# Generate2DAMRDataSetWithPulse

VTKExamples/Cxx/CompositeData/Generate2DAMRDataSetWithPulse

### Description

This utility code generates a simple 2D AMR dataset with a Gaussian pulse at the center. The resulting AMR dataset is written using the vtkXMLHierarchicalBoxDataSetWriter.

Note

This original source code for this example is here.

### Code

Generate2DAMRDataSetWithPulse.cxx

    // .NAME Generate2DAMRDataSetWithPulse.cxx -- Generates sample 2-D AMR dataset
    //
    // .SECTION Description
    //  This utility code generates a simple 2D AMR dataset with a gaussian
    //  pulse at the center. The resulting AMR dataset is written using the
    //  vtkXMLHierarchicalBoxDataSetWriter.

    #include <iostream>
    #include <cmath>
    #include <sstream>

    #include <vtkSmartPointer.h>
    #include <vtkAMRUtilities.h>
    #include <vtkCell.h>
    #include <vtkCellData.h>
    #include <vtkDataArray.h>
    #include <vtkDoubleArray.h>
    #include <vtkOverlappingAMR.h>
    #include <vtkPointData.h>
    #include <vtkPoints.h>
    #include <vtkUniformGrid.h>
    #include <vtkAMRBox.h>

    #include <vtkCompositeDataWriter.h>
    #include <vtkHierarchicalBoxDataSet.h>
    #include <vtkMultiBlockDataSet.h>
    #include <vtkXMLHierarchicalBoxDataReader.h>
    #include <vtkXMLImageDataWriter.h>
    #include <vtkXMLMultiBlockDataWriter.h>

    namespace AMRCommon
    {
      void WriteUniformGrid( vtkUniformGrid *g, const std::string &prefix );
      void WriteAMRData( vtkOverlappingAMR *amrData, const std::string &prefix );
      vtkHierarchicalBoxDataSet* ReadAMRData( const std::string &file );
      void WriteMultiBlockData( vtkMultiBlockDataSet *mbds, const std::string &prefix );
      vtkUniformGrid* GetGrid( double* origin,double* h,int* ndim );
      void ComputeCellCenter( vtkUniformGrid *grid, const int cellIdx, double c[3] );
    }
    namespace
    {
    struct PulseAttributes {
      double origin[3]; // xyz for the center of the pulse
      double width[3];  // the width of the pulse
      double amplitude; // the amplitude of the pulse
    } Pulse;
    //
    // Function prototype declarations
    //

    // Description:
    // Sets the pulse attributes
    void SetPulse();

    // Description:
    // Constructs the vtkHierarchicalBoxDataSet.
    vtkOverlappingAMR* GetAMRDataSet();

    // Description:
    // Attaches the pulse to the given grid.
    void AttachPulseToGrid( vtkUniformGrid *grid );
    }

    //
    // Program main
    //
    int main( int, char *[] )
    {
      // STEP 0: Initialize gaussian pulse parameters
      SetPulse();

      // STEP 1: Get the AMR dataset
      vtkOverlappingAMR *amrDataSet = GetAMRDataSet();

      AMRCommon::WriteAMRData( amrDataSet, "Gaussian2D" );
      amrDataSet->Delete();
      return EXIT_SUCCESS;
    }

    namespace
    {
    //=============================================================================
    //                    Function Prototype Implementation
    //=============================================================================

    void SetPulse()
    {
      Pulse.origin[0] = Pulse.origin[1] = Pulse.origin[2] = -1.0;
      Pulse.width[0]  = Pulse.width[1]  = Pulse.width[2]  = 6.0;
      Pulse.amplitude = 0.0001;
    }

