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, coordinate systems in a DataSet simply pointed to field data
specifying the coordinate information (although the ability to get that
back out of the DataSet was missing). This makes sense since point
coordinates are in fact just fields with a particular semantic meaning
to them.
However, there is an issue with this approach. It turns out that there
are special representations that are very common for point coordinates
and very uncommon for other types of fields. For example, a uniform
(a.k.a. regular or image) grid has point coordinates that are easily
derived from the point index, but such fields are quite uncommon
elsewhere.
Representing this kind of structure in the Field list of a DataSet is
problematic. Either all fields have to check to see if they are this
type, which will cause an explosion of unnecessary generated code, or
you will have to actually write out the coordinates in memory, which is
really wasteful but what was done previously.
However, by storing fields representing coordinate systems in a separate
batch, we can use these special types without the stated explosion.
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.
Previously there was a Connectivity* structure for both the control
environment and the execution environment. This was necessary before
because the connectivity is explicit to the from and to topology
elements, so you would get this structure from the appropriate call to
CellSet*. However, the symantics are changed so that the type of
connectivity is selected in the worklet's dispatcher. Thus, it is now
much cleaner to manage the CellSet structure in the CellSet class itself
and just have a single set of Connectivity* classes in the execution
environment.
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.
The Invoke of the topology dispatcher is also changed to expect a
concrete cell set (which the DynamicCellSet is automatically cast to)
rather than a connectivity structure. The dispatcher calls the
GetNodeToCellConnectivity method for you. (That is currently the only
one supported.)
The most common changes were making class members uppercase and spelled
out, adding "this->" whenever a class member is used, and declare
functions and members with export macros. Also fixed some uses of int
(instead of vtkm::Id or something similar) and a bit of indentation. I
also sprinkled some const goodness over the code.
It should be noted that I had about a week delay between first making
these changes and checking them in. In the mean time Sujin also made
some similar changes, so there might be some repetative changes.
CellSetExplicit can now use different storage backends to allow
for cheaper representations of the data. For example a pool of triangles
can now implicit handles for shape and num indices.
This does raise the question if runtime polymorphism is the best approach
for CellSet, or if we should do some from of CRTP.
ExplicitConnectivity can now use different storage backends to allow
for cheaper representations of the data. For example a pool of triangles
can now implicit handles for shape and num indices.
