Hierarchy op "getLength" is not global

[jeanlucf22]

In classes like HierarchyCellDataOpsReal<TYPE>, operations are typically global, with a call to some MPI reduce function at the end when necessary. The exception seems to be:

template<class TYPE> int64_t HierarchyCellDataOpsReal<TYPE>::getLength( const int data_id, const bool interior_only) const

where no sum across MPI tasks is done. I am guessing that this function was introduced to support Sundials5.0. If this is the main purpose, then it would be another reason to have a sum across MPI tasks since Sundials needs a global vector length.