text: /*=========================================================================
   *
   *  Copyright Insight Software Consortium
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *         http://www.apache.org/licenses/LICENSE-2.0.txt
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *=========================================================================*/
  
  #include "itkImage.h"
  #include "itkVector.h"
  #include "itkExponentialDeformationFieldImageFilter.h"
  
  #include "vnl/vnl_random.h"
  
  
  int itkExponentialDeformationFieldImageFilterTest(int, char* [] )
  {
    // Define the dimension of the images
    const unsigned int ImageDimension = 3;
  
    typedef itk::Vector< double, ImageDimension >   PixelType;
  
    // Declare the types of the images
    typedef itk::Image<PixelType, ImageDimension>  ImageType;
  
    // Declare Iterator types apropriated for each image
    typedef itk::ImageRegionIteratorWithIndex< ImageType>  IteratorType;
  
  
    // Declare the type of the index to access images
    typedef itk::Index<ImageDimension>         IndexType;
  
    // Declare the type of the size
    typedef itk::Size<ImageDimension>          SizeType;
  
    // Declare the type of the Region
    typedef itk::ImageRegion<ImageDimension>   RegionType;
  
    // Create the input image
    ImageType::Pointer inputImage = ImageType::New();
  
    // Define their size, and start index
    SizeType size;
    size[0] = 2;
    size[1] = 2;
    size[2] = 2;
  
    IndexType start;
    start[0] = 0;
    start[1] = 0;
    start[2] = 0;
  
    RegionType region;
    region.SetIndex( start );
    region.SetSize( size );
  
    // Initialize Image A
    inputImage->SetLargestPossibleRegion( region );
    inputImage->SetBufferedRegion( region );
    inputImage->SetRequestedRegion( region );
    inputImage->Allocate();
  
    // Create one iterator for the Input Image (this is a light object)
    IteratorType it( inputImage, inputImage->GetBufferedRegion() );
  
    // Initialize the content of Image A
    PixelType vectorValue;
    vectorValue.Fill( 5.0 ); // FIXME: replace with something more interesting...
  
    it.GoToBegin();
    while( !it.IsAtEnd() )
      {
      it.Set( vectorValue );
      std::cout << it.Get() << std::endl;
      ++it;
      }
  
    // Declare the type for the filter
    typedef itk::ExponentialDeformationFieldImageFilter<
                                    ImageType, ImageType  >   FilterType;
  
  
    // Create one filter
    FilterType::Pointer filter = FilterType::New();
  
  
    // Connect the input images
    filter->SetInput( inputImage );
  
    filter->SetMaximumNumberOfIterations( 20 );
  
    // Execute the filter
    filter->Update();
  
    // Get the Smart Pointer to the Filter Output
    ImageType::Pointer outputImage = filter->GetOutput();
  
    // Create an iterator for going through the image output
    IteratorType ot(outputImage, outputImage->GetRequestedRegion());
  
    //  Check the content of the result image
    std::cout << "Verification of the output " << std::endl;
    const PixelType::ValueType epsilon = 1e-6;
  
    bool testpassed = true;
  
    ot.GoToBegin();
    it.GoToBegin();
    while( !ot.IsAtEnd() )
      {
      PixelType input  = it.Get();
      PixelType output = ot.Get();
      // The input is a constant field, its exponential
      // should be exactly equal
      testpassed &= ( (input-output).GetNorm() < epsilon );
      std::cout << input << " => ";
      std::cout << output  << std::endl;
      ++ot;
      ++it;
      }
  
  
    // Ask for the inverse deformation
    filter->ComputeInverseOn();
  
    // Execute the filter
    filter->Update();
  
    // Get the Smart Pointer to the Filter Output
    ImageType::Pointer outputImage2 = filter->GetOutput();
  
    // Create an iterator for going through the image output
    IteratorType ot2(outputImage2, outputImage2->GetRequestedRegion());
  
    //  Check the content of the result image
    std::cout << "Verification of the inverse output " << std::endl;
  
    ot2.GoToBegin();
    it.GoToBegin();
    while( !ot2.IsAtEnd() )
      {
      PixelType input  = it.Get();
      PixelType output = ot2.Get();
      // The input is a constant field, its inverse exponential
      // should be exactly equal to its opposite
      testpassed &= ( (input+output).GetNorm() < epsilon );
      std::cout << input << " => ";
      std::cout << output  << std::endl;
      ++ot2;
      ++it;
      }
  
