This commit address issue #713 and removes the need to pass information
about the spatial decomposition (block origins, block sizes, block index
and blocks per dimension) to the contour tree filter. Block origin
information is added to CellSetStructured (as GlobalPointSize) and the
distributed contour tree filter will get this information from
CellSetStructured instead of expecting it as parameters to the
constructor. Information about blocks per dimension and block indices
are computed from the information in CellSetStructure albeit requiring
global communication across all ranks. To avoid this communication cost,
the caller of the filter may explicitly specify this information via the
SetBlockIndices() method.
We have been doing a better job at hiding device code (and moving code
into libraries). Smoke out source that no longer needs to be compiled by
device compilers.
The `MultiBlock` class has been renamed to `PartitionedDataSet`, and its API
has been refactored to refer to "partitions", rather than "blocks".
Additionally, the `AddBlocks` method has been changed to `AppendPartitions` to
more accurately reflect the operation performed. The associated
`AssignerMultiBlock` class has also been renamed to
`AssignerPartitionedDataSet`.
This change is motivated towards unifying VTK-m's data model with VTK. VTK has
started to move away from `vtkMultiBlockDataSet`, which is a hierarchical tree
of nested datasets, to `vtkPartitionedDataSet`, which is always a flat vector
of datasets used to assist geometry distribution in multi-process environments.
This simplifies traversal during processing and clarifies the intent of the
container: The component datasets are partitions for distribution, not
organizational groupings (e.g. materials).
Ref #405