    //------------------------------------------------------------------------------
    void AttachPulseToGrid( vtkUniformGrid *grid )
    {
      vtkSmartPointer<vtkDoubleArray> xyz =
        vtkSmartPointer<vtkDoubleArray>::New();
      xyz->SetName( "GaussianPulse" );
      xyz->SetNumberOfComponents( 1 );
      xyz->SetNumberOfTuples( grid->GetNumberOfCells() );

      for(int cellIdx=0; cellIdx < grid->GetNumberOfCells(); ++cellIdx )
      {
          double center[3];
          AMRCommon::ComputeCellCenter( grid, cellIdx, center );

          double r = 0.0;
          for( int i=0; i < 2; ++i )
          {
             double dx = center[i]-Pulse.origin[i];
             r += (dx*dx) / (Pulse.width[i]*Pulse.width[i]);
          }
          double f = Pulse.amplitude*std::exp( -r );

          xyz->SetTuple1( cellIdx, f );
      } // END for all cells

      grid->GetCellData()->AddArray( xyz );
    }

    //------------------------------------------------------------------------------
    vtkOverlappingAMR* GetAMRDataSet()
    {
      int NumLevels = 2;
      int BlocksPerLevel[2] = {1,2};
      double origin[3];
      origin[0] = origin[1] = -2.0; origin[2] = 0.0;

      vtkOverlappingAMR *data = vtkOverlappingAMR::New();
      data->Initialize(NumLevels,BlocksPerLevel);
      data->SetOrigin(origin);
      data->SetGridDescription(VTK_XY_PLANE);

      double h[3];
      int    ndim[3];

      // Root Block -- Block 0,0
      ndim[0]   = 6; ndim[1]   = 5; ndim[2] = 1;
      h[0]      = h[1]      = h[2]      = 1.0;

      int    blockId   = 0;
      int    level     = 0;
      vtkUniformGrid *root = AMRCommon::GetGrid(origin, h, ndim);
      vtkAMRBox box(origin, ndim, h, data->GetOrigin(), data->GetGridDescription());
      AttachPulseToGrid( root );

      data->SetSpacing(level,h);
      data->SetAMRBox( level,blockId,box);
      data->SetDataSet(level,blockId,root);
      root->Delete();

      // Block 1,0
      ndim[0]   = ndim[1]   = 9; ndim[2] = 1;
      h[0]      = h[1]      = h[2]       = 0.25;
      origin[0] = origin[1] = -2.0; origin[2] = 0.0;
      blockId   = 0;
      level     = 1;
      vtkUniformGrid *grid1 = AMRCommon::GetGrid(origin, h, ndim);
      vtkAMRBox box1(origin, ndim, h, data->GetOrigin(), data->GetGridDescription());
      AttachPulseToGrid( grid1 );

      data->SetSpacing(level,h);
      data->SetAMRBox( level,blockId,box1);
      data->SetDataSet( level, blockId,grid1);
      grid1->Delete();

      // Block 1,1
      ndim[0]   = ndim[1]   = 9; ndim[2]   = 1;
      h[0]      = h[1]      = h[2]         = 0.25;
      origin[0] = 1.0; origin[1] = origin[2] = 0.0;
      blockId   = 1;
      level     = 1;
      vtkUniformGrid *grid3 = AMRCommon::GetGrid(origin, h, ndim);
      vtkAMRBox box3(origin, ndim, h, data->GetOrigin(), data->GetGridDescription());

      AttachPulseToGrid( grid3 );
      data->SetSpacing(level,h);
      data->SetAMRBox(level,blockId,box3);
      data->SetDataSet( level, blockId,grid3);
      grid3->Delete();

      vtkAMRUtilities::BlankCells(data);
      data->Audit();
      return( data );
    }
    }
    namespace AMRCommon {

