iRel interface updates

[seol at scorec.rpi.edu]

Most things look fine. A few comments and questions below.

- I think iBase_EntityIterator should be defined in iBase.

- it's not clear what iRel_getEntArrSetIterArrRelation is for, and how
much it is useful

- Any specific reasons for not having iRel_getEntSetArrRelation and
iRel_getSetSetArrRelation?

- parameter type (in/out/inout) missed in iRel.h

- For consistant naming, how about iRel_create and iRel_destroy?
(respecting the discussion of create/destroy name change proposal in
http://lists.mcs.anl.gov/pipermail/tstt-interface/2010-May/000166.html)

- Do we have a mechanism to set the classification (relation between mesh
entity and geometric entity) at time of the mesh entity creation either in
iRel or iMesh?

> * Minor changes to documentation
>
> Another change I'll suggest but have no strong attachment to is that we
> change iRel_RelationHandle to iRel_PairHandle to make a distinction
> between the relation of two interfaces (a "pair") and the relation of
> entities/sets (a "relation"). The changes would be as follows:
>
> * iRel_RelationHandle  -> iRel_PairHandle
> * iRel_createRelation  -> iRel_createPair
> * iRel_destroyRelation -> iRel_destroyPair
> * iRel_getRelationInfo -> iRel_getPairInfo
> * iRel_findRelations   -> iRel_findPairs

Multiple relations under pair umbrella is suggested. Not so sure if "pair"
is the most appropriate term, iow, multiple pairs under relation umbrella
makes more sense to me.

Seegyoung
>
> Does anyone have any comments on these changes (either in the attachment
> or above)? Ideas? Complaints?
>
> Thanks,
> Jim
>