itaps-parallel iMeshP_syncPartitionAll, iMeshP_getNumGlobalParts, and communication

[Onkar Sahni]

See my comments below:

>
> 1) Do global communication for all partitions during file load to cache
>     global number of parts for each partition read from file.
>

   iMesh_load allows only one partition (i.e., iMeshP_PartitionHandle) as
an input. So I do not know what load of 'all partitions' means... (may
be I am missing something). And as per my understanding either
iMesh_load is collective or is followed by call to
iMeshP_syncPartitionAll

>
> 2) Require application to associate an an MPI_Comm with any partition (we
>     don't have an API for this) and call iMeshP_syncPartitionAll on it
>     before expecting to be able to get any global data.
>

  iMeshP_createPartitionAll takes MPI_Comm as an input and as per my
understanding thats how application will associate an MPI_Comm with any
partition.

>
> 3) Require application it associate an an MPI_Comm with any partition (we
>     don't have an API for this) and do the communication in
>     iMeshP_getNumGlobalParts
....
> iMeshP_getNumGlobalParts?  Do we really expect any application to a) not
> call this collectively and b) call it more than once?
>

  My recollection is that answer to both (a) and (b) is true (we expect
application to a) not call this collectively and b) call it more than
once). Other may provide use case scenarios or otherwise correct me...

I do not know how much this helps.

- Onkar