VTK/Array Refactoring

Overview

Now that we have N-Way Array Data Structures, it would be ideal if we could use them as attributes in data objects. This will likely involve some tricky work to somehow merge the vtkAbstractArray- and vtkArray- hierarchies.

Recent Work

• Merged vtkFactoredArrayData / vtkFactoredArrayDataAlgorithm into vtkArrayData / vtkArrayDataAlgorithm.

• Added vtkArray::GetName() and vtkArray::SetName().

• vtkDenseArray memory management.
  • vtkDenseArray::MemoryBlock.
  • vtkDenseArray::StaticMemoryBlock.
  • vtkDenseArray::HeapMemoryBlock.

• vtkSparseICSArray.
  • Changes the way coordinates are stored, one contiguous array of coordinates per dimension, instead of a single contiguous array for all dimensions.
  • Implements value sorting.
  • Could probably replace the current vtkSparseArray implementation.

Proposed Work

• Provide iterators, memory layout functionality in vtkDenseArray to support in-situ work.
• Support vtkArray as attributes. Some different approaches:
  1. vtkArray derives from vtkAbstractArray.
     • Worst possible approach, there are methods in vtkAbstractArray (GetVoidPointer()) that are totally incompatible with sparse arrays.
  2. vtkArray and vtkAbstractArray remain apart.
     • vtkFieldData would store vtkArray as a distinct type. Unfortunately, GetArray() is already taken by vtkDataArray.
     • vtkAbstractArray derivatives HAVE-A vtkDenseArray to eliminate duplicate implementations.
  3. vtkAbstractArray derives from vtkArray.
     • Implementing vtkArray in current vtkAbstractArray implementations should be straightforward.
     • vtkFieldData would have to provide methods that return vtkArray. Same problems with GetArray().
     • Implies changes to Get/SetInputArrayToProcess().

Action Items

• Performance comparisons between vtkDataArray & vtkDenseArray (Tim Shead)
• Modify vtkAbstractArray to provide access to an (optional) underlying vtkArray (Tim Shead)
• Modify vtkDataArray to use vtkDenseArray as an implementation (Andy Bauer?)
• Update vtkFieldData and vtkDataSetAttributes APIs to support vtkArray directly (Andy Bauer?)
• Deprecate vtkAbstractArray and its derivatives (Brian Wylie)