From: Michael P. <pov...@in...> - 2005-08-12 09:42:13
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MessageDear Ben, yes, my problem is exactly what you have stated. Really, it would be very nice to be able to account for "other" DOFs. As for the "quick" solution that you have suggested, I think that I can try to use it, because number of "other" DOFs is certanly smaller than number of elements. Thank you, Michael. So, your linear system includes some other unknowns that are not associated with typical nodes or elements? All that really needs to happen is for additional DOFs to get accounted for in the matrix and vector. Problem is, as it stands now the DofMap loops over nodes & elements when it does its indexing. Sounds like what is needed is some mechanism to account for "other" DOFs? The quick & dirty way would be to create an additional variable in the system that is of type, say constant order monomial. This will give you one DOF per element to play with. You can pack your N "global" variables into the first N elements and then set the remainder to 0 as a standard Dirichlet constraint. By default the discontinuous DOFs have no implicit coupling with their neighbors, so the memory penalty for this approach should be minimal. That is, the sparse matrix entries for all these additional DOFs should be simply diagonal. -Ben -----Original Message----- From: lib...@li... [mailto:lib...@li...] On Behalf Of Michael Povolotskyi Sent: Wednesday, August 10, 2005 7:47 AM To: lib...@li... Subject: [Libmesh-users] additional degree of freedom Dear Libmesh developers, I 'd like to solve a linear system with Libmesh. The problem is that in addition to the DOFs that are defined on the mesh, I have to consider some other variables. These variables are, in some sence, global for the whole similation domain and can not be connected with a particular node or cell. So, I have add a new "global" DOF to the system. Is this possible? Thank you, Michael. ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ Libmesh-users mailing list Lib...@li... https://lists.sourceforge.net/lists/listinfo/libmesh-users |