AdjacencyMatrixToEdgeTable

/* The output is:

10 20 30
40 50 60
70 80 90

+-----------------+------------------+
|                 | value            |
+-----------------+------------------+
| 2               | 30               |
| 1               | 20               |
| 0               | 10               |
| 2               | 60               |
| 1               | 50               |
| 0               | 40               |
| 2               | 90               |
| 1               | 80               |
| 0               | 70               |
+-----------------+------------------+

The first column is the column index of the item in the 'value' column.
The row index is given by the number of times we've previously seen the column index.
For some reason, zeros in the matrix are not reported in the table.

For example, the first row says that the value '30' is in column 2 of the matrix (0-based indexing).
Since we have not previously seen an item in column 2, it is in row 0 of the matrix.

The fourth row says that the value '60' is also in column 2. We infer that '60' is row 1 of the
matrix because we have already seen one item (the '30') in column 2.
*/

#include <vtkSmartPointer.h>
#include <vtkDenseArray.h>
#include <vtkArrayToTable.h>
#include <vtkTable.h>
#include <vtkArrayData.h>
#include <vtkAdjacencyMatrixToEdgeTable.h>
#include <vtkArrayPrint.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkDenseArray<double> > array =
    vtkSmartPointer<vtkDenseArray<double> >::New();

  array->Resize(3,3);

  unsigned int counter = 1;
  for(vtkIdType i = 0; i < array->GetExtents()[0].GetEnd(); i++)
  {
    for(vtkIdType j = 0; j < array->GetExtents()[1].GetEnd(); j++)
    {
      array->SetValue(i, j, counter*10);
      counter++;
    }
  }

  vtkPrintMatrixFormat(std::cout, array.GetPointer());

  vtkSmartPointer<vtkArrayData> arrayData =
    vtkSmartPointer<vtkArrayData>::New();
  arrayData->AddArray(array);

  vtkSmartPointer<vtkAdjacencyMatrixToEdgeTable> adjacencyMatrixToEdgeTable =
    vtkSmartPointer<vtkAdjacencyMatrixToEdgeTable>::New();
  adjacencyMatrixToEdgeTable->SetInputData(arrayData);
  adjacencyMatrixToEdgeTable->Update();

  adjacencyMatrixToEdgeTable->GetOutput()->Dump();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(AdjacencyMatrixToEdgeTable)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkInfovisCore QUIET)
if (NOT VTK_FOUND)
  message("Skipping AdjacencyMatrixToEdgeTable: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(AdjacencyMatrixToEdgeTable MACOSX_BUNDLE AdjacencyMatrixToEdgeTable.cxx )
  target_link_libraries(AdjacencyMatrixToEdgeTable PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(AdjacencyMatrixToEdgeTable MACOSX_BUNDLE AdjacencyMatrixToEdgeTable.cxx )
  target_link_libraries(AdjacencyMatrixToEdgeTable PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS AdjacencyMatrixToEdgeTable
    MODULES ${VTK_LIBRARIES}
    )
endif () 

cd AdjacencyMatrixToEdgeTable/build 

cmake ..

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

make

./AdjacencyMatrixToEdgeTable