Hello, first of all: I'm new to libmesh and therefore I have still difficulties to fully understand how certain things work with libmesh. So please be patient with me ;-) I wrote a code to compute displacements and drilling moments for flat shell elements with FEM. It imports a mesh file (xda or msh), assembles the system matrix and RHS, solves the system and exports the results as vtk files. When I run my program with one processor it all works fine and the displacements are correct. The problem occurs with more than one processor. Simple example: Plane mesh (e.g. 8x8 quadrilaterals). Left edge is clamped, the force is applied at the right edge and only at this edge. If I run this example with e.g. 2 processors the partitioning cut halves the mesh in a left and a right part. The result looks as follows: The left part has no displacement at all, while the right part has a huge displacement. I studied your example codes and couldn't see any special code fragments that is needed for a parallelized version of the code, so I thought: 'Hey, libmesh seems to handle the parallelization internally - that's great!'. But when I look at my results; in my opinion every processor solves its own partial system with its own boundary condition, mesh nodes and RHS and produces its own solution - so no communication or exchange between the processes at all...
Now to my questions: Do I need additional configurations in my code to make it work (at the LinearImplicitSystem, the mesh, the system matrix, etc.)? Additional MPI code to exchange values/vectors/matrices by my own? Libmesh seems to use MPI communication extensively internally and it's difficult for me right now to see where the problem is. Perhaps you can give me a hint to be back on track soon. Thanking you in anticipation for your help. Bye, Stephan Herb ------------------------------------------------------------------------------ _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
