Dear Prof. Bangerth, In my limited knowledge, I think that my solution wrong come from the assembling the matrix and right hand side. Because as you mentioned, the solution remains the same no matter how I change the mesh.
My question for assembling the system is when I set the cell right hand side is none zero at a given dofs (source dofs), should I assemble the cell matrix at these dofs none zeros? Should both cell matrix (i,j) and cell right hand side (i) be zeros for the dofs i , j which are not at the source dof? I saw from testing my codes that the cell right hand side also changed when the volume of the cell changed although I remained the length of 1 edge. Is this because the integral over all cell also be scaled by a certain factor? Thank you very much. Best regards, Pham Ngoc Kien Vào Th 3, 26 thg 3, 2019 vào lúc 07:48 Wolfgang Bangerth < [email protected]> đã viết: > On 3/22/19 5:39 PM, Phạm Ngọc Kiên wrote: > > I mean the solution here is the solution vector I get after solving the > > system. > > > > I think that there should be a way to scale the entries to get the > solution. > > > > Could you please give me the idea to do it? > > Well, the "scaling" is obtained by computing the solution as > > u_h(x) = \sum_j U_j \varphi_j(x) > > The values of U_j by itself are meaningless without the shape functions > \varphi_j. If someone decided to multiply every shape function by ten, > but then also divided all of the U_j by ten, then the solution u_h(x) > remains the same. > > Best > W. > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: [email protected] > www: http://www.math.colostate.edu/~bangerth/ > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see > https://groups.google.com/d/forum/dealii?hl=en > --- > You received this message because you are subscribed to the Google Groups > "deal.II User Group" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
