/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: NeighborhoodSampler.cxx,v $
  Language:  C++
  Date:      $Date: 2005/11/20 13:27:55 $
  Version:   $Revision: 1.12 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#if defined(_MSC_VER)
#pragma warning ( disable : 4786 )
#endif

// Software Guide : BeginLatex
//
// \index{Statistics!Sampling measurement vectors using radius}
// \index{itk::Statistics::NeighborhoodSampler}
//
// When we want to create an \subdoxygen{Statistics}{Subsample} object that
// includes only the measurement vectors within a radius from a center in a
// sample, we can use the \subdoxygen{Statistics}{NeighborhoodSampler}. In this
// example, we will use the \subdoxygen{Statistics}{ListSample} as the input
// sample.
//
// We include the header files for the ListSample and the
// NeighborhoodSampler classes.
//
// Software Guide : EndLatex 


// Software Guide : BeginCodeSnippet
#include "itkListSample.h"
#include "itkNeighborhoodSampler.h"
// Software Guide : EndCodeSnippet

// Software Guide : BeginLatex
//  
// We need another header for measurement vectors. We are going to use the
// \doxygen{Vector} class which is a subclass of the \doxygen{FixedArray}.
//  
// Software Guide : EndLatex

// Software Guide : BeginCodeSnippet
#include "itkVector.h"
// Software Guide : EndCodeSnippet

int main()
{
  // Software Guide : BeginLatex
  //
  // The following code snippet will create a ListSample object
  // with two-component int measurement vectors and put the measurement
  // vectors: [1,1] - 1 time, [2,2] - 2 times, [3,3] - 3 times, [4,4] -
  // 4 times, [5,5] - 5 times into the \code{listSample}.
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  typedef int MeasurementType;
  const unsigned int MeasurementVectorLength = 2;
  typedef itk::Vector< MeasurementType , MeasurementVectorLength > 
                                                    MeasurementVectorType;
  typedef itk::Statistics::ListSample< MeasurementVectorType > SampleType;
  SampleType::Pointer sample = SampleType::New();
  sample->SetMeasurementVectorSize( MeasurementVectorLength );

  MeasurementVectorType mv;
  for ( unsigned int i = 1 ; i < 6 ; i++ )
    {
    for ( unsigned int j = 0 ; j < 2 ; j++ )
      {
      mv[j] = ( MeasurementType ) i;
      }
    for ( unsigned int j = 0 ; j < i ; j++ )
      {
      sample->PushBack(mv);
      }
    }
  // Software Guide : EndCodeSnippet

  // Software Guide : BeginLatex
  //
  // We plug-in the sample to the NeighborhoodSampler using the
  // \code{SetInputSample(sample*)}. The two required inputs for the
  // NeighborhoodSampler are a center and a radius. We set these two inputs
  // using the \code{SetCenter(center vector*)} and the
  // \code{SetRadius(double*)} methods respectively. And then we call the
  // \code{Update()} method to generate the Subsample object. This
  // sampling procedure subsamples measurement vectors within a
  // hyper-spherical kernel that has the center and radius specified.
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  typedef itk::Statistics::NeighborhoodSampler< SampleType > SamplerType;
  SamplerType::Pointer sampler = SamplerType::New();

  sampler->SetInputSample( sample );
  SamplerType::CenterType center( MeasurementVectorLength );
  center[0] = 3;
  center[1] = 3;
  double radius = 1.5;
  sampler->SetCenter( &center );
  sampler->SetRadius( &radius );
  sampler->Update();

  SamplerType::OutputType::Pointer output = sampler->GetOutput();
  // Software Guide : EndCodeSnippet

  
  // Software Guide : BeginLatex
  //
  // The \code{SamplerType::OutputType} is in fact
  // \subdoxygen{Statistics}{Subsample}. The following code prints out
  // the resampled measurement vectors.
  //
  // Software Guide : EndLatex

  // Software Guide : BeginCodeSnippet
  SamplerType::OutputType::Iterator iter = output->Begin();
  while ( iter != output->End() )
    {
    std::cout << "instance identifier = " << iter.GetInstanceIdentifier() 
              << "\t measurement vector = " 
              << iter.GetMeasurementVector() 
              << "\t frequency = " 
              << iter.GetFrequency() << std::endl;
    ++iter;
    }
  // Software Guide : EndCodeSnippet

  return 0;
}
