Difference between revisions of "VTK/Examples/Cxx/DataStructures/OctreeTimingDemo"

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(Replaced content with "= '''See [https://lorensen.github.io/VTKExamples/site/Cxx/DataStructures/OctreeKClosestPoints OctreeKClosestPoints] on the new [https://lorensen.github.io/VTKExamples/site...")
 
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<div class="floatright">[[File:VTK_Examples_Baseline_DataStructures_TestOctreeTimingDemo.png]]</div>
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= '''See [https://lorensen.github.io/VTKExamples/site/Cxx/DataStructures/OctreeKClosestPoints OctreeKClosestPoints] on the new [https://lorensen.github.io/VTKExamples/site/ VTKExamples website].''' =
This example runs several closest point queries on octrees with varying MaxPointsPerRegion and plots the result.
 
 
 
==OctreeTimingDemo.cxx==
 
<source lang="cpp">
 
#include <vtkVersion.h>
 
#include <vtkSmartPointer.h>
 
#include <vtkAxis.h>
 
#include <vtkTimerLog.h>
 
#include <vtkMath.h>
 
#include <vtkXMLPolyDataReader.h>
 
#include <vtkPoints.h>
 
#include <vtkPolyData.h>
 
#include <vtkIdList.h>
 
#include <vtkOctreePointLocator.h>
 
#include <vtkRenderWindowInteractor.h>
 
#include <vtkRenderWindow.h>
 
#include <vtkSmartPointer.h>
 
#include <vtkChartXY.h>
 
#include <vtkPlot.h>
 
#include <vtkTable.h>
 
#include <vtkFloatArray.h>
 
#include <vtkContextView.h>
 
#include <vtkContextScene.h>
 
#include <vtkSphereSource.h>
 
 
 
#include <vector>
 
 
static void RandomPointInBounds(vtkPolyData* polydata, double p[3]);
 
static double TimeOctree(vtkPolyData* polydata, int maxPoints, int numberOfTrials);
 
 
int main(int, char *[])
 
{
 
  /*
 
  vtkSmartPointer<vtkXMLPolyDataReader> reader =
 
    vtkSmartPointer<vtkXMLPolyDataReader>::New();
 
  reader->SetFileName(argv[1]);
 
  reader->Update();
 
  */
 
  vtkSmartPointer<vtkSphereSource> reader =
 
    vtkSmartPointer<vtkSphereSource>::New();
 
  reader->SetThetaResolution(30);
 
  reader->SetPhiResolution(30);
 
  reader->Update();
 
 
  std::cout << "Timing octree..." << std::endl;
 
  std::vector<std::pair<int, double> > results;
 
  int numberOfTrials = 1000;
 
  for(int i = 1; i < 100; i++)
 
    {
 
    double t = TimeOctree(reader->GetOutput(), i, numberOfTrials);
 
    std::pair<int, double> result(i,t);
 
    results.push_back(result);
 
    }
 
 
  // Create a table with some points in it
 
  vtkSmartPointer<vtkTable> table =
 
    vtkSmartPointer<vtkTable>::New();
 
 
  vtkSmartPointer<vtkFloatArray> maxPointsPerRegion =
 
    vtkSmartPointer<vtkFloatArray>::New();
 
  maxPointsPerRegion->SetName("MaxPointsPerRegion");
 
  table->AddColumn(maxPointsPerRegion);
 
 
  vtkSmartPointer<vtkFloatArray> runtime =
 
    vtkSmartPointer<vtkFloatArray>::New();
 
  runtime->SetName("Run time");
 
  table->AddColumn(runtime);
 
 
  // Fill in the table with some example values
 
  size_t numPoints = results.size();
 
  table->SetNumberOfRows(numPoints);
 
  for(size_t i = 0; i < numPoints; ++i)
 
    {
 
    table->SetValue(i, 0, results[i].first);
 
    table->SetValue(i, 1, results[i].second);
 
    std::cout << "Put " << results[i].first << " " << results[i].second << " in the table." << std::endl;
 
    }
 
 
  // Set up the view
 
  vtkSmartPointer<vtkContextView> view =
 
    vtkSmartPointer<vtkContextView>::New();
 
 
  // Add multiple line plots, setting the colors etc
 
  vtkSmartPointer<vtkChartXY> chart =
 
    vtkSmartPointer<vtkChartXY>::New();
 
  view->GetScene()->AddItem(chart);
 
  vtkPlot *line = chart->AddPlot(vtkChart::LINE);
 
#if VTK_MAJOR_VERSION <= 5
 
  line->SetInput(table, 0, 1);
 
#else
 
  line->SetInputData(table, 0, 1);
 
#endif
 
  line->SetColor(0, 255, 0, 255);
 
  line->SetWidth(3.0);
 
  line->GetXAxis()->SetTitle("Max Points Per Region");
 
  line->GetYAxis()->SetTitle("Run time");
 
 
  // Set up an interactor and start
 
  view->Render();
 
  view->GetInteractor()->SetRenderWindow(view->GetRenderWindow());
 
  view->GetInteractor()->Initialize();
 
  view->GetInteractor()->Start();
 
 
  return EXIT_SUCCESS;
 
}
 
 
void RandomPointInBounds(vtkPolyData* polydata, double p[3])
 
{
 
  double bounds[6];
 
  polydata->GetBounds(bounds);
 
 
  double x = bounds[0] + (bounds[1] - bounds[0]) * vtkMath::Random(0.0,1.0);
 
  double y = bounds[2] + (bounds[3] - bounds[2]) * vtkMath::Random(0.0,1.0);
 
  double z = bounds[4] + (bounds[5] - bounds[4]) * vtkMath::Random(0.0,1.0);
 
 
  p[0] = x;
 
  p[1] = y;
 
  p[2] = z;
 
}
 
 
double TimeOctree(vtkPolyData* polydata, int maxPoints, int numberOfTrials)
 
{
 
  vtkSmartPointer<vtkTimerLog> timer =
 
    vtkSmartPointer<vtkTimerLog>::New();
 
  timer->StartTimer();
 
 
  vtkMath::RandomSeed(0); // this should be changed to time(NULL) to get random behavior
 
 
  // Create the tree
 
  vtkSmartPointer<vtkOctreePointLocator> octree =
 
    vtkSmartPointer<vtkOctreePointLocator>::New();
 
  octree->SetDataSet(polydata);
 
  octree->SetMaximumPointsPerRegion(maxPoints);
 
  octree->BuildLocator();
 
 
  std::cout << "With maxPoints = " << maxPoints << " there are " << octree->GetNumberOfLeafNodes() << " leaf nodes." << std::endl;
 
 
  for(int i = 0; i < numberOfTrials; i++)
 
    {
 
    double p[3];
 
    RandomPointInBounds(polydata, p);
 
    //vtkIdType iD = octree->FindClosestPoint(p);
 
    octree->FindClosestPoint(p);
 
    }
 
 
  timer->StopTimer();
 
 
  std::cout << "Octree took " << timer->GetElapsedTime() << std::endl;
 
 
  return timer->GetElapsedTime();
 
}
 
</source>
 
 
 
{{VTKCMakeLists|{{SUBPAGENAME}}}}
 

Latest revision as of 19:04, 30 July 2019

See OctreeKClosestPoints on the new VTKExamples website.