of the documentation how to declare > each preconditionner : > > http://download.gna.org/getfem/html/homepage/gmm/iter.html#preconditioners > > Yves. > > > Danesh Daroui <[email protected]> a écrit : > >> Dear all, >> >> I would like to use GMM++ iterative solvers. The problem is that I can >> not use for example incomplete LU factorization preconditioner. Let say >> that I have the equation Ax=b. The I define the preconditioner as: >> >> gmm::dense_matrix<double> A(100, 100); >> >> // filling the matrix >> >> gmm::ilu_precond<double> P1(A); >> >> but I get compilation errors. It just compiled successfullt when I define: >> >> gmm::ilu_precond<double> P1; >> >> but there is no hint and neither sample code to show which function >> should I call to create the preconditioner. >> >> Can anybody help? >> >> Regards, >> >> D. >> >> >> >> >> >> _______________________________________________ >> 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 -- Danesh Daroui Ph.D Student Lulea University of Technology http://www.ltu.se [email protected] Tel: +46-(0)920-492451 Cell phone: +46-(0)704-399847 _______________________________________________ Getfem-users mailing list [email protected] https://mail.gna.org/listinfo/getfem-users
