On Mon, Dec 11, 2023 at 4:32 AM Gong Yujie <[email protected]> wrote:

Dear PETSc developers,

I have a DMPlex DM with 1 field 1dof. I'd like to output a vector with block size equals to 3. It seems that there is no response using command line option or using some code about PetscViewer.

I am not sure how we can do this. If you only have 1 dof per cell (I assume), how can we have a blocksize of 3? Thanks, Matt

The DM is generated with (note that I'm not using PetscFE for discretization, just for allocate dof.)

*PetscCall(DMPlexCreateExodusFromFile(PETSC_COMM_WORLD,"tube.exo",interpolate,&dm));*

*PetscCall(PetscFECreateLagrange(PETSC_COMM_SELF,dim,1,PETSC_TRUE,1,PETSC_DETERMINE,&fe));* *PetscCall(PetscObjectSetName((PetscObject)fe,"potential_field"));* *PetscCall(DMSetField(dm,0,NULL,(PetscObject)fe));* *PetscCall(DMPlexDistribute(dm,0,&sf,&dmParallel));*

The Vector is created using *PetscCall(DMCreateGlobalVector(dm,&phi_1));* *PetscCall(VecSetLocalToGlobalMapping(phi_1,Itog));* *PetscCall(VecGetLocalSize(phi_1,&vec_local_size_test));* *PetscCall(VecCreateMPI(PETSC_COMM_WORLD, vec_local_size_test*3, PETSC_DETERMINE, &u_grad_psi));* *PetscCall(VecSetBlockSize(u_grad_psi, 3));* *PetscCall(VecSetLocalToGlobalMapping(u_grad_psi,Itog));*

The output command line option is just --vec_view vtk:test.vtk. The PETSc version I'm using is 3.19.5.

Could you please give me some advice?

Best Regards, Yujie

-- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>