Now that the dispatcher does its own TryExecute, filters do not need to
do that. This change requires all worklets called by filters to be able
to execute without knowing the device a priori.
Adding API to DataSet to `CopyStructure` from another dataset. This
copies the cellsets and coordinate systems while leaving the fields
unchanged.
CreateResult no longer copies all input fields to the output dataset
created.
Furthermore, if a Filter subclass doesn't provide `MapFieldOntoOutput`,
then the default implementation simply copies only the selected fields
to the output dataset.
This revamps Filter API to improve support for multiblock dataset and
distributed use-cases. Filters now operate on MultiBlock alone thus
`Filter::Execute(MultiBlock&)` is the primary method.
`Filter::Execute(DataSet*)` is only provided as an convenience that
internally puts the dataset into a MultiBlock and calls the primary
method.
Subclasses can provides PreExecute and PostExecute overrides to handle
init/reduction operations for filters with operating on multiple blocks.
Since blocks can be distributed, filters are expected to handle that as
well.
Subclasses can provide `PrepareForExecution(MultiBlock*..)` to customize
behavior for handling multiblock inputs. Default is to simply loop
over blocks.
This commit removes `vtkm::filter::Result`. All methods that used
`vtkm::filter::Result` simply change to use `vtkm::cont::Dataset` instead.
The utility API on `Result` that was used to add fields to the resulting
dataset is now available via `vtkm::filter::internal::CreateResult`.
Previously you passed a FieldSelection to Filter::Execute to specify
which fields to pass from input to output. There is no real reason for
this as other information about input and output fields are member
variables to Filter. This moves field selection as a member variable as
well. (This should also help confusion when updating old code to new to
prevent users from mistaking field passing with input fields.
Also added a few convenience constructors to FieldSelection so that you
can call Field::SetFieldsToPass() with just the string of what you want
to pass.
Filters now support executing on a dataset to produce a result dataset
with automatic mapping of fields to the output dataset. Fields to map
can be selected using `vtkm::filter::FieldSelection` class, which provides
constructors to map all or no fields, along with a selection of fields.
This updates all tests to use the new filter API.
