Previously, all Fetch objects received an Invocation object in their
Load and Store methods. The point of this was that it allowed the Fetch
to get data from any of the execution objects. However, every Fetch
either just got data directly from its associated execution object or
else used a secondary execution object (the input domain) to get indices
into their own execution object.
This left two potential areas for improvement. First, pulling data out
of the Invocation object was unnecessarily complicated. It would be much
nicer to get data directly from the associated execution object. Second,
when getting index information from the input domain, it was often the
case that extra computations were necessary (particularly on structured
cell sets). There was no way to share the index information among
Fetches, and therefore the computations were replicated.
This change removes the Invocation from the Fetch Load and Store.
Instead, it passes the associated execution object and a new object type
called the ThreadIndices. The ThreadIndices are customized for the input
domain and therefore have all the information needed for a redirected
lookup. It is also a thread-local object so it can cache computed
indices and save on computation time.
Previously, when you requested a CellShape in the ExecutionSignature,
you just got an ID stored in a vtkm::IdComponent. This change returns a
cell shape tag of the appropriate type (or generic if the type is not
known at compile time). This will allow functions called from the
worklet to specialize on the cell type better.
We have been using the term "shape" in the cell set and connectivity
classes. To be consistent, use the term "shape" for the geometric
identify of the cell everywhere.
Previously when you fetched the indices from an explicit cell set, you
would get back a Vec of a fixed length an expected to use a subset of
it. Now you get back a Vec-like object that reports the exact length.
This Vec-like is implemented with VecFromPortal, so that the data does
not need to be copied to the stack. Rather, it is pulled from memory as
requested.
We want to be able to get topological connections where it is difficult
to know how many values you get each time. In this change, the type of
the vector holding the from indices is determined from the connectivity
object, and the worklet does not know the type (it must be templated).
Although you do not need to specify the max number for this value set
(you still currently do for field values), we still need to change the
type for explicit sets that uses something that does not rely on the Vec
class. The cell-to-point method also needs a Vec wrapper that allows it
to shorten the vector dynamically.
(Re-) Add a helper structure that holds the connectivity information for
a particular topology connection (e.g. from points to cells) to make it
easier to manage connections in multiple different directions in
CellSetExplicit.
Unlike the previous version of connectivity, this structure is
considered "internal" and not exposed through the API so that
CellSetExplicit can better manage the data. Also, many of the helper
methods remain in CellSetExplicit since they were specific for point-to-
Also, CellSetExplicit has a mechanism to take an arbitrary pair of
TopologyElementTags and get the appropriate connectivity. This should
simplify adding connections in the future.
Most of VTK-m follows the convention of calling the 0D topology elements
"points" (which follows the convention of VTK). However, there were
several places where they were referred to as "nodes." Make things
consistent by calling them points everywhere.
Also merged some redundant ExecutionSignature tags.
Also moved from vtkm namespace to vtkm::internal namespace. This change
is to then move the structured connectivity classes to the cont and exec
namespaces.
