subroutine DMPlexLandauDestroyVelocitySpace(a,z)
       import tDM
       DM a ! DM
       PetscErrorCode z
       end subroutine DMPlexLandauDestroyVelocitySpace
      subroutine DMPlexLandauPrintNorms(a,b,z)
       import tVec
       Vec a ! Vec
       PetscInt b ! PetscInt
       PetscErrorCode z
       end subroutine DMPlexLandauPrintNorms
      subroutine DMPlexLandauCreateMassMatrix(a,b,z)
       import tDM,tMat
       DM a ! DM
       Mat b ! Mat
       PetscErrorCode z
       end subroutine DMPlexLandauCreateMassMatrix