Dear Petsc developers, I am writing my own code to calculate the FEM matrix. The following is my general framework,
DMPlexCreateGmsh(); MPI_Comm_rank (Petsc_comm_world, &rank); DMPlexDistribute (.., .., &dmDist); dm = dmDist; //This can create separate dm s for different processors. (reordering.) MatCreate (Petsc_comm_world, &A) // Loop over every tetrahedral element to calculate the local matrix for each processor. Then we can get a local matrix A for each processor. *My question is : it seems we should build a global matrix B (assemble all the As for each partition) and then transfer B to KSP. KSP will do the parallelization correctly, right? * If that is right, I should define a whole domain matrix B before the partitioning (MatCreate (Petsc_comm_world, &B); ), and then use localtoglobal (which petsc function should I use? Do you have any examples.) map to add A to B at the right positions (MatSetValues) ? Does that make sense? Thanks, Xiaodong