    //------------------------------------------------------------------------------
    // Description:
    // Writes a uniform grid as a structure grid
    void WriteUniformGrid( vtkUniformGrid *g, const std::string &prefix )
    {
      vtkXMLImageDataWriter *imgWriter = vtkXMLImageDataWriter::New();

      std::ostringstream oss;
      oss << prefix << "." << imgWriter->GetDefaultFileExtension();
      imgWriter->SetFileName( oss.str().c_str() );
      imgWriter->SetInputData( g );
      imgWriter->Write();

      imgWriter->Delete();
    }

    //------------------------------------------------------------------------------
    // Description:
    // Writes the given AMR dataset to a *.vth file with the given prefix.
    void WriteAMRData( vtkOverlappingAMR *amrData, const std::string &prefix )
    {
      vtkCompositeDataWriter *writer = vtkCompositeDataWriter::New();

      std::ostringstream oss;
      oss << prefix << ".vthb";
      writer->SetFileName(oss.str().c_str());
      writer->SetInputData(amrData);
      writer->Write();
      writer->Delete();
    }

    //------------------------------------------------------------------------------
    // Description:
    // Reads AMR data to the given data-structure from the prescribed file.
    vtkHierarchicalBoxDataSet* ReadAMRData( const std::string &file )
    {
      vtkXMLHierarchicalBoxDataReader *myAMRReader=
       vtkXMLHierarchicalBoxDataReader::New();

      std::ostringstream oss;
      oss.str("");
      oss.clear();
      oss << file << ".vthb";

      std::cout << "Reading AMR Data from: " << oss.str() << std::endl;
      std::cout.flush();

      myAMRReader->SetFileName( oss.str().c_str() );
      myAMRReader->Update();

      vtkHierarchicalBoxDataSet *amrData =
       vtkHierarchicalBoxDataSet::SafeDownCast( myAMRReader->GetOutput() );
      return( amrData );
    }

    //------------------------------------------------------------------------------
    // Description:
    // Writes the given multi-block data to an XML file with the prescribed prefix
    void WriteMultiBlockData( vtkMultiBlockDataSet *mbds, const std::string &prefix )
    {
      // Sanity check
      vtkXMLMultiBlockDataWriter *writer = vtkXMLMultiBlockDataWriter::New();

      std::ostringstream oss;
      oss.str(""); oss.clear();
      oss << prefix << "." << writer->GetDefaultFileExtension();
      writer->SetFileName( oss.str( ).c_str( ) );
      writer->SetInputData( mbds );
      writer->Write();
      writer->Delete();
    }

    //------------------------------------------------------------------------------
    // Constructs a uniform grid instance given the prescribed
    // origin, grid spacing and dimensions.
    vtkUniformGrid* GetGrid( double* origin,double* h,int* ndim )
    {
      vtkUniformGrid *grd = vtkUniformGrid::New();
      grd->Initialize();
      grd->SetOrigin( origin );
      grd->SetSpacing( h );
      grd->SetDimensions( ndim );
      return grd;
    }

    //------------------------------------------------------------------------------
    // Computes the cell center for the cell corresponding to cellIdx w.r.t.
    // the given grid. The cell center is stored in the supplied buffer c.
    void ComputeCellCenter( vtkUniformGrid *grid, const int cellIdx, double c[3] )
    {
      vtkCell *myCell = grid->GetCell( cellIdx );

      double pCenter[3];
      double *weights = new double[ myCell->GetNumberOfPoints() ];
      int subId       = myCell->GetParametricCenter( pCenter );
      myCell->EvaluateLocation( subId,pCenter,c,weights );
      delete [] weights;
    }

    } // END namespace

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Generate2DAMRDataSetWithPulse)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(Generate2DAMRDataSetWithPulse MACOSX_BUNDLE Generate2DAMRDataSetWithPulse.cxx )

    target_link_libraries(Generate2DAMRDataSetWithPulse ${VTK_LIBRARIES})

### Download and Build Generate2DAMRDataSetWithPulse

Click here to download Generate2DAMRDataSetWithPulse and its CMakeLists.txt file. Once the tarball Generate2DAMRDataSetWithPulse.tar has been downloaded and extracted,

    cd Generate2DAMRDataSetWithPulse/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./Generate2DAMRDataSetWithPulse

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.