# vtkCelllocator slow in the version VTK 9 than VTK 8
**URL:** https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068
**Category:** Support
**Created:** [January 27, 2021, 8:59am UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068 "2021-01-27T08:59:36Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Ahmed](https://discourse.vtk.org/u/Ahmed)
#### Post date: [January 27, 2021, 8:59am UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/1 "2021-01-27T08:59:36Z")
Hi,
I compare the performance of vtkCelllocator in vtk 9 compared to the VTK 8, I use FindClosestPoint method
I find that the VTK 9 is 2x more slow than VTK 8
Did some people identify the same problem ? What is the solution ?
Thks
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### Author:  [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [January 27, 2021, 9:05am UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/2 "2021-01-27T09:05:17Z")
Can you compare against the vtkStaticCellLocator ?
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### Author:  [@Ahmed](https://discourse.vtk.org/u/Ahmed)
#### Post date: [January 27, 2021, 9:10am UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/3 "2021-01-27T09:10:18Z")
Yes, I tried it and I confirm that the vtkStaticCellLocator is very speed thant vtkCelllocator
But vtkStaticCellLocator not give the same result, see this topic and not solution is given
[https://gitlab.kitware.com/vtk/vtk/-/issues/17911](https://gitlab.kitware.com/vtk/vtk/-/issues/17911)
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### Author:  [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [January 27, 2021, 9:17am UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/4 "2021-01-27T09:17:32Z")
FYI @will.schroeder @Charles_Gueunet
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### Author:  [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)
#### Post date: [January 27, 2021, 11:06am UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/5 "2021-01-27T11:06:02Z")
I’ll look into this if you provide data and a test please. Note the cell locators can and will give different results if there are two or more equivalent results, e.g., given a query point, two cells are within the exact same distance.
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### Author:  [@Ahmed](https://discourse.vtk.org/u/Ahmed)
#### Post date: [January 27, 2021, 1:16pm UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/6 "2021-01-27T13:16:49Z")
I re-use the case shared in the [https://gitlab.kitware.com/vtk/vtk/-/issues/17911](https://gitlab.kitware.com/vtk/vtk/-/issues/17911) topic
- Bunny mesh: [https://drive.google.com/file/d/1nL8FqaOAN8U8QrhnZFo6-p4-cxI1Ek8a/view?usp=sharing](https://drive.google.com/file/d/1nL8FqaOAN8U8QrhnZFo6-p4-cxI1Ek8a/view?usp=sharing)
- Sphere mesh: [https://drive.google.com/file/d/1Yh6cZcX0CYgYo2KhJIGJ4LMrQOOFi9gd/view?usp=sharing](https://drive.google.com/file/d/1Yh6cZcX0CYgYo2KhJIGJ4LMrQOOFi9gd/view?usp=sharing)
I re-adapt the code, and the sample must be called with Bunny.stl Sphere.stl in this order
VTK 8: Elapsed time (ms) = 63523
VTK 9: Elapsed time (ms) = 84815
35% more in VTK 9 than VTK 8.
My case with 2x time is more complex and I can’t share the data. But this example show this problem.
```
#include
#include
#include
#include
#include
#include
#include
#include
vtkSmartPointer readSurfaceMeshStl(const std::string& filename)
{
// Create STL reader
const auto reader = vtkSmartPointer::New();
reader->SetFileName(filename.c_str());
reader->Update();
// Get read surface mesh
vtkSmartPointer surfaceMesh = reader->GetOutput();
return surfaceMesh;
}
int main(int argc, char** argv)
{
auto start = std::chrono::system_clock::now();
if (argc != 3)
{
cout << "Usage: ./testCellLocator interiorMeshStl boundingMeshStl" << endl;
return EXIT_FAILURE;
}
std::string interiorMeshFileName = argv[1];
std::string boundingMeshFileName = argv[2];
std::cout << "Reading interior mesh...\n";
vtkSmartPointer interiorMesh = readSurfaceMeshStl(interiorMeshFileName);
std::cout << "\nReading bounding mesh...\n";
vtkSmartPointer boundingMesh = readSurfaceMeshStl(boundingMeshFileName);
const vtkIdType interiorMeshNumberOfPoints = interiorMesh->GetNumberOfPoints();
// Octree
auto boundingMeshLocator = vtkSmartPointer::New();
boundingMeshLocator->SetDataSet(boundingMesh);
boundingMeshLocator->BuildLocator();
// Loop variables
auto boundingMeshClosestCell = vtkSmartPointer::New();
///////////////////////////////////////////////////////////
// Iterate through every vertex in the interior mesh
///////////////////////////////////////////////////////////
double interiorMeshVertex[3];
double closestBoundingMeshPoint[3];
const int idMax(10);
for (vtkIdType idx = 0; idx < idMax; ++idx)
{
for (vtkIdType i = 0; i < interiorMeshNumberOfPoints; ++i)
{
// Get point
interiorMesh->GetPoint(i, interiorMeshVertex);
// Find closest bounding mesh point
vtkIdType boundingMeshClosestCellId = -1;
int subId = -1;
double dist = -1;
boundingMeshLocator->FindClosestPoint(interiorMeshVertex, closestBoundingMeshPoint, boundingMeshClosestCell,
boundingMeshClosestCellId, subId, dist);
}
}
const auto elapsed = std::chrono::duration_cast(std::chrono::system_clock::now() - start);
std::cout << "\nNbr of iterations = " << idMax << "\n";
std::cout << "\nElapsed time (ms) = " << elapsed.count() << "\n";
return EXIT_SUCCESS;
}
```
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### Author:  [@Ahmed](https://discourse.vtk.org/u/Ahmed)
#### Post date: [February 3, 2021, 1:41pm UTC](https://discourse.vtk.org/t/vtkcelllocator-slow-in-the-version-vtk-9-than-vtk-8/5068/7 "2021-02-03T13:41:04Z")
@Charles_Gueunet the sample help you to analyze the problem ?