  
    // Try with 0 iterations
    filter->ComputeInverseOff();
    filter->SetMaximumNumberOfIterations( 0 );
  
    // Execute the filter
    filter->Update();
  
    // Get the Smart Pointer to the Filter Output
    ImageType::Pointer outputImage3 = filter->GetOutput();
  
    // Create an iterator for going through the image output
    IteratorType ot3(outputImage3, outputImage3->GetRequestedRegion());
  
    //  Check the content of the result image
    std::cout << "Verification of the output with 0 iterations " << std::endl;
  
    ot3.GoToBegin();
    it.GoToBegin();
    while( !ot3.IsAtEnd() )
      {
      PixelType input  = it.Get();
      PixelType output = ot3.Get();
      // The input is a constant field, its inverse exponential
      // should be exactly equal to its opposite
      testpassed &= ( (input-output).GetNorm() < epsilon );
      std::cout << input << " => ";
      std::cout << output  << std::endl;
      ++ot3;
      ++it;
      }
  
  
    // Try inverse with 0 iterations
    filter->ComputeInverseOn();
    filter->SetMaximumNumberOfIterations( 0 );
  
    // Execute the filter
    filter->Update();
  
    // Get the Smart Pointer to the Filter Output
    ImageType::Pointer outputImage4 = filter->GetOutput();
  
    // Create an iterator for going through the image output
    IteratorType ot4(outputImage4, outputImage4->GetRequestedRegion());
  
    //  Check the content of the result image
    std::cout << "Verification of the inverse output with 0 iterations " << std::endl;
  
    ot4.GoToBegin();
    it.GoToBegin();
    while( !ot4.IsAtEnd() )
      {
      PixelType input  = it.Get();
      PixelType output = ot4.Get();
      // The input is a constant field, its inverse exponential
      // should be exactly equal to its opposite
      testpassed &= ( (input+output).GetNorm() < epsilon );
      std::cout << input << " => ";
      std::cout << output  << std::endl;
      ++ot4;
      ++it;
      }
  
  
    // See if the output is consistent when the spacing is changed
    // (in an isotropic manner)
    const double isospacing = 10;
    typedef ImageType::SpacingType SpacingType;
    SpacingType spacing;
    for (unsigned int d=0; d<ImageDimension; ++d)
      {
      spacing[d] = isospacing;
      }
  
    filter->SetInput( inputImage );
    filter->SetMaximumNumberOfIterations( 20 );
    filter->ComputeInverseOff();
  
    // Random number generator
    vnl_random rng;
    const double power = 5.0;
  
    it.GoToBegin();
    while( !it.IsAtEnd() )
      {
      for (unsigned int d=0; d<ImageDimension; ++d)
        {
        it.Value()[d] = power * rng.normal();
        }
      ++it;
      }
  
    filter->Update();
    ImageType::Pointer outputImage5 = filter->GetOutput();
    outputImage5->DisconnectPipeline();
  
    // Change the spacing
    inputImage->SetSpacing(spacing);
    it.GoToBegin();
    while( !it.IsAtEnd() )
      {
      it.Value() *= isospacing;
      ++it;
      }
  
    filter->Update();
    ImageType::Pointer outputImage6 = filter->GetOutput();
  
    IteratorType ot5(outputImage5, outputImage5->GetRequestedRegion());
    IteratorType ot6(outputImage6, outputImage6->GetRequestedRegion());
  
    std::cout << "Verification of the consistency when spacing is changed " << std::endl;
  
    ot5.GoToBegin();
    ot6.GoToBegin();
    while( !ot5.IsAtEnd() )
      {
      testpassed &= ( (ot5.Value()-(ot6.Value()/isospacing)).GetNorm() < epsilon );
      std::cout << ot5.Value() << " => ";
      std::cout << ot6.Value()/isospacing << std::endl;
      ++ot5;
      ++ot6;
      }
  
    if (!testpassed)
      {
      std::cout<<"Test failed"<<std::endl;
      return EXIT_FAILURE;
      }
  
    std::cout<<"Test passed"<<std::endl;
    return EXIT_SUCCESS;
  }
  