Shuenhoy/vtk-m
1
0
Fork 0
mirror of https://gitlab.kitware.com/vtk/vtk-m synced 2024-09-19 02:25:42 +00:00
Code Issues 2 Actions Packages Projects Releases Wiki Activity
086439e71e
vtk-m/docs/changelog/readportalget.md
NAThompson 46faf574fa ReadPortal().Get(idx) is slow in a loop.
2020-05-08 11:30:59 -04:00

719 B
Raw Blame History

ReadPortal().Get(idx)

Calling ReadPortal() in a tight loop is an antipattern. A call to ReadPortal() causes the array to be copied back to the control environment, and hence code like

for (vtkm::Id i = 0; i < array.GetNumberOfValues(); ++i) {
    vtkm::FloatDefault x = array.ReadPortal().Get(i);
}

is a quadratic-scaling loop.

We have remove almost all internal uses of the ReadPortal().Get antipattern, with the exception of 4 API calls into which the pattern is baked in: CellSetExplicit::GetCellShape, CellSetPermutation::GetNumberOfPointsInCell, CellSetPermutation::GetCellShape, and CellSetPermutation::GetCellPointIds. We expect these will need to be deprecated in the future.