subroutine DMProductGetDM(a,b,c,z)
       import tDM
       DM a ! DM
       PetscInt b ! PetscInt
       DM c ! DM
       PetscErrorCode z
       end subroutine DMProductGetDM
      subroutine DMProductSetDM(a,b,c,z)
       import tDM
       DM a ! DM
       PetscInt b ! PetscInt
       DM c ! DM
       PetscErrorCode z
       end subroutine DMProductSetDM
      subroutine DMProductSetDimensionIndex(a,b,c,z)
       import tDM
       DM a ! DM
       PetscInt b ! PetscInt
       PetscInt c ! PetscInt
       PetscErrorCode z
       end subroutine DMProductSetDimensionIndex