typedef SAF_RelRep SAF_TopoRelRep;
 #define SAF_STRUCTURED          saf_find_relrep_structured()    /* N-dimensional rectangular topology */
 #define SAF_UNSTRUCTURED        saf_find_relrep_unstructured()  /* unstructured, finite element zoo topology */
 #define SAF_ARBITRARY           saf_find_relrep_arbitrary()     /* arbitrary topology */