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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkNthElementTest1.cxx,v $
Language: C++
Date: $Date: 2008-04-30 06:06:31 $
Version: $Revision: 1.2 $
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
#include "itkListSample.h"
#include "itkStatisticsAlgorithm.h"
#include "itkMersenneTwisterRandomVariateGenerator.h"
#include <fstream>
#include <vector>
#include <algorithm>
int itkNthElementTest1(int argc, char * argv [] )
{
std::cout << "Statistics Algorithm Test \n \n";
bool pass = true;
typedef float MeasurementType;
const unsigned int Dimension = 1;
const unsigned int testDimension = 0;
typedef itk::FixedArray< MeasurementType, Dimension > MeasurementVectorType;
typedef itk::Statistics::ListSample< MeasurementVectorType > SampleType;
typedef itk::Statistics::Subsample< SampleType > SubsampleType;
SampleType::Pointer sample = SampleType::New();
sample->SetMeasurementVectorSize( Dimension );
typedef std::vector< MeasurementType > VerificationVectorType;
VerificationVectorType verificationVector;
if( argc > 1 )
{
//
// Read the values from a file
//
std::cout << "Reading input file " << argv[1] << std::endl;
std::ifstream valuesFile;
valuesFile.open( argv[1] );
MeasurementVectorType vector;
valuesFile >> vector[testDimension];
while( !valuesFile.eof() )
{
sample->PushBack( vector );
MeasurementType value;
valuesFile >> value;
vector[testDimension] = value;
verificationVector.push_back( value );
}
valuesFile.close();
}
else
{
//
// Generate values using a Random number generator
//
typedef itk::Statistics::MersenneTwisterRandomVariateGenerator NumberGeneratorType;
NumberGeneratorType::Pointer randomNumberGenerator = NumberGeneratorType::New();
randomNumberGenerator->Initialize();
unsigned int numberOfValues = 100;
MeasurementVectorType vector;
for(unsigned int i=0; i<numberOfValues; i++)
{
MeasurementType value = randomNumberGenerator->GetNormalVariate( 0.0, 1.0 );
vector[testDimension] = value;
sample->PushBack( vector );
verificationVector.push_back( value );
}
}
SubsampleType::Pointer subsample1 = SubsampleType::New();
subsample1->SetSample( sample );
subsample1->InitializeWithAllInstances();
// Sort all the values in subsample1
itk::Statistics::HeapSort< SubsampleType >( subsample1, testDimension, 0, subsample1->Size());
try
{
//
// Test the NthElement Algorithm by asking k-th elements in subsample2 and
// comparing them to the entries in the sorted subsample1.
//
for( unsigned int kth = 0; kth < subsample1->Size(); kth++)
{
SubsampleType::Pointer subsample2 = SubsampleType::New();
subsample2->SetSample( sample );
subsample2->InitializeWithAllInstances();
MeasurementType kthValue1 = itk::Statistics::NthElement< SubsampleType >(
subsample2, testDimension, 0, subsample2->Size(), kth );
MeasurementType kthValue2 =
subsample1->GetMeasurementVectorByIndex( kth )[testDimension];
for(unsigned int i=0; i<sample->Size(); i++)
{
verificationVector[i] = sample->GetMeasurementVector(i)[testDimension];
}
std::nth_element( verificationVector.begin(),
verificationVector.begin() + kth,
verificationVector.end() );
MeasurementType kthValue3 = verificationVector[kth];
if( vnl_math_abs( kthValue1 - kthValue2 ) > vnl_math::eps )
{
std::cerr << "Comparison failed for component kth= " << kth << std::endl;
pass = false;
}
if( vnl_math_abs( kthValue1 - kthValue3 ) > vnl_math::eps )
{
std::cerr << "Comparison with std::nth_element failed for component kth= " << kth << std::endl;
for(unsigned int k=0; k<verificationVector.size(); k++)
{
std::cerr << "STL: " << verificationVector[k] << " : " << subsample2->GetMeasurementVectorByIndex(k)[testDimension] << std::endl;
}
pass = false;
}
}
}
catch( itk::ExceptionObject & excp )
{
std::cerr << excp << std::endl;
return EXIT_FAILURE;
}
if( !pass )
{
std::cerr << "Test FAILED " << std::endl;
return EXIT_FAILURE;
}
std::cout << "Test passed." << std::endl;
return EXIT_SUCCESS;
}
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