[petsc-dev] why exist named global and local vectors

[Smith, Barry F.]

  Why have 

PETSC_EXTERN PetscErrorCode DMHasNamedGlobalVector(DM,const char*,PetscBool*);
PETSC_EXTERN PetscErrorCode DMGetNamedGlobalVector(DM,const char*,Vec*);
PETSC_EXTERN PetscErrorCode DMRestoreNamedGlobalVector(DM,const char*,Vec*);
PETSC_EXTERN PetscErrorCode DMHasNamedLocalVector(DM,const char*,PetscBool*);
PETSC_EXTERN PetscErrorCode DMGetNamedLocalVector(DM,const char*,Vec*);
PETSC_EXTERN PetscErrorCode DMRestoreNamedLocalVector(DM,const char*,Vec*);

  when one can simply using the already existing PetscObjectCompose() and PetscObjectQuery() to attach named vectors to a given DM (or any other object in fact)?

   Barry